Physiological response to fluid resuscitation with Ringer lactate versus Plasmalyte in critically ill burn patients

The metabolic consequences in vivo of various balanced solutions are poorly known in critically ill patients. The main objective of this study was to describe the metabolic consequences of Plasmalyte versus Ringer lactate (RL) in critically ill burn patients, with a special focus on the plasma clearance of buffer anions (i.e., gluconate, acetate, and lactate). We conducted a randomized trial between August 2017 and October 2018 in a tertiary teaching hospital in Paris, France. Patients with burn total body surface area >30% were randomized to receive Plasmalyte or RL. The primary end point was the base excess 24 h after inclusion. The secondary end points were acetate, gluconate, and lactate plasma concentration, the strong ion difference (SID). Twenty-eight patients were randomized. Twenty-four hours after inclusion, plasma BE was not significantly different in the Plasmalyte and RL groups {-0.9 [95% confidence interval (95% CI): -1.8-0.9] vs. -2.1 [95% CI: -4.6-0.6] mmol/L, respectively, P = 0.26}. Plasma gluconate concentration was higher in the Plasmalyte group (P < 0.001), with a maximum level of 1.86 (95% CI: 0.98-4.0) mmol/L versus 0 (95% CI: 0-0.15) mmol/L. Plasma acetate and lactate were not significantly different. Ionized calcium level was lower in the Plasmalyte group (P = 0.002). Hemodynamics did not differ between groups. To conclude, the alkalinizing effect of Plasmalyte was less important than expected with no difference in base excess compared with RL, in part due to gluconate accumulation. Acetate and lactate did not significantly accumulate. Plasmalyte led to significantly lower ionized calcium levels. NEW & NOTEWORTHY During fluid resuscitation in burns the alkalinizing effect of Plasmalyte was less important than expected, with no difference in base excess compared with Ringer lactate (RL), in part due to gluconate accumulation. Acetate and lactate did not significantly accumulate. Plasmalyte led to significantly lower ionized calcium levels.