Cisatracurium in different doses versus atracurium during general anesthesia for abdominal surgery

BACKGROUND: Cisatracurium in clinical practice is devoid of histamine-induced cardiovascular effects. On the other hand, 2 ED(95) doses of cisatracurium (100 µ g/kg) do not create satisfactory intubating conditions such as those seen with equipotent doses of atracurium. The recommended intubating dose of cisatracurium is 3 ED(95). To understand this discrepancy better, we evaluated the potency and onset of atracurium and cisatracurium. MATERIALS AND METHODS: The study designed as randomized controlled clinical trial to compare between atracurium (2×ED(95)) and different doses of cisatracurium (2×ED(95), 4×ED(95), 6×ED(95)) regarding onset time, duration of action, condition of intubation, hemodynamic effects, and sings of histamine release clinically. Sixty four patients were randomly assigned to one of four groups, the first group (group 1) received 2×ED(95) dose of atracurium, group 2 received 2×ED(95) dose of cisatracurium, group 3 received 4×ED(95) dose of cisatracurium, while group 4 received 6×ED(95) dose of cisatracurium. The Datex relaxograph (Type NMT-100-23-01, S/N: 37541) for neuromuscular monitoring was used. RESULTS: HR, MABP was statistically significant increased post-intubation with administration of 2×ED(95) dose of atracurium in group 1 and the same dose of cisatracurium in group 2 but 5-20 min later was not statistically significant with administration of 4×ED(95) and 6×ED(95) doses of cisatracurium in groups 3 and 4, respectively. Onset time was found to be significantly lower with 2×ED(95) dose of atracurium than with the same dose of cisatracurium. At the same time, higher doses of cisatracurium (4×ED(95) and 6×ED(95)) showed onset time and longer duration of action that was significantly lower than with atracurium and with lower dose of cisatracurium (2×ED(95)). Only 6×ED(95) dose of cisatracurium showed statistically significant difference versus the atracurium dose with higher percentages of patients with excellent condition of intubation. 4×ED(95) and 6×ED(95) doses of cisatracurium were significantly better than 2×ED(95) dose of cisatracurium. 2×ED(95) dose of atracurium and 2×ED(95) dose of cisatracurium were similar, while 4×ED(95) and 6×ED(95) doses of cisatracurium were significantly better than atracurium and 2×ED(95) dose of cisatracurium. CONCLUSION: The same dose (2×ED(95) dose) atracurium is more effective neuromuscular blocking agent than cisatracurium, while higher doses of cisatracurium 4×ED(95) and 6×ED(95) provide more effective, more rapid neuromuscular blocking with longer duration of action, stable hemodynamic status, and no associated signs of histamine release clinically.