Resp Tests

Question 1

What are the uses of pulmonary function tests?

Answer 1

the tests look at how:
-much air lungs can hold
-quickly air can move in and out of lungs
-well the lungs put O2 into and remove CO2 from the blood

Question 2

Differentiate between the different lung volumes.

Answer 2

tidal volume (TV):
-air exhaled during normal respiration
inspiratory reserve volume (IRV):
-maximum air inhaled above TV
expiratory reserve volume (ERV)
-maximum air exhaled below TV
residual volume (RV):
-volume of air remaining after maximal expiration

Question 3

What is the total lung capacity?

Answer 3

sum of all 4 volumes (TV, IRV, ERV, RV)
total volume of air in the lungs at maximal inspiration

Question 4

What is the functional residual capacity?

Answer 4

volume of air in the lungs at the end of normal expiration

Question 5

What is the vital capacity?

Answer 5

total volume of air exhaled after maximal inhalation

Question 6

What is the FEV1?

Answer 6

forced expiratory volume in 1 second
-patient inspires to TLC and exhales maximally
-volume of air exhaled in first second=FEV1

Question 7

What is FEV1 the best measure for?

Answer 7

assessing severity of airflow obstruction

Question 8

What is the FVC?

Answer 8

forced vital capacity
-total volume of air expired as rapidly as possible from TLC

Question 9

What is the use of the FEV1/FVC ratio?

Answer 9

differentiate between restrictive from obstructive lung disease

Question 10

What are the airflow measures?

Answer 10

FEV1
FVC
FEV1/FVC ratio

Question 11

What are the many uses of spirometry?

Answer 11

diagnosing lung disease & assessing severity
measuring the effect of a disease on lung function
monitoring course of disease or result of therapeutic intervention
assessing surgical risk
assessing prognosis for pulmonary conditions
pre-employment screening and surveillance of employees
assessing the potential effects of environmental lung disease

Question 12

Briefly describe how spirometry is performed.

Answer 12

patient takes the deepest breath they can
then exhale into the sensor as hard possible, for as long as possible, preferably for at least 6 seconds

Question 13

What are the important indices measured with spirometry? What are the results of spirometry compared to?

Answer 13

FEV1, FVC, FEV1/FVC ratio
compared to personal best, and predicted normal

Question 14

What is the most accurate test for predicting and measuring lung disease?

Answer 14

spirometry

Question 15

What are the limitations of spirometry?

Answer 15

requires full cooperation of the patient
CI: increased intracranial or intraocular pressure, increased intrathoracic and intrabdominal pressure, increased myocardial demand or changes in bp, risk of infection

Question 16

Differentiate between obstructive and restrictive lung disease.

Answer 16

obstructive:
-inability to get air out of the lung
-FEV1/FVC ratio=decreased
restrictive:
-inability to get air in the lung and maintain normal lung volumes
-FEV1/FVC=normal or maybe increased

Question 17

How do we determine reversibility of airway obstruction?

Answer 17

PFTs are repeated 10-15min after administration of inhaled B2 agonist (salbutamol)
increase of FEV1 of 12% after an inhaled agonist=acute bronchodilator response

Question 18

Describe peak expiratory flow rate.

Answer 18

measured with a portable peak flow meter
maximal flow rate that can be produced during forced expiration (L/min, L/sec)
results are compared to PB or predicted values
requires maximum patient effort
intended for patient self-monitoring once diagnosis is established

Question 19

Describe carbon monoxide diffusing capacity.

Answer 19

measurement of the ability of carbon monoxide to diffuse across the alveolar-capillary membrane
two methods: steady state, single breath or breath-holding

Question 20

What is a scenario where the carbon monoxide diffusing capacity will be reduced?

Answer 20

clinical situations where gas transfer from the alveoli to capillary blood is impaired

Question 21

What is pulse oximetry?

Answer 21

utilizes light absorptive characteristics of hemoglobin and the pulsating nature of blood to aid in determining oxygenation status

Question 22

What do arterial blood gases reflect?

Answer 22

how well the lungs are oxygenating the blood and are useful to assess acid-base status
-critically ill patients, effectiveness of therapy, titrate oxygen flow rates, assess patient for home oxygen

Question 23

Differentiate PaCO2 and PaO2.

Answer 23

PaCO2: pressure/tension exerted by CO2 in the blood
PaO2: level of oxygenation of arterial blood

Question 24

How do we interpret acid-base disturbances?

Answer 24

1. check the pH (indicates if blood is acidic, normal, alkaline)
2. determine the primary cause of the disturbance
   -check PaCO2 (indicates lung function to excrete CO2)
   -check HCO3 (indicates kidney function)
3. check for compensation/correction
   -resp comp occurs quickly (mins)
   -metabolic comp occurs slowly (days)
4. calculate the anion gap
   -Na - (Cl+HCO3)
   -normal range: 3-11mmol/L (if elevated=metabolic acidosis)
5. check the PaO2 and O2 saturation

Question 25

List the normal values for the following:
pH
PaO2
O2 saturation
PaCO2
HCO3

Answer 25

pH: 7.40 (7.35-7.45)
-<7.35=acidosis
->7.45=alkalosis
PaO2: 80-100mmHg
O2 saturation: >95%
PaCO2: 35-45mmHg
HCO3: 22-26mmol/L

Question 26

What is a bronchoscopy?

Answer 26

endoscopic technique of visualizing the airways
-inserted through the nose or mouth
-tissue/fluid samples can be taken

Question 27

Who should conduct spirometry?

Answer 27

trained personnel where there is a quality assurance program