Early and late reversal of rocuronium and vecuronium with neostigmine in adults and children.

We investigated the influence of the timing of neostigmine administration on recovery from rocuronium or vecuronium neuromuscular blockade. Eighty adults and 80 children were randomized to receive 0.45 mg/kg rocuronium or 0.075 mg/kg vecuronium during propofol/fentanyl/N2O anesthesia. Neuromuscular blockade was monitored by train-of-four (TOF) stimulation and adductor pollicis electromyography. Further randomization was made to control (no neostigmine) or reversal with 0.07 mg/kg neostigmine/0.01 mg/kg glycopyrrolate given 5 min after relaxant, or first twitch (T1) recovery of 1%, 10%, or 25%. Another eight adults and eight children received 1.5 mg/kg succinylcholine. At each age, spontaneous recovery of T1 and TOF was similar after rocuronium and vecuronium administration but was more rapid in children (P < 0.05). Spontaneous recovery to TOF0.7 after rocuronium and vecuronium administration in adults was 45.7 +/- 11.5 min and 52.5 +/- 15.6 min; in children, it was 28.8 +/- 7.8 min and 34.6 +/- 9.0 min. Neostigmine accelerated recovery in all reversal groups (P < 0.05) by approximately 40%, but the times from relaxant administration to TOF0.7 were similar and independent of the timing of neostigmine administration. Recovery to T1 90% after succinylcholine was similar in adults (9.4 +/- 5.0 min) and children (8.4 +/- 1.1 min) and was shorter than recovery to TOF0.7 in any reversal group after rocuronium or vecuronium administration. Recovery from rocuronium and vecuronium blockade after neostigmine administration was more rapid in children than in adults. Return of neuromuscular function after reversal was not influenced by the timing of neostigmine administration. These results suggest that reversal of intense rocuronium or vecuronium neuromuscular blockade need not be delayed until return of appreciable neuromuscular function has been demonstrated. Implications: These results suggest that reversal of intense rocuronium or vecuronium neuromuscular blockade need not be delayed until return of appreciable neuromuscular function has been demonstrated. Although spontaneous and neostigmine-assisted recovery is more rapid in children than in adults, in neither is return of function as rapid as after succinylcholine administration.     

Can early administration of neostigmine, in single or repeated doses, alter the course of neuromuscular recovery from a vecuronium-induced neuromuscular blockade?

The authors sought to determine whether neostigmine, given at a time when no response to peripheral nerve stimulation could be elicited, hastened recovery from a vecuronium-induced neuromuscular blockade (NMB). The effect of neostigmine (70 micrograms/kg) in antagonizing a profound (no-twitch) vecuronium-induced (0.1 mg/kg) NMB in 40 healthy patients was studied. Patients were randomly assigned to one of four groups specifying the sequence of neostigmine administration. Fifteen minutes after the administration of vecuronium, when there was no detectable twitch response, each patient received either neostigmine (70 micrograms/kg) with glycopyrrolate (15 micrograms/kg) or an equivalent volume of normal saline (placebo). When T1 (the first response in the train-of-four [TOF] sequence) recovered to 10% of control, patients again received either neostigmine with glycopyrrolate in the same doses as before or the placebo. The following variables were measured: times from vecuronium injection until T1 recovered to 10% (t [10]) and 90% (t [90]) of control, and time until the TOF ratio was equal to 75% (t [TOF75]). Mean values of t (90) and t (TOF75) were shorter (54.7-75.2 min and 60.4-79.5 min, respectively) for the three groups who received neostigmine as compared with patients who received two doses of placebo (104.3 and 122.6 min, respectively). There were no differences in the t (90) and t (TOF75) values among the three groups who received neostigmine.(ABSTRACT TRUNCATED AT 250 WORDS)     

Antagonism of vecuronium paralysis: comparison between edrophonium and neostigmine.

