Risk factors for intraoperative hypotension in traumatic intracranial hematoma

Patients suffering from traumatic intracranial hemorrhage (TICH) may experience an episode of catastrophic intraoperative hypotension (IHT), after decompression of the brain. The aim of this study was to investigate the risk factors for IHT during emergency craniotomy A total of 67 patients, who underwent emergency craniotomy due to TICH, were divided into two groups: IHT ( n=31 ) or without IHT ( n=36 ). Data concerning (1) age; (2) gender; (3) mechanism of injury; (4) Glasgow Coma Scale (GCS) on admission; (5) abnormality of the pupils (anisocoria or mydriasis); (6) mean arterial blood pressure; (7) heart rate; (8) time elapsed before craniotomy from injury; (9) initial brain CT scans; (10) duration of craniotomy; and (11) total infusion or urine volume until craniotomy were collected prospectively as IHT risk factors. Low GCS score (<5), tachycardia (heart rate >112min(-1)) and hypertension (mean blood pressure >131mmHg) before emergency craniotomy were strongly ( P<0.05 ) associated with IHT. Delayed surgery (>173min until craniotomy) also had a significant ( P<0.005 ) effect on IHT. The risk factors for IHT were considered as a low GCS score on admission, tachycardia, hypertension before emergency craniotomy and delayed surgery. These results suggested the patients with IHT had a high sympathetic tone before emergency craniotomy A sudden reduction in sympathetic tone after surgical decompression of the brain might cause IHT. We concluded that an important factor in the occurrence of IHT was not only the injury severity, but also the balance between sympathetic and parasympathetic activity before decompression surgery.