Sensibilité à l’atracurium des muscles abdominaux latéraux

Abstract

Objective: To study the effect of atracurium on the electromyographic activity of the lateral abdominal muscles and adductor pollicis in anaesthetized subjects. Study design: Prospective, comparative, open study. Patients and methods: Sixteen patients, ASA physical status 1 or 2, undergoing elective orthopaedic surgery under general anaesthesia were studied. Anaesthesia was induced with propofol/fentanyl and orotracheal intubation performed after glottic local anaesthesia without using muscle relaxant. Anaesthesia was maintained with isoflurane/nitrous oxide/oxygen and fentanyl reinjections. Supramaximal percutaneous stimulations in a simple twitch mode (0.1 Hz) were applied at the 9th–10th intercostal nerve on the posterior axillary line and at the ulnar nerve at the wrist. The electromyographic responses were enregistered using skin surface electrodes, placed on the D9–D10 dermatome in regard of the lateral abdominal muscles and of the thenar muscles. After a single bolus dose of atracurium 0.5 mg·kg –1, the following parameters were studied : the maximum effect (Emax), the time for obtaining Emax (Delay) and the recovery time of 5,10, 25, 50,75 and 100% of the control neuromuscular response (T5, T10, T25, T50, T75, T100). Results: The dose of 0.5 mg·kg –1 of atracurium induced 100% block in both lateral abdominal muscles and adductor pollicis. Lateral abdominal muscles blockade had faster onset (136 ± 4 s versus 205 ± 29 s) and shorter recovery, T5, T10, T25, T50, T75 and T100 were significantly ( p < 0.05) shorter than at the adductor pollicis. Conclusion: Lateral abdominal muscles blockade have faster onset and recovery than adductor pollicis.