Miscellaneous Flashcards
1
Q
What are the diagnostic criteria for ARDS?
A
An acute lung injury - within one week of the insult
Bilateral infiltrates on a chest x-ray, not explained by other lung pathology
Respiratory failure not explained by fluid overload
A Decreased PaO2/FiO2 ratio
2
Q
A patient with COPD has saturations of 95% OA and MRC score of 1. They want to know if they need further investigations before they fly
A
No. No HCT required . Not meeting criteria for in flight oxygen
3
Q
A patient with COPD has saturations of 95% OA and MRC score of 3. They want to know if they need further investigations before they fly
A
Yes , given MRC 3 , guidelines recommend 6MWT or SWT and if sats <84% review if hx of hypercapnia. If yes then need HCT, if no then inflight O2 @ 2l/min.
If sats on 6MWT/ SWT are > 84% then no need for HCT/ in flight O2
4
Q
A patient with COPD has saturations of 91% OA and not on LTOT. They want to know if they need further investigations before they fly
A
Yes. Is there a history of hypercapnia ? If Yes then need HCT, if no then in flight O2 @ 2l/min
5
Q
A patient with COPD has saturations of 91% on 1L LTOT. They want to know if they need further investigations before they fly
A
If known T1RF - no , just increase LTOT by 2l/min
If known T2RF - yes , needs HCT
6
Q
Who needs a hypoxic challenge test for flying ?
A
- those with sats ≤ 95% , not usually on LTOT and at risk of hypercapnia OR sats < 84% on 6MWT or SWT with concerns re hypercapnia
- severe asthma with persistent symptoms or frequent exacerbations despite optimal treatment regardless of SpO2 at sea level
- ILD patients with sats <95% on exercise and resting sea level PaO2 ≤9.42 or TLCO ≤ 50%
- Severe chest wall deformity / severe resp muscle weakness FVC <1L
- Those with existing or previous hypercapnia and those at risk of T2RF already on LTOT
7
Q
What HCT results indicate need for in flight O2 ?
A
PaO2 < 6.6 or Sats <85%
8
Q
Patient with IPF wants to know if they need in flight O2 . There sats are 96% following 6MWT
A
No , HCT not req and in flight O2 not required
9
Q
Patient with IPF wants to know if they need in flight O2 . There sats are 92% following 6MWT and they are not on LTOT
A
Need ABG:
- if PaO2 < 9.42 on room air then need to review TLCO. If TLCO < 50% predicted then need in flight O2 at 2l/min
- if PaO2 > 9.42 then still review TLCO . If <50% predicted then should have HCT. If more then doesn’t require HCT
10
Q
Patient with IPF on LTOT wants to know if they need in flight O2 .
A
Yes , 2L greater than usual prescription
11
Q
What are recommendations for CF patients when flying ?
A
Review spirometry if FEV1 <50% should have HCT . If sats <90% will need in flight O2
12
Q
What is the advice following thoracic surgery and air travel?
A
Four weeks for non essential travel , 2 weeks for essential
13
Q
What is the advice for air travel following TBB/TBNA/EBUS/Endobronchial valve insertion?
A
Those with no PTX on X ray should wait 1 week
14
Q
What is the advice for flying with PTX?
A
Can’t fly with untreated PTX
Can fly 1 week after resolution of PTX
Be aware those high risk of recurrence
15
Q
What is the advice for patients who develop sinus barotrauma after flying ?
A
Topical / oral decongestants and appropriate analgesia.
If allergic component intranasal steroids for 1 week prior to travel and /or oral corticosteroids
Symptoms and signs of barotrauma should have resolved prior to flying
16
Q
What is the advice for air travel following otitis media ?
A
Advised not to fly for 2 weeks
17
Q
What are the viral infections you are advised not to fly with?
A
Measles , chicken pox , mumps , SARs, MERS, COVID
18
Q
When can patients with TB fly?
A
Smear positive patients must not fly until there are two consecutive smear negative samples on treatment
Those starting TB treatment when all info not available should not fly for at least 2 weeks
For those who are smear negative treatment should render them non infectious in 2 weeks
For MDR/XDR TB this is prohibited until 2 negative samples produced and clinical evidence of improvement
Extra pulmonary TB no restrictions
19
Q
When can patients with Pneumonia fly?
