4-Pulmonary Function Tests

Question 1

physiologic dead space is = to

Answer 1

VD = anatomic dead space + functional dead space

physiologic dead space = volume of conducting airways + alveoli that not participate in gas xchange

Question 2

minute ventilation

Answer 2

total rate of air movement into/out of lungs

= tidal volume x respiration rate

Question 3

alveolar minute ventilation

Answer 3

rate that new air reaches the gas exchange areas of lungs

= respiration rate x (tital vol - dead space)

Question 4

effects on alveolar minute ventilation

Answer 4

inc respiration rate and dec tidal vol = greater proportion of alveolar ventilation contributing to dead space

inc tidal vol greater effect that respiration rate

Question 5

spirometry

Answer 5

measure lung volumes and air flow
-shown on a graph, slope = airflow

need other tests for helium dilution, whole body plethysmograph, esophageal balloon

Question 6

imaging

Answer 6

1. ventilation perfusion lung scan for detecting embolisms
2. chest x ray

Question 7

forced vital capacity

Answer 7

total vol that can be forcibly expired after maximal inspiration

Question 8

lung volume differences in obstructive vs restrictive

Answer 8

restricted = dec all lung vols
obstructive = inc in TLC, inc residual, inc FRC

Question 9

spirometry analysis of obstructive

Answer 9

graph can show flat inspiratory cuve, flat expiratory, or both
-if upper airway obstruct then variable or fixed

common causes are tumors and fibrotic structures

Question 10

spirometry analysis of restrictive

Answer 10

lung vols are lower in general
-dec vital capacity, IC, lower RV/ERV/FRC

looks like an orange slice

Question 11

evaluating FEV1 and FVC

Answer 11

normal ratio = 0.8
obstruct = FEV1 < FVC so dec ratio <0.7
restrict = FEV1 > FVC so ratio inc