Abstract
Manual breathing assist is most basic technique to improve ventilation without patient's voluntary effort. The purpose of this study was to investigate the effect of this technique on lung volumes in healthy young subjects. The following techniques were used : 1) to assist upper chest motion in sitting position, 2) to assist upper chest motion in supine position, and 3) to assist lower chest motion in supine position. Lung volumes was obtained by using spirometer during breathing assist, and compared with those in resting condition.
Tidal volume was increased almost twice in all techniques. Functional residual capacity was decreased to 7-12% converted into % FRC. Main factor of increasing of tidal volume was that expiratory reserve volume was decreased by breathing assist at expiration. In half of the subjects, inspiratory reserve volume was decreased by expansion of rebound of chest cage. The study results support the use of manual breathing assist to improve ventilation in any clinical conditions.
