Intracranial pressure mean arterial pressure and heart rate after rapid paralysis with atracurium in cats.

The effect of atracurium on intracranial pressure (ICP) was investigated in six cats with normal and increased ICP. The cats were anaesthetized with intraperitoneal pentobarbitone (33 mg . kg-1), acepromazine (0.6 mg . kg-1) and incremental fentanyl (p.r.n. approximately equal to 20 micrograms . kg-1), intubated, and ventilated with nitrous oxide in oxygen. Mean arterial pressure (MAP), heart rate (HR), twitch response and ICP were continuously recorded. After the effect of atracurium had been ascertained under the condition of normal ICP, and after full recovery of twitch response, pH-adjusted Ringer's lactate solution was infused into the cisterna magna until an ICP baseline of 26 +/- 2 mmHg was established and stabilized. Atracurium was then administered again to determine its effect under the condition of elevated ICP. Complete ablation of twitch response was obtained in 68 +/- 15 sec with 0.4 mg . kg-1 atracurium, and there was no significant change in ICP, MAP, HR or cerebral perfusion pressure (CPP) whether initial ICP was normal or elevated.