Resp Physio and Pulm Symptoms

Question 1

What are the expected changes in PFTs and lung function in a pregnant patient?

Answer 1

No change in FEV1, FVC, or ratio. TLC may slightly decline. RV/ERV/FRC decrease as the uterus pushes upwards on the diaphragm. Inspiratory capacity and vital capacity doesn’t change due to hormonal relaxation of respiratory muscles. Reduction in FRC coupled with closure of small airways and increased oxygen demand can cause rapid desaturation during intubation. Tidal volume increases due to increased ventilatory drive. Will see a chronic respiratory alkalosis.

Question 2

What are causes of reduced MVV (measured max voluntary ventilation) on CPET?

Answer 2

reduced lung volumes from lung disease, NM impairment, and poor effort. MVV should be 35-40 times the FEV1 (lower values suggest poor effort or NM impairment). Differentiate NM from poor effort by pCO2 response ->no compensation in NM disease

Question 3

How is asthma managed in pregnant patients?

Answer 3

Continue regimens as worsening asthma in pregnancy can lead to worse outcomes. Continue biologics but don’t start while pregnant. Steroids given in first trimester has small increased risk of cleft palate (0.1-0.3% increased risk)

Question 4

How are mycetomas with massive hemoptysis managed?

Answer 4

Initially with bronchial artery embolization once airway is stabilized. Bleeding recurs in up to 55% of cases. Major complications include spinal cord ischemia leading to transverse myelitis (1.4-6.5%) and transient dysphagia. Can consider candidacy for lobectomy once bleeding stabilized.

Question 5

What are the phases of pertussis and how is it managed?

Answer 5

Incubation phase- 7-10 days (longer than most resp viruses)
Catarrhal phase- URI, 1-2 weeks. Paroxysmal phase starts in the second week with sequential coughing and sometimes whooping (not as common in adults), posttussive vomit. Can only Dx with PCR. Macrolides in early stage to reduce transmission and duration
Convalescent phase- months, slowly resolving cough

Question 6

What are the markers of exercise limitation on CPET?

Answer 6

decreased end-exercise workload (reduced work capacity), decreased peak VO2 aerobic capacity), and decreased predicted maximal peak VO2 (low anaerobic threshold). Then determine cause of exercise limit (are they able to increase tidal volume? desaturation? HR limitation?)

Question 7

How is exercise induced bronchoconstriction diagnosed?

Answer 7

Fall in FEV1 of 10% or more. Validity depends on no warm-up period, 17.5x FEV1 during high intensity exercise for 6-8 min

Question 8

What are the features of Erdheim-Chester disease?

Answer 8

Histo- sheets of foamy histocytes
Features- sclerotic lesions in long bones. Manifestations to skin/sinuses/retroperitoneum/lungs/heart/CNS. May have DI. BRAF V600 somatic mutation.
Dx- pleural thickening, subQ avidity on PETCT

Question 9

What are the features of mastocytosis?

Answer 9

Features- skin most frequently affects, but seen in all organ systems, increased risk of anaphylaxis, c-KIT gene
Dx- bone marrow biopsy, serum tryptase under 20
Tx- trigger avoidance and anaphylaxis management

Question 10

What are the features of Rosai-Dorfman disease?

Answer 10

Features- massive bilateral cervical LAD in children and young adults. Fever/night sweats, weight loss, potentially associated with IgG4-related disease

Question 11

What is the acceptability criterion for PFTs?

Answer 11

back-extrapolated volume must be <5% of FVC or 0.1L, whichever is greater, no evidence of a faulty-zero setting, no cough in first or second second of expiration, no glottic closure during first second of expiration
DLCO- Vi>90% largest VC in same session (or Vi>85% AND within 200mL largest Va), 85% of Vi inhaled <4sec, stable breath hold for 10 +/-2 sec, no leaks/Valsalva(decreases result)/Mueller (increases result), sample collection completed within 4sec

Question 12

What is the repeatability criterion for PFTs?

Answer 12

difference between the 2 largest FVC values to be <0.15L, difference between the 2 largest FEV1 values to be <0.15L
at least 2 DLCO within 2mL/min/mmHg of each other

Question 13

Who benefits from long term oxygen therapy?

Answer 13

ILD with exertional room air hypoxemia under 88% on 6MWT
COPD with resting hypoxemia (PaO2 <55/SpO2<88% or PaO2 56-59 or SpO2 89% plus edema/Hct>55/pPulmonale on EKG

Wear for 15hr/day

Question 14

How is a DL/VA interpreted when alveolar volume is reduced?

