19. Effect of hypertonic saline and mannitol on patients undergoing supratentorial tumor surgery

Background: To compare the efficacy of equimolar, equivolemic solutions of 3% hypertonic saline and 20% mannitol on intraoperative brain relaxation in patients with clinical and radiological evidence of raised ICP undergoing surgery for supratentorial tumors. Materials and Methods: This study was carried out on 30 ASA I-III patients with age group ranging between 18-65 years, undergoing supratentorial tumor surgery. Patients received equimolar, equivolemic solutions of 3% hypertonic saline (osmolarity-1024) and 20% mannitol (osmolarity-1098). Both the agents were administered at the dose of 5 ml/kg over a period of 15 minutes. Patients with previous history of electrolyte imbalance and getting hypertonic saline (HTS) prior to the surgery were excluded from the study. Brain relaxation was assessed by anesthesiologist (on a 3 point scale) and surgeon (on a 4 point scale). Results: Equimolar solutions of both mannitol and 3% saline produced similar relaxation as assessed by surgeon and anesthesiologist. Urine output was more in mannitol group where as hypertonic saline group had increased serum sodium concentration, which returned to normal in 48 hours. CVP and mean arterial pressure were maintained close to the baseline in HTS group but CVP was higher in mannitol group but returned to normal in 3-4 hours. Conclusions: Since both these agents’ mannitol and HTS have nearly equimolar concentration, they produce similar brain relaxation. Gemma et a., l (1997) and Rozet et al., (2007) also had similar observations. Equimolar concentration of HTS and mannitol produce similar brain relaxation in patients undergoing surgery for supratentorial tumors.