Background: This prospective randomized controlled study was designed to evaluate the effect of fluid restriction alone versus fluid restriction + low central venous pressure (CVP) on hepatic surgical field bleeding, intraoperative blood loss, and the serum lactate concentration in patients undergoing partial hepatectomy. Methods: One hundred forty patients undergoing partial hepatectomy with intraoperative portal triad clamping were randomized into a fluid restriction group (Group F) or fluid restriction + low CVP group (Group L). Both groups received limited fluid infusion before the liver lesions were removed. Ephedrine was administered if the systolic blood pressure (SBP) decreased to <90 mmHg for 1 min. When the urine output was <20 ml/h or the SBP was <90 mmHg for 1 min more than three times, an additional 200 ml of crystalline solution was quickly infused within 10 min. In addition to fluid restriction, patients in Group L received continuous nitroglycerin and esmolol infusion to maintain a low CVP. The duration of portal triad clamping, frequency of additional fluid infusion, frequency of ephedrine administration, intraoperative blood loss, extent of liver resection, and bleeding score of the hepatic surgical field were recorded. Arterial blood gas analysis was performed before anesthesia (T1), after liver dissection and immediately before liver resection (T2), 10 min after removal of the liver lesion (T3), and before the patient was discharged from the postanesthesia care unit (T4).Results: Being in the fluid restriction Group (Group F) (odds ratio = 5.04) and cirrhosis (odds ratio = 3.28) were risk factors for hepatic surgical field bleeding. Factors contributing to intraoperative blood loss were the operation time, duration of portal triad clamping, and extent of resection. No significant between-group difference was observed for blood loss or blood transfusion. The serum lactate concentration peaked at T3 in both groups. Conclusions: Maintaining a lower CVP during hepatectomy provides an optimal surgical field but has no significant effect on intraoperative blood loss. Moreover, lower CVP does not increase the serum lactate concentration. Trial registration: "A comparative study of the effect fluid restriction and low CVP pressure on the oozing of blood in liver wounds and blood lactate in patients undergoing partial hepatectomy" was prospectively registered as a trial (registration number: ChiCTR-INR-17014172, date of registration: 27 December 2017).

Background: This prospective cohort study was designed to investigate the factors related to serum lactate in hepatectomy patients with fluid restriction before resection of liver lesions. Methods: Patients for an open procedure for elective partial hepatectomy were chosen for this study. Limited fluid was infused at a rate of 6 ml·kg -1 ·h -1 before liver resection. The infusion speed was increased after resection of liver lesion. Stable hemodynamics was maintained by additional fluid infusion or vasoconstrictor drug. An additional infusion of 200 ml crystalloid liquid over ten min was given when urine output was less than 20ml/h, and/or when systolic blood pressure was less than 90mmHg for 1 minute and for more than 3 times. An injection of 6mg Ephedrine was given when the systolic blood pressure was less than 90 mm Hg for 1 minute. The duration of portal triad clamping, the central venous pressure (CVP), the frequency of additional fluid infusion , the frequency of ephedrine , and the intraoperative blood loss were recorded. The serum lactate was measured from arterial blood-gas analysis at 4 time points: T1: before anesthesia; T2: after liver dissection, and immediately before liver resection; T3: 10 min after the liver lesion was removed; and T4: before the patient was discharged from the post-anesthesia care unit . The lactate clearance rate was calculated and linear regression analysis was employed to identify the relationship between serum lactate level and the influence factors. Results: The highest serum lactate was observed at T3 in all 110 patients. Lactate clearance rate averaged 14.4±17.2% in all patients. The i nfluence factors contributed to the highest serum lactate listed by level of importance: duration of portal triad clamping, frequency of ephedrine, operation time. Conclusions: Hepatic portal clamping can result in the increase of serum lactate. The inadequate perfusion of organ during the fluid restriction may be due to increased serum lactate. Accelerated fluid infusion after resection of liver lesions can improve the tissue perfusion. Trial registration: The registration number is ChiCTR1900023167. Retrospectively registered on 14th, May, 2019