The reversal of vecuronium paralysis was studied in three series of anesthetized (methohexital, fentanyl, N2O/O2) informed adult patients receiving either 40 micrograms/kg neostigmine (NEO40) (n = 6), either 500 micrograms/kg edrophonium (EDRO500) (n = 6) or 1000 micrograms/kg edrophonium (EDRO1000) (n = 6). These drugs were given randomly once the adductor pollicis twitch height regained 10% of its initial value. The neuromuscular transmission recovery was assessed during 15 minutes after the antagonist administration, by recording twitch height (TH), train of four--2 Hz--every 3 minutes (TOF Ratio) and finally tetanic fade--50 Herz (TET50) and 100 Hz (TET100), 5 seconds duration, one minute apart--. At 15 minutes, the TH values (mean +/- SEM) were for EDRO500 92% +/- 7, for EDRO1000 93% +/- 3 and for NEO40 100% +/- 4 percent (n.s.). For the TOF Ratio, a statistical difference (p less than 0.05) was found between NEO40 86% +/- 4 and the two other groups: EDRO500 73% +/- 3, EDRO1000 69% +/- 4. For the TET50, the values were: EDRO500 93% +/- 3, EDRO1000 86% +/- 5 and NEO40 94% +/- 2 (n.s.). At 100 Hz, the values were: NEO40 61% +/- 8, EDRO500 43 +/- 151 and EDRO1000 31 +/- 12 (p less than 0.01). In conclusion, in the conditions studied, 40 micrograms/kg neostigmine restores the neuromuscular transmission of the adductor pollicis at a higher level than edrophonium 500 micrograms/kg does. Edrophonium, 1000 micrograms/kg instead of 500 micrograms/kg does not change the neuromuscular transmission recovery.     

High concentration sevoflurane induction of anesthesia accelerates onset of vecuronium neuromuscular blockade

PURPOSE: To investigate neuromuscular block using accelography after administration of vecuronium under sevoflurane 8% induction and maintenance with sevoflurane 2% in adults. METHODS: Patients were allocated to three groups: (1) group I: anesthesia was induced and maintained with propofol and fentanyl (n= 15), (2) group II: anesthesia was induced with propofol and maintained with N2O(66%)-O2-sevoflurane 2% (n = 15), (3) group III: anesthesia was induced with sevoflurane 8% using a vital capacity inhalation induction and maintained with N2O(66%)-O2-sevoflurane 2% (n = 15). 0.1 mg x kg(-1) vecuronium was used for paralysis three minutes after anesthetic induction and reversed using intravenous 0.04 mg x kg(-1) neostigmine with 0.02 mg kg atropine when the train-of-four (TOF) ratio returned to 25%. RESULTS: The onset time from initial administration of vecuronium to maximal block in the group III was shorter than that in the groups I and II (139 +/- 35, 193 +/- 35 and 188 +/- 47s, respectively: P < 0.05). The clinical duration from maximal block to 25% recovery of TOF ratio in group II and III was longer than that in the group I (47 +/- 15, 48 +/- 14 and 36 +/- 10 min, respectively: P < 0.05). The reversal times from administration of neostigmine to 75% of TOF ratio in groups II and III were longer than that in the group I (196 +/- 53, 208 +/- 64 and 136 +/- 28s, respectively: P < 0.05). CONCLUSIONS: Vital capacity inhalation induction of anesthesia with sevoflurane accelerates onset and prolongs duration of vecuronium neuromuscular block compared with propofol-fentanyl anesthesia.     

Dose-response relationships for edrophonium and neostigmine as antagonists of atracurium and vecuronium neuromuscular blockade

