Recovery from mivacurium block with or without anticholinesterase following continuous infusion in obstetric patients.
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 micrograms/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.
Department of Anaesthesiology, Queen Mary Hospital, Hong Kong.
G S
GS
Jan
W N
WN
Tong
A M
AM
Chan
T W
TW
Hui
J W
JW
Lo
D000759:Adjuvants, Anesthesia / Q000008:administration & dosage; D000328:Adult; D000762:Anesthesia Recovery Period; D000769:Anesthesia, Inhalation; D000771:Anesthesia, Intravenous; D000773:Anesthesia, Obstetrical; D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D001285:Atropine / Q000008:administration & dosage; D002585:Cesarean Section; D002800:Cholinesterase Inhibitors / Q000627:therapeutic use*; D002802:Cholinesterases / Q000097:blood; D004558:Electric Stimulation; D004737:Enflurane / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007275:Injections, Intravenous; D007546:Isoquinolines / Q000008:administration & dosage* / Q000037:antagonists & inhibitors; D008614:Meperidine / Q000008:administration & dosage; D000077590:Mivacurium; D009119:Muscle Contraction / Q000187:drug effects; D009388:Neostigmine / Q000627:therapeutic use*; D019148:Neuromuscular Blockade; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage* / Q000037:antagonists & inhibitors; D009609:Nitrous Oxide / Q000008:administration & dosage; D011247:Pregnancy; D014459:Ulnar Nerve / Q000187:drug effects
D000759:Adjuvants, Anesthesia; D018685:Anesthetics, Inhalation; D002800:Cholinesterase Inhibitors; D007546:Isoquinolines; D003473:Neuromuscular Nondepolarizing Agents; D009388:Neostigmine; D000077590:Mivacurium; D001285:Atropine; D004737:Enflurane; D008614:Meperidine; D002802:Cholinesterases; D009609:Nitrous Oxide