From the Guidelines
Abnormal pulmonary function test results indicating potential lung disease require immediate interpretation and management to prevent morbidity and mortality, and the most recent and highest quality study 1 suggests that spirometry is the first step in determining the pattern of impairment. When evaluating abnormal PFTs, clinicians should first determine the pattern—obstructive (reduced FEV1/FVC ratio), restrictive (reduced TLC with normal FEV1/FVC), or mixed—and assess severity through percent predicted values.
- The pattern of impairment can be determined by the FEV1/FVC ratio, with a reduced ratio indicating obstructive impairment, and a reduced TLC with normal FEV1/FVC ratio indicating restrictive impairment.
- The severity of the impairment can be assessed through percent predicted values, with lower values indicating more severe impairment. Management begins with additional diagnostic testing including chest imaging, bronchodilator challenge testing, and possibly bronchoscopy or high-resolution CT to confirm the underlying condition.
- For obstructive patterns suggesting asthma or COPD, treatment typically includes bronchodilators such as albuterol (90 mcg, 2 puffs every 4-6 hours as needed) and, if indicated, inhaled corticosteroids like fluticasone (100-500 mcg twice daily) 1.
- Restrictive patterns may require treatment of the underlying cause, such as corticosteroids for interstitial lung disease (prednisone 0.5-1 mg/kg/day with gradual taper) or CPAP for sleep apnea 1. Serial PFTs should be performed to monitor disease progression and treatment response, typically at 3-6 month intervals for chronic conditions.
- Lifestyle modifications are essential, including smoking cessation, avoiding environmental triggers, pulmonary rehabilitation, and vaccination against respiratory pathogens 1. The interpretation of PFTs must always consider clinical context, as abnormal results may reflect technical factors or normal physiological variations rather than pathology, and the use of arm span instead of height may be recommended for patients with osteogenesis imperfecta or skeletal abnormalities 1.
From the Research
Interpretation of Pulmonary Function Test Results
The provided pulmonary function test results indicate potential lung disease, with abnormal values for FVC, FEV1, and other parameters.
- FVC (Forced Vital Capacity) is lower than expected, which can indicate a restrictive lung disease pattern 2.
- FEV1 (Forced Expiratory Volume in 1 second) is also lower than expected, which can indicate an obstructive lung disease pattern 3.
- The FEV1/FVC ratio is lower than normal, which further supports the presence of an obstructive lung disease pattern 4.
Management of Abnormal Pulmonary Function Test Results
Management of abnormal pulmonary function test results depends on the underlying cause of the lung disease.
- For restrictive lung diseases, treatment is primarily supportive, with oxygen therapy, pulmonary rehabilitation, and management of comorbid conditions 2.
- For obstructive lung diseases, such as COPD, long-acting bronchodilators are the mainstay of maintenance treatment, and can help reduce symptoms and improve lung function 3, 5.
- Triple fixed-dose combinations of inhaled corticosteroids, long-acting β2-agonists, and long-acting muscarinic antagonists may also be effective in improving symptoms and lung function in COPD patients 5.
Further Evaluation and Treatment
Further evaluation and treatment of lung disease depend on the individual patient's needs and underlying condition.
- Preoperative evaluations should assess pulmonary risk, in addition to cardiac risk, with a thorough history, laboratory tests, and functional capacity assessments 2.
- Optimization of management may include weight loss, pulmonary rehabilitation, oxygen therapy, and respiratory support 2.
- Referral for evaluation for lung transplantation may be recommended for appropriate patients with advanced lung disease 2.