Positive end-expiratory pressure reduces pneumocephalus in spinal intradural tumor surgery

We tested the hypothesis that 5 cm H2O of positive end-expiratory pressure (PEEP) reduces the incidence of pneumocephalus in patients who undergo spinal intradural tumor surgery. Fifty-three ASA I to III patients who underwent thoracolumbar intradural tumor surgery between the years 2003 and 2006 were included in this study. All patients received propofol, fentanyl, and cisatracurium for induction of the anesthesia. Maintenance was provided by propofol infusion and, oxygen (50%) and air (50%). Group I (n=28) did not receive PEEP whereas group II (n=25) received PEEP as 5 cm H2O. Cranial computerized tomography was taken at 8 hours after the surgery and cases were evaluated for pneumocephalus using BAB Bs200ProP Image System software. Pneumocephalus areas between 0.03 and 4.24 cm2 were observed in 9 patients, 8 in group I and 1 patient in group II at the 8th postoperative hour, at various localizations. There were no neurologic findings in other patients except for 2 patients in group I who presented with headache and mental status change. Although the cerebrospinal fluid leakage is minimal, N2O is not used and the patients are well hydrated, pneumocephalus with neurologic deficits may occur in patients undergoing microsurgical spinal intradural tumor surgery in prone position. In our study, we showed that using 5 cm H2O PEEP perioperatively reduced the risk of pneumocephalus. However, more cases must be studied to support this hypothesis.