Central venous pressure and liver resection: a systematic review and meta-analysis

Background: A liver resection under low central venous pressure (CVP) has become standard practice; however, the benefits beyond a reduction in blood loss are not well reported. Moreover, the precise method to achieve CVP reduction has not been established. A systematic review and meta-analysis of randomized controlled trials (RTCs) was performed to assess the effects of CVP on clinical outcome and to identify the optimum method of CVP reduction. Methods: EMBASE, Medline, PubMed and the Cochrane database were searched for trials comparing low CVP surgery with controls. The primary outcome was post-operative complications within 30 days. Secondary outcomes included estimated blood loss (EBL), blood transfusion rates and length of stay (LOS). Sub-group analysis was performed to assess the CVP reduction method on the outcome. Results: Eight trials were identified. No difference was observed in the morbidity rate between the high CVP and control groups [odds ratio (OR) = 0.96 (95% confidence interval (CI) 0.66, 1.40) P = 0.84, I-2 = 0%]. EBL [weighted mean difference (WMD) = -308.63 ml (95% CI -474.67, -142.58) P = < 0.001, I-2 = 73%] and blood transfusion rates [OR 0.65 (95% CI 0.44, 0.97) P = 0.040, I-2 = 37%] were significantly lower in the low CVP groups. Neither anaesthetic nor surgical methods of CVP reduction were associated with a reduced post-operative morbidity. Conclusion: Low CVP surgery is associated with a reduction in EBL; however, this does not translate into an improvement in post-operative morbidity. The optimum method of CVP reduction has not been identified.