Effects of Fentanyl-induced Rigidity on the Intracranial Pressure in Rabbits / 대한마취과학회지

ABSTRACT

BACKGROUND: It is important to control of intracranial pressure(ICP) in patients with intracranial pathology. To decrease ICP and to attenuate the adverse cardiovascular reflexes associated with anesthetic induction and tracheal intubation, we are often administered potent opiates during anesthetic induction. A side effect of these agents when used in large doses is muscle rigidity. We investigated the effects of high dose fentanyl on ICP, central venous pressure (CVP) and mean arterial pressure (MAP) during fentanyl-induced rigidity in rabbits. METHODS: Under halothane anesthesia, polyethylene catheters were surgically inserted into the femoral artery and vein for measurement of MAP and CVP in 10 rabbits. ICP was measured between epidural and subdural space through the burr hole of the frontal bone by means of fiberoptic ICP monitor. The animals were mechanically ventilated to achieve normocarbia. Following instrumentation, halothane was discontinued and fentanyl 50 microgram/kg administered intravenously at the first movement during emergence from halothane anesthesia. RESULTS: In the seven rabbits that developed rigidity, ICP and CVP were increased significantly compared to control value (delta ICP 9.2+/-1.9 mmHg, delta CVP 5.0+/-0.9 cmH2O P<0.05). But MAP was decreased significantly from 95+/-5 to 74+/-4 mmHg (P<0.05). These variables except MAP were returned to baseline when rigidity was abolished with vecuronium. In three rabbits that did not show rigidity, ICP and CVP did not change following injection of fentanyl. But MAP in the non-rigidity group was significantly decreased like the rigidity group (P<0.05). CONCLUSIONS: These observations suggest that rigidity should be prevented when opiates like fentanyl are used as an induction drug of patients with ICP problems.