A
Air travel should be postponed for 7 days in those with sats < 94%
20
Q
What is the advice for those with OSA/OHS re air travel?
A
Daytime flights where posssible and take CPAP in hand luggage
Avoid EtOH/sedation
If night flight should use CPAP, if day avoid falling asleep
21
Q
What is the advice for muscle wall weakness for air travel
A
FVC < 1L then HCT
If can’t tolerate spiro then consider 6MWT /SWT
22
Q
What is the advice we provide to avoid VTE with air travel?
A
Ensure hydrated , avoid alcohol , keep mobile , compression stockings , for high risk patients LMWH ie 40mg Enox /DOAC for long haul (6-8 hr) flight
Low risk - all
Mod risk- over 60, preggo , minor surgery , extensive varicose veins
High risk- precious VTE (and not on anticoag) , thrombophilia , 6/52 major surgery , malignancy
23
Q
How long should air travel be delayed after acute PE/DVT?
A
2 weeks
24
Q
For pulmonary HTN what NYHA category are patients advised to have in flight O2 ?
A
NYHA III or IV
25
Should patients with lung cancer / mesothelioma fly if on chemo?
No, high risk of infection and side effects
26
What are the contraindications to air travel?
Untreated respiratory failure
PTX (unresolved)
Active infection (TB, COVID, MERS, SARS)
Bronchogenic cysts - cerebral air embolism following rupture risk
27
How do they perform a HCT?
Patient inspires gas mixture containing 15% oxygen
28
What type of drug is Tacrolimus?
Calcineurin Inhibitor
29
What type of drug is Ciclosporin?
Calcineurin Inhibitor
30
What type of drug is Azathioprine?
Purine synthase inhibitor
31
What type of drug is MMF?
Purine synthase inhibitor
32
What type of drug is Sirolimus inhibitor?
An mTOR inhibitor
(mTOR is the mammalian target of Rapamycin)
33
What type of drug is Everolimus inhibitor?
An mTOR inhibitor
(mTOR is the mammalian target of Rapamycin)
34
Who may be harmed by unecessary high O2?
CO2 retainers
MI (may increase infarct size)
Paraquat poisoning or Bleomycin lung injury
35
What FiO2 and flow rate is the blue Venturi ?
24% (2-3l/min)
36
What FiO2 and flow rate is the white Venturi ?
28% (4-6L/min)
37
What FiO2 and flow rate is the yellow Venturi ?
35% (8-12l/min)
38
What FiO2 and flow rate is the red Venturi ?
40% (10-15 l/min)
39
What FiO2 and flow rate is the green Venturi ?
60% (12-15l/min)
40
How often should O2 saturations be measured in hospital?
4 hourly
41
What do we do with target sats in COPD?
ABG, if normal then for normal targets UNLESS hx of previous hypercapnia
42
What can happen with sudden cessation of oxygen?
Rebound hypoxia with rapid fall in O2 sats
43
Above what BMI should we lower target saturations?
40
44
What are the equivalent sats of pO2 <7
<85%
45
Patient on immunosuppressant medications should avoid what vaccines ?
Need to avoid live vaccines :
Measles
Mumps
Rubella
BCG
Yellow Fever
Oral Polio
Oral Typhoid
46
Patients on immunosuppressive medication who have never had varicella zoster and are exposed should have ?
Immunoglobulin therapy
47
Patients on immunosuppressive medication who have never had measles and and are exposed should have ?
Immunoglobulin
48
What should be checked prior to starting and during AZT treatment ?
Prior to starting : FBC, LFT, TPMT
During treatment : FBC ever 2/52 for 3/12 and then monthly , monthly LFTs
49
At what parameters should AZT /MTX be held ?
WCC <3
PLT < 100
ALP / transaminases > x3
50
What % of patients have no TPMT activity and should therefore should avoid AZT ?
0.3%
51
What is Azathioprine ?
Pro-drug of 6-mecaptopurine
52
What are the side effects of AZT?
Sore mouth, mouth ulcers , nausea , vomiting , diarrhoea , skin rash , alopecia , incr risk of skin cancer
53
What should be checked prior to starting and during treatment with MTX?
