Introduction Lung collapse is a contributory factor in the hypoxaemia that is observed after open endotracheal suctioning (ETS) in patients with acute lung injury and acute respiratory distress syndrome. Lung recruitment (LR) manoeuvres may be effective in rapidly regaining lung volume and improving oxygenation after ETS. Materials and method A prospective, randomized, controlled study was conducted in a 15-bed general intensive care unit at a university hospital. Eight consecutive mechanically ventilated patients with acute lung injury or acute respiratory distress syndrome were included. One of two suctioning procedures was performed in each patient. In the first procedure, ETS was performed followed by LR manoeuvre and reconnection to the ventilator with positive end-expiratory pressure set at 1 cmH(2)O above the lower inflexion point, and after 60 min another ETS (but without LIR manoeuvre) was performed followed by reconnection to the ventilator with similar positive end-expiratory pressure; the second procedure was the same as the first but conducted in reverse order. Before (baseline) and over 25 min following each ETS procedure, partial arterial oxygen tension (Pao(2)) and end-expiratory lung volume were measured. Results After ETS, Pao(2) decreased by 4.3 (0.9-9.7) kPa (median and range; P<0.005). After LR manoeuvre, Pao(2) recovered to baseline. Without LR manoeuvre, Pao(2) was reduced (P=0.05) until 7 min after ETS. With LIR manoeuvre end-expiratory lung volume was unchanged after ETS, whereas without LR manoeuvre end-expiratory lung volume was still reduced (approximately 10%) at 5 and 15 min after ETS (P=0.01). Discussion A LIR manoeuvre immediately following ETS was, as an adjunct to positive end-expiratory pressure, effective in rapidly counteracting the deterioration in Pao(2) and lung volume caused by open ETS in ventilator-treated patients with acute lung injury or acute respiratory distress syndrome.