To determine the potencies of edrophonium and neostigmine as antagonists of nondepolarizing neuromuscular blockade produced by atracurium and vecuronium, dose-response curves were constructed for both antagonists when given at 10% spontaneous recovery of first twitch height. Ninety ASA physical status 1 and 2 adults were given either 0.4 mg/kg atracurium or 0.08 mg/kg vecuronium during thiopental-nitrous oxide-enflurane anesthesia. Train-of-four stimulation was applied to the ulnar nerve every 12 s, and the force of contraction of the adductor pollicis muscle was recorded. When spontaneous recovery of first twitch height reached 10% of its initial control value, edrophonium (0.1, 0.2, 0.4, or 1 mg/kg) or neostigmine (0.005, 0.01, 0.02, or 0.05 mg/kg) was administered by random allocation. Neuromuscular function in another ten subjects was allowed to recover spontaneously. Assisted recovery was defined as actual recovery minus mean spontaneous recovery observed in patients who were not given antagonists. First twitch recovery was initially more rapid when vecuronium was antagonized compared with atracurium, but no difference was detected after 10 min. At 10 min the neostigmine ED80 was 0.022 +/- 0.003 (SEM) mg/kg after atracurium and 0.024 +/- 0.003 mg/kg after vecuronium. The edrophonium ED80 was 0.44 +/- 0.11 mg/kg with atracurium and 0.46 +/- 0.12 mg/kg with vecuronium, giving a neostigmine:edrophonium potency ratio of 20. Atracurium train-of-four fade could be antagonized more easily with edrophonium, whereas that of vecuronium was more easily antagonized by neostigmine. It is concluded that edrophonium and neostigmine are not equally effective against atracurium and vecuronium.     

Influence of neostigmine on the course of neuromuscular blockade with rocuronium or cisatracurium: a randomized, double-blind trial

OBJECTIVES: To compare the time-course of neuromuscular blockade with rocuronium or cisatracurium during intravenous anesthesia, in terms of both the time to spontaneous recovery or time to reversal after administration of neostigmine. MATERIAL AND METHODS: Patients classified as ASA 1-2 were randomized to receive blinded administration of a single injection of twice the 95% effective dose of rocuronium or cisatracurium for general anesthesia, and then neostigmine plus atropine at recovery of the first train-of-4 (TOF) twitch at 5% or 25%, or normal saline solution as placebo at recovery of the first TOF twitch at 25%. The neuromuscular blockade was monitored by acceleromyography. Intergroup comparisons were carried out by Student t test and analysis of variance. RESULTS: Sixty patients were enrolled. Mean (SD) time to onset was faster with rocuronium at (1.04 [0.32] minutes) compared with cisatracurium at (2.58 [0.81] minutes) and duration was shorter: time to the first twich at 5% was 30 (6.4) minutes with rocuronium and 38.1 (9.7) minutes with cisatracurium. The total duration of blockade (time to the 80% TOF ratio) was also shorter with rocuronium when the neuromuscular blockade was reversed, but there were no differences in the time to block reversal when neostigmine was not used: 62 (18.9) minutes to recovery from the rocuronium blockade vs 66.96 (15.9) minutes to recover from a cisatracurium blockade. A high percentage of patients had less than an 80% TOF ratio at 60 and 90 minutes of administration of the neuromuscular blockerswhen reversal was not used (patients receiving rocuronium, 60% at 60 minutes, and 20% at 90 minutes; patients receiving cisatracurium, 80% at 60 minutes, and 40% at 90 minutes). CONCLUSION: Not antagonizing a rocuronium- or cisatracurium-induced neuromuscular blockade in surgical procedures lasting less than 90 minutes can lead to a high percentaje of residual blockade (TOF ratio <80%).     

Vecuronium in infants and children: clinical and neuromuscular effects

The neuromuscular and cardiovascular effects of vecuronium (Norcuron, Organon Teknika) were studied in 58 infants (1 day-10 months) and 65 children (1-6 years) anaesthetized either with halothane or under balanced anaesthesia. After a bolus dose of 70 micrograms/kg vecuronium the time course of neuromuscular blockade was determined using an electromyographic equipment. Onset time (time to maximal effect) was significantly shorter in infants compared with children; 1.4 +/- 0.7 min (min +/- SD) and 2.7 +/- 0.8 min, respectively. In contrast the recovery index (time for 25% to 75% recovery) was longer in infants than in children 18 +/- 6.7 min and 10 +/- 2.3 min, respectively. Repetitive administration of vecuronium, up to five maintenance doses, did not show any cumulative effects in children under balanced anaesthesia. After repetitive administration the recovery index was 12 +/- 1.7 min. Vecuronium (a bolus dose of 80 or 100 micrograms/kg) did not cause any significant change of blood pressure in infants and children anaesthetized either with halothane or by balanced anaesthesia. Infants under balanced anaesthesia showed a significant decrease in heart rate 15 min after administration of vecuronium. In contrast an increase in heart rate could be observed in children under halothane anesthesia, which was not attributed to vecuronium.     

