Objectives
Assessment of the value of using mannitol for the reduction of intracranial pressure and optimizing surgical condition during awake craniotomy.
Methods
Forty patients; 21 males and 19 females; 21 ASA I and 19 ASA II patients. Twenty patients had left hemispheric tumors and 14 patients had right hemispheric tumors, while six patients suffered from epilepsy. Patients were randomly allocated into two equal groups. Group A, was given mannitol, while to group B no mannitol was given (but kept as a rescue drug). Intracranial pressure (ICP) and blood gases were recorded every 15 min till the end of surgery. Surgeon satisfaction regarding brain status, tense or slack was recorded. Postoperative nausea and vomiting (PONV), fits and electrolyte disturbances were noted.
Results
Intracranial pressure (ICP) readings were comparable between the two groups at baseline, skin incision and 15 min after. Mannitol effect on ICP appeared as a lower reading of ICP in group A from 30 min after skin incision till dural exposure and incision. Impact of hyperventilation on ICP measures was evident in both groups since prior to dural incision till after dural closure. However, there was no difference regarding brain status judged by the surgeon between the two groups as brain was found to be slack in 19 patients versus18 patients in groups A and B, respectively. Blood CO levels in blood gases showed progressive declination in both groups from the start of hyperventilation till the end of surgery. Potassium (K) correction was needed in four patients in the mannitol group. Three patients in group A suffered from nausea versus one patient in group B. A single patient in each group suffered from fits.
Conclusion
Usage of mannitol did not add much benefit over ICP perception and brain status in elective awake craniotomy and mannitol should be kept as a rescue drug if needed.