Guidelines

Question 1

Definition of FRC

Answer 1

volume of gas present in the lung at end expiration during tidal breathing

Question 2

Definition of Expiratory Reserve Volume

Answer 2

volume of gas maximally exhaled from FRC

Question 3

Definition of Inspiratory Capacity

Answer 3

Maximum amount of gas that can be inspired from FRC

Question 4

Definition of Inspiratory Reserve Volume

Answer 4

Volume of gas maximally inhaled from end-inspiratory level during tidal breathing

Question 5

Definition of Residual Volume

Answer 5

Volume of gas remaining in the lung after maximal exhalation

Question 6

Definition of Tidal Volume

Answer 6

volume of gas inhaled or exhaled during the respiratory cycle

Question 7

Definition of Total Lung Capacity

Answer 7

volume of gas in the lungs after maximal inspiration (of the sum of all volume compartments)

Question 8

Definition of Vital Capacity

Answer 8

volume change between full inspiration and complete exhalation

Question 9

What is the preferred time to measure ERV?

Answer 9

Immediately after acquisition of FRC followed by slow IVC

Question 10

What are 4 ways you get measure FRC?

Answer 10

1. Body Plethysmography
2. Gas washout
3. Gas dilution
4. Radiography

Question 11

Key points of Plethysmography (ie. what does it measure)

Answer 11

1. Includes ventilated and non-ventilated regions of the lung - thus HIGHER than dilution/washout methods
2. May also be increased by gas in other areas of the body (ie abdo)

Question 12

Key points of gas dilution/washout methods

Answer 12

1. Tend to underestimate the true FRC

2. Simple and inexpensive to do

Question 13

How does Plethysmography work?

Answer 13

• Measures volume of intrathoracic gas measured when airflow occlusion happens at FRC
• Minimal difference compared to washout/dilution in healthy people
• Plethys results HIGHER in those with lung disease and gas trapping
• Based on Boyle’s law: P1V1 = P2V2

Question 14

Measurement technique of Body Plethysmography

Answer 14

1. Turn on and calibrate machine
2. Patient to close mouth over mouthpiece with neutral neck position
3. Close door and allow to equilibrate
4. Patient to breathe quietly until stable and expiratory level is met
5. Shutter closes at/near FRC
6. Patient pants for 2-3 seconds (freq of 0.5-1 Hz). If can’t pant, can do rapid inspiratory maneuvers against closed shutter

Question 15

Repeatability criteria for Plethysmography

Answer 15

If 3 FRC results are within 5%

Question 16

Calculation of Delta V in Plethysmography

Answer 16

Box: P1V1 = P2 (V1-delta V)
Lung: P3 FRC = P4 (FRC + Delta V)

Question 17

Key points for Nitrogen washout

Answer 17

• Based on washing out nitrogen from lungs while patient breathes 100% O2

Question 18

Measurement technique for Nitrogen washout

Answer 18

• Turn on machine and calibrate
• Patient sits comfortably and breathes for 30-60 seconds to assure stable end-tidal expiratory level
• Patient breathes 100% oxygen
• Exhaled nitrogen is measures
• Considered complete if Nitrogen concentration <1.5% for at least 3 breaths
• Need to wait at least 15 min between attempts

Question 19

Equation for FRC N2

Answer 19

FRC N2 = (N2 washed out -N2 from tissue)/ (FN21 - FN22)
FN21 = fraction of nitrogen before the washout
FN22 = fraction of nitrogen after the washout
(volume = area under the curve of a N2 fraction % vs volume graph)

Question 20

Key point of measuring FRC using helium dilution

Answer 20

Based on equilibration of gas in lungs with known volume containing helium
C1V1 = (C1 + FRC) V2

Question 21

Measurement technique for Helium Dilution

Answer 21

• Breathe for 30-60 seconds to ensure stable end tidal expiratory level
• Patient connected to test gas at end of normal tidal exhalation
• Continues to breathe regular tidal breaths
• O2 is increased to compensate for O2 consumption
• Helium concentration checked q15 seconds
• Test complete when change in concentration = <0.02% for 30 seconds

Question 22

What is an important value for derivation of the references values

Answer 22

Height = most important factor

** Lung growth typically falls behind growth spurt in adolescents

Question 23

Definition of FVC

Answer 23

Maximal volume of air exhaled with maximally forced effort from a max inspiration

Question 24

Definition of FEV1

Answer 24

Maximal volume of air exhaled in the first second of a forced exhalation from a position of full inspiration

Question 25

What is useful about the flow-volume loop?

Answer 25

Useful for assessing magnitude of effort * *Should show 1 sec before start to allow for calculation of the back extrapolated volume * * Last 2 seconds should be displayed to show end of test criteria

Question 26

Definition of Calibration

Answer 26

finding the relationship between the measured values of flow and the actual values of flow ** should be within 3%

Question 27

3 phases of spirometry

Answer 27

1) Maximal Inspiration 2) Blast of Exhalation 3) Continued Complete Exhalation

Question 28

Procedure for recording FVC

Answer 28

1) check calibration 2) Explain and prepare patient and get H & W 3) Correct position, noseclip and mouthpiece in mouth with lips closed around 4) For closed and open circuit = inhale completely and rapidly to TLC with <1 s pause, Exhale completely until no more air can be expelled while sitting upright, repeat for 3-8 maneuvers

Question 29

If there is a delay between TLC and forced expiration, what would that affect?

Answer 29

Delay shown to cause reduction in PEF and FEV1

Question 30

What is the Back Extrapolated Volume?

Answer 30

- creates a new "time zero" - found by tracing back from the steepest part (largest slope) of the curve (volume/time) over an 80ms time period - to be accurate: extrapolated value must be <150mls or <5% of FVC

Question 31

2 recommended End of Test criteria

Answer 31

1. Patient cannot or should not continue further exhalation 2. Volume/time curve shows no change in volume (<0.025L) for >1 sec in someone who has exhaled long enough: <10 = >3 seconds, >10 = >6 seconds *If test does not meet EoT criteria, it should not count towards one of the 3 acceptable maneuvers

Question 32

7 factors for Acceptable curves

Answer 32

1. Good start (extrapolated volume <5% of FVC or <150 mls) 2. No cough during first second, or other times that affects accuracy of results 3. No early termination (good end of test) 4. No Valsalva/glottic closure/hesitation (reduced FEV1 +/- FVC) 5. No mouthpiece leak 6. No obstructed mouthpiece 7. No extra breath during maneuver

Question 33

3 Between maneuver criteria

Answer 33

1. Need 3 acceptable curves 2. Repeatability = FVC and FEV1 is <0.15L between largest and next (<0.1L if FVC <1L) 3. Try not to exceed 8 blows

Question 34

Test result selection

Answer 34

- Select largest FVC and FEV1 from acceptable curves | - May also obtain slow VC or IVC (IC tends to be larger than FVC)

Question 35

Maneuver for doing Maximal Expiratory Flow-Volume Loops

Answer 35

Take rapid full inspiration to TLC from mouth - insert mouthpiece - then maximal expiration followed by maximal inspiration OR Insert mouthpiece during tidal breathing - at FRC make slow expiration to RV - slow inspiration to TLC- maximal expiration to RV - rapid inspiration back to TLC

Question 36

When should patients not take meds before spirometry?

Answer 36

If aim of the study is to document reversible airflow limitation - should do test before regular drugs (SABA > 4 hours, LABA > 12 hours, no smoking <1hr) *If aim of study = determine whether lung function can be improved with therapy in addition to current therapy - subject can continue with regular meds

Question 37

Method for documenting reversibility in spirometry

Answer 37

- After 3 pre-BD loops, give SABA (ventolin) via spacer (dose = 400ug) or ipratropium (4x40ug) - wait 10-15 min for SABA or 30 min for anticholinergic - Improved deposition with CFC free MDIs (smaller particle size)

Question 38

When during the test should you measure Slow VC?

Answer 38

Should be done prior to FVC (due to potential for fatigue and history effects - repeated measurements may increase FRC due to gas trapping in those with severe airflow obstruction) Can do either IVC or EVC maneuver

Question 39

Maneuver for Peak Expiratory Flow

Answer 39

Flow achieved from maximal forced expiratory maneuver Procedure must be rapid - deliver blow without delay Repeat x 3 - need to be within 0.67L/s to be repeatable

Question 40

Maneuver for Maximum Voluntary Ventilation

Answer 40

Maximum volume of air a subject can breathe over a specified time (12 sec for normal subjects) - 3 resting tidal breaths - breathing at a rate of 90-110/min - maximal effort (as deep and rapid as possible) - Sum of all individual exhalations calculated, multipled by correction factor during the best 12 seconds - minimum of 2 attempts (should be within 20% of each other) Goal = VT of 50% of VC with RR ~90/min

Question 41

Definition of Accuracy

Answer 41

The closeness of agreement between the result of a measurement and the true value

Question 42

Definition of Repeatability

Answer 42

Closeness of agreement between results of successive measurements with the same conditions

Question 43

Definition of Reproducibility

Answer 43

Similar to repeatability, however the conditions are changed

Question 44

Patient considerations for lung function testing

Answer 44

- Not within 1 month of MI | - chest/abdo pain, oral/facial pain exacerbated by mouthpiece, stress incontinence, dementia, confusion

Question 45

What measurement can you use as a surrogate for height?

Answer 45

Armspan (tips of middle fingers)

Question 46

Things to avoid before PFT

Answer 46

- Smoking within 1 hour - Alcohol within 4 hours - Vigourous exercise within 30 min - clothing that restricts full chest and abdominal expansion - large meals withn 2 hours - SABA use within 4 hours

Question 47

Ways to prevent infection in the PFT lab

Answer 47

- Hand washing, barrier devices - wear gloves when handling potentially contaminated equipment - wash hand between patients - disinfect/sterilize reusable mouthpieces, tubes, valves and manifolds - equipment that comes in contact with mucosal surfaces should be sterilized, disinfected or discarded - closed circuit equipment should be flushed with room air 5 times - open circuit - only the portion of the circuit where re-breathing occurred should be decontaminated - Decontaminate equipment esp with hemotypsis or oral lesions - TB: ventilation, air filtration, UV decontamination

Question 48

What do the references values mean for PFTs?

Answer 48

Comparison to healthy subjects of same anthropometric characteristics and ethnicity * important to measure height and weight for each person * adjust for race if possible

Question 49

Definition of air flow obstruction on PFT

Answer 49

Reduction in FEV1/FVC below 5th percentile of predicted value *Earliest change = slowing in the terminal portion of the spirogram

Question 50

Causes of reduced FVC and FEV1 in airflow obstruction

Answer 50

- patients who fail in inhale or exhale completely - if flow is so slow that they can't exhale to RV - lower airway collapse causing gas trapping (RV may be elevated)

Question 51

Definition of air flow restriction on PFT

Answer 51

Reduction in TLC below the 5th percentile of predicted value and a normal FEV1/VC *Suspect with reduced VC, increased FEV1/FVC ratio or convex curve

Question 52

Other causes for high ratio and reduced VC apart from restriction

Answer 52

- submaximal effort | - patchy peripheral airflow obstruction

Question 53

Does a reduced VC alone qualify for air flow restriction?

Answer 53

No - Need to have reduced TLC as well ** Special = Pneumothorax and non-communicating bullae: normal ratio and normal TLC (on plethys), low FEV1 and low VC, (low TLC if gas dilution)

Question 54

Definition of Mixed Abnormality on PFT

Answer 54

Presence of obstruction and restriction | *Present when low FEV1/VC AND low TLC

Question 55

Which measure do you look at for severity classification for airflow obstruction?