FBC/ U&E/LFT
CXR
Folic Acid
Pregnancy
Avoid if significant hepatic or renal impairment or if ascites / pleural effusion as can accumulate
During :
Bloods every 2/52 for 3/52 and then monitoring
54
What are the side effects of MTX?
Mouth Ulcers, Skin rashes, nausea , macrocytosis , myelosuppression , pneumonitis
55
What should be checked prior to starting and during cyclophosphamide treatment ?
FBC /U&E/LFT
Urine Dip
Semen store
Pregnancy check - avoid & if BF (and for 6/12 after for both M & F)
Should have bloods weekly for 1 month then every 2 months
56
How long does cyclophosphamide take to work?
12-14/7 hence why usually combined with high dose steroids
57
What are the side effects of cyclophosphamide ?
Haemorrhagic cystitis , bladder cancer , nausea and vomiting , hair thinning , alopecia , cervical cancer
58
What should be checked prior to starting and during Rituximab treatment ?
FBC/U&E/LFT
Hep B and C
ECG
CXR
First week check FBC/ U&E/LFT and then weekly
Alternative to cyclophosphamide
59
Side effects of Rituximab
Abdominal pain; acne; alopecia; anaemia; anxiety; appetite decreased; arthralgia; asthenia; asthma; conjunctivitis; constipation; cough; cytokine release syndrome; depression; diarrhoea; dysphagia; ear pain; epistaxis; fever; gastrooesophageal reflux disease; headache; increased risk of infection; influenza like illness; infusion related reaction; leucopenia; lymphadenopathy; malaise; muscle complaints; muscle weakness; myocardial infarction; neutropenia; pain; pancytopenia; peripheral oedema; sensation abnormal; skin papilloma; stomatitis; sweat changes; throat irritation; thrombocytopenia; tremor; vomiting; weight decreased
60
What is the empey index?
The ratio of FEV1 (in ml) to PEFR (in L)
Useful in predicting if someone has upper airway obstruction , normal result is <10 and if >10 should prompt further evaluation
The PEFR is clipped first by the presence of upper airflow obstruction relative to the FEV2
61
Where are perfusion and ventilation greatest in the lungs ?
At the bases
62
What causes an increased DLCO?
Pulmonary haemorrhage
Polycythemia
Obesity
High altitude
Hyperthyroidism
AV malformations
63
What causes a decreased DLCO?
ILD
Emphysema
Severe anaemia
PE
Increased carboxyhaemoglobin
Hypothyroidism
CCF
Pneumonectomy
64
What is DLCO ?
The diffusing capacity for carbon monoxide and is the same as transfer factor for carbon monoxide. It is a measure of gas transfer from inspired air to the red blood cells . diseases that decrease blood flow to the lung or damage alveoli cause less efficient gas exchange resulting in lower DLCO
65
If the PaCO2 is normal the PaO2 for different FiO2 can be estimated how ?
FiO2 (%) x 0.75
66
In CPET what are indicators of a maximal test ?
- Respiratory Exchange Ratio (RER) > 1.1 (switch from aerobic to anaerobic)
- Low HRR (ie close to maximal HR)
- Rise in lactate
- Anaerobic threshold reached (if given as graph it’s where VCO2 raises faster than VO2)
67
What are the lung function changes seen in pregnancy?
Expiratory reserve volume decreased , FRC decreased , minute ventilation increased , TLC no change , arterial pCO2 decreased
68
What are the contraindications to CPET?
- Known history of exercise induced syncope or pre-syncope
- MSK problem limiting exercise
- ACS/MI within 7 days
- Unstable angina
- Poorly controlled HF
- Aortic dissection / Aneurysm
- Acute exacerbation of COPD/Asthma
- Severe Pulmonary HTN
- Resp failure pO2<8
- Acute PE
- Recent DVT
- Frailty
- Hx of seizures / syncope
69
Most common adverse event during CPET?
Vasovagal / dizzyness
70
What should VO2 max be in normal individuals in CPET?
>80% predicted
If > 80% predicted very unlikely that the individual has any significant pathology of heart or lungs (slight caveat with athletes but for purposes of exam)
71
What should HR be in normal individuals in CPET?
≥ 80% predicted maximal HR
(NB Maximal HR is 220 - age)
72
What should VE (minute ventilation) be in normal individuals in CPET?
