Comparison of Two Muscle Relaxants for Tracheal Intubation in Patients Undergoing Surgery at Goa Medical College and Hospital

Abstract

BACKGROUND Cisatracurium and atracurium are intermediate acting muscle relaxants which do not depend on renal or hepatic metabolism for elimination since they undergo Hofmann elimination. Despite the advantages of cisatracurium such as minimal effects on the cardiovascular system, no accumulative effects, no metabolite toxicity, and metabolic product has no neuromuscular blocking effects, due to slow onset and unsatisfactory intubating conditions, the use of cisatracurium is limited compared with those seen with equipotent doses of other neuromuscular blocking agents. This study was undertaken to find onset time and intubating conditions with 3 × ED95 doses of atracurium versus cisatracurium. METHODS ASA grade 1 or 2 patients, (N = 220) were randomly allocated into 2 groups to receive equipotent doses of either atracurium or cisatracurium. Intubating conditions were assessed using Cooper et al scale and neuromuscular monitoring done using TOF Watch SX. Haemodynamic responses and any adverse effects were noted. RESULTS The onset time was 167.36 ± 75.41 seconds (2.78 ± 1.25 minutes) in atracurium group whereas in cisatracurium group, onset time was 249.26 ± 75.90 seconds (4.15 ± 1.26) and the difference was statistically significant with p value of < 0.001. The difference in intubating conditions between the groups was statistically insignificant. However, atracurium produced a higher incidence of clinically acceptable conditions (excellent in 94.4 %) than cisatracurium (excellent in 87.3 %). The incidence of adverse effects such as erythema, flushing and bronchospasm was greater in Atracurium group though hypotension was observed in both groups. CONCLUSIONS Onset time and intubating conditions are significantly better with equipotent doses of atracurium compared to cisatracurium. But atracurium is associated with higher incidence of adverse effects such as erythema, flushing and bronchospasm, though the potential of cisatracurium to cause anaphylactoid reactions cannot be ignored. KEYWORDS Cisatracurium, Atracurium, Muscle Relaxants, Neuromuscular Blocking Agents, Erythema, Flushing, Bronchospasm, Hypotension, Anaphylactoid Reactions