Spirometery Basics
This test measures inspired and expired air while analyzing volume, time, and flow.
Spirometry
The maximum amount of air forcibly exhaled following a maximal inspiration.
FVC
This size syringe is used for daily spirometer calibration verification.
3-L syringe
An FEV₁/FVC ratio below this value typically indicates obstruction.
0.70 (70%)
On a flow-volume loop, this measurement is located on the Y-axis.
Flow (L/sec)
Spirometry is considered objective and noninvasive, but results depend heavily on this patient factor.
Effort
The volume exhaled during the first second of an FVC maneuver.
FEV1
Calibration verification should be performed this often before patient testing
Daily
In this type of disease, FVC and FEV₁ are reduced proportionally, leaving the FEV₁/FVC ratio normal or elevated.
Restrictive disease
A restrictive flow-volume loop generally maintains this but has a reduced FVC.
Normal shape
During an FVC maneuver, the patient begins with this type of inspiration.
Maximal inspiration
This measurement assesses airflow through the small airways.
FEF25-75%
The acceptable calibration check limit is this percentage.
±3.5%
In this type of disease, the major problem is expiratory airflow.
Obstructive disease
A “scooped-out” expiratory flow-volume loop is associated with this type of obstruction.
Variable intrathoracic obstruction
Name the three physiological factors that influence gas flow during an FVC maneuver.
Mechanical properties of the lungs, resistive elements, and airway collapsibility
This measurement assesses flow through the large, central airways.
FEF200-1200
At least this many acceptable spirometry maneuvers should be obtained.
3 acceptable maneuvers
Asthma causes increased airway resistance primarily because of this.
Bronchospasm
Flattening/reduction of inspiratory flow with relatively normal forced expiratory flow indicates this.
Variable extrathoracic obstruction
This is the point where pressure inside the airway equals the pressure outside the airway.
Equal Pressure Point (EPP)
A patient has an FEV₁ of 3.6 L and FVC of 4.5 L. Calculate the FEV₁/FVC ratio.
0.80 or 80%
The two largest FVC measurements and two largest FEV₁ measurements must agree within this amount to demonstrate repeatability.
0.150 L
Emphysema reduces expiratory airflow because of the loss of this mechanical property.
Elastic recoil
Equal reduction of inspiratory and expiratory airflow producing a rectangular loop indicates this condition.
Fixed obstruction