Effects of vecuronium bromide on intracranial pressure and cerebral perfusion pressure. A preliminary report

Neuromuscular blocking agents in the neurosurgical intensive care unit

The long-term administration of neuromuscular blocking (NMB) agents in the ICU has increased in frequency the last several years. NMB agents in the ICU patient facilitate intubation and ventilatory support, decrease oxygen demand and consumption, facilitate bedside procedures and diagnostics, and potentially decrease intracranial pressure. However, NMB agents have extensive adverse effect profiles and require close monitoring. Two major classes of NMB agents exist: depolarizing and nondepolarizing. Depolarizing NMB agents work by mimicking the effect of acetylcholine at the nicotinic cholinergic receptor. Continuous depolarization inhibits repolarization, resulting in paralysis. Nondepolarizing NMB agents induce muscle paralysis by their competitive antagonism at the nicotinic cholinergic receptor. The neurosurgeon must be aware that NMB agents are paralytics only and should only be used in patients who are sedated and receiving adequate analgesia. Appropriate drug selection demands a thorough knowledge and understanding of each patient's neurologic, metabolic, and cardiovascular status and the hemodynamic, autonomic, pharmacokinetic, pharmacodynamic, and cost profiles of the NMB agents.

Effects of cisatracurium on cerebral and cardiovascular hemodynamics in patients with severe brain injury

BACKGROUND

For neuroanesthesia and neurocritical care the use of drugs that do not increase or preferentially decrease intracranial pressure (ICP) or change cerebral perfusion pressure (CPP) and cerebral blood flow (CBF) are preferred. The current study investigates the effects of a single rapid bolus dose of cisatracurium on cerebral blood flow velocity, ICP, CPP, mean arterial pressure (MAP) and heart rate (HR) in 24 mechanically ventilated patients with intracranial hypertension after severe brain trauma (Glasgow coma scale <6) under continuous sedation with sufentanil and midazolam.

METHODS

Patients were randomly assigned to receive either 2xED95 (n=12) or 4xED95 (n=12) of cisatracurium as a rapid i.v. bolus injection. Before and after bolus administration mean cerebral blood flow velocity (BFV, cm/s) was measured in the middle cerebral artery using a 2-MHz transcranial Doppler sonography system, ICP (mm Hg) was measured using an extradural probe, and MAP (mm Hg) and HR (b/min) were measured during a study period of 20 min. Cerebral perfusion pressure (CPP=MAP-ICP) was also calculated.

RESULTS

Our data show that a single bolus dose of up to 4xED95 cisatracurium caused no significant (P<0.05) changes in BFV, ICP, CPP, MAP and HR. Possible histamine-related events were not observed during the study.

CONCLUSIONS

The results from this study suggest that cisatracurium is a safe neuromuscular blocking agent for use in adult severe brain-injured patients with increased ICP under mild hyperventilation and continuous sedation.