Resp Physiology

Question 1

PPO FEV1 or DLCO anatomic method

Answer 1

PPO FEV1 [or DLCO]= preoperative FEV1 [or DLCO] x (1-y/z)

Question 2

PPO FEV1 or DLCO perfusion method

Answer 2

PPO FEV1 [or DLCO]= preoperative FEV1 [or DLCO] x(1- fraction of total perfusion to resected lung)

Question 3

Algorithm for consideration for pneumonectomy or lobectomy

Answer 3

1. FEV1 and DLCO >60%- no further physiologic stratification required–> low risk
2. FEV1 or DLCO <30%–> CPET to determine VO2 max to further stratify
3. If FEV1 or DLCO 60-30%- low technology activity test (stair climb or shuttle-walk)
   - Stair climb <73ft/22m or 400m in shuttle walk–> CEPET

• VO2 max <10mL/kg/min or 35% predicted is high risk
• VO2 max 10-20 or 35-75% is moderate risk
• VO2 max ?20ml/kg/min or >75% is low risk

Question 4

Central respiratory centers (and location)

Answer 4

1. Dorsal Respiratory Group (medulla)
2. Ventral respiratory group (medulla)
3. Apneustic Center (lower pons)
4. Pontine respiratory group (upper pons)

Question 5

This is the pacemaker of the respiratory system

Answer 5

Pre-Botzinger complex

Question 6

Location of “fine-tuning” breathing pattern

Answer 6

pontine respiratory group (upper pons)

Question 7

1. Central chemoreceptors respond to?

2. Peripheral chemoreceptors respond to?

Answer 7

1. pH, pCO2

2. pH, pCO2, pO2 (carotid»aortic)

Question 8

Appropriate Compensation for Acid Base disorder

1. Met acidosis
2. Met alkalosis
3. Resp Acidosis
4. Resp Alkalosis

Answer 8

Metabolic acidosis: Winter’s Formula- pCO2=1.5 (bicarb) +8 +/- 2
Met alk: change in pCO2= 0.6 x (change in bicarb) +/- 2
Resp acidosis: increase pCO2 by 10 results in –>inc of bicarb by 1 (acute) or 4 (chronic)
Resp alkalosis: dec of pCO2 by 10 results in–> dec of bicarb by 2 (acute) or 4 (chronic)

Question 9

Accetability Criteria

Answer 9

1. Sharp takeoff, extrapolated volume <5%, FVC 0.15L
2. Plateau on volume-time-curve
3. Exhalation >6s
4. No artifacts (cough, glottis closure, leak)

Question 10

Reproducibility Criteria

Answer 10

1. 3 acceptable spirograms

2. 2 largest FVC within 0.15L of each other

Question 11

MVV:

• Calculation
• Uses

Answer 11

1. MVV= FEV1 x40 (expressed as L/min)

2. Disprop decrease in MVV compared to FEV1 can indicate NM disease or upper airway obstruction

Question 12

Absolute contra-indication to methacholine challenge test:

Answer 12

1. Severe obstruction (FEV1 <50)
2. MI or CVA within 3 months
3. Uncontrolled HTN (>200/>100)
4. Known aortic aneurysm

Question 13

Medications Withheld before Methacholine Challenge:

Answer 13

SABA- 8hr
SAMA- 24hr
LABA- 48hr
LAMA- 7d
Theophylline 24-48h

Question 14

O2 pulse (Oxygen Pulse)

Answer 14

VO2/HR

Question 15

Acceptability of DLCO

Answer 15

1. Inspired volume (Vi) >90% largest VC
   or
   Vi >85% of largest VC AND VA within 200mL or 5% of largest VA from other maneuvers
2. 85% of test gas Vi inhaled in <4sec
3. stable calculated breath hold for 10 +/- 2 secs
4. No evidence of leaks, Valsalva, or Mueller maneuvers
5. collection completed within 4 secs of start exhalation

Question 16

Repeatability of DLCO

Answer 16

at least 2 acceptable maneuvers within 2mL/min/mmHg of each other

Question 17

GLI

Answer 17

global multi-ethnic reference equations of spirometry that span all ages (3-95)
-to predict predicted, ULN, LLN

Better taller, shorter, extremes of age

Question 18

Spirometry of Acceptability

Answer 18

1. Free from artifacts (no cough first sec, glottic closure, early termination)
2. Efforts have good start (<0.15L or <5% of total FVC)
3. duration >6sec or plateau in volume-time curve

3 acceptable maneuvers

Question 19

Repeatability of spirometry

Answer 19

1. 3 acceptable spirograms (take up to 8). 2 largest values for FEV1 and FVC are within 0.15L of each other
2. continued if 2 largest values for both FEV1 and FVC are not within 0.15L

Question 20

Minimally clinically significant difference in 6MWT

Answer 20

30m