Accelerated reversal of atracurium blockade with divided doses of neostigmine

The hypothesis that administration of neostigmine in divided doses might accelerate the antagonism of neuromuscular blockade was investigated. Neostigmine 0.05 mg X kg-1 was administered either in a single bolus dose (Group I, n = 16) or in an initial dose of 0.01 mg X kg-1 followed three minutes later by 0.04 mg X kg-1 (Group II, n = 16) for antagonism of atracurium-induced blockade. Reversal was attempted at 10 per cent spontaneous recovery of twitch height. The mean time (+/- SD) from the first injection of the drug until the train-of-four (TOF) ratio value had reached 0.75 was significantly shorter in Group II (p less than 0.05) than in Group I (391.8 +/- 83.3 and 468.6 +/- 150.3 seconds respectively). The rate of TOF ratio recovery was 2.5 times faster after neostigmine administration in divided doses. It is concluded that administration of neostigmine in divided doses, as described in this study, produced a significantly faster reversal of residual atracurium-induced neuromuscular blockade as compared to a single bolus administration.     

Sugammadex比新斯的明更快逆转维库溴铵所致神经肌肉阻滞的多中心随机对照研究

背景 Sugammadex是一种具有特异结构的γ-环糊精,能选择性地与肌松药结合快速逆转罗库溴铵所致的神经肌肉阻滞,并较小程度地逆转维库溴铵所致的神经肌肉阻滞.该研究中,我们对比了行择期手术的患者中sugammadex和新斯的明对逆转维库溴铵所致神经肌肉阻滞的作用.方法 年龄≥18岁,ASA分级Ⅰ～Ⅲ级拟行择期手术的患...     

Atracurium and vecuronium: repeated bolus injection versus infusion.

The purpose of this study was to compare the characteristics of recovery from neuromuscular blockade after either atracurium or vecuronium given by intravenous infusion or by repeated injection. Four groups of 10 patients each were studied during nitrous oxide narcotic anesthesia. An initial intravenous dose of 2 x ED95 of either muscle relaxant was followed by an intravenous infusion started at 5% recovery of control twitch tension and adjusted for 95% block or by repeated injection of 0.6 x ED95 administered whenever twitch tension had returned to 25% of control. There were no significant differences between the maintenance doses required based on method of administration: atracurium repeated injection, 1.6 +/- 0.3 x ED95 h-1; atracurium infusion, 1.7 +/- 0.3 x ED95 h-1; vecuronium repeated injection, 1.8 +/- 0.5 x ED95 h-1; and vecuronium infusion, 1.6 +/- 0.4 x ED95 h-1. Nevertheless, differences of up to 20 min were noted in the recovery indices in the following order: atracurium repeated injection = atracurium infusion less than vecuronium repeated injection less than vecuronium infusion. A single dose of neostigmine (7 micrograms/kg) significantly reduced the recovery indices, thereby eliminating their differences.     

Effect of volatile anesthetics on vecuronium-induced neuromuscular blockade in children

We studied 60 children undergoing elective surgery to evaluate the effect of interactions between vecuronium and isoflurane or halothane on the potency and duration of neuromuscular blockade, as measured by electromyography. Vecuronium was first administered by a logarithm-based cumulative method (14, 22, 35, 56, 89 micrograms/kg) in 10 children anesthetized with thiopental (5 mg/kg), alfentanil (15 micrograms/kg first dose, then 10 micrograms/kg), and N2O/O2 (60:40) until a 95% +/- 2% twitch depression (ED95) was obtained. Thirty children given the same balanced anesthesia were then randomly assigned to three groups (n = 10 in each) to receive a single ED20 (21 micrograms/kg), ED50 (33 micrograms/kg), or ED80 (47 micrograms/kg) intravenous bolus of vecuronium calculated from the mean regression line of twitch responses of the first 10 children. In the second part of the study, 20 children were anesthetized with isoflurane (1.2%) or halothane (0.7%) and compared with the previous 10 children anesthetized with alfentanil-N2O. Potency of vecuronium determined by single-bolus or logarithm-based cumulative techniques was not significantly different. Isoflurane and halothane significantly decreased ED50 (22.3 +/- 1.6 and 25.4 +/- 1.4 micrograms/kg, respectively; mean +/- SE) and ED95 (41.5 +/- 3.3 and 46.7 +/- 3.2 micrograms/kg, respectively) compared with alfentanil-N2O (ED50: 32.8 +/- 0.8 micrograms/kg, ED95: 70.5 +/- 2.6 micrograms/kg). Recovery rate from vecuronium-induced neuromuscular blockade was significantly longer with isoflurane than with alfentanil-N2O or halothane. We conclude that in children single-bolus and logarithm-based cumulative techniques give similar potency estimates for vecuronium. Isoflurane and halothane increase by similar amounts the neuromuscular potency of vecuronium.(ABSTRACT TRUNCATED AT 250 WORDS)     

