BACKGROUND: There were many reports about the effect of succinylcholine on the action of nondepolarizing muscle relaxants. The results are inconsistent depend on the nondepolarizing muscles relaxants used, time when nondepolarizing blockers administered and methods of experiments etc. We investigated the effect of succinylcholine on the neuromuscular blockade induced with mivacurium, a new short acting nondepolarizing muscle relaxant, when mivacurium was administered during early and late recovery from succinylcholine block and when different dose of succinylcholine were used. METHODS: 30 rabbits were divided into 5 groups including control group. Control group was administered mivacurium only. In other 2 groups, succinylcholine (3xED95) was administered, and mivacurium was given at 5% and 100% recovery from succinylcholine. In the other two groups, succinylcholine (6xED95) was administered, and mivacurium was given at 5% and 100% recovery from succinylcholine. We investigated onset time, duration of relaxation, and recovery index of mivacurium induced neuromuscular block. RESULTS: Onset time was shortened in all groups compare to control group. Duration and recovery index were not changed significantly at 5% and 100% recovery of succinylcholine (3xED95) administered group, but prolonged significantly (p<0.05) in succinylcholine (6xED95) administered groups compare to control group. CONCLUSION: Mivacurium induced block were more prolonged at 100% recovery of succinylcholine (3xED95) induced block and these effect were more potentiated by the increasing the dose of succinlycholine (6xED95) administered group.
Muscles ; Neuromuscular Blockade* ; Neuromuscular Nondepolarizing Agents ; Rabbits ; Relaxation ; Succinylcholine*

BACKGROUND: It has long been held that antiepileptics reduce the duration of action, and increase the requirement for, neuromuscular blocking agents. However, levetiracetam, a relatively novel antiepileptic agent, possesses different pharmacokinetic properties to other, conventional antiepileptics, such that its effect on neuromuscular blocking agents might also differ. The purpose of this retrospective study is to investigate the effect of levetiracetam on the clinical duration of rocuronium. METHODS: In this study, the duration of neuromuscular blockade induced by rocuronium was compared between control and levetiracetam-receiving groups. The data were retrieved from one of our previous studies. RESULTS: The control and levetiracetam groups comprised 16 and 13 patients, respectively, all of whom underwent cerebrovascular surgery. Subjects received supplementary rocuronium (0.15 mg/kg) whenever the train-of-four count reached 2 during surgery. The interval between supplementary rocuronium (0.15 mg/kg) injections was significantly longer in the levetiracetam vs. control group (50 and 39 minutes, respectively; P = 0.036). CONCLUSIONS: The present results challenge the convention that antiepileptics decrease the duration of action of neuromuscular blockers, thereby alerting clinicians to the possibility of prolonged neuromuscular blockade in patients taking levetiracetam. Anesthetic management should encompass careful neuromuscular monitoring in such patients.
Anticonvulsants ; Humans ; Neuromuscular Blockade ; Neuromuscular Blocking Agents ; Neuromuscular Monitoring ; Neuromuscular Nondepolarizing Agents ; Retrospective Studies

BACKGROUND: The train of four (TOF) stimulation is valuable to study pharmacodynamics associated with the interaction between muscle relaxants and receptors in the neuromuscular junction. TOF fade expresses presynaptic effect diminished output of transmitters. The aim of this study was to examine differences in presynaptic effects of different relaxants by measuring the TOF ratio during the onset and offset of block. METHODS: Eighty four healthy adult patients of ASA grades I or II were included in the study. The muscle relaxants studied were vecuronium (0.08 mg/kg), atracurium (0.5 mg/kg), mivacurium (0.15 mg/kg), rocuronium (0.6 mg/kg) and succinylcholine (1.0 mg/kg, 0.1 mg/kg, 0.2 mg/kg, 0.4 mg/kg). The TOF ratios were measured at approximate height of first response in the TOF (T1) of 75, 50 and 25% during onset and offset. Especially its ratios were measured at first depress of T1 during onset and its corresponding T1 during offset following administration of subclinical doses of succinylcholine. RESULTS: In the non-depolarizing muscle relaxants, TOF fade is more evident during offset than onset (p<0.05). The extent of fade varies between muscle relaxants. The greatest TOF fade has been shown in rocuronium during onset. In the succinylcholine, the TOF fade is apparent during onset and related to doses given (p<0.05). However the significant TOF fade is not seen during offset. CONCLUSIONS: All muscle relaxants, including both depolarizing and nondepolarizing agent, have predominantly postsynaptic and presynaptic effects. Furthermore, the fact that moderate TOF fade after subclinical doses of succinylcholine occurred obviously during onset of block is possibly indicating a greater presynaptic receptor blocking action.
Adult ; Atracurium ; Humans ; Neuromuscular Blockade* ; Neuromuscular Blocking Agents* ; Neuromuscular Junction ; Neuromuscular Nondepolarizing Agents ; Receptors, Presynaptic ; Succinylcholine ; Vecuronium Bromide

