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[Mivacurium--a new muscle relaxant compared with atracurium and vecuronium]
J Scholz1, G von Knobelsdorff, K Peters
1Abteilung für Anästhesiologie des Universitäts-Krankennauses Eppendorf, Hamburg.
Abstract:
This study investigates the effects of mivacurium (3 times ED95) on neuromuscular block, intubation conditions and general safety in comparison with equipotent doses of atracurium and vecuronium. Following Ethical Care Committee approval and informed consent, 90 ASA I+II patients aged 18 to 65 were studied undergoing elective ENT surgery. Anaesthesia was induced with 1.5 mg/kg propofol and 0.2 mg/kg alfentanil and maintained through continuous infusion of propofol (8 to 10 mg . kg-1 . h-1) and nitrous oxide in oxygen. After achieving stable anaesthesia, the patients received bolus injections of mivacurium (0.20 mg/kg, n = 30), atracurium (0.69 mg/kg, n = 30) or vecuronium (0.14 mg/kg, n = 30) for endotracheal intubation. Intubation was attempted 120 s after drug application and the intubation conditions were assessed. Relaxation was recorded using peripheral nerve stimulation (Train of four). During the observation period, signs of histamine release, respiratory difficulty, cardiovascular events or other adverse signs were monitored. Onset of relaxation was longer for mivacurium (2.3 +/- 1.3 min) compared with atracurium (1.4 +/- 0.7 min) or vecuronium (1.3 +/- 0.3 min). Intubation conditions 120 s after drug application were good or very good in only 67% of cases given mivacurium compared with 90% given atracurium and 100% given vecuronium. The recovery time (DUR 25) was shorter in the mivacurium group (19.5 +/- 7.9 min) compared with atracurium (54.7 +/- 6.6 min) and vecuronium (44.3 +/- 8.6 min). Heart rate and blood pressure were similar in all groups. Facial flushing and mild bronchospasms as signs of histamine release resulted more often in the mivacurium (20%) and atracurium groups (23%) than in the vecuronium group (3%). In contrast to atracurium and vecuronium, recovery from mivacurium-induced neuromuscular blockade is rapid. However, the onset time after 3 times ED95 was significantly longer for mivacurium than for atracurium or vecuronium.
Insights
Mivacurium offers rapid recovery from neuromuscular blockade, but has a slower onset compared to atracurium and vecuronium. This study compared these neuromuscular blocking agents for intubation conditions and safety.
Area of Science:
- Anesthesiology
- Pharmacology
Background:
- Neuromuscular blocking agents are crucial in anesthesia for facilitating endotracheal intubation and surgical procedures.
- Mivacurium, atracurium, and vecuronium are commonly used non-depolarizing neuromuscular blockers with varying pharmacokinetic and pharmacodynamic profiles.
Purpose of the Study:
- To compare the efficacy and safety of mivacurium with equipotent doses of atracurium and vecuronium for endotracheal intubation.
- To evaluate neuromuscular block characteristics, intubation conditions, and adverse events associated with these agents.
Main Methods:
- A randomized study involving 90 ASA I+II patients undergoing elective ENT surgery.
- Anesthesia was induced with propofol and alfentanil, maintained with propofol infusion and nitrous oxide.
- Patients received bolus injections of mivacurium (0.20 mg/kg), atracurium (0.69 mg/kg), or vecuronium (0.14 mg/kg) for intubation.
Main Results:
- Mivacurium demonstrated a significantly longer onset of relaxation (2.3 min) compared to atracurium (1.4 min) and vecuronium (1.3 min).
- Intubation conditions were optimal in 67% of mivacurium cases versus 90% for atracurium and 100% for vecuronium.
- Recovery time (DUR25) was substantially shorter with mivacurium (19.5 min) than with atracurium (54.7 min) or vecuronium (44.3 min).
- Histamine release signs (flushing, bronchospasm) were more frequent with mivacurium (20%) and atracurium (23%) than vecuronium (3%).
Conclusions:
- Mivacurium provides rapid recovery from neuromuscular blockade, which is advantageous in certain clinical scenarios.
- However, its slower onset of action at 3x ED95 makes intubation conditions less favorable compared to atracurium and vecuronium.
- Vecuronium offered the best intubation conditions, while mivacurium offered the fastest recovery, highlighting distinct clinical utility profiles.