Dose-response relationships for neostigmine antagonism of rocuronium-induced neuromuscular block in children and adults

Dose-response relationships for the antagonism of intermediate-acting neuromuscular blocking agents have not been evaluated previously in children. We have examined the dose-response relationships for neostigmine antagonism of 90% rocuronium-induced neuromuscular block in children and adults, during nitrous oxide-1 MAC of isoflurane anaesthesia. We studied 40 children, aged 2-10 yr, and 50 adults, aged 18-60 yr; all received a single bolus dose of rocuronium 0.6 mg kg-1 and accelerometry was used to monitor neuromuscular transmission. When the first twitch of the train-of-four (TOF) response (T1) recovered to 10% of its control (T0), one of five doses of neostigmine 0, 5, 10, 20 or 50 micrograms kg-1 was given by random allocation to each of the study groups (n = 8 children and n = 10 adults). Recovery of T1 and TOF ratio (T4/T1%) was recorded for 10 min after initial administration of neostigmine. Onset time of rocuronium-induced block was faster in children than in adults (mean 64.6 (95% confidence intervals 57.7-71.5) s vs 83.7 (70.7-96.6) s; P < 0.05). The time to 10% recovery of T1/T0 was shorter in children than in adults (25.4 (22.9-27.9) min vs 38.8 (36.1-41.4) min; P < 0.001). Spontaneous and antagonist-assisted recovery were more rapid in children than in adults. Adequate recovery (T4/T1 of 80%) occurred in children at 4, 5 and 8 min after neostigmine 50, 20 and 10 micrograms kg-1, respectively. Adequate recovery was not produced in adults by any dose of neostigmine within 10 min. The effective doses of neostigmine required to achieve a TOF ratio of 80% (ED80) after 10 min in children and adults were, respectively, 7.10 (5.2-9.8) micrograms kg-1 and 56.56 (45.5-71.9) micrograms kg-1 (P < 0.001). There was no advantage in administering doses of neostigmine greater than 20 micrograms kg-1 to antagonize 90% rocuronium-induced neuromuscular block in children. In contrast, it appeared prudent to use neostigmine 50 micrograms kg-1 or more for adequate antagonism of a similar degree of block in adults.      

Postoperative neuromuscular function in pediatric day-care patients.

After anesthesia employing nondepolarizing muscle relaxants, 30%-40% of adult patients demonstrate residual paralysis with a train-of-four ratio less than 70%, but it is not known if the same is true for children. This study was designed to investigate neuromuscular transmission in 91 ASA physical status I or II day-care children (aged 0-10 yr) after halothane anesthesia in which pancuronium (n = 34), atracurium (n = 32), or vecuronium (n = 25) was administered. Peripheral nerve stimulation was used clinically to assess neuromuscular blockade during surgery. In the recovery room, the evoked response of the adductor pollicis muscle was measured by train-of-four stimulation of the ulnar nerve. This measurement was made (mean +/- SEM) at 18.0 +/- 1.5, 15.0 +/- 1.3, and 15.0 +/- 1.7 min after pharmacologic antagonism with 0.02 mg/kg atropine and 0.06 mg/kg neostigmine in the pancuronium, atracurium, and vecuronium groups, respectively. There were no differences in the ages of the patients in the three groups at 4.3 +/- 0.4, 4.0 +/- 0.4, and 5.0 +/- 0.5 yr, with 17 children less than 2 yr. Recovery from neuromuscular blockade in all three groups was almost complete. The train-of-four ratio (height of fourth twitch compared with the first) was similar in patients who had received pancuronium (96.7% +/- 0.9%), atracurium (95.5% +/- 0.9%), or vecuronium (96.3% +/- 1.3%). Therefore, postoperative muscle weakness or respiratory impairment is unlikely in pediatric day-care surgical patients more than 2 yr old when these anesthetic techniques are used.     

