End-expiratory occlusion manoeuvre does not accurately predict fluid responsiveness in the operating theatre

Background. The objective of this study was to determine whether assessment of stroke volume (SV) and measurement of exhaled end-tidal carbon dioxide (E'(CO2)) during an end-expiratory occlusion (EEO) test can predict fluid responsiveness in the operating theatre. Methods. Forty-two subjects monitored by oesophageal Doppler who required i.v. fluids during surgery were studied. Haemodynamic variables [heart rate, non-invasive arterial pressure, SV, cardiac output (CO), respiratory variation of SV (Delta respSV), variation of SV during EEO, and E'(CO2)] were measured at baseline, during EEO (Delta(EEO)), and after fluid expansion. Responders were defined by an increase in SV over 15% after infusion of 500 ml of crystalloid solution. Results. Of the 42 subjects, 28(67%) responded to fluid infusion. A cut-off of >2.3% Delta SVEEO predicted fluid responsiveness with an area under the receiver-operating characteristic (AUC) curve of 0.78 [95% confidence interval (95% CI): 0.63-0.89, P=0.003]. The AUC of Delta respSV was 0.89 (95% CI: 0.76-0.97, P<0.001). With an AUC of 0.68 (95% CI: 0.51-0.81, P=0.07), Delta E'(CO2EEO). was poorly predictive of fluid responsiveness. Conclusions. Delta SVEEO and Delta E'(CO2), were unable to accurately predict fluid responsiveness during surgery.