Answer 55

FEV1 ``` Mild >70 Moderate 60-69 Moderate-severe 50-59 Severe 35-49 Very severe <35 ```

Question 56

Why do FRC, RV, TLC and RV/TLC increase with severe obstruction?

Answer 56

Reduced lung elastic recoil

Question 57

What is considered a meaningful bronchodilator response?

Answer 57

12-15% change from baseline in FEV1 +/- FVC (changes <8% are likely to be within measurement variability) ATS: change in 12% AND 200ml difference (>12 yrs) from baseline

Question 58

What variable seems most affected by upper airway obstruction on spirometry?

Answer 58

PEF (can be reduced)

Question 59

Examples of variable extrathoracic airflow obstruction

Answer 59

Repeatable plateau of inspiratory flow (decreased because the pressure surrounding the airways cannot oppose the negative pressure generated by inspiratory effort) Ex: VCD

Question 60

Examples of variable intrathoracic airflow obstruction

Answer 60

Repeatable plateau of forced expiratory and normal forced inspiratory loop Ex: Tracheomalacia

Question 61

Examples of fixed airflow obstruction

Answer 61

Repeatable plateau during both expiratory and inspiratory loops Ex: Subglottic stenosis

Question 62

What does a sawtooth pattern on inspiratory or expiratory phases mean?

Answer 62

May represent mechanical instability of airway wall

Question 63

What do you see on spirometry with unilateral mainstem bronchi obstruction?

Answer 63

Maximum inspiratory flow tends to be higher at the beginning than the end, because of a delay in gas filling

Question 64

What is considered a significant changes in lung function over time?

Answer 64

If FVC or FEV1 change by more than 11-12% in 1 week - likely clinically significant (>15% in one year = significant)

Question 65

What is the lower limit of normal for DLCO?

Answer 65

Lower 5th percentile of reference population | Mild >60% but

Question 66

What can cause isolated reduced DLCO?

Answer 66

``` Anemia Pulmonary Vascular Disorders ILD Emphysema PH ```

Question 67

Causes of normal DLCO in the context of restrictive lung disease

Answer 67

Chest wall or neuromuscular condition

Question 68

Causes of reduced DLCO in the context of restrictive lung disease

Answer 68

ILD Sarcoidosis Pulmonary fibrosis

Question 69

Causes of reduced DLCO in the context of obstructive lung disease

Answer 69

Emphysema | Lymphangioleiomyomatosis

Question 70

What can cause an elevated DLCO?

Answer 70

Asthma Obesity Intrapulmonary hemorrhage

Question 71

What does a high DLCO/VA suggest?

Answer 71

Extrapulmonary abnormality (pneumonectomy or chest wall restriction)

Question 72

What does a low DLCO/VA suggest?

Answer 72

Parenchymal abnormality

Question 73

Steps in doing a single-breath CO test

Answer 73

- Tidal breathing after nose clips on and patient on mouthpiece - Exhalation to RV (if severe obstruction, must be <12 seconds) - At RV, patient connected to test gas and patient inhales to TLC (inspiratory volume should be at least 90% of VC) - test gas: 0.3% CO, 21% O2, tracer + nitrogen - tracer should be insoluble, chemically, and biologically inert - DLCO calculated using alveolar volume, breath hold time, barometric pressure, frac concentration of CO and tracer gas in inspired and exhaled gas

Question 74

How is dead space measured in the single breath CO test?

Answer 74

Fowler method (the volume at which the shaded area above the tracer gas on the gas washout vs exhaled volume curve = the shaded area below the curve)

Question 75

How can you measure TLC from the single breath CO test?

Answer 75

Calculated by adding the expired volume to the end expiratory volume and subtracting dead space

Question 76

What are the acceptability criteria for DLCO testing?

Answer 76

- Adequate inspiratory volume (>90% of the largest VC) - Inhalation of > 85% of the test gas in 4 seconds - Stable breath hold for 10 seconds with no leak - Sample collection within 4 seconds of exhalation

Question 77

What are the repeatability criteria for DLCO testing?

Answer 77

- 2 acceptable maneuvers within 2ml/min/mmHg | - should do at least 2 maneuvers and average results

Question 78

What adjustments are made to predicted value of DLCO prior to interpretation?

Answer 78

1) Hemoglobin 2) Carboxyhemoglobin and CO back pressure (COHb can affect binding sites and CO also reduces the driving pressure for CO transport from alveoli to capillary) * 2% decrease in DLCO for each 1% increase in COHb 3) Barometric Pressure: as BP decreases, the PiO2 decreases and DLCO increases (0.53% increase in DLCO for every 100m in increase in altitude)

Question 79

3 Lung function test options for Sedated Infants

Answer 79

1) Raised-volume rapid thoracoabdominal compression (RVRTC) technique 2) Infant Pleth 3) Multiple breath washout = LCI

Question 80

5 Lung function test options for Preschoolers

Answer 80

1) Spirometry 2) Pleth (specific airway resistance = sRaw) 3) Interrupter resistance technique (= Rint) 4) Forced oscillation technique (FOT) 5) Multiple breath washout = LCI

Question 81

Equation for lung clearance index

Answer 81

Cumulative expired volume/FRC | Volume when concentration falls below 1/40th of original

Question 82

Which lung disease as infant RVRTC been shown to be helpful in predicting early disease?

Answer 82

CF

Question 83

What is the most accurate method for detecting early lung disease in preschoolers?

Answer 83

LCI (LCI > sRaw > spirometry) *recommendation - 25% decrease in sRaw as cut-off for asthma in young children

Question 84

What are the 3 major roles for any lung function test?

Answer 84

1) Monitor disease severity over time 2) Evaluate response to treatment 3) Serve as objective outcome measures in clinical research studies

Question 85

What are developmental differences in preschoolers vs older children regarding their ability

Answer 85

1) FEV1/FVC ratio is 90-95% in 5-6 year olds and even higher in young children 2) Utility in FEV1 in older children is due to its location on the effort-independent part of the curve 3) Unlikely that preschool children will not have the respiratory muscle strength to maintain flow limitation to lung volumes as low as 85-90%

Question 86

What is the most useful lung function test for preschoolers with CF?

Answer 86

Lung Clearance Index

Question 87

Spirometry recommendations for preschoolers (13)

Answer 87

1) Live flow-volume curves 2) Review FVC, FEV1, VBE, point when flow ceases as proportion of PEF 3) Acclimatize child to equipment and lab 4) Flow and Volume-driven incentives may be useful 5) Posture and nose-clip use should be recorded 6) Make sure no leak 7) Minimum 3 maneuvers, no max 8) Inspect curves for rapid rise to peak flow and smooth descent without cough or glottic closure 9) if VBE > 80mls or 12.5% FEV1 - inspect curve but dont always reject 10) Premature termination = cessation of flow at >10% FVC (may use FEV1 but not FVC or ratios) 11) Report highest FEV1 and FVC 12) starting point for FEV1 determined from back extrapolation 13) At least 2 acceptable curves with FEV1 and FVC within 0.1L or 10% of highest value

Question 88

2 ways to measure tidal volume?

Answer 88

1. Tidal expiratory flow analysis | 2. Thoraco-abdominal motion analysis

Question 89

Maneuver for tidal expiratory flow analysis?

Answer 89

- Stable breathing in seated/standing position - At least 30 seconds /10 tidal breaths - Report mean, SD, coefficient of variability - inspect Flow volume curve for repeatability and flow-time to ensure steady tidal breathing *Flow at the airway determined by driving pressure and resistance (F = P/R) P determined by elastic recoil of the respiratory system and net pressure due to respiratory muscle activity *Those with wheezing with have increased Time to Peak tidal expiratory flow/total expiratory time AND increased Volume at peak tidal expiratory flow/expired tidal volume (both decrease with ventolin)

Question 90

Maneuvers involved in Thoraco-Abdominal Motion Analysis

Answer 90

With increasing negative intrathoracic pressure, rib cage lags behind abdomen and may even more inwards initially - Measure with child seated, with mouthpiece - Occlusion with valve closing in <10ms and for <100 ms - Occlusion triggered by PEF in expiration - Record 10 occlusions to get 5 acceptable maneuvers - Report median *During sudden occlusion, alveolar P will rapidly equilibrate with P at the mouth (Pmo) Rint = Pmo/flow

Question 91

Principles of Forced Oscillation Technique

Answer 91

External pressure wave applied at the mouth | Resulting pressure-flow pattern is analyzed in terms of respiratory impedance

Question 92

Procedure for Forced Oscillation Technique

Answer 92

- System should be able to measure a reference impedance of >1.5 kPa.s/L within 10% of <0.1L - Excitation frequency = 4-8 Hz - Child is seated, breathing through mouthpiece with noseclips - Acquisition over several breathing cycles, typically 8-16 - 3-5 measurements - Mean reported as well as SD and CV

Question 93

Point of doing Multiple Breath Washout Test

Answer 93

Assesses ventilation distribution and FRC

Question 94

Procedure for Multiple Breath Washout Test

Answer 94

- child seated upright with mouthpiece or sealed facemark - Deadspace = <1-2ml/kg - Sufficiently long wash-in to allow gas to equilibrate in lung - usually 10s after inspired/expired concentrations are equal - Washout continues until end-tidal concentration = 1/40th starting concentration, over 3 breaths - Watch Vt and gas concentration to detect for any leaks - FRC and indices of ventilation inhomogeneity should be calculated on each washout. Mean values, with different <10% from 2 washouts can be reported - LCI = cumulative expired volume, minus dead space times number of breaths divided by FRC

Question 95

Procedure for Bronchial Responsiveness Tests in Preschoolers

Answer 95

- Perform in children who are free from respiratory infection (>3 weeks), normal auscultation and PFTs including sat > 95% - Agent should be delivered by tidal breathing (standard nebulizer output for 2 min) or dosimeter method (deep inhalation, nebulization 0.6 seconds, repeated every 5 min) - if transcut pp O2 used - change >20% - Avoid SpO2 as a sole marker of bronchoconstriction - An increase in resistance of up to 35-40% = negative test - Test should be ended with bronchodilator and confirmation that PFT is at baseline

Question 96

For DMD, what is the best negative predictor of survival?

Answer 96

FVC <1L

Question 97

What is considered to be ineffective airway clearance?

Answer 97

Peak cough flow <160L/min | MEP <45 cm H20

Question 98

According to ATS, what values would benefit from assisted cough techniques?

Answer 98

Peak cough flow <270L/s MEP <60 cm H20 *CDC: FVC <40% BTS: peak cough flow <270 L/s

Question 99

When should you offer nocturnal NIV to DMD patients?

Answer 99

Awake PaCO2 >45 O2 sat <92-95% FVC <30-40%

Question 100

When should you consider daytime NIV to DMD patients?

Answer 100

Daytime PaCO2 >50 or O2 sat <92%

Question 101

What is the worry about providing oxygen to DMD patients?

Answer 101

Can mask underlying cause and they may lose their hypoxic drive to breathe

Question 102

At what FVC is the prognosis for recovery from scoliosis surgery best?

Answer 102

FVC >40%

Question 103

What should the extubation protocol for DMD kids include?

Answer 103

Airway clearance techniques | Immediate use of NIV following extubation

Question 104

Indications for tracheostomy in DMD?

Answer 104

patient and family preference cannot tolerate NIV medical infrastructure can't support NIV 3 failures to achieve extubation despite NIV and cough assist Failure of cough assist to prevent aspiration of secretions

Question 105

Gene for CCHS

Answer 105

Phox2B | "Paired like homeobox"

Question 106

Inheritance pattern for CCHS

Answer 106

Autosomal dominant Mosaicism in 5-10% De novo mutations (most = de novo unless parents are affected)

Question 107

Clinical picture of CCHS

Answer 107

Reduced tidal volumes, monotonous respiratory rates awake and asleep More profound hypoventilation occurs with sleep Often become hypoxic and hypercarbic Lack responsiveness to the physiologic changes and often do not arouse Lack perception of asphyxia during wakefulness (and exertion)

Question 108

Aspects of autonomic dysregulation in CCHS

Answer 108

``` Hirschsprungs Neural crest tumours Reduced pupillary light response Esophageal dysmotility Breath holding spells Reduced basal temperature Sporadic profuse sweating Lack of perception to dyspnea Altered response to exercise challenge and environmental stressors ```

Question 109

Mutations on PHOX2B that play a role in CCHS

Answer 109

Two polyalanine repeat regions in exon 3 - SECOND one is important! Normal = 20 alanines either PARM or NPARM mutations (NPARM worse) Affected individuals have more polyalanines in this sequence (24-33) **Most common = 20/25, 20/26, 20/27

Question 110

How many patients have NPARM mutations in CCHS?

