Effects of goal-directed fluid management with 0.9% normal saline on metabolic acidosis in patients undergoing brain surgery: a prospective and randomized-controlled study

Abstract

Excessive administration of 0.9% normal saline (NS) can cause hyperchloremic metabolic acidosis during surgery. It was hypothesized that intraoperative administration of 0.9% NS by goal-directed fluid management based on stroke volume variation (SVV) could alleviate metabolic acidosis, compared to central venous pressure (CVP) based fluid management. Forty-eight patients, scheduled for elective craniotomy, were randomly allocated to CVP or stroke volume variation (SVV) groups. Cut-off values to challenge the fluids were set at 5 mmHg in the CVP group and 13 in the SVV group, respectively. Arterial blood samples were taken at T1 (immediately after induction), T2 (4 hours after induction), and T3 (at the end of surgery). The pH, standard base excess, and sum of all anion charges of weak plasma acid values at T2 and T3 were significantly lower than values at T1 in both groups. Apparent strong iron differences at T2 and T3 in the CVP group were significantly lower than those in T1, while there were no significant differences between time points in the SVV group. Lactate levels were significantly greater at T2 and T3 than at T1 in both groups. All measured values at each time point and interactions between the groups were comparable. In conclusion, intraoperative goal-directed administration of 0.9% NS did not alleviate the severity of metabolic acidosis, compared to CVP-guided fluid therapy, in patients undergoing brain tumor surgeries.