Effects of recruitment manoeuvres on haemodynamics, oxygen exchange and oxygen delivery in patients with acute lung injury and acute respiratory distress syndrome.

Objective: To evaluate the impact of a recruitment manoeuvre (RM) on haemodynamics, gas exchange, and oxygen transport in patients with acute lung injury (ALI) an acute respiratory distress syndrome (ARDS) under mechanical ventilation.

Design, Setting And Participants: Prospective interventional study in the intensive care unit of a teaching hospital in Buenos Aires, Argentina. The study was carried out between June 2002 and March 2003. Eleven consecutive patients with ALI and ARDS who required an RM were included. Haemodynamic measurements and blood samples were taken before and during the RM, and at 2 and 30 minutes after the RM.

Intervention: After baseline measurements, positive end-expiratory pressure (PEEP) was set at 40cmH(2)O for 45 seconds.

Main Outcome Measures: Systemic haemodynamics, oxygen exchange and oxygen delivery.

Results: Mean PEEP before the RM was 14 (SD, 3) cmH(2)O, and was maintained after the RM. The RM did not modify the arterial partial pressure of oxygen (PaO(2)) but did induce small but significant changes in the mean arterial partial pressure of carbon dioxide (Pa-ETCO(2)) and arterial minus end-tidal PCO(2) gradient (PaCO(2)) at 2 minutes and 30 minutes after the RM (P<0.05). The mean cardiac index dropped from 3.08 (SD, 0.84) to 2.37 (SD, 0.75) L/min/m(2) (P<0.001) during the RM and then returned to baseline values. Mean systolic blood pressure also fell transitorily during the RM, from 131 (SD, 15) to 104 (SD, 25) mmHg, but diastolic and mean arterial pressures remained unchanged. Oxygen consumption and the arterial mixed venous oxygen content gradient increased after the RM (P<0.05).

Conclusion: In our small series of patients with ALI/ARDS ventilated with high levels of PEEP, the RM failed to improve oxygen exchange and induced deleterious effects on haemodynamics.