Mivacurium: dose-response relationship and administration by repeated injection or infusion.

The dose-response relationship and neuromuscular blockade after infusion or repeated injection of mivacurium were studied in 65 patients in nitrous oxide-narcotic anesthesia. The ED95 (twitch tension) was determined in 45 patients by intravenous injection of a single bolus of 30, 39, 47, 54, or 60 micrograms/kg (9 patients per dose). Another 20 patients received an initial bolus of 2 x ED95 followed either by an infusion started at 5% twitch recovery (i.e., 95% depression) and adjusted to sustain 95% twitch depression (n = 10) or by repeated injection of 0.6 x ED95 whenever twitch tension had recovered to 25% of control (n = 10). Five patients in each of these two groups received 7 micrograms/kg of neostigmine at 25% twitch recovery, and the others recovered twitch tension spontaneously. The mean ED95 was 73 micrograms/kg. A 2 x ED95 bolus was followed by complete twitch depression within 2.2 +/- 0.7 min. The mean infusion rate resulted in 6 +/- 2 micrograms.kg-1.min-1. The ensuing recovery index was 6 +/- 3 min. A 6 +/- 2 min recovery index was found after up to 10 repeat injections given every 9 +/- 3 min. There was no significant effect of neostigmine in both groups. In conclusion, the recovery indices after the infusion or repeat injection of near-equal doses of mivacurium were identical.     

Dose-response relationships for edrophonium and neostigmine antagonism of atracurium and cisatracurium- induced neuromuscular block

PURPOSE: To study the dose-response relationships for neostigmine and edrophonium during antagonism of neuromuscular block induced by atracurium and cisatracurium. METHODS: One hundred and twenty eight, ASA group 1 or 2 adults were given either 0.5 mg x kg(-1) atracurium or 0.1 mg x kg(-1) cisatracurium during fentanyl-thiopental-nitrous oxide-isoflurane anesthesia. The neuromuscular block was measured by an acceleration-responsive transducer. Responses were defined in terms of percent depression in the first twitch (T1) and train-of-four (TOF) response. When spontaneous recovery of first twitch height reached 10% of its initial control value, edrophonium (0.1, 0.2, 0.4, or 1 mg x kg(-1)) or neostigmine (0.005, 0.01, 0.02, or 0.05 mg x kg(-1)) was administered by random allocation. Neuromuscular function in another sixteen subjects was allowed to recover spontaneously. RESULTS: At five minutes, unlike edrophonium, neostigmine was equally effective against atracurium and cisatracurium with respect to T1 recovery. The neostigmine T1-ED50 was 10.3 +/- 1.06 (SEM) microg x kg(-1) after atracurium and 11.2 +/- 1.06) microg x kg(-1) after cisatracurium. The edrophonium ED50 was 157 +/- 1.07 microg x kg(-1) with atracurium and 47.4 +/- 1.07 microg x kg(-1) with cisatracurium, giving a neostigmine:edrophonium potency ratios of 15.2 +/- 1.7 and 4.2 +/- 0.41 (P < 0.001) for atracurium and cisatracurium, respectively. At 10 min neostigmine was 13 +/- 1.4 times as potent as edrophonium for achieving 50% TOF recovery after atracurium paralysis. After cisatracurium the potency ratio was 11.8 +/- 1.3 (NS). CONCLUSIONS: Although there were differences at five minutes, neostigmine:edrophonium potency ratios at 10 min, were similar in both relaxants studied.     

