Normal saline versus balanced-salt solution as intravenous fluid therapy during neurosurgery: effects on acid-base balance and electrolytes.

Background: This prospective, randomized controlled study compared the changes in acid-base balance and serum electrolytes with the use of intravenous balanced and non-balanced crystalloid solutions intraoperatively during elective neurosurgery.
Methods: Thirty consented adult patients who underwent craniotomy were randomly allocated into two groups of 15 patients each. The non-balanced group received 0.9% normal saline while the balanced group received Sterofundin®ISO as the intraoperative fluid for maintenance. Biochemical indices for acid-base balance and serum electrolytes were analyzed periodically.
Results: In the non-balanced group, significant changes were noted in the pH, base excess and bicarbonate values over time compared to its respective baseline values (P<0.01). Four patients (27.7%) also developed a pH<7.35 and 5 patients (33.3%) developed marked acidosis with base excess <-4.0 at the end of surgery. Both mean sodium and chloride levels were also significantly higher compared to its baseline values respectively (142.6±2.4 versus 138±2.7 mmol/L, P<0.01 and 105.7±4.1 versus 113.2±3.0 mmol/L (P<0.01).
Conclusions: A balanced solution (Sterofundin®ISO) provided significantly better control over acid-base balance, sodium and chloride levels when used as intraoperative fluid maintenance and replacement during elective neurosurgery.