Comparison of the Effects of Hypertonic Saline 3.2% and Mannitol 20% on Brain Relaxation during Brain Tumor Surgery

Background: In this study, we compared the effects of hypertonic saline (HTS) 3.2% and mannitol 20% on brain relaxation during brain tumor surgery. Methods: This prospective, randomized study included patients who were selected for elective craniotomy for brain tumors. Patients received either 1 g/kg of HTS 3.2% (HTS group; n = 20) or 1 g/kg of mannitol 20% infusion (M group, n = 20) for 10 minutes at the start of scalp incision. Carbon dioxide partial pressure (PCO2) in arterial blood was maintained at 30-35 mmHg. Brain relaxation was rated as 0-3 by a surgeon. Surgeons assessed the condition of the brain as tight, appropriate, or soft immediately after opening the dura. Data was collected using a checklist and then analyzed by chi-square test with SPSS16. Findings: The mean age of the HTS and M groups was 48.9 ± 10.8 and 47.4 ± 12.1, respectively (P = 0.670). There was not a significant difference between the American Society of Anesthesiologists (ASA) scores of the two groups (P = 0.430). In the HTS group, 60.0% of patients were in class II of brain relaxation conditions and 40.0% were in class III. In the M group, 42.1%, 52.6%, and 5.3% were in class I-III of brain relaxation conditions, respectively (P = 0.043).  Intracranial pressure (ICP) 20 minutes after the operation was lower in the HTS group compared to the M group (P = 0.001). However, ICP at the 30th and 40th minutes was not significantly different between the two groups. Conclusion: Our results suggest that HTS provided better brain relaxation than did mannitol during elective brain tumor surgery. HTS is also cheaper than mannitol. HTS can increase cardiac output, accelerate resuscitation, and decrease inflammation and ICP. Keywords: Hypertonic saline, Mannitol, Brain relaxation, Tumor surgery