Neostigmine and edrophonium antagonism of varying intensity neuromuscular blockade induced by atracurium, pancuronium, or vecuronium

To compare the time course of neostigmine and edrophonium antagonism of varying intensity neuromuscular blockade induced by atracurium, pancuronium, or vecuronium, the authors studied 98 patients anesthetized with nitrous oxide (60%) and halothane or enflurane. Neuromuscular blockade, as monitored by single stimulus-induced twitch tension (TT), was antagonized at varying degrees of spontaneous recovery (2-80% of control TT). Time to antagonism (time from injection of neostigmine or edrophonium to 90% recovery of control TT) was not different between edrophonium, 0.5 mg/kg, and neostigmine, 0.04 mg/kg, when spontaneous recovery had been allowed to occur to at least 11% of control TT prior to antagonist administration (P greater than 0.05). For profound neuromuscular blockade (TT less than or equal to 10% of control) induced by pancuronium or vecuronium, time (mean +/- SD) to antagonism with neostigmine, 0.04 mg/kg, was 7.0 +/- 2.2 min and 5.6 +/- 1.7 min, respectively, while the same for edrophonium, 0.5 mg/kg, was 20.0 +/- 8.0 min and 15.0 +/- 12.5 min, respectively (P less than 0.05). Time to antagonism of profound atracurium-induced neuromuscular blockade was 8.5 +/- 3.3 min for neostigmine, 0.04 mg/kg, and 9.8 +/- 7.0 min for edrophonium, 0.5 mg/kg, (P less than 0.05). For profound vecuronium-and pancuronium-induced neuromuscular blockade, time to antagonism by edrophonium, 1.0 mg/kg, was 4.6 +/- 3.0 min and 3.9 +/- 1.6 min respectively. The authors conclude that neostigmine, 0.04 mg/kg, antagonizes neuromuscular blockade within 12 min when TT is greater than 2% of control at time of reversal. When TT is greater than 10% of control, edrophonium, 0.5 mg/kg, produces similar time to antagonism.(ABSTRACT TRUNCATED AT 250 WORDS)     

The prolonged duration of rocuronium in Chinese patients

We compared the potency and duration of action of rocuronium in Chinese and Caucasian patients during general anesthesia. Thirty-six women (18 Caucasian and 18 Chinese) and 36 children (18 Caucasian and 18 Chinese) were evaluated during the administration of propofol/fentanyl anesthesia. Patients in each age group were randomized into three subgroups to receive single doses of 0.06, 0. 12, or 0.18 mg/kg rocuronium (adults) or 0.12, 0.18, or 0.24 mg/kg rocuronium (children). Neuromuscular blockade was assessed by electromyography of the adductor pollicis after train-of-four (TOF) stimulation of the ulnar nerve. Dose response curves were constructed when maximum neuromuscular depression of the first twitch of the train (T(1)) was obtained. A second bolus dose of rocuronium was then administered to a total dose of 0.6 mg/kg. The times of spontaneous recovery to T(1) 10%, 25%, and 90% of control and to TOF 0.25, 0.50, and 0.70 were recorded. For both adults and children, recovery occurred later in Chinese than in Caucasian patients (P<0.05 for T(1) of 10%, 25%, 75%, and 90% and TOF to 0.7). The 50% effective dose was smaller in Chinese adults (125+/-63 vs. 159+/-66 microg/kg) and Chinese children (171+/-43 vs. 191+/-46 microg/kg) than in Caucasian adults and children, but the difference was not statistically significant. In adults, time to 25% T(1) recovery was 43+/-13 min in Chinese patients and 33+/-10 min in Caucasian patients (P<0.05). The corresponding values were more rapid for children: 30+/-10 and 24+/-6 min (P<0.05). We conclude that the recovery from rocuronium neuromuscular blockade was longer in Chinese compared with Caucasian patients and in adults compared with children.     