BACKGROUND: Potent inhalation anesthetics potentiate the neuromuscular blocking effects of non-depolarizing muscle relaxants. Therefore, sevoflurane may increase the safety margin at the end of anesthesia by reducing the muscle relaxant dose requirements. We studied the recovery from rocuronium-induced neuromuscular blockade during sevoflurane- versus propofol-based anesthesia in children. METHODS: Fifty pediatric patients were randomly allocated to maintenance of anesthesia with sevoflurane (n = 25) or propofol (n = 25). Neuromuscular block was maintained with rocuronium and monitored by acceleromyography (TOF-Watch?) using train-of-four (TOF) stimulation every 12 seconds. Anesthetic agent administration was gradually reduced and then stopped toward the end of procedure. At the end of surgery, neostigmine 0.04 mg/kg was administered. Time of tracheal extubation, time of arrival in PACU, amount of rocuronium given were recorded. RESULTS: TOF ratio at the end of surgery was greater in sevoflurane group (73.0 +/- 30.0) than in propofol group (50.0 +/- 37.1)(P < 0.05). The dose of rocuronium administered as supplemental increments in sevoflurane group was significantly smaller than that in propofol group (0.9 +/- 1.6 vs 2.8 +/- 2.4microgram/kg/min)(P < 0.05). Time to extubation (7.3 +/- 2.0 vs 9.0 +/- 2.6 min), and time to arrival in PACU (11.5 +/- 2.9 vs 13.9 +/- 2.6 min) from end of surgery were shorter in sevoflurane group than in propofol group (P < 0.05). CONCLUSIONS: These results support the postulate that the potentiation of neuromuscular block by sevoflurane may provide additional safety for pediatric patients by reducing the muscle relaxant dose requirements.
Airway Extubation ; Anesthesia* ; Anesthetics, Inhalation ; Child ; Humans ; Neostigmine ; Neuromuscular Blockade* ; Neuromuscular Nondepolarizing Agents ; Propofol*

BACKGROUND: It is important to consider the sequential administration of long- and short-acting non-depolarizing muscle relaxants. The purpose of this study is to evaluate the interaction between non-depolarizing muscle relaxants under isolated forearm test. METHODS: Ethics committee approval for all the volunteers (n=12) experiments was obtained. Pancuronium, 0.3 mg in 20 mL saline, was injected into one forearm; and vecuronium, 0.3 mg in 20 mL saline, was injected simultaneously into the other forearm in 6 volunteers. Three minutes later both tourniquets were released. Following spontaneous recovery in each forearm to 50% of the control twitch, the tourniquet was reinflated and the dose of drug of the same dilution used in the contralateral forearm was then injected (i. e., vecuronium following pancuronium in one forearm and pancuronium following vecuronium in the other forearm). Tourniquet was again released after 3 minutes and spontaneous recovery was allowed to occur. Interactions between pancuronium (0.3 mg) and rocuronium (2.0 mg) in 6 volunteers were also evaluated in a same method. RESULTS: Prior administration of pancuronium significantly prolonged the recovery rate from subsequent rocuronium (23.9 vs. 32.1 min, p<0.05), and rocuronium significantly shortened the recovery rate of pancuronium (32.4 vs. 25.9 min, p<0.05). There was simple additive interaction between pancuronium and vecuronium. CONCLUSION: The possible mechanism of these phenomena may be due to interaction of drug with acetylcholine receptors in the neuromuscular junction rather than due to residual plasma drug concentration.
Ethics Committees ; Forearm* ; Neuromuscular Junction ; Neuromuscular Nondepolarizing Agents ; Pancuronium* ; Plasma ; Receptors, Cholinergic ; Tourniquets ; Vecuronium Bromide* ; Volunteers

BACKGOUND: Succinylcholine (SCC) injection may be associated with adverse effects including elevated serum potassium (K ) and creatinine phosphokinase (CPK) level, and postoperative myalgia. Many studies have been made to prevent these adverse effects such as pretreatment with non-depolarizing muscle relaxants. The effects of the pretreatment with vecuronium or mivacurium, a new non-depolarizing neuromuscular blocker, on SCC-induced fasciculation, serum K and CPK level was investigated in this study. METHODS: ASA physical status I or II, 40 patients were allocated randomly into 4 groups. Group I as a control group received SCC 1 mg/kg only, while the other groups were pretreated with vecuronium 0.02 mg/kg (0.4 x ED95) (group II), mivacurium 0.02 mg/kg (0.25 x ED95) (group III) and 0.03 mg/kg (0.4 x ED95) (group IV) before the SCC 1.5 mg/kg injection, respectively. Serum K concentration was measured just before anesthetic induction and 5 minute after SCC injection, and serum CPK was estimated before induction and at 24~36 hours postoperatively. And the fasciculation after SCC injection was graded by Cullen's suggestion. RESULTS: Serum K concentration was increased in group I and decreased in pretreated groups, but the difference was not significant within each group and between the groups. Serum CPK level was increased in group I, II and IV but these changes were also insignificant between all groups. The grade of SCC-induced fasciculation was attenuated in group II and IV (p<0.05). CONCLUSIONS: Like vecuronium, mivacurium 0.03 mg/kg is effective to reduce fasciculation after SCC injection, but 0.02 mg/kg is not. However, any complication does not occur in the two dosages.
Creatinine ; Fasciculation* ; Humans ; Myalgia ; Neuromuscular Blockade ; Neuromuscular Nondepolarizing Agents ; Potassium ; Succinylcholine ; Vecuronium Bromide

