Phy-shit-ology

Question 1

Does the M1 muscarinic receptor cause bronchoconstriction or bronchodilation and name a drug that acts on this receptor.

Answer 1

Bronchoconstriction - facilitates ganglionic transmission

Ipratropium - antagonist

Question 2

Does the M2 muscarinic receptor cause bronchoconstriction or bronchodilation and name a drug that acts on this receptor.**

Answer 2

**Bronchoconstriction by inhibiting adenylyl cyclase (which inhibits relaxation)
Methacholine - agonist

**This answer was debated

Question 3

Does the M3 muscarinic receptor cause bronchoconstriction or bronchodilation and name a drug that acts on this receptor.

Answer 3

Bronchoconstriction -

Tiotropium - antagonist

Question 4

What are GIVE the negative effects of high PEEP on the cardiorespiratory system?

Answer 4

1. Increased pulmonary vascular resistance
2. Decreased venous return
3. Overdistention of normal alveoli with increased capillary resistance and redistribution of blood flow to other regions thereby worsening VQ mismatch/hypoxemia
4. Reduced cardiac output/sBP and oxygen delivery
5. Can exacerbate right to left shunt with increased PVR

Question 5

What is the formula for deadspace ventilation?

Answer 5

VD/VT = (PACO2 - PECO2)/PACO2

Question 6

What is the formula for deadspace VOLUME?

Answer 6

VD = VT((PACO2-PECO2)/PACO2)

Question 7

What are four methods of obtaining the AT on CPET?

Answer 7

1. V-slope
2. Ventilatory equivalents
3. Respiratory exchange ratio
4. Direct measurement measurement of Lactate

Question 8

What are the PFT “end of test criteria” as per ATS 2019 Guidelines? (Danica)

Answer 8

One of three:

1.

Question 9

Where in the bronchial tree is the highest resistance?

Answer 9

5-7th generation

Question 10

MIF50/MEF50 in fixed extrathoracic obstruction?

Answer 10

~1

Question 11

MIF50/MEF50 in variable extrathoracic obstruction?

Answer 11

<1

Question 12

MIF50/MEF50 in variable intrathoracic obstruction?

Answer 12

> 1

Question 13

What is the normal VD/VT at rest?

Answer 13

0.3-0.4

Question 14

What is the normal VD/VT with exercise?

Answer 14

Normal is decrease to 0.1 to 0.15 because VD increases by 150 - 200 cc but overall, VT &raquo_space;> VD

Question 15

CPET: What are three diseases that decrease O2 pulse?

Answer 15

Surrogate for stroke volume

CHF, pulmonary vascular disease, deconditioning

NB: Not valid if significant desaturation or impaired skeletal muscle extraction (based on Fick equation)

Question 16

What are the determinants of ventilation distribution?

Answer 16

West zones/gravity/positioning
Number of alveolar segments
Lung compliance
Airway resistance

Question 17

Why is helium used for DLCO?

Answer 17

Freely distributed throughout the alveolar space

Doesn’t cross the alveolar-capillary membrane nor bind to Hb

Question 18

What makes DLCO vary in a healthy individual?

Answer 18

Ambient temperature
Barometric pressure
Humidity
Effort
Exercise
Valsalva maneuver
Supine position
Recent smoking
NOT inhalers (per new 2017 guidelines)

Question 19

List 6 Acceptability Criteria for FVC

Answer 19

Must meet one of 3 End of forced expiration criteria
Back extrapolated volume < 5% or 100ml
No leak
no Obstructed mouth piece
No glottic closure in 1st sec Expiration
No glottic closure after 1st sec

Other acceptable
No faulty zero flow setting

Question 20

List 2 Repeatability criteria for PFT

Answer 20

The difference between the two largest FVC values is less than 150ml
the difference between the two largest FEV1 is Less than 150ml

Question 21

List 6 contraindications to spirometry

Answer 21

1. MI<1 week
2. Eye surgery <1 week
3. Cerebral Aneurysm
4. Pneumothorax
5. Active TB
6. Uncontrolled systemic hypertension

Question 22

Four activities to avoid prior to spirometry

Answer 22

Smoking within 1 hr
Exercise within 1 hour
Alcohol within 8 hrs
Tight clothing