Answer 14

When VA is reduced only due to poor inspiration, the losses of surface area and blood volume sare small despite loss of gas volume and therefore DL/VA increases (often above ULN). In intrinsic lung disease, VA loss is both surface area and derangements of alveolar-capillary interface, to both values decrease proportionally (leading to normal DL/VA) or DLCO decreases more than VA (low DL/VA)

Question 15

What are the normal physiologic changes during sleep?

Answer 15

Hypercapneic/hypoxemic ventilatory drives are reduced in NREM and more in REM, set point for response to CO2 increases, upper airway muscle activity decreases to increase upper airway resistance, FRC decreases by 200mL in N2 and 300mL in N3/REM, decreased MV due to decreased Vt

Question 16

How is pre-eclampsia managed?

Answer 16

For mild disease, delivery at 37w. For severe features, delivery at 34w. For severe features before 34 weeks, may require hospitalization for Mg/BP management and close monitoring for further complications. Prevent pre-eclampsia in subsequent pregnancies with ASA

Question 17

What are some indications of deconditioning on CPET?

Answer 17

impairment of work and aerobic capacity but not reaching physiologic maximums at end0exercise and is symptom limited

Question 18

What affect does the Valsalva maneuver have on DLCO?

Answer 18

Decreases. Increased intrathoracic pressure then decreases pulmonary capillary blood volume. Can drop up to 30%.

Question 19

How long can it take for PPI to affect a cough due to GERD?

Answer 19

1-3 months, some can see results in as little as 1 week

Question 20

What is swimming-induced pulmonary edema?

Answer 20

Hydrostatic effect of immersion translocated about 700cc of blood to the thorax, increasing cardiac size and pressure. More likely in cold water (due to vasoconstriction of the systemic vasculature), vigorous exercise, and increased breathing effort

Question 21

What are the features of idiopathic pulmonary hemosiderosis?

Answer 21

Histo: intraalveolar hemorrhage, hemosiderin-laden macrophages, type 2 pneumocyte hyperplasia, intraalveolar septal wall thickening
Features: more common in kids, intermittent hemoptysis

Question 22

What are some relative contraindications for spirometry?

Answer 22

AMI within 1 week
Eye surgery within 1 week
Brain surgery within 4 weeks
Thoracic surgery within 4 weeks
Presence of PTX

Question 23

What are some age-related PFT changes?

Answer 23

VC decreases
RV increases
DLCO decreases
TLC stays the same

Question 24

What are some significant MIP/MEP values to remember?

Answer 24

Normal MIP excludes inspiratory muscle weakness
MIP below 1/3 of normal predicts hypercarbic respiratory failure
MEP less than 60 predicts a weak cough and difficulty clearing secretions

Question 25

What is forced oscillation technique in PFTs used for?

Answer 25

Small pressure fluctuations applied to the mouth to measure airflow and pressure reflections to derive resistance

Cannot be corrected for changes in lung volumes

Question 26

How long do medications have to be withheld before a methacholine challenge?

Answer 26

SABA- 6h
LABA- 36-48h
SAMA- 12h
LAMA- 168h (1 week)

Question 27

What are some findings of a normal CPET?

Answer 27

Respiratory mechanical reserve or mechanical ventilatory reserve is confirmed by exercise tidal flow volume curves
Normal gas exchange

In the super fit, can see flattening of VO2 max curve and see ventilatory constraint representing true peak performance

Question 28

What constitutes maximal exercise in CPET?

Answer 28

Plateau in the VO2
Maximal work rate >90%
Maximal HR >90%
Ve/MVV approaches or exceed 1.0
RER >1.15
Significant oxygen desaturation: SpO2 falls >5% (but may not be exercise limiting)

Question 29

How is active TB and LTBI managed in pregnancy?

Answer 29

TB- RIE x 9 months (pyrazinamide is not well studied)
LTBI- low risk with clear CXR can defer until after delivery, high risk 9m INH or perhaps 4m rifampin (new distant second choice)

Question 30

What are the features of tuberous sclerosis?

Answer 30

Autosomal dominant,
Seizures, brain tumors, cognitive impairment, sebaceous adenomas, angiomylolipomas, pulmonary LAM in up to 25%

Question 31

What therapies are helpful for acute cough?

Answer 31

First generation antihistamines (newer generation isn’t helpful), inhaled ipratropium, albuterol only if there’s wheezing

Question 32

What is the equation for oxygen delivery?

Answer 32

CaO2 x CI x 10
CaO2= (1.36 x Hb x Sat) + (0.003 x paO2)