A dynamic elastance-based protocol to guide intraoperative fluid management in major abdominal surgery: A randomised clinical trial.

Background: Arterial hypotension during major surgery is related to postoperative complications and mortality. Both fluids and vasopressors increase blood pressure (BP) by inducing different physiological response. We devised a protocol which relies on dynamic arterial elastance (Eadyn) to guide BP optimisation during major abdominal surgery, and tested its effectiveness on tissue perfusion.

Objective: to explore if an Eadyn-based optimisation protocol could affect lactate levels, fluid administration, and postoperative clinical complications.

Design: randomised open-label clinical trial.

Setting: High-volume tertiary care centre for pancreatic surgery.

Patients: From 58 patients scheduled for cephalic duodenopancreatectomy 46 were eligible for the study.

Main Outcomes And Measures: The primary endpoint was the lactate value one hour after extubation. Secondary endpoints were fluid balance, intraoperative hypotension and postoperative complications. In the control group, hypotension (mean arterial pressure < 65 mmHg) was treated based on stroke volume variation (SVV) while in the experimental group the treatment was based on assessment of dynamic arterial elastance (Eadyn group). Patient demographic and preoperative laboratory data were recorded. All haemodynamic data, including oxygen delivery and consumption, were recorded at four time points: after intubation (T0), after fascia opening (T1), after fascia closing (T2) and one hour after extubation (T3).

Results: The patients were 70 [63 to 76] years and 15 (33%) were ASA 3. Lactate levels at T3 were similar between the control and Eadyn groups. Oxygen consumption was higher in the Eadyn group at T3, and lactate had a significant percentage decrease from T2 to T3: median [IQR], -24.5 [-30 to -14] vs. 0 [-24 to 7.6]%, P = 0.004). Those in Eadyn group received more vasopressors and had a lower fluid balance at T3: 2700 [2100 to 3800] vs. 2200 [1060 to 3000] ml, P = 0.020). There were no significant differences either in postoperative complications or hospital stay.

Conclusions: A protocol including Eadyn to treat hypotension did not reduce lactate after major abdominal surgery, but it was associated with a significant reduction in fluid balance and increase in oxygen consumption.

Registered At Clinical Trialsgov Nct: 05187273.