Should not reach 80% of predicted during exercise (as should have ventilatory reserve, NB can be super maximal in athletes)
73
What is an abnormal fall of O2 sats in CPET?
A fall >4% from resting value is abnormal and implies lung issue, PVD or opening of R to L shunt
74
What is oxygen pulse ?
A non invasive CPET given idea of CO
75
What should oxygen pulse be in normal individuals in CPET?
>10ml/beat at peak exercise
76
What should AT (anaerobic threshold) be in normal individuals in CPET?
>40% of predicted VO max (NB predicted, not achieved)
77
If VO2 max is >80% predicted , how would you interpret the CPET?
Normal
78
If VO2 max is <80% predicted, max HR <80% predicted and VE max <80% predicted how would you interpret the CPET?
Submaximal effort
79
If VO2 max is <80% predicted, max HR <80% predicted and VE max >80% predicted how would you interpret the CPET
Lung disease
80
If VO2 max is <80% predicted, max HR >80% predicted and fall in O2 says >4% how would you interpret the CPET
Pulmonary vascular disease
81
If VO2 max is <80% predicted, max HR >80% predicted and fall in O2 says not less than 4% how would you interpret the CPET
Heart disease
Or
Deconditioning
82
What is the expected time length of CPET?
9 mins
83
What is chronotropic incompetence V
Inability of HR to increase the rate to commensurate with increased activity or demand,
84
What do we see on CPET demonstrating dysfunctional breathing ?
- Relatively well preserved /low/normal VO2 max
- Normal AT
- High erratic RER (Resp exchange Ratio> aerobic to anaerobic )
- Occ high resting HR that assumes normal chronotropic profile
85
What do we see on CPET demonstrating Deconditioning ?
- Low VO2 max (maybe within LLN)
- Low HRR
- High VE reserve
- Maximum O2 pulse at border of low/normal
- AT at 40-50% of predicted VO2 max
- Following should be normal: Sats, ECG , BP
86
What do we see on CPET demonstrating heart disease ?
- Low VO2 max
- Rapid early rise in HR
- Low HRR
- Flat O2 pulse with peak value below LLN
- Early <40% anabolic threshold at predicted VO2 max
- Abnormal BP (blunted systolic or very high BP rise)
87
What do we see on CPET in lung disease ?
- Low VO2 max
- High HRR (ventilation limitation has stopped exercise)
- Low VE reserve
- Desaturation
- High VECO2
88
What do we see on CPET demonstrating Pulmonary Vascular Disease ?
- Low VO2 max
- Low HRR and steep chronotropic profile
- Flat O2 pulse with low maximum value
- Low AT
- Desaturation +/- shunt open signal
89
What do we see on CPET demonstrating muscle disease ?
- Low VO2 max
- Early AT
- Early blood lactate rise with submaximal fixed work protocol
- steep chronotropic profile because of impaired peripheral O2 extraction
- Often low O2 pulse
90
What do we see on CPET demonstrating peripheral vascular disease?
- Low VO2 max
- High HRR
- High VE reserve
- Low AT
- Often heightened /exaggerated BP response
91
When should oxygen supplementation be used in bronchoscopy as per BTS guidelines ?
When desaturation > 4% or sats <90% and prolonged for >1 minute to reduce risk of hypoxaemic complications
92
What are the risk factors for hypoxaemic complications in bronchoscopy ?
Baseline arterial sats
Lung Function
Co-Morbidity
Sedation
Procedural sampling
93
What is the most common arrhythmia during bronchoscopy?
Sinus tachycardia and atrial / ventricular premature contraction
94
What is the risk of bleeding complications in bronchoscopy ?
Minor 0.19%
Severe 0.26%
95
How many days prior to bronch should Clipidogrel be held ?
7 days
96
What is the platelet cut off for bronch
BAL safe above >20 ; if biopsies speak to haem as may need transfusion prior
97
What is the risk of pneumothorax in bronch?
1 in 1000 (0.1%)
98
How long should bronch be delayed post MI?
4 weeks
99
What is the desired depth of sedation in bronchoscopy ?
Verbal contact possible at all times
100
Why is Midazolam preferred sedation agent in bronch?
Rapid onset of action, Required sedation depth , Reversible
101
How many mg of Midazolam drawn up for <70 and > 70?
