Air-embolism in the semi-sitting position for craniotomy: A narrative review with emphasis on a single centers experience.

Albeit the semi-sitting position in neurosurgery has been in use for several decades, its application remains controversial in the neurosurgical and neuro-anaesthesia communities. The imminent and most feared risk of the sitting position is air entry into the vascular system due to the negative intravascular pressure leading to potentially life-threatening air embolism with its consequences. Recent advents in neurosurgical (improvement of the operating microscope, employment of intra-operative neurophysiological monitoring) and neuro-anaesthesia care (new anaesthetics, advanced monitoring modalities) have significantly impacted the approach to these surgeries. Vigilant intra-operative observation by an experienced team and peri-operative patient management guided by institutional protocols improves the safety profile of these surgeries. This review outlines the workflow and protocols used in our institution for all cases of semi-sitting position for skull base neurosurgery.

Non-convulsive status epilepticus in the postanesthesia care unit following meningioma excision.

PURPOSE: Non-convulsive status epilepticus (NCSE) is an underdiagnosed clinical entity in which electrical seizures occur with subtle or no overt clinical manifestations. It can cause delayed recovery from anesthesia and constitutes an important differential diagnosis for prolonged postoperative unconsciousness. This condition can be diagnosed only by electroencephalogram (EEG), and the institution of early treatment is associated with better prognosis. This case is presented to illustrate the occurrence of this rare clinical entity in a patient who had undergone extradural surgery. CLINICAL FEATURES: An elderly female with no history of seizures or predisposing factors for convulsions underwent an uncomplicated left frontotemporal craniotomy for excision of an extradural meningioma. She was unresponsive following surgery, which could not be explained by the imaging and laboratory investigations. A subsequent EEG demonstrated periodic epileptiform discharges in lateralized left hemispheric distribution characteristic of seizures. The seizures were not effectively prevented by prophylactic fosphenytoin; however, the patient responded slowly to intravenous levetiracetam, which is known to be a more effective treatment for NCSE. The patient had no predisposing factors for the development of seizures and was undergoing an extradural surgery. CONCLUSIONS: This case illustrates NCSE and emphasizes the importance of obtaining an electro-encephalogram early following craniotomy to diagnose any changes in the patient's mental status. This case also emphasizes that institution of early treatment is important to assure better prognosis.