For the assessment the effect of succinylcholine (SCh) on atracurium, 59 adult patients undergoing elective surgery under general anesthesia were subjected to this study in which the nEMG response (twitch height) of the hand to TOF stimulation
(0.2
Hz)
of ulnar nerve was monitored and recorded with Datex Relaxograph.
According to the amount and mode of the drugs administered, the patients were divided into four experimental groups;
1) Group Ⅰ, a bolus injection of atracurium in dose of 0.5 mg/kg
2) Group Ⅱ, atracurium 1.0 mg/kg, a double dose of groupⅠ
3) Group Ⅲ, atracurium 0.5 mg/kg after 25 to 50% recovery of initial twitch height from twitch height depression induced by SCh (1 mg/kg)
4) Group Ⅳ, mixed injection of SCh (1 mg/kg) and atracurium (0.5 mg/kg) Followings were the results.
1. Mean onset time of the atracurium, which was 4.5±0.6 minutes in group Ⅰand 4.0±0.7 minutes in group Ⅱ, changed to 2.7±0.6 and 4.0±0.8 minutes in group Ⅲand Ⅳrespectively, showing no significance.
2. Mean action duration of atracurium was 49.1±3.4 minutes in group Ⅰand 72.0±3.7 minutes in group Ⅱ, the latter being significant (p<0.001). It was, however, 49.0±3.6 minutes in group Ⅲ, indicating that SCh showed a little effect, while
it
was
38.1±1.8 minutes in group Ⅳ, being significantly shorter than those of group Ⅰand Ⅲ(p<0.01).
3. Mean potency of atracurium expressed by the percentage change of initial twich height was 0.7±0.5% in group Ⅰand it was decreased to 0% in group Ⅱbut it was not sinificant. In group Ⅲ, it was increased to 0.9±0.6% but it was also no
significance. In group Ⅳ, it was decreased to 0.4 0.2% which was not significant.
4. Presence of atracurium (0.5 mg/kg) in group Ⅳdid not have any effect on the intensity of fasciculation induced by SCh.
These results indicated that succinylcholine did not attect the onset time and action potency of atracurium. However, in group of the mixed injection, SCh shortened only the duration of action of atracurium.
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