EVALUATION OF CISATRACURIUM, A NEW NEUROMUSCULAR BLOCKING-AGENT, FOR TRACHEAL INTUBATION

Purpose: The primary objective of this study was a blinded, randomized comparison of the recommended intubating dose of atracurium (0.5 mg . kg(-1)) with an approximately equipotent dose of cisatracurium (0.1 m g . kg(-1)) during N2O/O-2/propofol/fentanyl anaesthesia. Methods: Eig hty ASA physical status I or 2 patients: 18-70 yr of age, within 30% o f ideal body weight, scheduled for elective low to model-ate risk surg ical procedures were studied. Adductor pollicis evoked twitch response s were measured with Grass FT 10 force displacement transducer(Grass I nstruments, Quincy, MA) and continuously recorded on a Gould multichan nel polygraph (Gould Instrument Systems, Cleveland OH) after induction of anaesthesia. Results: Increasing the initial dose of cisatracurium (from 0.1 to 0.15 and 0.2 mg . kg(-1), decreased mean time of onset ( from 4.6 to 3.4 and 2.8 min, respectively), and increased mean time of clinically effective duration (45 to 55 and 61 min, respectively). Re covery to a T-4:T-1 ratio of 0.7 occurred approximately seven minutes following administration of the reversal agent neostigmine for all tre atment groups. Intubation conditions were good or excellent in over 90 % of patients in all treatment groups (two minutes after approximately 2 x ED(95) doses of cisatracurium or atracurium and 1.5 minutes after 3 x and 4 x ED(95) doses of cisatracurium). Conclusion: The intubatio n results reported in this study together with the combination of pred ictable recovery from neuromuscular block and apparent haemodynamic st ability make cisatracurium a potentially useful muscle relaxant in cli nical practice.