Miscellaneous

Question 1

How do you calculate a normal A-a Gradient for an individual?

Answer 1

(Age/4) + 4

Question 2

What is the calculation for A-a gradient?

Answer 2

A-a = [FiO2*(Patm - PH2O) - PaCO2/R)] - PaO2

Where:
FiO2* (Patm-PH2O) = 150
AND
R = 0.8

Question 3

What are two general categories that cause a normal A-a gradient?

Answer 3

Normal A-a = Normal gas exchange.

1) Hypoventilation
(2) Low Inspired O2 (altitude

Question 4

What are the 3 general categories that cause a widened A-a gradient?

Answer 4

(1) V/Q Mismatch
(2) Shunt
(3) Diffusion Abnormality (ILD)

Question 5

How do you tell the difference between V/Q mismatch and shunt?

Answer 5

A V/Q mismatch improves with 100% FiO2 whereas a shunt will not completely improve.

Question 6

What are the requirements for home oxygen in Ontario?

Answer 6

(1) PaO2 < 55
(2) SaO2 < 88%
(3) PaO2 55-59 WITH
- Cor pulmonale
- pulmonary HTN
- Persistent Erythrocytosis

Question 7

What is the metabolic compensation for acute respiratory acidosis?

Answer 7

For every 10 rise in CO2, there is a rise in HCO3 by 1.

Question 8

What is the expected metabolic compensation for chronic respiratory acidosis?

Answer 8

For every 10 point increase in PaCO2, we expect at 3-4 point rise in HCO3

Question 9

What is the expected metabolic compensation in acute respiratory alkalosis?

Answer 9

For every 10 point fall in CO2, we expect a fall in HCO3 by 2

Question 10

What is the expected metabolic compensation in chronic respiratory alkalosis?

Answer 10

For every 10 point fall in PaCO2, we expect HCO3 to fall by 5.

Question 11

What is the definition of massive hemoptysis?

Answer 11

Variable ~200-600 cc/24 hours

Question 12

When do solid lung nodules < 6 mm need follow up?

Answer 12

ONLY if the patient is high risk, should do a follow up CT at 12 months if single or multiple nodules

Question 13

For multiple solid lung nodules > 6 mm, what is the recommended follow up?

Answer 13

CT at 3-6 months, then (“consider of for low risk”) at 18-24 months for all.

Question 14

What are the follow up recommendations for SINGLE lung nodules that are 6-8mm in size?

Answer 14

CT at 6-12 months in both high and low risk patients, then a CT in follow up at 18-24 months (“consider in low risk”)

Question 15

How do you follow up solid lung nodules > 8 mm in size?

Answer 15

Consider CT at 3 months, PET/CT or tissue sampling.

Question 16

What are the follow up recommendations for a ground glass nodule seen on imaging?

Answer 16

< 6 mm - NO routine follow up

> 6 mm - CT at 6-12 months, then CT every 2 years until 5 years (or resolved)

Question 17

How do you follow up a partially solid single lung nodule?

Answer 17

< 6mm - No routine follow up

> 6 mm - CT at 3-6 months, then annual CT x 5 years

Question 18

How do you follow up multiple sub solid lung nodules?

Answer 18

< 6 mm CT at 3-6 months - if stable then consider at 2 and 4 years.
> 6 mm - CT in 3-6 months, with subsequent management based on the most suspicious nodules.

Question 19

What are the features of NSIP on CT?

Answer 19

Ground Glass
Reticulation
Traction Bronchiectasis

** Lack of honeycombing**