effect of magnesium sulphate [MgSo4] pretreatment on atracurium induced neuromuscular blockade

Magnesium inhibits the release of acetylcholine from the motor nerve terminals and thus potentiates the action of the non- depolarizing neuromuscular blocking drugs. The effect of pretreatment with magnesium sulfate on the neuromuscular block after atracurium administration was studied. Forty adult patients were allocated randomly into two groups. Control group [n=20] received atracurium only, while the MgSO4 group [n=20] received atracurium after pretreatment with MgSO4 [40 mg kg-1]. In all patients midazolam was given as premedication and anesthesia was induced with fentanyl and thiopentone and tracheal intubation was performed with atracurium 0.5 mg kg-1. The neuromuscular transmission was monitored using mechanomyography and TOF stimulation. For each patient the onset time, the clinical duration, the recovery index were determined. The intubation time and the intubation conditions were also described. The results are given and discussed

Comparison of cardiovascular and neuromuscular properties of pancuronium, doxacurium and pipecuronium during induction of anesthesia for open heart surgery

This study compared hemodynamic and neuromuscular properties of pancuronium, doxacurium and pipecuronium during induction of anesthesia in 45 patients undergoing open valvular heart surgery. Anesthesia was induced with fentanyl 10 mg.kg-1 and thiopentone 23 mg.kg-1. Each patient received twice the ED95 of either pancuronium [0.15 mg.kg-1, n=15] or doxacurium [0.05 mg.kg-1, n=15] or pipecuronium [0.1 mg.kg-1 n=15]. Hemodynamic measurements were recorded before induction of anesthesia, before intubation, immediately after intubation and five minutes post-intubation. Pancuronium significantly increased heart rate and mean arterial blood pressure, but this decrease was not statistically significant and heart rate was nearly stable. On the other hand, there was minimal change in heart rate and mean arterial blood pressure with pipecuronium. Other hemodynamic parameters did not change. The time from muscle relaxant administration to 95% suppression of the first twitch of train of 4 stimuli was significantly longer for doxacurium than that for pancuronium and pipecuronium. Therefore, pipecuronium seems to be more satisfactory neuromuscular blocker than either pancuronium or doxacurium for induction of anesthesia for open heart surgery