Planning for early emergence in neurosurgical patients: a randomized prospective trial of low-dose anesthetics

For early detection of a cerebral complication, rapid awakening from anesthesia is essential after craniotomy. Systemic hypertension is a major drawback associated with fast tracking, which may predispose to formation of intracranial hematoma. Although various drugs have been widely evaluated, there are limited data with regards to use of anesthetics to blunt emergence hypertension. We hypothesized that use of low-dose anesthetics during craniotomy closure facilitates early emergence with a decrease in hemodynamic consequences.

Three emergent techniques were evaluated in 150 normotensive adult patients operated for supratentorial tumors under standard isoflurane anesthesia. At the time of dural closure, the patients were randomized to receive low-dose propofol (3 mg.kg(-1).h(-1)), fentanyl (1.5 microg.kg(-1).h(-1)) or isoflurane (end-tidal concentration of 0.2%) until the beginning of skin closure. Nitrous oxide was discontinued after head dressing.

Median time to emergence was 6 min with propofol, 4 min with fentanyl, and 5 min with isoflurane (P=0.008). More patients had hypertension in the pre-extubation compared with extubation or postextubation phase (P=0.009). Comparing the three groups, fewer patients required esmolol with fentanyl use overall, and in the pre-extubation phase (P=0.01). Significant midline shift in the preoperative cerebral imaging scans was found to be an independent risk factor for emergence hypertension.

Pain during surgical closure may be an important cause of sympathetic stimulation leading to emergence hypertension. The use of low-doses of fentanyl during craniotomy closure is more advantageous than propofol or isoflurane for early emergence in neurosurgical patients and is the most effective technique for preventing early postoperative hypertension.