Instantaneous responses to high-frequency chest oscillation in patients with respiratory failure receiving ventilation

Seventy-three patients (52 men) aged 71.5 ± 13.4 years who were intubated with mechanical ventilation for pneumonic respiratory failure were recruited and randomly classified into 2 groups (HFCWO group, n = 36; and control group who received conventional chest physical therapy (CCPT, n = 37). HFCWO was applied with a fixed protocol, whereas CCPT was conducted using standard protocols. Both groups received sputum suction after the procedure. Changes in ventilator settings and the subjects’ responses were measured at preset intervals and compared within groups and between groups.

Oscillation did not affect the ventilator settings (all P > 0.05). The mean airway pressure, breathing frequency, and rapid shallow breathing index increased, and the tidal volume and SpO2 decreased (all P < 0.05). After sputum suction, the peak airway pressure (Ppeak) and minute ventilation decreased (all P < 0.05). The HFCWO group had a lower tidal volume and SpO2 at the end of oscillation, and lower Ppeak and tidal volume after sputum suction than the CCPT group.

HFCWO affects breathing pattern and SpO2 but not ventilator settings, whereas CCPT maintains a steadier condition. After sputum suction, HFCWO slightly improved Ppeak compared to CCPT, suggesting that the study extends the indications of HFCWO for these patients in intensive care unit.