MKSAP 1: Pulmonary Diagnostic Tests

Question 1

What are the important points to remember in terms of spirometry that is dependable and reproducible? What 2 values are generally used? How are normal reference ranges determined?

Answer 1

The results of spirometry are highly dependent on patient technique and patient effort. Sitting upright, , head erect and mouthpiece tightly between lips. 2 largest volumes within 150mL of each other should be used.
Normals are dependent on age, gender, height and race

Question 2

What ratio do we care about and what value indicates obstruction?

Answer 2

FEV1/FVC, less than 70% indicates obstruction

Question 3

Name the ranges of FEV1 and how we determine degree of obstruction

Answer 3

FEV1 50-80%: moderately reduced
34-49%: severely reduced
<34%: very severely reduced

Question 4

What is considered a positive bronchodilator response?

Answer 4

an increase in FEV1 of 12% AND at least 200mL

Question 5

What is the pattern consistent with if the FEV1 and FVC are reduced proportionally and below predicted normal values

Answer 5

Restrictive defect

Question 6

What is the typical protocol for bronchial challenge testing?

Answer 6

the provocative dose 20% is the dose of methacholine that causes a significant drop in the FEV1 of 20% or greater; similar principles apply to other forms such as after cold air or exercise

Question 7

DLCO is a measure of what in terms of lung function?
Disorders that elevate DLCO?
Disorders that reduce DLCO?

Answer 7

DLCO is a measure of the capacity for gas transfer through the alveolar capillary membrane.
Disorders that recruit blood to the alveoli: cardiac shunt, asthma, erythrocytosis, alveolar hemorrhage
Disorders that decrease permeability or interfere with gas exchange: parenchymal or interstitial processes, COPD

Question 8

What is recorded in a 6MWT and how is it used?

Answer 8

Oxygen sat, HR, dyspnea, fatigue level and distance walked in 6 minutes.

Question 9

What clinical condition is pulse oximetry falsely elevated? How can this be overcome?

Answer 9

High levels of carboxyhemoglobin in CO poisoning.

Co-oximetry is then used and the preferred test

Question 10

What conditions are primary assessed for the following type of CT chest imaging:?

Answer 10

CT with contrast: evaluate mediastinal structures, assess lymphadenopathy
HRCT: diffuse parenchymal lung disease
CTA: pulmonary embolus or dissection
Low dose CT: lung nodule surveillance

Question 11

What size do lung nodules need to be in order to be accurately detected as malignant on FDG?

Answer 11

As long as nodule is 1cm or larger