ATS Pulmonary Function Laboratory Manual

chapter  8

Equipment and Supplies 1. System description (e.g., XYZ Corp., Model 101 Pulmonary Function System with volume displacement/ flow sensing spirometer, infrared helium [He] analyzer [katharometer], and emission-type N 2 analyzer). 2. Compressed-gas cylinder(s) of test gas(es) used by the laboratory (e.g., 100% O 2 , or 10% He, 21% O 2 with balance N 2 ). 3. Appropriate size mouthpiece, tubing, nose clip, CO 2 and O 2 absorbers, and other miscellaneous equipment or supplies needed (e.g., facial tissue). Patient Preparation (Pre-Test Instructions) 1. The patient should refrain from smoking for at least 1 hour before the test (4). 2. The patient should not have had a large meal shortly before testing. 3. Diurnal variation does occur with lung volumes. If serial measurements are anticipated, the time of day should be kept the same (2). 4. The patient’s chest expansion should not be restricted by clothing (e.g., brassieres or vests). 5. Medications that affect lung function and volumes (e.g., beta-2 agonists) should be withheld, if clinically feasible. Note: The length of time necessary to withhold various medications varies. Guidelines (4) for withholding medications include: Table 8.3 Recommended times periods for withholding bronchodilators prior to bronchodilator-response testing. Medication Length of Abstention Inhaled bronchodilators Short-acting 4 to 6 hours Long-acting 12 hours Anticholinergics Short-acting 6 hours Long-acting 24-48 hours Ultra long-acting agents 24 hours 6. The patient should be seated upright as body position influences lung volumes (5, 6). If another position is used, it should be noted. 7. Interruption of supplemental O 2 is necessary during measurements of static lung volumes. The following considerations must be addressed before initiating testing: 7.1. If FRC N2 is to be performed, the patient should not have supplemental O 2 for at least 15 minutes. Breathing room air for > 15 minutes should be adequate in most instances to assure alveolar nitrogen (N 2 ) is near 80% (2). 7.2. Discontinuation of supplemental O 2 may be contraindicated in some patients with very severe lung disease or hypoxemia. Check with the physician before doing so.

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