Recovery from Mivacurium Block with or without Anticholinesterase following Continuous Infusion in Obstetric Patients

Abstract

Neostigmine antagonism after suxamethonium followed by mivacurium chloride bolus and infusion was studied. Thirty ASA group I or II patients were given mivacurium 0.15 mg/kg followed by infusion during nitrous oxide-enflurane-pethidine anaesthesia. Train of four (TOF) stimuli were applied to the ulnar nerve at the wrist and TOF twitch height and ratio measured by TOF-GUARD nerve stimulator. Mivacurium infusion was titrated to give a 90% block of first twitch height. Patients were randomized into two groups. Group I patients recovered from the mivacurium block spontaneously while Group II patients were given neostigmine 0.05 mg/kg and atropine 0.02 mg/kg. Time to reach train of four ratio (TOFR) of 25%, 50% and 70% were measured. This study demonstrated a mean infusion rate of 5.1±1.8 µg/kg/min to maintain a 90% neuromuscular block. In the spontaneous recovery group, time to reach TOFR of 25%, 50% and 70% were 9.3±2.7 min, 13.5±3.0 min and 16.7±3.0 min respectively while the corresponding times in the neostigmine group were 5.2±1.7 min, 10.9±2.2 min and 16.1±7.4 min respectively. There were significant differences in the time taken to TOFR of 25% (P<0.0001) and 50% (P<0.05) but no difference in the time taken for TOFR to return to 70%. We concluded that mivacurium is suitable for use in caesarean section despite a decrease in plasma cholinesterase activity. Neostigmine antagonism is not required as a routine.

Reversal of mivacurium‐induced neuromuscular blockade with a cholinesterase inhibitor: A systematic review

“…Sixteen randomized controlled studies with data from 546 patients were included . Six studies compared spontaneous recovery with both neostigmine and edrophonium reversal .…”

“…Six studies compared spontaneous recovery with both neostigmine and edrophonium reversal . Five studies compared spontaneous recovery with neostigmine reversal and five studies compared spontaneous recovery with edrophonium reversal No studies on pyridostigmine were included. The overall assessment of the risk of bias for individual studies resulted in three studies judged as high quality, 11 as acceptable and two as low (Table ).…”

“…In Jan all patients were given suxamethonium before intubation. When T 1 had returned to 70% of the baseline twitch, a mivacurium bolus was given followed by an infusion titrated to T 1 10%.…”

The tof-guard neuromuscular transmission monitor and its use in horses

“…Mean recovery index (T1 25-75%) of pancuronium and atracurium was twice and four times respectively, when comparing to the values presented by CULLEN (1996) with the dosage of 82-140µg/kg of pancuronium (T1=50%) and 70-85µg/kg of atracurium (T1=100%). The time points chosen for this study were established in recent human medical studies with muscle relaxants (JENSEN et al, 1993;HODGES, 1996;ANSERMINO, 1996;JAN et al, 1996; -*** 72.5 58.4 SD: standard deviation *: did not reach a T1=0 **: did not decrease the T1 under 25% ***: did not lower its TOF ratio below 0.7 Figure 2 -Mean values of time for onset (T1 = 0), clinical duration of action (T1 = 25%), recovery index (T1 25-75%) and action time (TOF=0.7) of the muscle relaxants pancuronium (5 animals) and atracurium (7 animals) given intravenously to horses. al., 1996;LLLWITZ et al, 1997;HANS et al, 1997).…”

“…Previous studies made in human medicine comparing the TOF-Guard with the Myograph 2000, showed that there is a very close positive correlation between the values of T1 (control twitch height), the TOF ratio and PTC, simultaneously measured by both methods (UEDA et al, 1994;MELLONI, 1995). However, other studies suggested that the TOF-Guard should not be used interchangeably with the Myograph because of a wide limit of agreement between the two monitors (MCCLUSKEY et al, 1997;LOAN et al, 1995) Recent studies had been performed using the TOF-Guard to evaluate different nondepolarizing neuromuscular blocking agents in children (HODGES, 1996;ANSERMINO, 1996) and adults (JENSEN et al, 1993;JAN et al, 1996;HANS et al, 1996;LLLWITZ et al, 1997;HANS et al, 1997).…”