Answer 110

10%

Question 111

Are PARM or NPARM mutations worse in CCHS?

Answer 111

NPARM * Includes sequence changes outside of the polyalanine repeat and can cause frameshift variants * Typically more severe phenotypes

Question 112

Phenotypes with increased risk if you have NPARM mutation in CCHS

Answer 112

Continuous ventilatory support Hirschsprungs Neural crest tumours

Question 113

Phenotypes with increased risk if you have PARM mutation in CCHS

Answer 113

Neural crest tumours (20/29-20/33) | Autonomic nervous system dysregulation

Question 114

What is the theory behind later onset CCHS?

Answer 114

likely a reflection of variable penetrance of the 20/24 and 20/25 mutations or NPARM with environmental cofactor

Question 115

Evaluation for CCHS

Answer 115

1. H&P (including response to sedation/anesthesia and delayed recovery, unexplained seizures and neurocognitive impairment) 2. Review photographs for facial dysmorphology 3. 72 hour holter for investigation of prolonged sinus pauses 4. PSG for ventilation impairment 5. Hematocrit and reticulocyte count (polycythemia and response to hypoxemia) 6. Bicarb level 7. CXR, echo, or ECG (pulmonary HTN) 8. Barium enema or manometry in cases of constipation

Question 116

What disease is important to distinguish from CCHS?

Answer 116

ROHHAD-NET | Presents with rapid obesity, hypothalamic disorders, OSA, hypoventilation, autonomic dysregulation

Question 117

Recurrence rates for CCHS

Answer 117

50% of transmitting it if affected parents | 50% chance of recurrence with unaffected mosaic parents

Question 118

Mechanism of PARM in CCHS

Answer 118

regarded as flexible spacer elements essential to conformation, protein-protein interaction and DNA binding

Question 119

Mechanism of PHOX2B mutations in CCHS

Answer 119

Typically responsible for expression regulation of genes involved in the development of the ANS

Question 120

Diagnosis and clinical course for CCHS

Answer 120

1) Need to send for PHOX2B screening test for diagnosis. Rule out other causes of hypoventilation + other lung disease muscle weakness, cardiac disease 2. Investigations for Hirschsprungs 3. Serial chest and abdo imaging essential for PARM and NPARM with 20/29-20/33 4. Annual 72 hour holter for abhorrent cardiac rhythms 5. Annual echo, hematocrit, reticulocyte count (at risk for PH) 6. Ophthalmologic evaluation 7. Reported to have decreased school performance - neurocognitive test annually 8. Biannual then annual comprehensive physiologic studies to assess ventilatory needs

Question 121

What is the hallmark of CCHS?

Answer 121

Alveolar hypoventilation * *Diminished tidal volume and minute ventilation is most easily seen in non-REM sleep but also abnormal in REM and wakefulness * *Need for ventilatory support tied to PARM mutations (worse with more PARM >20/27) and NPARMs

Question 122

Options for ventilatory management in CCHS

Answer 122

Trach BiPAP Negative pressure ventilators Diaphragmatic pacing

Question 123

Problem with diaphragmatic pacing?

Answer 123

Will be picked up in ECG so may artificially elevate HR and hide the sinus pauses

Question 124

Should kids with CCHS swim?

Answer 124

NO! | Prohibited from underwater swimming as they won't perceive asphyxia that occurs with drowning and breath holding

Question 125

Is NIV optimal management in CCHS?

Answer 125

No | *Considered after 6-8 years

Question 126

What form of ventilation is recommended for CCHS especially in the first few years?

Answer 126

Trach **Portable postive pressure ventilator via trach = most common method of providing home ventilation **Must have power generator and placement on emerge list for local power company and fire dept

Question 127

4 signs that a trach needs upsizing

Answer 127

1. Difficulty achieving adequate gas exchange and plateau on ETCO2 2. Increasing ventilator settings to those above other similar aged children 3. More frequent pneumonia 4. Audible leak *Bronch q12-24 months for assessment

Question 128

Recommendation for BiPAP in CCHS

Answer 128

Can be used via nasal mask, prongs or facemark (but discouraged) Provide continuous flow with fixed leak Can adjust pressure accordingly Should not be used outside of sleep - interferes with activity, skin breakdown, mid face hypoplasia

Question 129

Recommendation for Negative Pressure Ventilation in CCHS

Answer 129

- Many children still need a trach - Not portable - Requires supine position - Causes skin irritation and a "chilled" sensation - Possible when older (6-8)

Question 130

Mechanism for Diaphragmatic Pacing in CCHS

Answer 130

- Generates respiratory rate using the diaphragm - Uses battery operated external transmitter sent via antenna with a radio signal sent to subcutaneous bilateral receiver - generates an electrical impulse which stimulates a breath **Can give 12-15 hours of support If needing 24 hours - need a second method of ventilation for part of the day MUST have backup support OSA may be a complication *dyssynchrony with the upper airway muscles

Question 131

Optimal CCHS candidates for Diaphragmatic pacing

Answer 131

No or mild lung disease Not obese Intact phrenic nerve/diaphragm integrity Needs tracheostomy initially

Question 132

Lifestyle recommendations for CCHS

Answer 132

No alcohol or drug use Be careful with pregnancy - increases respiratory load, decreases minute ventilation and central drive Low mortality for those managed aggressively Most children have prolonged survival with good quality of life

Question 133

2 techniques for Multiple Breath Washout

Answer 133

1) Nitrogen | 2) SF6

Question 134

Explain how nitrogen washout works

Answer 134

1) RA in (nitrogen ~80%) 2) Washout: 100% O2 Done with N2 < 1.5% x 3 breaths Cheapest and most commonly used No wash-in needed Intert but "intrinsic" gas - lungs excrete nitrogen

Question 135

Explain how SF6 washout works

Answer 135

1) Wash-in: SF6 with 21% O2 - to 4% 2) Washout: RA (open circuit) "Extrinsic", not produced by the lungs Easier detection Disadvantages: greenhouse gas, expensive, longer wash-in period

Question 136

Equation for Lung Clearance Index

Answer 136

(Cumulation expired volume to reach 1/40th gas)/FRC

Question 137

What does LCI measure?

Answer 137

Measures ventilation homogeneity Higher LCI = more lung inhomogeneity Healthy = ~7 (5.7-7.7), age-dependent Decreases in 1st 2 years of life - plateaus (toddler) - then increases Can be normal in atelectasis/complete obstruction Main application = CF

Question 138

What are the 3 2019 End of Forced Expiration criteria for spirometry? (Need 1 of these)

Answer 138

1. Expiratory plateau ≤ 0.025L/s in the last second 2. Expiratory time > 15 seconds 3. FVC within repeatability tolerance > 6yr: ≤ 0.150L between 2 highest values for FVC and FEV1 <6yr: ≤ 0.100L or 10%

Question 139

Activities to avoid before lung function testing

Answer 139

- Smoking +/- vaping +/- water per use within 1 hr - Consuming intoxicants within 8 hr before testing - Performing vigorous exercise within 1 hour before testing - Wearing clothing that substantially restricts full chest and abdominal expansion

Question 140

According to Canadian TB guidelines, who are the most affected populations in Canada for TB?

Answer 140

Canadian-born aboriginals Foreign-born individuals Disproportionate number of incident cases in North

Question 141

Most common TB disease site

Answer 141

Pulmonary 64% Peripheral lymph nose second most common 13% Almost all cases culture confirmed (80%)

Question 142

What is the most common co-infection with TB?

Answer 142

HIV

Question 143

Characteristics relating to pathogenesis of M. tuberculosis

Answer 143

Almost exclusively a human pathogen Airborne transmission Distribution of inhaled droplet nuclei into the lung determined by pattern of regional ventilation - follows the most direct path to the periphery and favours middle and lower zones (which receive the most ventilation) If successfully cleared by host macrophages - IGRA and TST = negative

Question 144

At which time post infection would we expect the TST and IGRA to be positive?

Answer 144

After 3-8 weeks - the host develops specific cell-mediated immunity and delayed-type hypersensitivity Infection and immune conversion almost always asymptomatic

Question 145

Once infected, what is the progression of TB?

Answer 145

Granuloma formation - as more cellular infiltrates continue to the site of infection = centre becomes caseous or necrotizing Ghon focus = calcified granuloma Ghon complex = calcified granulomatous focus in a draining lymph node

Question 146

Other early manifestations of TB

Answer 146

Erythema nodosum - cutaneous immunology reaction to an extra cutaneous TB infection Phlyctebular conjunctivitis - hypersensitivity reaction

Question 147

Early disease progression in TB

Answer 147

Progression to disease = recently infected individuals unable to contain infection despite immune response and end up progressing to TB in months 4-12 mos = early disease manifestations include: - Complicated LN disease - Immunocompetent - intrathoracic adenopathy and unilateral pleural effusion

Question 148

Definition of late TB disease

Answer 148

Any individual with a dx of TB made within 18-24 most of infectious = primary disease Almost always the result of lymphs-hematogenous spread

Question 149

Definition of Latent TB infection

Answer 149

Positive TST or IGRA in the absence of active disease Organisms can shift into state of dormancy if allowed to settle through gradual reductions in oxygen tension

Question 150

Defnition of re-infection of TB

Answer 150

Takes up to 18 mos from initial infection for cell-mediated immunity to occur - reinfection during this time = same disease risk as initial infection

Question 151

Is reactivation or reinfection more common in Canada?

