Mini fluid chAllenge aNd End-expiratory occlusion test to assess flUid responsiVEness in the opeRating room (MANEUVER study)

BACKGROUND The fluid challenge response in surgical patients can be predicted by functional haemodynamic tests. Two tests, the mini-fluid challenge (mini-FC) and end-expiratory occlusion test (EEOT), have been assessed in a few small single-centre studies with conflicting results. In general, functional haemodynamic tests have not performed reliably in predicting fluid responsiveness in patients undergoing laparotomy. OBJECTIVE This trial is designed to address and compare the reliability of the EEOT and the mini-FC in predicting fluid responsiveness during laparotomy. DESIGN Prospective, multicentre study. SETTING Three university hospitals in Italy. PATIENTS A total of 103 adults patients scheduled for elective laparotomy with invasive arterial monitoring. INTERVENTIONS The study protocol evaluated the changes in the stroke volume index (SVI) 20 s (EEOT 20 ) and 30 s (EEOT 30 ) after an expiratory hold and after a mini-FC of 100 ml over 1 min. Fluid responsiveness required an increase in SVI at least 10% following 4 ml kg −1 of Ringer's solution fluid challenge infused over 10 min. MAIN OUTCOME MEASUREMENTS Haemodynamic data, including SVI, were obtained from pulse contour analysis. The area under the receiver operating characteristic curves of the tests were compared with assess fluid responsiveness. RESULTS Fluid challenge administration induced an increase in SVI at least 10% in 51.5% of patients. The rate of fluid responsiveness was comparable among the three participant centres ( P = 0.10). The area under the receiver operating characteristic curves (95% CI) of the changes in SVI after mini-FC was 0.95 (0.88 to 0.98), sensitivity 98.0% (89.5 to 99.6) and specificity 86.8% (75.1 to 93.4) for a cut-off value of 4% of increase in SVI. This was higher than the SVI changes after EEOT 20, 0.67 (0.57 to 0.76) and after EEOT 30, 0.73 (0.63 to 0.81). CONCLUSION In patients undergoing laparotomy the mini-FC reliably predicted fluid responsiveness with high-sensitivity and specificity. The EEOT showed poor discriminative value and cannot be recommended for assessment of fluid responsiveness in this surgical setting. TRIAL REGISTRATION NCT03808753.