The influence of 0.5 % isoflurane on a vecuronium-induced neuromuscular blockade

The influence of adding 0.5% isoflurane to a narcotic-based anaesthesia on the duration of effect and recovery time after repetitive administration of vecuronium was studied in ten healthy patients. The twitch response in the adductor pollicis muscle was recorded after supramaximal train-of-four (TOF) stimulation of the ulnar nerve at the wrist. Prior to endotracheal intubation a bolus dose of vecuronium (0.08 mg/kg b.w.) was given. During surgery repeated injections of vecuronium (0.02 mg/kg b.w.) were administered at a TOF ratio of 0.25. Hand-skin temperature, systolic blood pressure, end-tidal CO2 and isoflurane concentrations were continuously monitored. Before and after 90 min administration of isoflurane, the duration of effect was 21 +/- 4 and 24 +/- 5 min (mean +/- s.d., P less than 0.05) respectively. Corresponding recovery times were 270 +/- 60 and 280 +/- 70 s (n.s.). Skin temperature remained unchanged and systolic blood pressure showed only minor variations. The addition of 0.5% isoflurane to a narcotic-based anaesthesia causes a moderate increase in duration of effect but no change in recovery time from a repetitive vecuronium-induced neuromuscular blockade of 0.02 mg/kg.     

Comparative effects of desflurane and isoflurane on vecuronium-induced neuromuscular blockade.

STUDY OBJECTIVE: To evaluate the neuromuscular effects of a nondepolarizing muscle relaxant (vecuronium) during anesthesia with equipotent concentrations of either desflurane or isoflurane. DESIGN: Randomized open study comparing effects of desflurane and isoflurane on vecuronium-induced neuromuscular blockade. SETTING: University-affiliated medical center. PATIENTS: Forty-five healthy adults undergoing elective surgical procedures randomly assigned to receive either desflurane, nitrous oxide (N2O), and vecuronium or isoflurane, N2O, and vecuronium for maintenance of general anesthesia. INTERVENTIONS: Following a standardized induction sequence, patients receiving either desflurane and N2O or isoflurane and N2O were administered bolus doses of vecuronium equal to 0.01, 0.02, or 0.03 mg/kg intravenously (IV) during the maintenance period. Neuromuscular transmission was measured using a Relaxograph monitor. MEASUREMENTS AND MAIN RESULTS: Vecuronium produced similar depression of neuromuscular function at equipotent (50% of the minimum alveolar concentration) end-tidal concentrations of isoflurane 0.6% and desflurane 3.0%. Following administration of vecuronium 0.01 to 0.03 mg/kg IV, onset times (3.4 +/- 0.4 minutes to 3.2 +/- 0.4 minutes and 3.2 +/- 0.5 minutes to 3.0 +/- 0.6 minutes), maximum T1 twitch depression (80% +/- 10% to 95% +/- 9% and 81% +/- 9% to 97% +/- 10%), clinical duration of blockade (12 +/- 5 minutes to 20 +/- 8 minutes and 10 +/- 5 minutes to 19 +/- 17 minutes), and T1 recovery times (10 +/- 3 minutes to 12 +/- 6 minutes and 10 +/- 3 minutes to 12 +/- 4 minutes) were similar in the isoflurane and desflurane treatment groups, respectively (means +/- SD). CONCLUSION: Vecuronium has similar neuromuscular effects when administered in the presence of desflurane 3% and isoflurane 0.6%.     

Neostigmine and edrophonium as antagonists of atracurium and pancuronium

Edrophonium 0.5 mg/kg or neostigmine 0.04 mg/kg were administered to two groups of 30 patients each for antagonism of atracurium- or pancuronium-induced neuromuscular block at 25% single twitch recovery. Neuromuscular block was studied using both single twitch and train-of-four (TOF) nerve stimulation. The times to 100% single twitch recovery were significantly more rapid for patients receiving edrophonium (P less than 0.01) in both groups (atracurium and pancuronium); the TOF ratios were similar for atracurium, but for pancuronium they were greater after neostigmine than after edrophonium, and only at 25 min were these ratios similar. It is concluded that edrophonium in a dose of 0.5 mg/kg antagonizes neuromuscular blockade induced by atracurium, as does neostigmine in a dose of 0.04 mg/kg, but the former does not consistently antagonize neuromuscular blockade induced by pancuronium even at 25% of single twitch recovery.