The advanced age and associated medical problems affecting so many patients with chronic subdural hematomas has prompted many authorities to advocate burr hole or twist drill drainage under local anesthesia. Although this may be adequate for twist drill hematoma evacuation, multiple burr holes are best done under general endotracheal intubation. Otherwise, the patient obscured by the drapes is difficult to monitor intraoperatively. As intracranial pressure is relieved, patients often suddenly arouse from lethargy; their unrestrained movements may contaminate the operative field. Airway management would be problematic in the rare patient who deteriorates or in whom a craniotomy is found to be necessary. Nitrous oxide is best avoided or stopped several minutes prior to ceasing anesthesia. Accumulation of the gas in the residual subdural cavities can cause tension pneumocephalus.