Mannitol Improves Cerebral Oxygen Saturation

Effect of Preoperative Mannitol Infusion on Cerebral Oxygen Saturation and Patients' Recovery After Laparoscopic Cholecystectomy

Decreased cerebral oxygen saturation (rSO2) was reported to occur during insufflation for laparoscopic procedures due to increased Intracranial pressure (ICP) with resultant decrease in cerebral perfusion pressure.

Forty patients scheduled for laparoscopic cholecystectomy will be enrolled in this double blind, randomized controlled study. Patients will receive either 0.5g/kg of 20% intravenous (i.v.) mannitol infusion over 10 minutes immediately before induction of anesthesia (group M) or an equal volume of 0.9% normal saline instead (group C). Primary outcome measure is rSO2. Secondary outcome variables include 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 after recovery.

Inclusion Criteria:

• American Society of Anesthesiologists physical status I or II
• aged between 25 and 50 years
• with a body mass index (BMI) 22-34 kg/m2

Exclusion Criteria:

• obstructive or restrictive pulmonary disease
• cardiac dysfunction