Pulmonary Function Tests

Physiological impairment is potentially present in many lung disorders. Indicators for obtaining pulmonary function testing (PFT) include:

• History of any specific lung disease.
• Symptoms of shortness of breath, cough, chest tightness, or wheezing.
• Cigarette smoking in drivers 35 years of age or older.

Spirometry

You should obtain forced expiratory volume in the first second of expiration (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio when any of the following indicators are present:

• History of any specific lung disease.
• Symptoms of shortness of breath, cough, chest tightness, or wheezing.
• Cigarette smoking in drivers 35 years of age or older.

No further testing is necessary if the lung function is normal and no other abnormality is suspected. Abnormal lung function should be further evaluated.

Screening pulse oximetry and/or arterial blood gas (ABG) analysis are indicated when:

• Condition causes airway obstruction and pulmonary function test results are:
  • FEV₁ less than 65% of the predicted value.
  • FEV₁/FVC ratio less than 65%.
• Restrictive impairment is present and FVC is less than 60%.

Screening Pulse Oximetry

If oximetry is less than 92% (oximetry equals 70), the driver must have an ABG analysis.

Arterial Blood Gas Analysis

Recommend not to certify the driver when ABG measurements reveal:

• Partial pressure of arterial oxygen (PaO₂) less than:
  • 65 millimeters of mercury (mm Hg) at altitudes below 5,000 feet.
  • 60 mm Hg at altitudes above 5,000 feet.
• Partial pressure of arterial carbon dioxide (PaCO₂) greater than 45 mm Hg at any altitude.