What is a PFT Test?

1.0 Introduction: What is a PFT Test?

Pulmonary Function testing measures the function of lung capacity and lung and chest wall mechanics to determine whether or not the patient has a lung problem. Pulmonary Function Tests are commonly referred to as "PFTs". When a patient is referred for PFT's, it means that a battery of tests may be carried-out including: simple screening spirometry, static lung volume measurement, diffusing capacity for carbon monoxide, airways resistance, respiratory muscle strength and arterial blood gases.

Pulmonary Function Tests are used for the following reasons:

  1. Screening for the presence of obstructive and restrictive diseases
  2. Evaluating the patient prior to surgery - this is especially true of patients who:
    a. are older than 60-65 years of age
    b. are known to have pulmonary disease
    c. are obese (as in pathologically obese)
    d. have a history of smoking, cough or wheezing
    e. will be under anesthesia for a lengthy period of time
    f. are undergoing an abdominal or a thoracic operation
  1. Evaluating the patient's condition for weaning from a ventilator. If the patient on a ventilator can demonstrate a vital capacity (VC) of 10 - 15 ml/Kg of body weight, it is generally thought that there is enough ventilatory reserve to permit (try) weaning and extubation.
  2. Documenting the progression of pulmonary disease - restrictive or obstructive
  3. Documenting the effectiveness of therapeutic intervention