Five trials were included for review (n=173 patients). One trial scored 6 on the PEDro, one trial scored 5, two trials scored 4 and one trial scored 3. The median PEDro score was 4 points. Two trials reported sufficient detail to permit replication.
Resting lung function (two trials): One trial found that adding chest wall vibration to a regimen of spontaneous coughing did not result in a statistically significant improvement measured by forced expiratory volume in one second (FEV1). Another trial found that adding manual percussion to postural drainage, followed by breathing exercises and huffing, resulted in a statistically significant decrease of 7.3% (SD 6.5; p<0.1) in FEV1.
Sputum expectoration and clearance of inhaled particles (four trials): Three trials found statistically significant positive effects of postural drainage combined with breathing exercises, chest wall vibration, percussion and intermittent positive pressure breathing (p<0.05), adding chest wall vibration to spontaneous coughing in a forward leaning position (p=0.04), and adding non-oscillating positive expiratory pressure via a face mask to assisted coughing (p<0.01) on sputum clearance. Adding percussion to postural drainage, breathing exercises and huffing did not improve clearance of inhaled radio-labelled particles.
Gas exchange (four trials): One trial reported a statistically significant increase in arterial oxygen saturation 30 minutes after chest wall vibration combined with spontaneous coughing in patients requiring supplemental oxygen (p=0.02) compared with spontaneous coughing only. Three other trials did not show statistically significant benefits of intrapulmonary percussive ventilation, positive expiratory pressure mask or manual percussion on gas exchange compared with control treatments.
Use of non-invasive positive pressure ventilation (two trials): Intrapulmonary percussive ventilation resulted in a statistically significant reduction in the need for non-invasive positive pressure ventilation compared with control treatment (p<0.05; one trial). Positive expiratory pressure mask resulted in a statistically significant reduction in the duration of non-invasive positive pressure ventilation (p<0.01; one trial).
Length of stay in hospital (two trials): Intrapulmonary percussive ventilation was associated with a statistically significant reduction in the length of stay in hospital compared with control groups (p<0.05; one trial). However, postural drainage, breathing exercises, chest wall vibration, percussion and intermittent positive pressure breathing were not associated with a statistically significant reduction in the length of stay in hospital compared with usual care (one trial).