Answer 151

Reactivation

Question 152

Risk factors for progression from TB infection to disease

Answer 152

- Children < 5 yrs (especially infants), young adults (especially females) and older adults (especially male) - Undernutrition - Seasonality (highest incidence in spring and summer) Progression depends on immunocompetence of the host

Question 153

Characteristics of transmission of TB

Answer 153

- Aerosol route - Humans = reservoir - Droplet nuclei created by forced expiratory efforts and have an extremely slow settling rate - Rate of transmission can be measured by the percentage of close contacts whose TST and IGRA responses are converted - Transmission requires a TB patient to be able to produce airborne infectious droplets - Smear positive/culture postive TB more infectious than smear negative/culture positive - Cavitary disease more infections than non-cavitary disease - Laryngeal disease more infectious - Sneezing = most infectious (then coughing followed by breathing)

Question 154

Environmental factors relating to TB transmission

Answer 154

- Air circulation and ventilation - Proximity to the source case - Duration of exposure

Question 155

Areas that are included in the diagnosis of Respiratory TB

Answer 155

- Primary TB - Pulmonary TB - Tuberculous pleurisy - TB of the intrathoracic nodes, mediastinum, nasopharynx, nose and sinus

Question 156

Classic symptoms of TB

Answer 156

- cough at least 2-3 weeks duration - Dry -> productive - Fever and night sweats - Hemoptysis, anorexia, weight loss, chest pain (manifestations of advanced disease)

Question 157

Most common finding on exam for TB

Answer 157

Normal exam

Question 158

Signs of extra pulmonary TB

Answer 158

LAN, pleural effusion, abdominal and bone or joint involvement

Question 159

Algorithm for active TB testing

Answer 159

1. CXR - 2 views 2. Microbiology 3. Evaluation for drug resistance

Question 160

Components of microbiological testing for TB

Answer 160

1. Sputum: smear yield reduces with each collection, but culture yield can increase, sputum should be induced 2. Bronchoscopy: might consider if unable to perform sputum induction or if all samples are smear negative 3. Gastric aspirate: in those who cant expertorate 4. Smear-microscopy: Ziehl-Neelson (light micro), Auromine stain (fluorescence) - high specificity for mycobacteria 5. Mycobacterial culture = gold standard (Lowenstein Jensen media) 6. Nucleic acid amplification test - sensitive, PCR most common

Question 161

2 methods for testing for drug resistance in TB

Answer 161

1. Phenotypic (gold standard) | 2. Molecular methods

Question 162

Situations in which neither TST nor IGRA should be used for testing

Answer 162

- People who have a low risk of infection and a low risk that there will be progression to active TB disease if they are infected - For the diagnosis of active TB - For routine or mass screening for LTBI of all immigrants - For monitoring anti-TB treatment responses

Question 163

Situations in which IGRAs are preferred for testing but a TST is acceptable

Answer 163

- People who have received BCG vaccine after infancy (1 year of age) and/or have received BCG vaccination more than once - People from groups that historically have poor rates of return for TST reading.

Question 164

Situations in which TST is recommended for testing but an IGRA is NOT acceptable

Answer 164

It is planned to repeat the test later to assess risk of new infection (i.e. conversions), such as repeat testing in a contact investigation or serial testing of health care or other populations (e.g. corrections staff or prison inmates) with potential for ongoing exposure.

Question 165

Situations in which both tests can be used (sequentially, in any order) to enhance sensitivity

Answer 165

- When the risks of infection, of progression to disease and of a poor outcome, are high. - In children (under age 18 years) with suspected TB disease, IGRAs may be used as a supplementary diagnostic aid in combination with the TST and other investigations to help support a diagnosis of TB. - Repeating an IGRA or performing a TST might be useful when the initial IGRA result is indeterminate, borderline or invalid, and a reason for testing persists.

Question 166

Steps for performing a TB skin test

Answer 166

○ 5 TU of purified protein derivative is used (not 1-TU) ○ Refrigerated at 2-8 degrees celsius ○ 0.1 mL of solution ○ Try to limit light exposure ○ Use within one month of opening ○ Inject the inner aspect of the forearm, about 10 cm below the elbow ○ Do not use EMLA or other anesthetic cream ○ Use a ¼-½ inch 26 or 27 G needle ○ Insert at 5-15 degree angle so that needle is just visible below the surface of the skin ○ Slow intradermal injection ○ Site should not be bandaged and patient should be discouraged from scratching or touching the area ○ If the injection is too deep - it will not harm the patient, but the test will need to be repeated ○ Record : date of infection, dose of PPD, PPD manufacturer, lot number, expiration date, site of injection, person administering test ○ Reading should be performed 48-72 hours later ○ Induration should be palpated

Question 167

Contraindications to TST

Answer 167

- Positive, severe blistering TST reactions in past, extensive burns or eczema present over TST testing sites - Documented active TB or well-documented history of adequate treatment for TB infection or disease in the past - Those with current major viral infections (measles, mumps, varicella) - Live vaccine within the past 4 weeks (increases false negatives) TST can be used in those taking low doses of systemic corticosteroid (<15 mg prednisone daily)

Question 168

Potential causes of false-negative TST

Answer 168

1. Improper storage of tuberculin material or contamination, improper dilution or denaturation 2. injection of too little or injection too deeply 3. Administration > 20 min after drawing it up 4. Inexperience reader/technical issues 5. Active TB (especially if advanced) 6. Other bacterial infections (typhoid fever, brucellosis, typhus, leprosy, pertussis) 7. HIV infection (especially if CD4 count <200) 8. Other viral infection (measles, mumps, varicella) 9. Fungal infection 10. Live virus vaccination (MMR) 11. Immunosuppressive drugs and steroids 12. Metabolic disease (chronic renal failure, severe malnutrition, stress) 13. Disease of lymphoid organs (lymphoma, CLL, sarcoidosis) 14. Age: infants <6 mos, the elderly

Question 169

Management of a positive TST result

Answer 169

STEP 1 - deciding that a TST is positive - Based on size and using criteria STEP 2 - medical evaluation - Assess for symptoms suggestive of possible active TB, risk factors for TB, Chest X ray - In the presence of symptoms or abnormal CXR, microscopy and culture should be performed - If no evidence of active infection, then recommendations for treatment of LTBI be made

Question 170

Interpretation of a positive TST

Answer 170

- Size of induration - Positive predictive value - Risk of disease if person is truly infected

Question 171

People considered to have a positive TST with 0-4mm

Answer 171

- Child under 5 | - High risk of TB infection

Question 172

People considered to have a positive TST ≥ 5mm

Answer 172

- HIV infection - Contact with infectious TB case within the past 2 years - Presence of fibronodular disease on CXR - Organ transplantation - TNF alpha inhibitors - Other immunosuppressive drugs - End-stage renal disease

Question 173

People considered to have a positive TST ≥10mm

Answer 173

All others including: - TST conversion (within 2 years) - Diabetes, malnutrition, smoking, alcohol - Silicosis - Hematologic malignanies

Question 174

Typical CXR findings for TB

Answer 174

Infiltrates in apical-posterior segments of upper lobes or superior segments of the lower lobes Volume loss Cavitation Signs of complications: - Small nodular shadows from airway involvement - Pleural effusion - Pneumothorax

Question 175

BCG vaccination can be ignored as a cause of a positive TST under which circumstances?

Answer 175

- BCG vaccination was given in infancy, and the person tested is now aged 10 years or older - High probability of TB infection: close contacts of an infectious TB case, Aboriginal Canadians from a high-risk community or immigrants/visitors from a country with high TB incidence - High risk of progression from TB infection to disease

Question 176

BCG should be considered the likely cause of a positive TST under which circumstances

Answer 176

- BCG vaccine was given after 12 months of age AND - There has been no known exposure to active TB disease or other risk factors AND - the person is either Canadian-born non-Aboriginal OR - an immigrant/visitor from a country with low TB incidence.

Question 177

Definition of TST conversion

Answer 177

- TST of 10 mm or greater when earlier test < 5 mm induration - If earlier test 5-9 mm induration: - Increase of 6 mm or more - suggested for those who are immunocompromised with increased risk of disease or for an outbreak - Increase of 10 mm or more - all others TST conversion occurs within 8 weeks of exposure

Question 178

What is the booster effect that can be seen with 2-step TST?

Answer 178

- Single TST may stimulate an anamnestic immune response so that a second TST performed later on will elicit a greater response - This can be confused with conversion - Should be performed if likely to perform serial testing - If second TST 10 mm or more, patient should be referred for medical evaluation

Question 179

Types of IGRAs

Answer 179

IGRA = Interferon Gamma Release Assays 1. Quantiferon TB Gold in tube (QTF-GIT) 2. T spot.TB Specificity >95% for the diagnosis of LTBI, not affected by BCG vaccine Most NTM not picked up by IGRAs, except Mycobacterium kansasii and Mycobacterium marinum Sensitivity diminished by HIV infection → indeterminate result

Question 180

Are IGRAs recommended for active TB diagnosis or for serial testing purposes?

Answer 180

No

Question 181

What are the 2 phases of TB treatment?

Answer 181

1. Initial Intensive: 2 months, daily meds | 2. Continuation: 2 drugs given, length variable, daily or intermittent therapy

Question 182

Which TB drug requires the addition of Pyridoxine?

Answer 182

Isoniazid For: patients with diabetes, renal failure, malnutrition, substance abuse, seizure disorders or for women who are pregnant or breastfeeding

Question 183

Typical duration of the Continuation phase in TB treatment

Answer 183

4 months (7 months for elderly, hepatotoxicity, pregnant)

Question 184

When would you consider prolonging the continuation phase?

Answer 184

- More extensive disease - Cavities on chest x ray in the first 2 months of therapy - Being culture positive after 2 months of therapy - Having a cavity of CXR at the end of treatment - HIV patients not on ARV therapy

Question 185

Antibiotics for treatment of TB

Answer 185

Rifampin Isoniazid Pyrazinamide Ethambutol

Question 186

Criteria for intermittent therapy

Answer 186

- Should only be used with direct observed therapy (DOT) - In the intensive phase, daily therapy is recommended - this can be given 5 days per week if therapy is given by DOT - If DOT in the initial phase is difficult, patients may be treated with 3x weekly therapy if they are HIV-, have a low bacillary load and have demonstrated adherence to their DOT in the first 2 weeks - In the continuation phase, if DOT is used then 3 x weekly therapy is preferred. - Intermittent therapy not recommended for HIV infected patients

Question 187

When to add adjunctive steroid for TB treatment

Answer 187

TB meningitis and TB pericarditis

Question 188

Indications for hospitalization for TB

Answer 188

- Investigation and/or treatment of symptoms i.e. hemoptysis, malaise, cachexia - Establishment of an acceptable therapeutic regimen in patients with drug related adverse events or with known/suspected resistance - Drug desensitization - Management of associated medical conditions complicating TB i.e. HIV infection - Provision of airborne isolation if cannot be effectively provided as an outpatient - Involuntary admission

Question 189

Follow-up during active TB treatment

Answer 189

- Follow up during active TB treatment should be monthly to monitor response to therapy and adherence - Patients who are AFB smear positive should have weekly smear examination until smear negative. - Once smear negative, one culture should be done at the end of the second month of therapy to assess the risk of relapse, then again towards the end of therapy - CXR should be performed at 2 and 6 months

Question 190

Side effects of Isoniazid

Answer 190

``` Rash Hepatitis Neuropathy CNS toxicity Anemia ```

Question 191

Side effects of Rifampin

Answer 191

``` Drug interactions Rash Hepatitis "flu-like illness" Neutropenia Thrombocytopenia ```

Question 192

Side effects of Pyrazinamide

Answer 192

Hepatitis Rash Arthralgia Gout

Question 193

Side effects of Ethambutol

Answer 193

Eye toxicity Rash Baseline ophthalmological assessment should be obtained before starting EMB (especially in young children)

Question 194

Treatment of suspected TB drug induced hepatotoxicity

Answer 194

- Stop PZA, INH and RMP and start at least 2 alterative TB meds - Review history carefully, and check viral serologies (hep A, B, C) - When transaminases have returned to normal, restart RMP (not likely to give hepatitis) - Wait 2 weeks, then start INH. If severe hepatotoxicity, consider not rechallenging with INH - If RMP and INH are restarted and transaminases remain normal, assume that the hepatitis is due to PZA. Do not rechallenge with PZA

