Chest physiotherapy using a manual ventilation technique was carried out on 9 intubated patients. One patient was studied on two occasions. The maximum expiratory flow rate (MEFR) was recorded during: (A) manual ventilation without physiotherapy, (B) manual ventilation with chest compression, (C) manual ventilation and chest compression, after application of the abdominal binder. Statistical analysis was carried out to allow for differences in tidal volume (Vt). Chest physiotherapy increased the mean MEFR and application of an abdominal binder (together with physiotherapy) caused a further increase in MEFR. The mean MEFR (assuming a common Vt of 1360 ml) in each group was; (A) = 73.3 l min-1, (B) = 103.9 l min-1, (C) = 113.93 l min-1.