OVERVIEW Flashcards
Complete evaluation of the respiratory system includ;e
patient history
physical examination,
radiographic imaging
arterial blood gas analysis
and tests of pulmonary function
There are three categories of pulmonary function tests, measuring;
(1) dynamic flow rates of gases through the airways,
(2) lung volumes and capacities, and
(3) the ability of the lungs to diffuse gases.
the primary purposes of pulmonary function testing are to
identify pulmonary
impairment and quantify the severity of pulmonary impairment if present.
Indications OF PFT
- To identify and quantify changes in pulmonary function
- To evaluate need and quantify therapeutic effectiveness
- To perform epidemiologic surveillance for pulmonary disease
- To assess patients for risk for postoperative pulmonary complications
- To determine pulmonary disability
Contraindications OF PFT
- Acute, unstable cardiopulmonary problems (e.g., hemoptysis, pneumothorax, myocardial infarction, pulmonary embolism)
- Acute chest or abdominal pain.
- Nausea and vomiting
- Recent eye surgery
- Dementia or confusion
- Acutely ill patients
- Who recently smoked a cigarette
The primary problem in obstructive pulmonary disease is an
increased airway resistance (Raw).
Reduced lung compliance is usually the result of
alveolar inflammation, swelling, or scarring.
Measuring the diffusing capacity of the lung for carbon monoxide (DLCO) can identify the
destruction of alveolar tissue or loss of functioning surface area
Barach noted that airflow out of the lungs was important in detecting obstruction of the airways
During the 1930s
Tiffeneau described measuring the volume expired in the first second of a maximal exhalation in proportion to the maximal volume that could be inspired (FEV1/IVC) as an index of airflow obstruction.
1947
Gaensler began using a microswitch in conjunction with a water-sealed spirometer to time FVC. He observed that healthy patients consistently exhaled approximately 80% of their FVC in 1 second and almost all of it in 3 seconds.
1950
Leuallen and Fowler demonstrated a graphic method used to assess airflow. They measured airflow between the 25% and 75% points on a forced expiratory spirogram. This measure was described as the maximal mid-expiratory flow rate (MMFR).
1955
Hyatt and others began using the flow-volume display to assess airway function. The tracing was termed the maximal expiratory flow volume (MEFV) curve. By combining the forced expiration with an inspiratory maneuver, a closed loop can be displayed. This figure is called the flow-volume loop.
In the late 1950s
Cournand and Richards originally called it the maximal breathing capacity (MBC)
1941
Measurement of respiratory muscle strength is accomplished by assessing
MIP and MEP
