ATS Pulmonary Function Laboratory Manual

chapter  6

Table 6.2

Indications for spirometry

Diagnostic

To evaluate symptoms, signs, or abnormal laboratory tests To measure the effect of disease on pulmonary function To screen individuals at risk of having pulmonary disease To assess preoperative risk To assess prognosis To assess health status before enrollment in strenuous physical activity programs To assess therapeutic intervention To describe the course of diseases affecting lung function To monitor those exposed to injurious agents To monitor for adverse reactions to drugs with known pulmonary toxicity

Monitoring

Disability/Impairment Evaluations

To assess patients as part of a rehabilitation program To assess risks as part of an insurance evaluation To assess individuals for legal reasons

Public Health

Epidemiological surveys Derivation of reference equations Clinical research

Spirometers and procedures should meet the most current ATS/ERS recommendations (6, 13). There are two general groups of spirometers: volume-displacement and flow-sensing. Volume-displacement spirometers . Some spirometers use a bellows, or cylinder/piston assembly to translate physical displacement into a recording of volume change. Most volume-displacement spirometers use a potenti- ometer or digital encoder to generate an analog or digital signal proportional to volume change which is processed and stored by a computer (14). Flow-sensing spirometers . A large number of spirometers measure and integrate gas flow to determine volume. Available flow sensors use various principles including pressure-differential, heated-wire, and ultra-sound. Cor- rection of nonlinear flow signals from these devices is performed automatically, usually by computer. Many flow- sensing spirometers are available in small, portable configurations. Some indications for spirometry are provided in Table 6.2. Equipment and Supplies 1. Spirometer description (e.g., manufacturer, model, type, accessories, additional features, and software version) 2. Disposable/reusable supplies: mouthpieces, nose clips, large-bore tubing, flow-sensors (pneumotachom- eters), gas and water absorbers (if applicable). If testing children, appropriately sized mouthpieces should be available. 3. Infection-control supplies: disposable in-line bacteria filters (if used), gloves, gowns, masks, and protective eye wear 4. Computer/printing supplies: paper, pens, and computer media 5. Thermometer, hygrometer (if applicable), barometer [or source of local barometric pressure (PB)] for BTPS correction; stopwatch for checking mechanical recorders

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