Question 195

High Risk factors for reactivation of active disease from LTBI

Answer 195

Strongest = AIDS, but note that HIV also increases the risk - Transplant (related to immunosuppression) - Silicosis - Chronic renal failure requiring hemodialysis - Carcinoma of head and neck - Recent TB infection (≤ 2 years) - Abnormal CXR (fibronodular disease)

Question 196

Indications for treatment of LTBI

Answer 196

Recent infection and increased risk of reactivation

Question 197

Is LTBI treatment recommended if immune compromised and TST is negative

Answer 197

No

Question 198

Regimens for LTBI treatment

Answer 198

Standard regimen - 9 months of INH (Self-administered) **Now 4 mos daily RMP Alternative regimen - Six months of daily, self administered INH - less effective - Four months of daily, self administered of INH and RMP acceptable - Three months of once weekly directly observed INH and RPT - High rates of hypersensitivity

Question 199

Is Pregnancy and breastfeeding safe with LTBI treatment

Answer 199

Yes but supplement with Pyridoxine if using Isoniazid or Rifampin

Question 200

Clinical presentation of non-respiratory TB

Answer 200

- TB lymphadenitis - Urinary tract TB - Genital TB - Miliary TB - Spinal/vertebral TB (Pott’s disease) - Joint/arthritis - GI TB - Peritoneal TB - TB meningitis - Tuberculomas - Ocular TB - TB pericarditis

Question 201

Definition of drug-resistant TB

Answer 201

Drug resistant TB if strain is resistant to one or more first-line drugs (INH, RMP, PYR, EMB)

Question 202

Characteristics of paediatric TB

Answer 202

- TB diagnosis in young children is a sentinel event indicating recent transmission - Diagnosis is difficult since signs, symptoms and radiographic appearance is nonspecific and disease is often paucibacillary - Primary infection usually accompanied by occult, subclinical bacteremia that seeds distant sites including the apices of the lungs, lymph nodes, CNS and may rapidly lead to severe forms (especially in kids < 5 years) - No confirmatory test for LTBI - Cavitation is rare in childhood disease - Gastric aspirates: overall diagnostic yield is 50% - Pyridoxine recommended for all children on meat and milk deficient diets, breast fed infants, those with nutritional deficiencies, those with symptomatic HIV infection, adolescents who are pregnant or breastfeeding Diagnosis of TB depends on triad of: Positive TST or IGRA (delineating exposure), either an abnormal CXR and/or physical examination, discovery of a link to a known or suspected case of infectious TB

Question 203

Treatment modification and duration for pediatric TB

Answer 203

- Fully susceptible, intrathoracic TB, INH, rifampin and PZA should be used for 2 months, followed by 4 months of INH and RMP (ethambutol can be dropped if fully sensitive) - Minimum duration of therapy is 6 months - should be longer in patients with cavities or positive sputum cultures after 2 months (9 months) - If hilar adenopathy alone is present, treatment as for pulmonary disease should be given - Evaluation at least monthly - Dose adjustments with weight - Chest X ray 2 months into disease - however don’t change treatment based on cxr if clinical improvement - Follow patients at least one year post d/c of treatment

Question 204

Management of contacts of paediatric TB

Answer 204

- All exposed children should have a symptom inquiry and TST - Those < 5 years, and all close contact children should have a physical examination and CXR - Children < 5 years with negative TST should have window prophylaxis of INH - can be discontinued if asymptomatic and TST negative at that time - In the exposed child, if the initial TST >/= 5 mm , then full course of LTBI is recommended

Question 205

Targeted paediatric testing for latent TB infection

Answer 205

- Contacts of known TB - Children with suspected active disease - Children with known risk factors for progression of infection to disease - Children who have travelled or resided for 3 months or longer in an area with a high TB incidence - Children who arrived in Canada from countries with high TB incidence

Question 206

Recommended management of the newborn infant exposed to TB

Answer 206

- Clinical exam - TST - CXR - Cultures including a lumbar puncture - Abdominal ultrasound - HUS can be considered - Window prophylaxis x 6 months with IHN, when TST can be repeated - Congenital TB: oral isoniazid (10–15 mg/kg/day), oral rifampin (10–20 mg/kg/day), oral pyrazinamide (20–40 mg/kg/day), and IM streptomycin (20–40 mg/kg/day) for 2 months; isoniazid and rifampin should then be continued for an additional 6 months.

Question 207

Risk factors for spontaneous pneumothorax

Answer 207

Smoking (most important) Underlying lung disease Tall, thin body habitus

Question 208

Physical exam finding with pneumothorax

Answer 208

Reduced or absent breath sounds Reduced ipsilateral chest expansion and hyper-resonant percussion Haemodynamic compromise or significant hypoxia is unusual in primary pneumothorax

Question 209

Is size of the pneumothorax important?

Answer 209

- Size less important than degree of clinical compromize - Rim > 2 cm associated with large ptx (BTS, inter pleural distance) - Size does not correlate well with clinical symptoms

Question 210

Treatment options for pneumothorax

Answer 210

- Patients with lung dz tolerate pneumothorax less well - Important to distinguish btw primary and secondary ptx - Breathlessness indicates the need for active intervention - Size of ptx indicates rate or resolution and is relative indication for intervention Primary, asymptomatic and small - F/U 2-4 weeks Primary, symptomatic, >2 cm: Needle aspirate if no success - chest tube Secondary, small <1cm, asymptomatic: admit for oxygen, observe 24 hours Secondary, large 1-2 cm: needle aspirate Secondary large > 2cm: chest tube

Question 211

Follow-Up and further management pneumothorax

Answer 211

- Conservative management if no symptoms - outpatient review - Suction not routinely recommended - reserved for persistent air leak (Increase risk of reexpansion pulmonary edema) - Referral to a respiratory specialist within 24 hours of admission

Question 212

Management secondary spontaneous pneumothorax

Answer 212

- All patients with SSP should be admitted to hospital at least 24 hours and receive supplemental oxygen - Most will require insertion of a chest tube (aspiration less likely to be successful) - Early referral to chest physician - Persistent air leak > 48h should be discussed with surgeon - SSP persistent airleak, unsuitable candidate for surgery - Medical pleurodesis - Consideration for ambulatory management with Heimlich valve

Question 213

Discharge and follow-up post pneumothorax

Answer 213

- Patients should be advised to return to hospital if increasing breathlessness - CXR 2 weeks post observation or NA - Follow up by a respiratory physician until full resolution of ptx - Air travel should be avoided until full resolution (1 month since occurrence, or 1 week post resolution) - Diving avoided for life unless bilateral pleurodesis - Normal lung function and CT scan afterward - Return to work and resume normal activities once symptoms resolve - Sports involving contact or extreme exertion should be limited until full resolution

Question 214

Definition of Spontaneous vs Secondary Pneumothorax

Answer 214

Spontaneous pneumothorax = absence of any identified extrinsic cause. PSP occurs in the absence of clinically apparent underlying lung disease SSP occurs as a complication of a pre-existing underlying lung disease such as COPD, cystic fibrosis, lung malignancy ( primary or metastatic) or necrotising pneumonia of various causes.

Question 215

Definition of Recurrent Pneumothorax

Answer 215

A subsequent episode of pneumothorax occurring after either an ipsilateral or contralateral pneumothorax.

Question 216

When would a tension pneumothorax occur?

Answer 216

Tension pneumothorax occurs when the intrapleural pressure becomes greater than the atmospheric pressure throughout all phases of respiration. It can be seen in ventilated patients or after trauma or cardiopulmonary resuscitation, but is extremely rare in PSP

Question 217

Indications for definitive management of primary spontaneous pneumothorax (PSP)

Answer 217

``` Second episode of PSP Persisting air leak >3–5 days Haemopneumothorax Bilateral pneumothorax Professions at risk (aircraft personnel, divers) ```

Question 218

What is Medical chemical pleurodesis and who gets it?

Answer 218

Chemical pleurodesis should be reserved for people who cannot tolerate surgery Prevention of recurrent pneumothorax should be undertaken surgically - Lower recurrence rates than for medical pleurodesis Chemical sclerosing agents: - Minocycline, doxycycline - Tetracycline - Talc - Risk of recurrence 10-20%

Question 219

When to refer to surgery for management of pneumothorax

Answer 219

``` Persistent air leak - referral to surgeons at 3-5 days indicated Low morbidity of surgery Recurrence rates very low Accepted indications for surgical advice ○ Second ipsilateral pneumothorax ○ First contralateral ptx ○ Synchronous bilateral spontaneous ptx ○ Persistent air leak (Despite 5-7 days of chest tube) or lack of lung re-expansion ○ Spontaneous hemothorax ○ Professions at risk (pilots, i.e.) ○ Pregnancy ```

Question 220

What is the main etiological factor pneumothorax in the context of AIDS?

Answer 220

PJP

Question 221

Key points of pneumothorax associated with CF

Answer 221

- The development of a pneumothorax in a patient with cystic fibrosis requires early and aggressive treatment with early surgical referral - Pleural procedures, including pleurodesis, do not have a significant adverse effect on the outcome of subsequent lung transplantation - PTX more frequent with increasing age and disease severity - Up to 3.4% of CF patients - CT drainage has recurrence rate of 50% - Lung may be slow to expand - mucous impaction makes for a stiff lung - Partial pleurectomy = treatment of choice, if fit for surgery - If not fit for surgery - chemical pleurodesis

Question 222

Indications for tracheostomy

Answer 222

1. Structural airway problems: subglottic stenosis, hemangioma, tumours, craniofacial anomalies 2. Lung problems: CLD, chronic ventilation 3. Neurological problems: neuromuscular, SCI, vocal cord paralysis, diaphragmatic dysfunction

Question 223

When should cuffed tubes be used?

Answer 223

Requiring high pressures Only nocturnal ventilation Chronic aspiration

Question 224

Recommendations for trach suctioning

Answer 224

- Clean technique recommended for home care - Premeasured technique (measure until distal holes of suction catheter just exiting tip of trach tube) recommended for all routine suctioning - Suction prn but if no evidence of secretions then minimum morning and bedtime to check patency - Largest size catheter that will fit inside tube is recommended (usually double size of trach) - Use pressures of 80-100 mmHg - Rapid technique (< 5 sec) recommended to prevent atelectasis - Routine use of N/S not recommended

Question 225

Recommendation for humidification with tracts

Answer 225

If upper airway is bypassed then inspired air lacks humidity - loss of ciliary action, thickens secretions -impairs ventilation and increases risk of infection Recommend humidification with e.g. HME: traps the heat and moisture from exhalation and partly returns it during inspiration (but increases dead space and resistance)

Question 226

Criteria for use of a speaking valve

Answer 226

Speaking valve e.g. Passy-Muir: one way valve with air able to come in but not out so air is forced upwards through larynx/vocal cords to allow speech - Tube size should not exceed 2/3 of tracheal lumen (unless using fenestrated tube) - No aspiration risk and secretions thin - Medically stable with patency of airway above trach - Some ability to vocalize with trach occluded

Question 227

Recommendations for decannulation

Answer 227

- Sequential downsizing of tube, often with partial or complete plugging of the tube (over days-weeks) - After able to tolerate smallest tube then tube is removed - Majority of failures occur within 12-36 hours after decannulation (may already have closure of stoma)

Question 228

Complications for tracheostomy

Answer 228

50% will have complications from time of surgery to decannulation Mortality < 1% Early - Bleeding - Infection - False tract - Decannulation - Obstruction Late - Decannulation - takes hrs to days to close - Tube obstruction - Granuloma - Stenosis - suprastomal, stoma, at tip (secondary to infection, inflamm, pressure, mechanical irritation) - Infection - bypassing nasal filtration (microbial aspiration) and humidification (decreases efficiency of mucociliary clearance) - Hemorrhage - suctioning trauma or tracheoinominate fistula (risk factors: low tube tip, high pressure cuff, excessive tube movement) - TEF - related to posterior tracheal wall injury - Tracheomalacia - ischemic injury with subsequent weakness and destruction of supporting cartilage (reason why cuffed tubes not routinely used)

Question 229

New definition of PH in children

Answer 229

Resting mean pulmonary artery pressure (mPAP) >20 mmHg beyond the first few months of life (> 3 most at sea level)

Question 230

Definition of idiopathic PAH

Answer 230

pulmonary vasculopathy that remains a diagnosis of exclusion, specifically indicating the absence of diseases of the left side of the heart or valves, lung parenchyma, thromboembolism, or other miscellaneous causes.

