Objective: To evaluate the effectiveness and safety of infrahepatic inferior vena cava (IVC) clamping for reduction of central venous pressure (CVP) and blood loss during hepatic resection.
Background: Low CVP during parenchymal transection has been widely accepted to reduce intraoperative hemorrhage via the hepatic veins and is commonly achieved by anesthesiological interventions such as fluid restriction. We hypothesized that infrahepatic clamping of the IVC may lower the intraoperative blood loss more effectively and, moreover, prevent potential adverse effects of fluid restriction such as hemodynamic instability.
Methods: Patients scheduled for elective hepatic resection were enrolled and allocated randomly to CVP reduction by infrahepatic IVC clamping or anesthesiological interventions including primarily fluid restriction with additional use of diuretics, nitro compounds, and opioids (control group). The primary efficacy endpoint was total intraoperative blood loss. Analyses were done following intention-to-treat principles. The protocol was submitted to the clinicaltrials.gov registry (NCT00732979).
Results: From April 2007 to December 2009, a total of 152 patients were randomized and 128 were eligible for final analyses. Baseline data were similar between both study groups. Despite higher CVP values during resection (4.0 ± 3.2 vs. 2.6 ± 1.8 mm Hg; P = 0.003), infrahepatic IVC clamping significantly reduced total intraoperative blood loss [550 (350.0-1150) mL vs. 900 (500-1500) mL; P = 0.02] and blood loss during parenchymal transection [150 (85-500) mL vs. 400 (200-700) mL; P = 0.006] compared with the control group. Postoperative mortality [4 (6.1%) vs. 2 (3.2%); P = 0.42] and total morbidity rates [38 (58.5%) vs. 37 (58.7%); P = 0.97] were comparable between both study groups. Although intraoperative hemodynamic instability occurred less frequently in patients with infrahepatic IVC clamping [0 vs. 4 (6.3%); P = 0.04], the incidence of pulmonary embolism was increased in this study arm [4 (6.1%) vs. 0; P = 0.04].
Conclusions: Infrahepatic IVC clamping is associated with significantly less intraoperative blood loss and may reduce the incidence of intraoperative hemodynamic instability. The potential association with postoperative pulmonary embolism represents a significant concern.