Should Low Central Venous Pressure Be Maintained during Liver Transplantation?

Jong Hae Kim

doi:10.2174/1874321801711010017

Abstract

Low central venous pressure, which indirectly reflects free hepatic venous pressure, is maintained during hepatic resection surgery to reduce intraoperative blood loss by facilitating hepatic venous outflow. However, whether the low central venous pressure protocol established for non-transplant hepatobiliary surgery should be generalized to liver transplantation is controversial because patients with cirrhosis have decreased portal and hepatic venous blood flow and vulnerability to renal failure. However, consistent with observations from hepatic resection surgeries, lowering central venous pressure during the preanhepatic phase significantly reduces blood loss and transfusion volume. Conversely, inherent study limitations and different study designs have yielded different results in terms of renal dysfunction. Although hepatic venous outflow promoted by lowering blood volume seems to facilitate a liver graft to accommodate portal blood flow increased by portal hypertension-induced splanchnic vasodilatation, the association between low central venous pressure and reduced incidence of portal hyperperfusion injury has not been demonstrated. Stroke volume variation predicts fluid responsiveness better than central venous pressure, but it has not been associated with a greater clinical benefit than central venous pressure to date. Therefore, the safety of maintaining low central venous pressure during liver transplantation has not been verified, and further randomized controlled studies are warranted to establish a fluid management protocol for each phase of liver transplantation to reduce intraoperative blood loss and transfusion rate, thereby maintaining liver graft viability. In conclusion, low central venous pressure reduces intraoperative blood loss but does not guarantee renoprotection or graft protection.

Highlights

Maintenance of low central venous pressure has been advocated for hepatic resection surgery because it facilitates hepatic venous outflow, which decreases the resistance of blood flow from the hepatic venous system into the inferior vena cava and prevents hepatic congestion, thereby decreasing bleeding from the sinusoids or hepatic veins during surgery [1]
Despite that patients with cirrhosis show altered circulation patterns [53, 54], which may affect the accuracy of estimating vascular compliance and resistance and result in an incorrect calculation of stroke volume when using the FloTrac/Vigileo system, stroke volume variation is still a better predictor of fluid responsiveness compared to central venous pressure and pulmonary artery occlusion pressure [9, 55] and its performance is comparable to pulse pressure variability
The renal complications that can potentially result from hypovolemia associated with low central venous pressure must be considered

Summary

INTRODUCTION

Maintenance of low central venous pressure has been advocated for hepatic resection surgery because it facilitates hepatic venous outflow, which decreases the resistance of blood flow from the hepatic venous system into the inferior vena cava and prevents hepatic congestion, thereby decreasing bleeding from the sinusoids or hepatic veins during surgery [1]. In a recent prospective randomized controlled study [2], central venous pressure was reduced to below 5 mmHg or by 40% of the baseline value during the preanhepatic phase by minimizing infusion volume, adjusting posture with a head-up tilt, and administering somatostatin and nitroglycerin This low central venous pressure resulted in significant decreases in blood loss and transfusion quantity, as well as lower lactate levels at the end of surgery and better preservation of hepatic function after liver graft reperfusion. No significant differences in renal function or incidence of postoperative complications were observed between the treatment groups In another prospective randomized controlled parallel study [30], maintenance of central venous pressure below 5 mmHg or lower than the baseline by about 40% by the Trendelenberg position, limiting infusion volume, and administration of nitroglycerine and furosemide reduced the amount of intraoperative blood loss and transfusion. The total urine volume was comparable between the 2 groups (low central venous pressure and control groups)

Study Limitations

Study Design

Findings

CONCLUSION