< 70 years : 5 mg
> 70 years : 2 mg
To prevent inadvertent over sedation
102
Which opioids are preferred in bronchoscopy ?
Fentanyl or alfentanyl
103
When used in combination, should BDz or opioid be used first for bronchoscopy ?
Opioid should be given first
104
What is the maximum dose of local anaesthetic for bronchoscopy ?
15.4mg/kg ; but often sx ≥ 9.6mg/kg
105
What should be the diagnostic accuracy when comes to sampling visible endobronchial tumours ?
85%
106
How many biopsy samples should be taken from each site ?
5 ; plus brush and wash to increase yield
107
Investigations for invasive aspergillosis in bronch?
BAL Galactomannan
Microscopy for hyphae and fungal culture
Try to avoid TBLB and EBB
108
What are the issues with BAL in tubed ICU patients ?
Post BAL worse O2 sats with change in lung compliance, mPAP and increased pCO2
Ideally take blind catheter aspirations first and if not getting answer from that then bronch
109
What is used to disinfect bronchs?
Automated Endoscopic Reprocessor
110
What are the rules for bronch re NBM?
No food 4 hours before; clear fluid upto 2 hours before
111
What are the rules post procedure for bronch/EBUS with sedation?
Not to drive
Not to operate heavy machinery
Not to sign any legally binding documents
For 24 hours
112
What diseases causes random nodules in the lungs ?
Mets
Miliary TB
LCH
113
What diseases causes perilyhphatic nodules in the lungs ?
Sarcoid
Lymphangitic Carcinomatosis
Pneumoconiosis
Asbestosis
Silicosis
114
What diseases cause centrilobular nodules in the lungs ?
HSP
Bronchoalveolar Carcinoma
RB-ILD
115
What are the constrictions to spirometry?
Haemoptysis
Pneumothorax
CDV disease (recent MI, PE, Aneurysm , Unstable CDV status)
Nausea or vomiting
Recent chest / abdo / eye surgery
116
What are the common side effects of spirometry?
Usually well tolerated but can cause transient headache or pain in the chest
Dizzyness, cough, occ syncope
Major complication is bronchospasm during
117
Can we perform spirometry in acute respiratory infection?
In principle yes but the acute infection will affect the results and therefore rarely useful
118
What is the standard way to perform spirometry?
Seated (normal values based on seated position and high intrathoracic pressures may cause patients to pass out, so sitting is safer)
Best of 3 blows , required to demonstrate maximal blow has been consistently achieved seeing two identical tracings where 2 best blows have FEV1 and FVC within 150mls of each other
119
With LLN calculations for spirometry what parameters are included in calculation?
Age, Gender , Ethnicity and Height
120
What is the z score in spirometry ?
Another way of describing LLN is the Z score or the standard score
Z score is the number of standard deviations a certain value is above the mean value of a data set
Spirometric value is considered too low if more than -1.64 standard deviations from the predicted value
121
What is the LLN on spirometry?
The lower 5th percentile of the Gaussian bell curve: 95% of healthy people can blow better than the LLN
122
What causes variable extra thoracic obstruction?
Vocal cord palsy
Extra thoracic goitre
Laryngeal tumour
123
Why do we get the characteristic flattening of inspiratory limb with variable extrathoracic obstruction?
• Typically the expiratory part of the Flow Volume loop is normal: the obstruction is forced outwards by the force of the expiration
• During inspiration the obstruction is sucked into the trachea with partial obstruction and flattening of the inspiratory limb of the flow volume loop
124
What causes variable intrathoracic compression?
Tumour located near the bottom thoracic part of the trachea as it is sucked outwards during inspiration
125
What causes the characteristic flattening of the expiratory limb in variable intrathoracic obstruction?
• A tumour located near the intrathoracic part of the trachea is sucked outwards during inspiration with a normal morphology of the inspiratory limb of the Flow Volume loop
• During expiration the tumour is pushed into the trachea with partial obstruction and flattening of the inspiratory limb
126
What causes fixed large airway obstruction?
Tracheal stenosis caused by intubation or circular tracheal tumour
127
Why might patients not be able to produce reproducible flow volume loops ?