Question 231

Differences between paediatric and adult PH

Answer 231

1) Pediatric PH is intrinsically linked to issues of lung growth and development, 2) The development of PH in the neonate and young infant is often related to impaired functional and structural adaptation of the pulmonary circulation during transition from fetal to postnatal life. 3) Adult PH and pediatric PH differ in vascular function and structure, genetics, natural history, response of the right ventricle (RV), and responsiveness to PAH-specific therapies

Question 232

The 5 classifications of pulmonary hypertension

Answer 232

1. PAH (1' PVOD, 1.1'' PPHN) 2. PH due to left-sided heart disease 3. PH caused by lung disease or hypoxemia 4. Chronic thromboembolic disease 5. PH with unclear or multifactorial mechanisms

Question 233

Imaging to diagnose what disorders should be done at the time of PH diagnosis

Answer 233

pulmonary thromboembolic disease, peripheral pulmonary artery stenosis, pulmonary vein stenosis, pulmonary veno-occlusive disease (PVOD), and parenchymal lung disease

Question 234

What imaging/diagnostic modality is recommended before starting PH medications?

Answer 234

Cardiac catheterization is recommended before initiation of PAH-targeted therapy and should include acute vaso- reactivity testing (AVT)

Question 235

What is considered to be a positive response on cath to acute vasoreactivity testing?

Answer 235

Positive response to AVT for children should be considered as a ≥20% decrease in PAP and pulmonary vascular resistance (PVR)/systemic vascular resistance (SVR) without a decrease in cardiac output

Question 236

Pulmonary testing to consider when investigating the cause of PH

Answer 236

CXR PFT PSG V/Q scan

Question 237

Most common genetic cause for PH

Answer 237

BMPR2

Question 238

Genetic syndromes with increased risk for PH (+/- CHD)

Answer 238

``` T21 DiGeorge syndrome Scimitar syndrome Noonan syndrome Dursan syndrome Cantu syndrome ```

Question 239

O2 saturation goal in patients with established BPD and PH?

Answer 239

maintaining O2 saturations between 92% and 95% in patients with established BPD and PH

Question 240

When should lung biopsy be considered for PH?

Answer 240

Lung biopsy may be considered for children with PAH suspected of having PVOD, pulmonary capillary hemangiomatosis, or vasculitis

Question 241

When should lung transplant be considered for PH?

Answer 241

Referral to a lung transplantation center for evaluation is recommended for patients who have confirmed pulmonary capillary hemangiomatosis or PVOD

Question 242

Preventive care measures for health maintenance are recommended for pediatric patients with PH?

Answer 242

Respiratory syncytial virus prophylaxis (if eligible) Influenza and pneumococcal vaccinations Rigorous monitoring of growth parameters Prompt recognition and treatment of infectious Respiratory illnesses Antibiotic prophylaxis for the prevention of subacute bacterial endocarditis in cyanotic patients and those with indwelling central lines

Question 243

Which patients with PH should not participate in competitive sports

Answer 243

Pediatric patients with severe PH (WHO functional class III or IV) or recent history of syncope should not participate in competitive sports

Question 244

What is the most frequently noted abnormality of lung volumes in patients with respiratory muscle weakness?

Answer 244

Reduction in vital capacity (VC).

Question 245

With marked expiratory weakness, what happens to RV?

Answer 245

RV is usually normal or increased, the latter particularly with marked expiratory weakness

Question 246

With muscle weakness, what happens with TLC, RV/ TLC and FRC/TLC ratios?

Answer 246

Total lung capacity (TLC) is less markedly reduced than VC, and the RV/ TLC and FRC/TLC ratios are often increased without necessarily implying airway obstruction. The VC is limited by weakness of both the inspiratory muscles, preventing full inflation, and expiratory muscles, inhibiting full expiration. Reductions in compliance of both the lungs and chest wall also contribute to the reduction of VC Vital capacity reflects the combined effect of weakness and the static mechanical load on the respiratory muscles

Question 247

Im mild respiratory muscle weakness, which is more sensitive - VC or max respiratory pressure

Answer 247

In mild respiratory muscle weakness, VC is less sensitive than maximum respiratory pressures In more advanced disease, marked reductions in VC can occur with relatively small changes in maximum pressures.

Question 248

What happens to VC in patients with isolated or disproportionate bilateral diaphragmatic weakness or paralysis in the supine position?

Answer 248

In patients with isolated or disproportionate bilateral diaphragmatic weakness or paralysis, the VC shows a marked fall in the supine compared with the erect posture because of the action of gravitational forces on the abdominal contents.

Question 249

Advantages of VC in measuring muscle weakness

Answer 249

VC has excellent standardization, high reproducibility and well- established reference values It is quite sensitive for assessing progress in moderate to severe respiratory muscle weakness.

Question 250

Disadvantages of VC in measuring muscle weakness

Answer 250

VC has poor specificity for the diagnosis of respiratory muscle weakness. In mild weakness, it is generally less sensitive to changes than are maximum pressures

Question 251

In uncomplicated respiratory muscle weakness, is airway resistance generally normal?

Answer 251

yes

Question 252

Is maximum voluntary ventilation recommended for patients with respiratory muscle weakness as a measure of assessment and monitoring?

Answer 252

No - Maximum voluntary ventilation is not generally recommended for patients with known or suspected respiratory muscle weakness but may be helpful in the assessment and monitoring of patients with extrapyramidal disorders.

Question 253

In respiratory muscle weakness, when would you expect to see daytime hypercapnia?

Answer 253

Daytime hypercapnia is unlikely unless respiratory muscle strength is reduced to < 40% of prediced and VS is reduced to <50% of predicted

Question 254

Advantage of awake arterial blood gas in patients with respiratory muscle weakness

Answer 254

Advantages = Arterial blood gases assess the major functional consequence of respiratory muscle weakness. In patients with Duchenne muscular dystrophy, hypercapnia has been shown to predict shorter survival

Question 255

Disadvantage of awake arterial blood gas in patients with respiratory muscle weakness

Answer 255

Definitely abnormal arterial blood gases usually imply late and severe impairment of respiratory muscles

Question 256

Symptoms of nocturnal hypoventilation

Answer 256

morning headaches, daytime sleepiness, and lack of energy.

Question 257

Advantage of overnight oximetry in patients with respiratory muscle weakness

Answer 257

Overnight oximetry is simple to perform

Question 258

Disadvantage of overnight oximetry in patients with respiratory muscle weakness

Answer 258

Current evidence suggests that nocturnal hypoxemia is a less good prognostic indicator than either vital capacity or awake PaCO2

Question 259

3 aspects of Respiratory control

Answer 259

(1) sensory receptors (2) the central integrating circuits (3) motor output

Question 260

What is occlusion pressure?

Answer 260

The pressure generated in the airway (and by inference the pressure generated in the pleural space) by contraction of inspiratory muscles when the airway has been occluded at end expiration. Occlusion pressure amplitude does not directly assess either the degree of muscle weakness or the degree of neuronal adjustment to the weakness. P0.1 is the pressure generated in the first 100 milliseconds of inspiration against an occluded airway.

Question 261

What is considered normal values for P0.1?

Answer 261

Values of P0.1 are around 1 cm H2O in normal subjects at rest, around 3 cm H2O in patients with stable chronic obstructive pulmonary disease May be 10 cm H2O or more in acute respiratory failure due to chronic obstructive pulmonary disease or acute respiratory distress syndrome.

Question 262

Reason you may see a low DLCO in a patient with respiratory muscle weakness

Answer 262

Reduction is due to inability to achieve full distension of the lungs at TLC and consequent failure to expose all of the alveolar surface to CO. As with other extra- pulmonary causes of lung volume restriction, the transfer co- efficient (KCO) is often supernormal. The pattern of normal or mildly reduced DLCO and raised KCO directs attention to extrapulmonary conditions, that is, respiratory muscle weakness, pleural disease or rib cage abnormalities.

Question 263

What is the reason for the reduction in maximum oxygen consumption in patient with respiratory muscle weakness

Answer 263

Maximum oxygen consumption is reduced because of weakness of leg muscles rather than cardiorespiratory factors

Question 264

Physiologic reasons for ventilatory failure specific to infants and newborns?

Answer 264

Ventilatory failure can occur in newborns and infants due to: - immaturity of the chest wall and respiratory muscles - poor coupling between thoracic and abdominal movements - upper airway dysfunction. Adults can elevate the rib cage where in infants, the ribs are already elevated and this may be one reason why motion of the rib cage during RA breathing contributes little to tidal volume The orientation of the ribs does not change substantially until the infant assumes the upright posture. Dynamic end-expiratory lung volume in newborns and infants is substantially above the passively determined FRC. The inspiratory force reserve of respiratory muscles is reduced in infants with respect to adults because inspiratory pressure demand at rest is greater.

Question 265

Rationale for measuring crying pressure in infants

Answer 265

Mouth pressures generated during crying efforts may provide an index of respiratory muscle strength in awake infants. Airway occlusions are performed at the end or at the beginning of a crying effort to measure crying PImax and PEmax, respectively

Question 266

Definition of exercise-induced bronchoconstriction. Drop in FEV1 to count?

Answer 266

Exercise-induced bronchoconstriction (EIB) = acute airway narrowing that occurs as a result of exercise. The criterion for the percent fall in FEV1 used to diagnose EIB is >10%.

Question 267

How is the severity of EIB graded?

Answer 267

The severity of EIB can be graded as mild, moderate, or severe if the percent fall in FEV1 from the pre-exercise level Mild: >10% less then 25% Moderate: >25% but less than 50% Severe: >50%

Question 268

Surrogates for exercise testing

Answer 268

Eucapnic voluntary hyperpnea or hyperventilation Hyperosmolar aerosols (including 4.5% saline) Dry powder mannitol.

Question 269

1st line treatment for exercise-induced bronchoconstriction

Answer 269

An inhaled short-acting b2-agonist (SABA) before exercise. | The SABA is typically administered 15 minutes before exercise.

Question 270

When is a controller agent generally added in exercise-induced bronchoconstriction?

Answer 270

A controller agent is generally added whenever SABA therapy is used daily or more frequently.

Question 271

After regular controller, other options for add-ons for EIB

Answer 271

Don't use daily use of an inhaled long- acting b2-agonist as a single therapy Start daily administration of an inhaled corticosteroid (ICS) Do not give ICS only before exercise Start daily administration of a leukotriene receptor antagonist Administration of a mast cell stabilizing agent before exercise Administration of an inhaled anticholinergic agent before exercise

Question 272

Non-pharm interventions that are recommended for EIB

Answer 272

Interval or combination warm-up exercise before planned exercise For patients with EIB who exercise in cold weather, we suggest routine use of a device (i.e., mask) that warms and humidifies the air during exercise For patients with EIB who have an interest in dietary modification to control their symptoms: Implementation of a low-salt diet Dietary supplementation with fish oils Recommendation against dietary supplementation with lycopene Dietary supplementation with ascorbic acid

Question 273

What are the key roles of Nitric Oxide?

Answer 273

The functions and effects of NO in the lung/airways reflect its key roles as a vasodilator, bronchodilator, neurotransmitter, and inflammatory mediator. Patients with asthma have high levels of NO in their exhaled breath and high levels of inducible nitric oxide synthase (NOS2) enzyme expression in the epithelial cells of their airways, suggesting a role for NO in asthma pathogenesis.

Question 274

The pathophysiological role of NO in the airways and lungs

Answer 274

On the one hand, it may act as a proinflammatory mediator predisposing to the development of airway hyperresponsiveness (AHR). On the other, under physiological conditions NO acts as a weak mediator of smooth muscle relaxation, and protects against AHR. In exhaled air, NO appears to originate in the airway epithelium, as a result of NOS2 up-regulation which occurs with inflammation. Thus, exhaled NO may be regarded as an indirect marker for up-regulation of airway inflammation.

Question 275

Advantages for FENO

Answer 275

The noninvasive nature of the test Ease of repeat measurements The relatively easy use in patients with severe airflow obstruction where other techniques are difficult to perform

Question 276

Disadvantages of FENO

Answer 276

The methods and equipment for measuring FENO needed to be standardized

Question 277

What is the upper limit of FeNO?

Answer 277

We recommend that FENO greater than 50 ppb (35 ppb in children) be used to indicate that eosinophilic inflammation and, in symptomatic patients, responsiveness to corticosteroids are likely

Question 278

What is the lower limit of FeNO?

Answer 278

We recommend that low FENO less than 25 ppb (20 ppb in children) be used to indicate that eosinophilic inflammation and responsiveness to corticosteroids are less likely FENO values between 25 ppb and 50 ppb (20–35 ppb in children) should be interpreted cautiously and with reference to the clinical context. (strong recommendation, low quality of evidence).

Question 279

What is considered a significant increase in FENO?

Answer 279

greater than 20% for values over 50 ppb more than 10 ppb for values lower than 50 ppb from one visit to the next We suggest using a reduction of at least 20% in FENO for values over 50 ppb or more than 10 ppb for values lower than 50 ppb as the cut point to indicate a significant response to antiinflammatory therapy

Question 280

Definition of hypoxemia in children younger than 1 year old

Answer 280

Spending 5% of the recording time with SpO2 less than or equal to 90%

Question 281

Definition of hypoxemia in children older than 1 year old

Answer 281

Spending 5% of the time with SpO2 less than or equal to 93%

Question 282

When would you consider using an arterial blood gas for PaO2 assess hypoxemia?

Answer 282

When pulse oximetry may not accurately measure SpO2, including: Altered hemoglobin state Diseases affecting hemoglobin (SCD)

Question 283

Definition of severe chronic hypoxemia

Answer 283

1) greater than or equal to 5% of recording time spent with an SpO2 less than 90% if measurements are obtained by continuous recording or 2) at least three separate findings of an SpO2 less than 90% if measurements are obtained intermittently. A duration of 2 weeks defines chronicity of hypoxemia in a child.

Question 284

Definition of mild chronic hypoxemia

Answer 284

1) greater than or equal to 5% of recording time spent with an SpO 2 90–93% if measurements are obtained by continuous recording 2) at least three separate findings of an SpO2 90–93% if measurements are obtained intermittently.

Question 285

Risk factors for more severe BRUEs in premature infants

Answer 285

Central apnea longer than 30 seconds SpO2 less than 80% for 10 seconds Bradycardia to less than 50–60 beats per minute for 10 seconds Upper respiratory infection symptoms

Question 286

What factors can contribute to the development of severe nocturnal hypoxemia in SCD?

Answer 286

Hemoglobin SS is associated with more severe nocturnal hypoxemia than is hemoglobin SC, and treatment of patients with SCD with hydroxyurea is associated with improvement in hypoxemia

Question 287

When should home oxygen be prescribed in CF?

Answer 287

Severe chronic hypoxemia | Both mild chronic hypoxemia and dyspnea on exertion

Question 288

When should home oxygen be prescribed in BPD?

Answer 288

Chronic hypoxemia

Question 289

When should home oxygen be prescribed in sleep-disordered breathing?

Answer 289

Sleep-disordered breathing complicated by severe nocturnal hypoxemia who cannot tolerate positive airway pressure therapy or are awaiting surgical treatment of sleep- disordered breathing

Question 290

When should home oxygen be prescribed in SCD?

Answer 290

Severe chronic hypoxemia

Question 291

When should home oxygen be prescribed in PH?

Answer 291

For pulmonary hypertension without congenital heart disease complicated by chronic hypoxemia For patients with pulmonary hypertension with congenital heart disease complicated by chronic hypoxemia, supplemental oxygen will impact hemodynamics and physiology; we recommend that home oxygen therapy NOT be initiated in these children, regardless of previous reparative or palliative congenital heart surgery, until there has been consultation with a pediatric pulmonologist or cardiologist who has expertise in the management of pulmonary hypertension in this clinical setting

Question 292

When should home oxygen be prescribed in ILD?

Answer 292

Severe chronic hypoxemia | Both mild chronic hypoxemia and dyspnea on exertion or desaturation during sleep or exertion

Question 293

What is the primary source of home oxygen for infants and small children (if low flow rates and short duration)?

Answer 293

Size-adequate oxygen cylinders can be used in infants and small children as the primary source of home oxygen if flow rates are low (0.3 L/min) and if the duration of oxygen therapy is expected to be limited to a few months

Question 294

At what flow rate is the addition of humidification recommended?

Answer 294

Flow rates above 1 L/min Can be achieved through cold bubble or heated humidification devices

Question 295

Most common mode of oxygen delivery?

Answer 295

Nasal cannula

Question 296

Primary method of monitoring SpO2 in the pediatric population.

Answer 296

Pulse oximetry

Question 297

Limitations to accurate SpO2 determinations with pulse oximeters

Answer 297