The accelerometry(AMG) muscle relaxant monitor is the most widely used quantitative muscle relaxant monitor to assess the degree of neuromuscular at present. In this study, the ulnar nerve was stimulated by using train of four stimulation(TOF) mode of the AMG muscle relaxant monitor, and the movement of the adductor pollicis muscle was monitored. In this way, the distribution range of key parameters (acceleration peak value, response time, and TOF ratio) of the adductor pollicis muscle during the use of muscle relaxant in clinical practice is analyzed and will provide a practical basis for the development and improvement of the muscle relaxant monitor.
Electric Stimulation ; Muscle, Skeletal ; Neuromuscular Blockade ; Neuromuscular Nondepolarizing Agents ; Ulnar Nerve/physiology*

BACKGROUND: The use of volatile anesthetics for the maintenance of anesthesia can enhance the action and prolong the duration of non-depolarizing muscle relaxants. The objective of this study was to establish the relation between the post tetanic count (PTC) and the time to reappearance of the first response (T1) by train-of-four (TOF) nerve stimulation following rocuronium 0.6 mg/kg (ED95 X 2) during sevoflurane versus propofol anesthesia. METHODS: Fifty adult patients were randomized to one of two groups, which had anesthesia maintained with sevoflurane or propofol. During sevoflurane or propofol anesthesia, neuromuscular block was monitored by mechanography using TOF stimulation every 12 s. At 6 min intervals, a tetanic stimulation (50 Hz) was applied for 5 s, which was preceded and followed by a 15 s period of 1 Hz single stimulation until the reappearance of T1. RESULTS: First responses to PTS appeared earlier in the propofol group (12.5 +/- 5.2 min) than in the sevoflurane group (16.6 +/- 7.4 min), and first responses to TOF stimulation also occurred significantly sooner in the propofol group (24.8 +/- 5.1 min) than in the sevoflurane group (32.6 +/- 8.9 min). The interval between the appearance of PTC and T1 was shorter in the propofol than in the sevoflurane group. CONCLUSIONS: We conclude that sevoflurane prolonged recovery from deep neuromuscular block by rocuronium as compared to propofol. The PTC method can be used to predict the time to first response to TOF nerve stimulation during intense rocuronium induced neuromuscular blockade.
Adult ; Anesthesia* ; Anesthetics ; Humans ; Neuromuscular Blockade* ; Neuromuscular Nondepolarizing Agents ; Propofol* ; S Phase

The hypothesis of this study was that diabetes-induced desensitization of rat soleus (SOL) and extensor digitorum longus (EDL) to non-depolarizing muscle relaxants (NDMRs) depends on the stage of diabetes and on the kind of NDMRs. We tested the different magnitude of resistance to vecuronium, cisatracurium, and rocuronium at different stages of streptozotocin (STZ)-induced diabetes by the EDL sciatic nerve-muscle preparations, and the SOL sciatic nerve-muscle preparations from rats after 4 and 16 weeks of STZ treatment. The concentration-twitch tension curves were significantly shifted from those of the control group to the right in the diabetic groups. Concentration giving 50% of maximal inhibition (IC50) was larger in the diabetic groups for all the NDMRs. For rocuronium and cisatracurium in both SOL and EDL, IC50 was significantly larger in diabetic 16 weeks group than those in the diabetic 4 weeks group. For SOL/EDL, the IC50 ratios were significantly largest in the diabetic 16 weeks group, second largest in the diabetic 4 weeks group, and smallest for the control group. Diabetes-induced desensitization to NDMRs depended on the stage of diabetes and on the different kind of muscles observed while was independent on different kind of NDMRs. The resistance to NDMRs was stronger in the later stage of diabetes (16 versus 4 weeks after STZ treatment). Additionally, when monitoring in SOL, diabetes attenuated the actions of neuromuscular blockade more intensely than that in EDL. Nonetheless, the hyposensitivity to NDMRs in diabetes was not relevant for the kind of NDMRs.
Animals ; Diabetes Mellitus, Experimental* ; Inhibitory Concentration 50 ; Muscles* ; Neuromuscular Blockade ; Neuromuscular Junction ; Neuromuscular Nondepolarizing Agents ; Rats* ; Streptozocin ; Vecuronium Bromide

Humans ; Infant, Newborn ; Male ; Neuromuscular Nondepolarizing Agents ; therapeutic use ; Tetanus ; drug therapy ; Vecuronium Bromide ; therapeutic use