What are the contraindications for Pulmonary Function Tests (PFT)?

Contraindications for Pulmonary Function Tests (PFT)

Pulmonary function tests should not be performed in patients with acute myocardial infarction within 3-5 days, unstable angina, uncontrolled arrhythmias causing symptoms or hemodynamic compromise, active endocarditis, acute myocarditis or pericarditis, symptomatic severe aortic stenosis, uncontrolled heart failure, acute pulmonary embolus, thrombosis of lower extremities, suspected dissecting aneurysm, or significant pulmonary hypertension. 1

Absolute Contraindications

• Acute myocardial infarction (3-5 days) 1
• Unstable angina 1
• Uncontrolled arrhythmias causing symptoms or hemodynamic compromise 1
• Syncope 1
• Active endocarditis 1
• Acute myocarditis or pericarditis 1
• Symptomatic severe aortic stenosis 1
• Uncontrolled heart failure 1
• Acute pulmonary embolus or pulmonary infarction 1
• Thrombosis of lower extremities 1
• Suspected dissecting aneurysm 1
• Significant pulmonary hypertension 1

Relative Contraindications

• Left main coronary stenosis or its equivalent 1
• Moderate stenotic valvular heart disease 1
• Severe untreated arterial hypertension at rest (>200 mmHg systolic, >120 mmHg diastolic) 1
• Tachyarrhythmias or bradyarrhythmias 1
• High-degree atrioventricular block 1
• Hypertrophic cardiomyopathy 1
• Mental impairment leading to inability to cooperate 1
• Uncontrolled asthma 1
• Pulmonary edema 1
• Room air desaturation at rest ≤85% (consider supplemental oxygen during testing) 1
• Respiratory failure 1
• Recent thoracic, abdominal, or head surgery (traditionally 6 weeks, though newer evidence suggests this may be reduced to <3 weeks with modern surgical techniques) 2, 3
• Acute noncardiopulmonary disorder that may affect exercise performance or be aggravated by exercise (infection, renal failure, thyrotoxicosis) 1
• Orthopedic impairment that compromises exercise performance 1
• Advanced or complicated pregnancy 1
• Electrolyte abnormalities 1

Pre-Test Preparation Requirements

• Avoid caffeine within 2 hours of testing 4
• Avoid smoking within 1 hour of testing 4
• Avoid alcohol within 4 hours of testing 4
• Avoid vigorous exercise within 30 minutes of testing 4
• Avoid large meals within 2 hours of testing 4
• Record any deviations from preparation guidelines at the time of testing 4

Special Considerations

Positioning

• Testing may be performed either in the sitting or standing position, with the position recorded on the report 1
• Sitting is preferable for safety reasons to prevent falling due to syncope 1
• Chairs should have arms and be without wheels; if wheelchairs are used, wheels should be locked 1
• For obese subjects or those with excessive weight at the mid-section, standing position may allow deeper inspiration and improved forced expiratory volumes 1

Recent Myocardial Infarction

• While traditional guidelines recommend waiting one month after MI, recent evidence suggests PFTs may be safe within one month of MI in selected patients, though this is based on a small sample size 5
• The decision to perform PFT in these patients should be based on clinical necessity and risk-benefit assessment 2, 3

Pulmonary Disease

• Moderate to severe pulmonary disease (FEV1 or FVC <70% of predicted or FEV1:FVC ratio <65%) may be a contraindication in certain clinical contexts, such as for potential living kidney donors 1
• Patients with FEV1 <35% predicted should not undergo needle biopsy without further assessment by a multidisciplinary team 1

Risk Reduction Strategies

• Ensure proper monitoring during and after the procedure 1
• Have resuscitation equipment immediately available 1
• For patients at risk of syncope, place a chair behind standing patients 1
• Consider supplemental oxygen for patients with resting desaturation 1
• For patients with Raynaud phenomenon or poor finger perfusion, use ear or forehead oxygen saturation monitors instead of finger monitors 1
• For patients with decreased oral aperture (e.g., in systemic sclerosis), consider using a pediatric mouthpiece 1

By carefully screening patients for contraindications and taking appropriate precautions, pulmonary function testing can be performed safely in most clinical scenarios where the information gained will impact patient management decisions.