Stroke volume changes induced by a recruitment maneuver predict fluid responsiveness in patients with protective ventilation in the operating theater
Résumé
During abdominal surgery, the use of protective ventilation with a low tidal volume, positive expiratory pressure (PEEP) and recruitment maneuvers (RMs) may limit the applicability of dynamic preload indices. The objective of the present study was to establish whether or not the variation in stroke volume (SV) during an RM could predict fluid responsiveness. We prospectively included patients receiving protective ventilation (tidal volume: 6mLkg(-1), PEEP: 5-7cmH(2)O; RMs). Hemodynamic variables, such as heart rate, arterial pressure, SV, cardiac output (CO), respiratory variation in SV (Delta respSV) and pulse pressure (Delta respPP), and the variation in SV (Delta recSV) as well as pulse pressure (Delta recPP) during an RM were measured at baseline, at the end of the RM, and after fluid expansion. Responders were defined as patients with an SV increase of at least 15% after infusion of 500mL of crystalloid solution. Thirty-seven (62%) of the 60 included patients were responders. Responders and nonresponders differed significantly in terms of the median Delta recSV (26% [19-37] vs 10% [4-12], respectively; P < 0.0001). A Delta recSV value more than 16% predicted fluid responsiveness with an area under the receiver-operating characteristic curve (AU) of 0.95 (95% confidence interval [CI]: 0.91-0.99; P < 0.0001) and a narrow gray zone between 15% and 17%. The area under the curve values for Delta recPP and Delta respSV were, respectively, 0.81 (95% CI: 0.7-0.91; P = 0.0001) and 0.80 (95% CI: 0.70-0.94; P < 0.0001). Delta respPP did not predict fluid responsiveness. During abdominal surgery with protective ventilation, a Delta recSV value more than 16% accurately predicted fluid responsiveness and had a narrow gray zone (between 15% and 17%). Delta recPP and Delta respSV (but not Delta respPP) were also predictive.