- Poor understanding
- Bad Co-ordination
- Exercise Induced Asthma (forced manoeuvre of the FVC can cause asthma attach in active patients , therefore subsequent flow volume loops worse)
128
What is the simplest test for respiratory muscle weakness in clinic ?
Lying and standing VC
If the diaphragm is paralysed then on lying down the abdominal contents will push the diaphragm up and limit inspiration, on standing the abdominal contents drop and aid inspiration
129
What is an abnormal fall in VC?
>20% fall in VC when lying down , suggests significant, usually bilateral diaphragm weakness
10-20% suspicious for diaphragm weakness
<10% fall is normal
130
What is a normal SNIP (Sniff Nasal Inspiratory Pressure)?
>70cmH20 Men; > 60cmH20 women
131
What is the calculation for TCLO?
TLCO = VA x KCO
132
What does TLCO measure ?
The amount of gas exchanging surface available
TLCO - Total amount of CO transferred
KCO- when divided by total lung voulme
133
How is TLCO calculated ?
Gas mixture containing diffuser tracer (usually Carbon Monoxide) and a mixing tracer (for example helium) is inhaled using a single breath technique and following maximal inspiration subject holds breath for 10 secs then exhales
Amount of CO that has disappeared (by crossing the alveolar capillary membrane and being taken up by red cells) is calculated
134
What happens to TLCO and KCO in emphysema and why?
Both reduced
Alveoli have been destroyed
135
What happens to TLCO and KCO in ILD and why?
Both reduced
Alveolar capillary membrane is thick, reducing CO passage (NB in early disease KCO will likely be normal)
136
What happens to TLCO and KCO in weak respiratory muscles and why?
TLCO - Normal
KCO- Raised
Lungs poorly expanded and so more “concentrated” and transfers CO better when quoted per unit volume
137
What happens to TLCO and KCO in pulmonary haemorrhage and why?
Both raised (for a few days)
Free red cells lining the alveoli take up the CO directly and falsely elevate the figure . As Hb is broken down KCO returns to normal unless there is another bleed
138
What happens to TLCO and KCO in pneumonectomy and why?
TLCO reduced
KCO increased
More “concentrated”
139
How do we calculate RV?
FRC- ERV
140
How do we calculate TLC?
RV + VC
141
How does body pleythsmography work?
Subject makes inspiratory effort against closed mouthpiece this leads to decreased intrathoracic pressure and lung expands pushing chest wall out
In turn this compresses the gas in closed box and the pressure changes in the box and at the mouthpiece (which equate to changes in alveolar pressure can then be used to calculate the unknown volume of the lung or FRC
142
How do you detect the PTX/ bullae volumes on lung volume assessment?
The difference between the pleythsmographic lung volume and helium dilution lung volume
143
What is sensitivity ?
How often the test is positive if the patient has disease
A/ A + C
144
What is specificity ?
How often test is negative if patient is healthy
D/ D+B
145
What is Positive Predictive Value (PPV)?
Likelihood patient has disease if test is positive
A/ A+B
146
What is Negative Predictive Value (NPV) ?
Likelihood patient doesn’t have disease if test is -ve
D / (D+C)
147
What is likelihood ratio?
likelihood that a given test result would be expected in a patient with the target disorder compared to the likelihood that that same result would be expected in a patient without the target disorder
Sensitivity / (1- Specificity)
148
What are the variables in Qualitative Data?
Binary /Nominal
Ordinal (ie mild / mod/severe)
149
What are the variables in quantitative data?
Discrete (ie no of vaccines)
Continuous ( ie height , weight , lung function)
150
What is the mode ?
Most frequently occurring value in a data set
151
What is the median ?
The middle value when data put in ascending order
152
What are quantiles ?
Divides dataset into intervals with specified probabilities. Commonest quantile include the median (2nd quantile ) and Q1 and Q3
153
What is the mean?
Sum of all the variables divided by number of observation
154
What are measures of centrality ?
Mode, Median , Quantiles, Range
155
If significant extremes in data set what is the most robust assessment of centrality ?
Median
156
What measures of centrality can we use in Quantitative , Binary and Ordinal data sets?
Quantative : All
Binary: Mode
Ordinal: Mode and median
157
What are measure of variability we can use ?
Range , IQR , SD
158
What is the range?
Max - Min
159
What is IQR?