``` Improper probe placement Movement artifact Nail color Ambient light Reduced distal extremity perfusion Hypothermia Skin pigmentation Dysfunctional hemoglobin ```

Question 298

Concerns regarding home oximetry monitoring

Answer 298

The nuisance of frequent alarms Increased caregiver anxiety The potential for overreliance by caregivers on normal SpO2 versus overall clinical status

Question 299

Aspects of home safety with oxygen in the house

Answer 299

Risks of smoking and open flames in the home The use of oil-based products or other fuels near the oxygen source The focus on the dangers of exposure should include the flammability of compressed oxygen and the known harms that inhaled smoke imparts to growing infants and children It is also imperative to ensure access to reliable electricity and a telephone in case of emergencies

Question 300

Criteria for consideration of weaning home oxygen

Answer 300

Reassuring medical examination Reassuring objective measurements of oxygenation (Oxygen saturation measured at steady state (not spot checked) by continuous pulse oximetry in room air) Consider an echocardiogram to demonstrate absence of or improvement in findings suggestive of PH or right heart strain

Question 301

Guidelines to wean home oxygen

Answer 301

It is suggested either to decrease oxygen flow rate gradually or to withdraw its use during certain periods of the day When gradually decreasing the oxygen flow rate, it is practical to wean by halving because conventional home oxygen delivery devices easily allow for this (1 L/min to 0.5 L/min then 0.25 L/min, and so forth) before room air challenges. We suggest weaning the flow rate gradually over the course of weeks while frequently monitoring for adverse effects.

Question 302

When to consider room air challenges for those on home oxygen

Answer 302

Room air challenges can be considered for clinically stable children under 1 year of age receiving less than 0.1 L/min and children up to preschool age receiving 0.1–0.25 L/min.

Question 303

What should you do once a patient is considered for stopping nocturnal home oxygen

Answer 303

In-home, room air, nocturnal pulse oximetry study should be performed

Question 304

How quickly can you make changes to home oxygen?

Answer 304

Given the chronicity of these respiratory conditions, changes should be made on a weeks to months basis, as opposed to more quickly.

Question 305

What factors to monitor that reflect those assessed when considering patient readiness

Answer 305

Patient growth Development Cardiorespiratory status Stability of health (e.g., handling of respiratory illnesses, travel to altitude).

Question 306

Definition of ILD

Answer 306

Nonspecific term referring to disorders that feature remodeling of the lung interstitium and distal airspaces, with resultant abnormal gas exchange.

Question 307

What is considered the most prevalent sign in children with diffuse lung disease?

Answer 307

Tachypnea is consistently the most prevalent sign, occurring in 75–93% of patients. Hypoxemia is also common, as are crackles and cough. Failure to thrive is common in young children with DLD

Question 308

Criteria for chILD (need 3 of 4)

Answer 308

(1) respiratory symptoms (cough, rapid and/or difficult breathing, or exercise intolerance) (2) respiratory signs (e.g., resting tachypnea, adventitious sounds, retractions, digital clubbing, failure to thrive, or respiratory failure) (3) hypoxemia (4) diffuse abnormalities on CXR or a CT scan.

Question 309

The chILD syndrome requires that more common causes of DLD have been excluded. What do these include?

Answer 309

``` Cystic Fibrosis Congenital or acquired immunodeficiency Congenital heart disease Bronchopulmonary dysplasia Pulmonary infection Primary ciliary dyskinesia presenting with newborn respiratory distress Recurrent aspiration. ```

Question 310

3 main classifications of ILD

Answer 310

Disorders prevalent in infancy Disorders not specific to infancy Unclassified

Question 311

What disorders are considered part of ILD disorders prevalent in infancy

Answer 311

1) Diffuse developmental disorders (ie. ACDMPV) 2) Growth abnormalities (ie. pulmonary hypoplasia) 3) Specific condition of unknown etiology (PIG, NEHI) 4) Surfactant dysfunction mutations and related disorders

Question 312

What disorders are considered part of ILD disorders not specific in infancy

Answer 312

1) Disorders of the normal host 2) Disorders relating to systemic diseases processes 3) Disorders of immunocompromised host 4) Disorders masquerading as ILD

Question 313

What disorders are considered to be part of ILD disorders unclassified

Answer 313

End stage disease Non-diagnostic biopsies Those with inadequate material

Question 314

When should neonates or infants with established lung disease be investigated for potential co-existing chILD disorder

Answer 314

Neonates and infants who are diagnosed with one of the common diseases that can cause DLD, but whose severity of illness is out of proportion to that diagnosis, require further evaluation for coexisting chILD syndrome.

Question 315

What investigations are recommended for a chILD work-up?

Answer 315

Echo Thin section chest CT (CT scanning is superior to CXR at identifying DLD, and that CT scanning is superior to MRI in resolution, detecting characteristics of chILD diseases) Infant PFT Flexible bronchoscopy with BAL (to exclude infection or airway abnormalities as possible causes of DLD)

Question 316

Cytologic studies may be useful for excluding alternative causes of DLD, such as:

Answer 316

``` Pulmonary hemorrhage syndrome Pulmonary alveolar proteinosis Pulmonary histiocytosis Sarcoidosis Niemann-Pick disease Aspiration ```

Question 317

Findings consistent with pulmonary alveolar proteinosis should lead to an investigation for what conditions?

Answer 317

surfactant dysfunction mutations, GM-CSF pathway abnormalities, and lysinuric protein intolerance

Question 318

Other ways of assessing for aspiration besides lipid laden macrophages

Answer 318

Measuring gastric pepsin levels and/or determining alveolar macrophage localization of milk proteins

Question 319

When should a lung biopsy be considered for ILD?

