Perioperative micro-arterial function and extravasation in cytoreductive ovarian cancer surgery: an observational study

BACKGROUND: Patients undergoing extended multivisceral, non-cardiac surgery require a high demand for intravenous fluid administration, leading to substantial positive fluid balances. This study aimed to perioperatively characterize extravasation as a correlate of capillary leakage and micro-arterial regulation, as well as venous return characteristics, as possible causes for the positive fluid balances. METHODS: In this single center, observational trial we included patients undergoing abdominal debulking surgery due to ovarian cancer. The measurements were performed by a venous congestion plethysmography (VCP) protocol to determine extravasation, micro-arterial reagibility, and after deflation of congestion venous outflow characteristics at timepoints before and during surgery, and repeatedly during the postoperative course. RESULTS: Thirty patients with primary ovarian cancer undergoing cytoreductive surgery treated within a goal-directed hemodynamic algorithm (GDA) based on the esophageal Doppler were included in the analysis. Stroke volume index did not change throughout the procedure with an increase in heart rate and consequently an increase in cardiac index. The norepinephrine requirements to maintain mean arterial pressure increased during surgery. Patients received a median 1750[25-quartile 1075;75-quartile 2100]ml crystalloids and 1000[1000;1500]ml starches, transfusions of 0[0;1040]ml red-packed cells, and 360[0;2880]ml fresh-frozen plasma. The intraoperative fluid and blood loss of 1020[508;1695]ml resulted in a positive fluid balance (2820[1338;6075]ml). Extravasation did not increase during surgery, even in the presence of substantially positive fluid balances. On the third and fifth postoperative days, extravasation increased relative to the preoperative baseline value. The micro-arterial function deteriorated throughout the course of the surgery, recovering to baseline values within 4 h after surgery. The venous outflow characteristics of the limb after releasing the venous congestion deteriorated over the course of surgery. CONCLUSIONS: There was no increase in extravasation measured by VCP during surgery despite a substantial intraoperative positive fluid balance, showing that they were not associated with each other. The micro-arterial function and venous backflow characteristics deteriorated during surgery, indicating that vascular dilation rather than capillary leakage may contribute to the high fluid demands. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01311297.