Range between 1st and 3rd quartile , representing middle 50%
160
What is confidence interval ?
The evaluation of a parameter of a population by computing an interval range within which parameter variable likely to lie
161
What is the null hypothesis ?
The default assumption that there is no significant difference or effect
162
What is the alternate hypothesis?
The hypothesis researchers aim to support
163
What is the P value?
The probability of obtaining observed results (or more extreme) if the null hypothesis is true ; if P< significance level (0.05) we reject the null hypothesis
164
What is a type 1 error ?
False positive (incorrectly rejecting the null hypothesis )
165
What is Type II error?
False -ve (failing to reject a false null hypothesis )
166
For normally distributed data sets what hypothesis tests can we use ?
Z test and T test : comparing means between 2 groups (ie BP pre and post treatment) ; if <30 sample size T test better
Chi Squared test: assess association between categorical variables ( and also compare properties) ie investigating relationship between smoking and development of specific health conditions
ANOVA (Analysis of Variance) - comparing means of 3 or more groups ie comparing effect of different drug dosages on pain relief
167
What are the non parametric tests we can use if not normally distributed ?
Mann Whitney U test - comparing 2 groups
Wilcoxon Signed Rank test (compare 2 groups where same ie before and after tx)
Kruskal Wallis Test (if multiple groups)
Friedman test (repeated measures)
168
What does correlation mean and how do we rank it ?
Strength of relationship between two variables
0-0.25 Little or no relationship
0.25-0.5 Fair
0.5-0.75 Moderate
0.75- 1 Strong
1 : Perfect correlation
169
What can we use to assess correlation?
Pearson Correlation Coefficient - linear association between 2 continuous variables
Spearman’s rank - measures monotonic association between variables (not necessarily linear) suitable for ordinal or ranked data
170
How do you calculate AA gradient ?
FiO2 - (pCO2x 1.25) - pO2
171
What is normal AA gradient ?
<2 kPa
172
Outline coal workers pneumoconiosis
Simple Pneumoconiosios - regional LN blackened
With cont exposure get :
PMF- aggregation of the fibrotic nodules to form larger 2-10cm, “black scar”
Clinically - cough productive of mucoid or blackened sputum and SOBOE. No crepitations
173
What do you see on HRCT for pneumoconiosis ?
Simple- parenchymal nodule 1-10mm with upper zone predominance
PMF- nodules >1cm with irregular borders and associated parenchymal and distal emphysema
174
How do you manage pneumoconiosis ?
Minimise exposure
Industrial Benefits
NB - no incr risk of lung cancer with simple pneumoconiosis or PMF
175
What is Caplan’s Syndrome?
Seropositive RA (or RhF +ve) and pneumoconiosis - can occur with low exposure
176
Outline the other pneumoconioses
Iron - Siderosis
Barium - Baritosis
Tin- Stannosis
Aluminum -like silicosis
177
Outline silicosis
Caused by inhalation of silica particles - Quartz and Cristobalite forms
Very long lag time between exposure and clinical disease ; 10-30 years
Insidious and progressive onset
Acute /Sub-Acute/Chronic /Silicotuberculosis
Tx: All about prevention ; incr risk of cancer
178
What are the image changes seen with Silicosis ?
Acute : CXR - patchy bilateral lower airspace consolidation ; HRCT- irregular fibrosis
Subacute: CXR upper and mid nodules 3-5mm , can progressive to PMF; eggshell calcification and BHL
Chronic- fewer upper and mid zones nodules with hilar lymphadenopathy
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Outline Berylliosis
Caused by Beryllium - fluorescent lights /aviation
Acute Beryllium Disease - acute alveolitis , widespread oedema / pulmonary oedema . Steroids may prevent progression.
Subacute and Chronic Berylliosis - delayed hypersensitivity reaction can be clinically indistinguishable from sarcoid
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What are the image changes in Berylliosis ?
CXR: Fine reticulonodular shadowing UL, Hilar lymphadenopathy
HRCT- subpleural micronodular change, thickened interlobular spare , traction bronchiectasis and honeycombing . May be ground glass shadowing
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What is the key ix for Berylliosis?
Beryllium Lymphocyte Proliferation test - Blood or BAL
NB on BAL will get non caseating granulomas
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What is the management for Berylliosis?