Answer 319

For neonates and infants with chILD syndrome in whom other diagnostic investigations have not identified the pre- cise chILD disease, or in whom there is clinical urgency to identify the precise chILD disease, we recommend surgical lung biopsy Biopsy should performed using video-assisted thoracoscopy (VATS) rather than open thoracotomy VATS visualizes a greater percentage of the lung and permits the sampling of different lobes with the same incision sites. VATS also appears to be associated with less post- operative pain, shorter recovery time, and superior cosmetic results compared with a large thoracotomy incision.

Question 320

For newborns who present with chILD syndrome, congenital hypothyroidism, and hypotonia consider this syndrome

Answer 320

NKX 2.1 For infants beyond the neonatal period who have chILD syndrome with hypothyroidism and/or neurologic abnormalities (e.g., hypotonia or choreoathetosis), or those with severe disease, a family history of adult ILD or chILD, or other features of surfactant dysfunction mutations and negative testing for ABCA3 and SFTPC, we recommend genetic testing for NKX2.1

Question 321

For newborns who present with chILD syndrome leading to respiratory failure and refractory pulmonary hypertension, consider this genetic test

Answer 321

FOXF1 deletions or mutations

Question 322

For infants beyond the neonatal period who have chILD syndrome, we recommend testing for which mutations if initial studies do not provide a diagnosis

Answer 322

For infants beyond the neonatal period who have chILD syndrome, we recommend testing for SFTPC and ABCA3 mutations if initial studies do not provide a diagnosis

Question 323

For infants beyond the neonatal period who have chILD syndrome with alveolar proteinosis and whose genetic testing for SFTPC and ABCA3 are negative, which further testing is required.

Answer 323

For infants beyond the neonatal period who have chILD syndrome with alveolar proteinosis and whose genetic testing for SFTPC and ABCA3 are negative, we suggest genetic testing for CSF2RA and CSF2RB and obtaining serum levels of granulocyte- macrophage colony–stimulating factor (GM-CSF)

Question 324

Some ILD that can cause severe neonatal chILD

Answer 324

``` Acinar dysplasia Pulmonary hypoplasia/alveolar simplification ACDMPV PIG Surfactant protein B ABCA3 mutation TTF-1 (NKX 2.1) mutations Pulmonary hemorrhage syndromes Pulmonary lymphangiectasia ```

Question 325

Side effects to monitor for while on therapy for ILD

Answer 325

Monitor for side effects: bone density scanning, serial growth measurements, and ophthalmologic screening in children receiving chronic corticosteroids Periodic complete blood counts and ophthalmologic evaluations in children receiving chronic hydroxychloroquine

Question 326

When should infants with ILD be referred for lung transplant

Answer 326

Infants with chILD syndrome, diagnosis for whom a poor outcome is likely and effective treatment is unavailable should be referred to a center with experience in lung transplantation of infants to be considered for transplantation

Question 327

Supportive and preventative care recommendations for chILD

Answer 327

Children with severe respiratory impairment due to chILD syndrome may benefit from invasive or noninvasive ventilation. Many patients with chILD syndrome have poor somatic growth that requires nutritional intervention. Patients with chILD syndrome should avoid harmful environmental exposures, such as second-hand smoke. They may benefit from the pneumococcal vaccine, an annual influenza vaccination, and routine childhood immunizations, with the exception of live-virus vaccines in immunosuppressed patients. RSV can increase the morbidity and mortality of infants and young children with chronic lung diseases such as chILD syndrome Immunosuppressed children are routinely given prophylaxis for Pneumocystis jiroveci.

Question 328

Definition of PCD

Answer 328

Genetically heterogeneous, autosomal recessive disorder characterized by motile cilia dysfunction. caused by biallelic pathogenic mutations in one of the many identified PCD causative genes

Question 329

4 key clinical features characteristics of PCD

Answer 329

1) Year-round, daily, productive (wet) cough 2) Year- round, daily, nonseasonal rhinosinusitis present early and are almost universally present by 6 months of age. 3) Neonatal respiratory distress syndrome as term newborns, defined as the need for supplemental oxygen or positive pressure ventilation support for more than 24 hours without clear explanation Approximately 80% of children with PCD have a history of this 4) Laterality defects (e.g., situs inversus totalis), whereas other situs anomalies with or without congenital heart defects = 12% of affected individuals. Roughly 40–55% of patients with PCD

Question 330

Diagnostic tests for PCD

Answer 330

Previously, the diagnosis of PCD has been based on the presence of ultrastructural defects in the ciliary axoneme using TEM analysis Nasal nitric oxide (nNO) measurement Genetic testing Digital high-speed video microscopy with ciliary beat pattern analysis (HSVM) Immunofluorescence imaging for specific axonemal proteins.

Question 331

Recommendations for genetic testing for PCD

Answer 331

In patients presenting with a strong clinical phenotype for PCD, we suggest using an extended genetic panel as a diagnostic test over TEM ciliary testing and/or standard (<12 genes) genetic panel testing

Question 332

Recommendations for nasal NO for PCD

Answer 332

In cooperative patients 5 years of age or older with a clinical phenotype consistent with PCD and with CF excluded, we suggest using nNO testing for the diagnosis of PCD over TEM and/or genetic testing

Question 333

How many nNO values need to be measured to diagnose PCD

Answer 333

Because nNO values may be transiently decreased with acute viral respiratory infections or sinusitis, establishing a low nNO → two separate occasions is indicated.

Question 334

Can CBP analysis by HSVM be used as a replacement diagnostic test for PCD?

Answer 334

No - the recommendations suggest not using CBP analysis by HSVM as a replacement diagnostic test in patients with a high probability of having PCD

Question 335

Common reasons for flexible bronchoscopy in children

Answer 335

``` 1) Diagnostic unexplained wheeze or stridor chronic cough recurrent pneumonia microbiologic sampling suspected aspiration, structural abnormalities, endobronchial lesion OSA Radiographic abnormality Hemoptysis and pulmonary hemorrhage Monitoring of lung allograft Monitoring of artificial airway 2) Therapeutic Treatment of persistent atelectasis Control hemorrhage Bronchoscopic intubation Dilation of stenotic airway ```

Question 336

The only absolute contraindication to flexible bronchoscopy

Answer 336

Refusal of the parent or guardian to provide informed consent

Question 337

Consequences of flexible bronchoscopy

Answer 337

``` Minor epistaxis Partial airway obstruction Pharyngeal discomfort Minor dysphonia Cough Minor airway bleeding Transient inadvertent PEEP Transient increased ICP Transient minor fever ```

Question 338

Complications of flexible bronchoscopy

Answer 338

Mechanical (epistaxis, vocal cord spasm or trauma, significant stridor, airway trauma, hemorrhage, lower airway obstruction leading to hypoxemia, hypercapnia, air leak, bronchospasm, atelectasis) Microbiologic (Nosocomial infection, intrapulmonary spread of infection) Anesthetic (apnea, hypoxemia, hypercapnia, hypotension, nausea, aspiration, adverse drug reaction) Multifactorial (significant aspiration, prolonged fever >24 hours, cardiac arrhythmias, death)

Question 339

Preexisting conditions essential to recognize prior to bronchoscopy include:

Answer 339

``` Hemodynamic instability Severe or uncontrolled pulmonary HTN Profound upper or central airway obstruction Immunodeficiency Infectious risk to the team (TB) Severe bronchial hyperresponsiveness Uncorrected bleeding diathesis ```

Question 340

Medication recommendations pre bronchoscopy

Answer 340

May consider suspending or withholding antibiotics before the procedure to maximize the diagnostic yield of BAL. Patients with a history of bronchial hyperresponsiveness may benefit from an inhaled short-acting b-agonist immediately before the FAE

Question 341

Advantages of scoping through nose or mouth (without artificial airway)

Answer 341

Inspect entire airway Assess dynamics/malacia May allow for use of a larger scope Allows for airway evaluation with rigid scope Disadvantages: more difficult to monitor ventilation and airway patency Laryngospasm Anesthetic waste gas into OR environment

Question 342

Advantages of scoping through facemask

Answer 342

Inspect entire airway Assess dynamics/malacia Does not limit size of scope Disadvantages: More challenging for anesthetist than LMA or tube Laryngospasm May limit movement of the scope

Question 343

Advantages of scoping through LMA

Answer 343

Easy to place Relatively secure airway Can assist ventilation with positive pressure ``` Disadvantages: Can't assess upper airway or VC movement May limit scope size Aperture bars may limit passage of scope Requires more anesthetic Can mask lower airway dynamics ```

Question 344

Advantages of scoping through tube or trach

Answer 344

Faster and safer access to low airway Secure airway Quick to remove and reinsert scope if needed Enable PPV and extensive suctioning Potentially avoids contamination of lower airway with upper airway flora ``` Disadvantages: Can't assess upper airway or VC movement May limit scope size Requires more anesthetic Can mask lower airway dynamics ```

Question 345

Advantages of flexible scope compared to rigid

Answer 345

More thorough exam of distal airway and upper lobe segments Directed sampling by BAL Better assessment of airway dynamics (depending on sedation) Introduction through nasal passage, or tube (which allows for tube placement)

Question 346

Advantages of rigid scope compared to flexible

Answer 346

Allows for introduction of instruments into the scope Best for removal of foreign bodies Can ventilate through the scope Better assessment of the upper airway (assessing for laryngeal clefts etc.) May be best for evaluation and control of brisk alveolar hemorrhage

Question 347

Most frequently sampled lobes for BAL

Answer 347

The right middle lobe and lingula are the lung segments most frequently sampled because they provide maximal return

Question 348

In evaluating children for suspected aspiration, it may be optimal to sample which segments?

Answer 348

In evaluating children for suspected aspiration, it may be optimal to sample segments that are normally dependent.

Question 349

BAL findings of alveolar proteinosis

Answer 349

Gross: milky, sediment is often visible Cytology: PAS-positive, diastase-resistant, amorphic material Electron microscopy: Abundant extracellular multilamellated bodies and tubular myelin structures, alveolar macrophages with enlarged foamy cytoplasm

Question 350

BAL findings of alveolar hemorrhage

Answer 350

Gross: bloody, increasing with each sample Cytology: hemosiderin laden macrophages

Question 351

BAL findings of Langerhans Cell Histiocytosis

Answer 351

Immunostaining for S-100, CD1a, langerin

Question 352

BAL findings of Chronic Lipoid Pneumonia

Answer 352

Oil Red O staining with scoring for lipid-laden macrophages

Question 353

BAL findings of Pulmonary Alveolar Microlithiasis

Answer 353

Microlith staining with PAS or von Kossa stain

Question 354

The medical home for the ventilator dependent child must provide these things

Answer 354

Subspecialty management of the child’s chronic respiratory failure and its treatment including all aspects of ventilator management and associated therapies Support for technical aspects of the ventilator and tracheostomy Appropriate training of family caregivers Access to care 24h/d, 7d/wk Community -based primary care Coordination of all aspects of the child’s care Guidance to patient/family on all aspects of the child’s medical care Providers responsible for comprehensive care assessment and management of all aspects of the child’s health care

Question 355

Proposed standardized criteria for discharge of an invasively ventilated child to home

Answer 355

The child must be medically stable for discharge Caregivers must demonstrate willingness and ability to look after the child A DME company must be available and able to provide the required equipment and technical support Professional in home caregivers as required to support family must be arranged before discharge The home and community environment must be safe and allow access to routine and urgent care as needed