Preoperative mannitol infusion improves perioperative cerebral oxygen saturation and enhances postoperative recovery after laparoscopic cholecystectomy

OBJECTIVES To test the effect of preoperative mannitol infusion on perioperative decreased cerebral oxygen saturation (rSO2) during laparoscopic cholecystectomy. METHODS Forty patients scheduled for laparoscopic cholecystectomy were enrolled in this study conducted at Dammam Hospital of the University, Dammam, Kingdom of Saudi Arabia from December 2013 to June 2014. Patients received either 0.5 g/kg of 20% intravenous mannitol infusion over 10 minutes before induction of anesthesia (group M), or an equal volume of normal saline instead (group C). Primary outcome variable was rSO2. Other variables included extubation time, clinical assessment of consciousness recovery using the Modified Observer's Assessment of Alertness/Sedation Scale (OAA/S), and the mini-mental state examination (MMSE) for cognitive evaluation. RESULTS Anesthesia induction increased rSO2 in both groups. Pneumoperitoneum decreased rSO2 in group C, but not in group M. This drop in rSO2 in the group C reached its maximum 30 minutes after extubation, and was significantly less than the preinduction value. Time to extubation in group M was significantly shorter compared with group C (p=0.007). The OAAS in group M at 10 min after extubation was significantly higher compared with group C. No differences were found between the 2 groups in cognitive function as measured by MMSE score. CONCLUSION Preoperative mannitol infusion maintains perioperative rSO2 during laparoscopic cholecystectomy and shortens extubation time with earlier resurgence of OAAS.