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 (rSO(2)) 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 rSO(2). 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 rSO(2) in both groups. Pneumoperitoneum decreased rSO(2) in group C, but not in group M. This drop in rSO(2) 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 to group C (p=0.007). The OAAS in group M at 10 min after extubation was significantly higher compared to group C. No differences were found between the 2 groups in cognitive function as measured by MMSE score. CONCLUSION: Preoperative mannitol infusion maintains perioperative rSO(2) during laparoscopic cholecystectomy and shortens extubation time with earlier resurgence of OAAS.