BACKGROUND: The ideal intravenous (IV) maintenance and resuscitation fluid for patients undergoing orthotopic liver transplantation (OLT) remains unknown. We aimed to determine whether bicarbonate-buffered solution was non-inferior to Plasma-Lyte™ in preventing metabolic acidosis during OLT. METHODS: We conducted a pilot single-center, open-label, randomized trial to compare the physiological effects of intravascular volume maintenance with a bicarbonate-buffered solution vs. Plasma-Lyte™ in adults undergoing OLT. Non-inferiority was defined as a median difference in the standard base excess (SBE) of less than -2.5 mEq/L. The primary endpoint was the standard base excess (SBE) at 5 minutes post-reperfusion. Quantile regression analysis was applied to confirm non-inferiority. Secondary endpoints included other forms of acid-base and electrolyte imbalances at pre-specified time points and postoperative complications. RESULTS: We randomized 52 adults undergoing OLT. The median (interquartile range [IQR]) volume infused was 5000 (3125, 7000) ml in the bicarbonate-buffered solution group and 5500 (4000, 10,500) ml in the Plasma-Lyte™ group (P = 0.37). The median (IQR) SBE at 5 minutes post-reperfusion was -4.857 (-6.231, -3.565) mEq/L in patients receiving bicarbonate-buffered solution and -4.749 (-7.574, -2.963) mEq/L amongst those in the Plasma-Lyte™ group. The estimated median difference by quantile regression was -0.043 mEq/L (95% CI -1.988 to 1.902 mEq/L
(one-sided P = 0.015). There were no significant differences in the acid-base secondary outcomes, number of complications, or patient mortality. There were no reported adverse events or safety concerns associated with the use of either solution. CONCLUSIONS: A bicarbonate-buffered solution was non-inferior to Plasma-Lyte™ for maintaining acid-base homeostasis post-reperfusion in OLT patients.