Steroids
Associated with delayed skin sensitivity to Tuberculin, granulomas don’t always resolve
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What are pneumoconioses?
Non neoplastic pulmonary diseases caused by the reaction of the lung to mainly mineral but also organic dusts
<5 microns reach the terminal airways of the alveoli and settle on epithelial layer of lung
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What drugs reduce theophylline levels
Carbamazepine
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What drugs increase theophylline levels ?
BB
Clarithromycin
Ciprofloxacin
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In health where are majority of eosinophils ?
90% GIT
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Outline Lofflers (Simple Pulmonary Eosinophilia)
- Caused by ASCARIS LUMBRICOIDES but also strongyloides and hookworm
- Occurs worldwide but particularly SE Asia , Africa , Central and South America
- CXR shows transient bilateral shadowing - disappears 6-12/7 can take a month
- Sputum contains Eos and Hyphae ; stool will reveal but only 2-3 months after , blood Eos not raised
Tx: Antihelminth agent : Albendazole or Mebendazole for 3 days ; may need steroids if pulmonary manifestation severe
*ACUTE, Perihilar on CT , Sinus and stool involvement
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Outline Tropical Pulmonary Eosinophilia
- Hypersensitivity to migrating larvae of filiarial worms - WUCHERIA BANCROFTI
- Occurs in India / Pacific
- May get cavitation and pleural effusion
- Sputum and BAL see Eos , blood Eos raised
Tx- Filaricide diethylcarbamazine for 3/52
** Indolent ; Cavities on CT
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Outline drug induced pulmonary eosinophilia
Shadowing within hours of starting drug and resolves within 1 week of stopping
Essentially an allergic reaction of the pulmonary vessel wall can be associated with a skin reaction, avoid the drug in future and give steroids if needed
Severity ranges from mild to severe
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What drugs cause drug induced pulmonary eosinophilia ?
Penicillin, Phenytoin
Carbamazepine , Cocaine
NSAIDs, Nitrofurantoin , Tetracycline , Methotrexate
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Outline Chronic Eosinophilic Pneumonia
Unknown cause ; 2:1 F:M
Insiduous onset ; dx usually clinical and radiological but may need BAL
Peripheral dense opacities on CT
Have sputum eosinophilia and BAL high Eos , may not have blood eosinophilia
Tx : Steroids - should improve quickly
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Outline acute eosinophilic pneumonia
Unknown cause ; any age /sex
Diagnostic Criteria:
- Acute febrile illness <7 days
- Hypoxic resp failure
- Interstitial or alveolar CXR infiltrates
- BAL Eos >25%
- No parasitic /fungal / other infection
- Prompt and complete response to steroids
- Failure to relapse after completing steroids
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Outline Hypereosinophilic Syndrome
Rare , common around 30-40 years
Fever , WL, cough , pruritius
Dx:
- Marked eosinophilia >1.5
- Signs /sx of eosinophilic tissue infiltration
- No evidence of another cause of eosinophilia
Get pulmonary involvement with interstitial infiltrates and effusions ; can get CDV involvement with myocarditis or cardiomyopathy ; skin - urticaria , GIT, alcohol intolerance ; Hepato/Splenomegaly
Can be fatal
IgE often high
Tx - High dose steroids
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When should NIV be started in MND when acutely unwell
If VC <1L and RR > 20
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What are the absolute contraindications to NIV?
Severe facial deformity
Facial Burns
Fixed upper airway obstruction
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What are the relative contraindications to NIV?
pH <7.15
GCS <8
Confusion/agitation
Cognitive impairment
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What is morbidity /mortality associated with bronch?
1.1% serious complications
0.02% mortality
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When should O2 supplementation be used in bronchoscopy?
When detect a desaturation of >4% for more than 1 minute
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What is significant pCO2 rise with LTOT?
> 1kPa of pCO2 or develop acidosis ; may have clinically unstable disease if so further medical optimisation needed and reassess 4 weeks. I’d have on 2 separate occasions when clinically stable should only have domicillary oxygen in conjunction with nocturnal ventilatory support
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What is the pO2 aim with LTOT?
Greater than or equal to 8
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What should non hypercapnic patients do during sleep?
Increase flow rate by 1L/min
