The effect of pulse pressure variation compared with central venous pressure on intraoperative fluid management during kidney transplant surgery: a randomized controlled trial.

Background: Traditionally, fluid administration during kidney transplant surgery is guided by central venous pressure (CVP) despite its limited reliability as a parameter for assessing intravascular fluid volume, particularly in patients with cardiovascular diseases. The recommended goals at graft reperfusion are a mean arterial pressure of 90 mm Hg and a CVP of 12-14 mm Hg. This approach may increase the risk of significant adverse effects due to volume overload. Perioperative fluid therapy guided by dynamic indices of fluid responsiveness has been shown to optimize intravascular volume and prevent complications associated with overzealous administration of fluids in major abdominal surgeries. We hypothesized that pulse pressure variation (PPV)-guided fluid administration would result in better optimization of intravascular fluid volume compared with a CVP-guided strategy during kidney transplant surgery.

Methods: In this single-centre randomized double blinded trial, 77 end-stage renal disease patients, who underwent kidney transplant surgery under general anesthesia with epidural analgesia, were randomized to receive either CVP-guided (n = 35) or PPV-guided (n = 35) fluid therapy using predefined hemodynamic endpoints. The primary outcome was the total volume of intraoperative fluids administered. Secondary outcomes were intraoperative hemodynamic changes, serum lactate levels, serum creatinine, need for dialysis within the first week, creatinine elimination ratio, and incidence of immediate and delayed graft dysfunction.

Results: Results were analyzed for 70 patients. Eighty percent of the patients underwent living-related donor allograft kidney transplant. Operative variables related to donor characteristics, duration of surgery, graft cold ischemia time, and blood loss were comparable in both groups. The mean (standard deviation) volume of intravenous fluids administered intraoperatively was 1,346 (337) mL in the PPV-guided group vs 1,901 (379) mL in the CVP-guided group (difference in means, 556 mL; 95% confidence interval, 385 to 727; P = 0.001). There were no significant differences in secondary outcomes between the two groups.

Conclusion: Pulse pressure variation -guided fluid administration significantly decreased the total volume of crystalloids compared with CVP-guided fluid therapy during the intraoperative period in patients who underwent kidney transplant surgery. Nevertheless, our study was underpowered to detect differences in secondary outcomes.

Trial Registration: www.ctri.nic.in (CTRI/2018/01/011638); registered 31 January 2018.