Hemodynamic effects of neuromuscular blocking agents

Use of Muscle Relaxants in the Intensive Care Unit

Muscle relaxants are now routinely used in intensive care units despite the relative paucity of literature regarding their use, safety, and efficacy in this setting. Although the theory of the pharmacology of muscle relaxants is simple, many clinicians involved in critical care receive little or no formal education about their use either in medical school or during postgraduate training. Proper dosing, careful monitoring, awareness of possible side effects, and adequate sedation facilitate safe use of muscle relaxants in the intensive care unit. Muscle relaxants are not, however, a substitute for sedatives, hypnotics, amnesties, or analgesics and should rarely, if ever, be used without appropriate sedation and analgesia. A wide variety of agents now available with substantial differences in dosing, pharmacology, and side-effect profiles makes clearly delineated indications for use and end points for discontinuation necessary. Using muscle relaxants without monitoring is like using antiarrhythmics without an electrocardiograph.

Hemodynamic and pharmacodynamic comparison of doxacurium and high-dose vecuronium during coronary artery bypass surgery: a cost-benefit study

Doxacurium (DOX), a new nondepolarizing neuromuscular blocking drug (NMBD), was compared in a randomized, double-blind fashion to high-dose vecuronium (VEC) in 60 coronary artery bypass grafting (CABG) patients. A third group of 15 patients older than 70 years of age (DOX-70) was added to compare the effects of DOX to VEC in the older population. Endpoints of the study were hemodynamic stability, ease of ventilation and intubation, anesthesiologist's satisfaction, drug interventions to correct hemodynamic instability, and total cost of the drug. Anesthesia was induced with fentanyl (30 micrograms/kg) along with the NMBD (DOX 80 micrograms/kg, VEC 400 micrograms/kg) over a 2-minute period. Following induction, heart rate (HR) and mean arterial pressure (MAP) were decreased (P < 0.01) in all groups. Tracheal intubation caused the HR to return to baseline in the DOX-70 group. There was no difference in central venous pressure, pulmonary artery occlusive pressure, cardiac index, systemic vascular resistance, and drug intervention for DOX and VEC. None of the patients had evidence of myocardial ischemia. There was a statistically significant but clinically irrelevant decrease in central venous pressure and systemic vascular resistance in the DOX-70 group. The durations of the induction and maintenance doses of DOX were similar in the younger and older patients. Although the intubating dose of VEC had a faster onset of action, this had no effect on the ease of ventilation, conditions for tracheal intubation, and overall anesthesiologist satisfaction. The total cost for each NMBD was not different.(ABSTRACT TRUNCATED AT 250 WORDS)