Four Steps of Pulmonary Function Testing

Pulmonary function testing involves the examinee performing various breathing maneuvers under the guidance of a physician, enabling the testing device to measure parameters such as vital capacity and ventilatory reserve. These measurements help diagnose potential ventilatory dysfunction or other related conditions. The specific procedure consists of the following four steps:

1. The examinee sits comfortably, and the physician applies a nose clip; the examinee is then instructed to breathe calmly through the mouth.

2. The examinee opens the mouth and places the mouthpiece between the lips, breathing calmly before exhaling slowly and completely until no further exhalation is possible, holding this position for three seconds.

3. Upon the physician’s instruction, the examinee exhales forcefully and rapidly for 12 seconds, then resumes calm breathing.

4. Upon completion of the test, the instrument generates quantitative results; the physician interprets these values in conjunction with the examinee’s clinical symptoms to determine whether any abnormalities in ventilatory function are present.