Introduction

Acute respiratory distress syndrome (ARDS) is a frequent complication in critically ill patients. Recruitment maneuver (RM) is a rescue procedure which improves oxygenation [13]. However, it is not clear whether improving oxygen delivery (DO2) exists after RM. The aim of this study was to evaluate the effects of RM on hemodynamics and DO2.

Methods

A prospective, randomized trial in ARDS patients (AECC criteria). The protocol was approved by the local ethics committee. Fifty-seven patients with extrapulmonary ARDS were randomized into three groups: group A (n = 17) - 40 × 40 RM (CPAP 40 cmH2O for 40 seconds), group B (n = 17) - PCV RM (PIP 40 to 50 cmH2O, PEEP 18 to 20 cmH2O for 120 seconds), and group C (n = 17) - stepwise PCV RM. Gas exchange and systemic hemodynamics by aortal blood flow (transesophageal Doppler; ARROW, USA) were measured before, after, 30 and 120 minutes after RM.

Results

In all groups we observed rapid increasing of paO2 (mmHg) from 65.9 ± 24.9; 77.2 ± 14.0; 87.0 ± 16.7 to 110.3 ± 38.7; 124.5 ± 45.5; 115.2 ± 32.6 (P < 0.0001) after RM. We also observed significant improvement of oxygenation 120 minutes after RM (95.6 ± 25.6; 99.3 ± 25.3; 108.1 ± 26.8). There was no statistical difference between groups. Contrarily, DO2 (ml/minute/m2) after RM statistically significantly decreased from 709.5 ± 297.5; 804.9 ± 217.3; 811.7 ± 638.3 to 569.8 ± 211.9; 675.5 ± 244.7; 661.7 ± 421.3 (P = 0.053) and lasted more than 2 hours. The reason for this alteration was decreasing of cardiac output (CO) from 5.3 ± 2.5 l/minute to 3.6 ± 1.7 l/minute (P < 0.0001) after RM. We hypothesized that the main reason for decreasing CO is rapid increasing of intrathoracic pressure during RM.

Conclusion

Three different RMs increase oxygenation and decrease CO equally. But RM does not improve oxygen delivery due to decreasing CO.