| The mediate acting neuromuscular blocking agent (vecuronium) has been widely used in the clinic. Traditionally, it will be administered by intermittent bolus injection, since it has a short effective duration and a fast recovery , we need to infuse it frequently. So it is difficult to keep plasma concentration stable to maintain constant neuromuscular blockade, even because of untimely or a large cumulative dose, we have to face the problem of residual block or prolonged recovery. Target-controlled infusion (TCI) is a new intravenous drug delivery technique which has shown its unique advantage in induction and maintenance of anesthesia, phamacodynamics study and patient control analgesia. TCI of barbiturates,midazolam,opoid et al has been much reported, but the account about myorelaxant is rarely. Therefore the purpose of the present study is to examine whether TCI has more advantage than intermittent bolus injection of vecuronim. 30 patient scheduled to undergo abdominal surgery divided into two equal groups were randomly allocated to target-controlled infusion (T group) or intermittent bolus injection (C group). Total intravenous anesthesia was adoped, all patients received premedication with scopolamine 0.3 mg im. before induction of anesthesia. The depth was monitored with BIS and the neuromuscular transimission (NMT) was monitored using train-of-four (TOF) stimulation of ulnar nerve and recording the force of contraction of the adductor pollicis muscle. Anesthesia was induced with midazolam 0.01mg.kg-1 and fentanyl 4ug. kg-1 , followed by TCI of propofol . NMT minitoring was preferably begun after the induction of sleep , then calibrated by the 100% reference level (Tc) .The lever of neuromuscular block was assessed by the value of T1/Tc ,T1 was the first response after TOF stimulation . Neuromuscular block of T group was induced and maintained with vecuronium given by TCI , the initial target concentration was 0.5ug.ml-1, while C group was induced by bolus injection of vecuronium 0.1mg.kg-1. when T1/Tc ≤5%, trachea was intubated . To keep T1/Tc ≤25% ,wetitrated the target concentration in T group, in C group increments 0.05mg.kg-1 was given iv., until 20-30 min before the end of the operation . Neostigmine was administered to the patient who couldn't respirate well 20 min after the operation.Inspected and memorized the following : (1) the value of HR,BP,BIS and T1/Tc when the stimulus of the operation was the most violent . (2) the total and average amount of fentanyl propofol and vecuronium (3) the recovery index of neuromuscular agent after stoping using myorelaxant (4) the number of which required increments of sedatives or analgesics 30 min before the end (5) postoperative extubation time (6) the number of which needed neostigmine antagonism . Results were expressed as mean + SD , comparisons were made throught test or x2 test. A value of p <0.05 was considered significant. There were no significant differences between T and C group with respect to anthropometric characteristics and types,time of surgery they had . The total and average amount of the drugs they used also had no statistics differences , but using TCI can...
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