Evaluation of cisatracurium, a new neuromuscular blocking agent, for tracheal intubation

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 mg. kg-1) during N2O/O2/propofol/fentanyl anaesthesia.

Eighty ASA physical status 1 or 2 patients, 18-70 yr of age, within 30% of ideal body weight, scheduled for elective low to moderate risk surgical procedures were studied. Adductor pollicis evoked twitch responses were measured with a Grass FT 10 force displacement transducer (Grass Instruments, Quincy, MA) and continuously recorded on a Gould multichannel polygraph (Gould Instrument Systems, Cleveland, OH) after induction of anaesthesia.

Increasing the initial dose of cisatracurium (from 0.1 to 0.15 and 0.2 mg. k-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). Recovery to a T4:T1 ratio of 0.7 occurred approximately seven minutes following administration of the reversal agent neostigmine for all treatment groups. Intubation conditions were good or excellent in over 90% of patients in all treatment groups (two minutes after approximately 2 x ED95 doses of cisatracurium or atracurium and 1.5 minutes after 3 x and 4 x ED95 doses of cisatracurium).

The intubation results reported in this study together with the combination of predictable recovery from neuromuscular block and apparent haemodynamic stability make cisatracurium a potentially useful muscle relaxant in clinical practice.