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Results for “Neuromuscular Blockade”

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PubMed2006

[Influence of neuromuscular blockade on the airway leak pressure of the ProSeal laryngeal mask airway].

BACKGROUND: The ProSeal laryngeal mask airway (PLMA) is increasingly used for surgical procedures that might require the intraoperative use of neuromuscular blocking agents. The airway seal of the PLMA depends on the interplay of the surrounding soft tissue of the neck and the cuff of the mask. An intraoperative neuromuscular blockade could lead to a decrease of the airway leak pressure (P (leak)) secondary to the relaxation of the muscles of the neck. With this study we tested the hypothesis that a neuromuscular blockade can result in a decreased P (leak) of the PLMA. METHODS: The P (leak) of the PLMA was studied in 73 female patients under total intravenous anaesthesia with propofol (0.1 - 0.15 mg kg (-1) min (-1)) and remifentanil (0.1 - 0.3 microg kg (-1) min (-1)) before and after a complete neuromuscular blockade produced by intravenous injection of 0.6 mg kg (-1) Rocuronium. RESULTS: The P (leak) decreased by more than 10 % of the baseline P (leak) in 8 out of 73 patients (11 %); however, in the entire study population there was no significant difference between the mean baseline P (leak) (28.5 +/- 7.3 cm H(2)O) and the mean P (leak) after complete neuromuscular blockade (29.1 +/- 7.0 cm H(2)O); (p = 0.128). CONCLUSION: No general correlation between application of a neuromuscular blocking agent and a decrease of the mean P (leak) was found. However, the decrease of the P (leak) by more than 10 % in 11 % of the patients shows that in certain patients the application of neuromuscular blocking agents can result in a decreased P (leak) of the PLMA and indicates the necessity to control the P (leak) of the PLMA under complete muscle paralysis preoperatively when neuromuscular blocking agents are used.

Adult↗

PubMed1991

Tactile evaluation of train-of-four count as an indicator of reliability of antagonism of vecuronium- or atracurium-induced neuromuscular blockade.

Recent evidence suggests that edrophonium is not the agent of choice to reverse profound neuromuscular blockade but remains an efficacious drug when the level of neuromuscular blockade to be antagonized is modest. We studied 90 healthy adults in an attempt to address the questions: 1) How much variability in such neuromuscular parameters as single twitch height and the train-of-four (TOF) fade ratio (T4/T1) exist when the TOF count first returns to four palpable responses? 2) Is edrophonium a reliable antagonist at this measured point of recovery? 3) What is the optimal dose of edrophonium needed to produce prompt (less than 10 min) and satisfactory (T4/T1 greater than 0.7) reversal when the fourth response of the thumb to indirect TOF stimulation just becomes palpable? Patients were given a bolus atracurium or vecuronium (n = 45 in each group) followed by an iv infusion sufficient to maintain single twitch as measured by electromyography at 10-15% of control values. At the end of surgery, the infusion was terminated and spontaneous recovery was allowed to begin. Once the tactile TOF count was four, edrophonium 0.3, 0.5, or 0.75 mg/kg was administered. At a count-of-four the first twitch averaged 37% of control (+/- 8.5% standard deviation; pooled data from all groups) and the mean T4/T1 ratio was 0.14 +/- 0.049. After atracurium neuromuscular blockade, edrophonium 0.3 mg/kg produced adequate antagonism in 10 min. At this time the mean T4/T1 ratio was 0.79 +/- 0.07 and the lowest observed value was 0.67. Increasing the edrophonium dose to 0.75 mg/kg accelerated recovery by 4-5 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1996

Double burst monitoring during recovery from atracurium-induced neuromuscular blockade: a comparison with train-of-four.

BACKGROUND: Double burst stimulation (DBS) was originally introduced for improved manual detection of residual neuromuscular blockade. Previous studies demonstrated a high correlation between mechanomyographical responses to DBS and train-of-four (TOF) stimulation during recovery from neuromuscular blockade. However, repeatability and bias analyses that are recommended when new monitoring devices are introduced into clinical practice [11] have not yet been performed. OBJECT: The object of the present study was to evaluate if DBS3,350/50 (3 stimuli at 50 Hz followed 0.750 sec later by 3 stimulations at 50 Hz) and TOF measurements are in so close agreement that they can be used interchangeably during spontaneous recovery from atracurium blockade. METHODS: The study comprised 20 women undergoing gynaecological laparotomy and anaesthetised with fentanyl, thiopentone, halothane, and nitrous oxide. The neuromuscular blockade was induced and maintained with atracurium. The ulnar nerve was stimulated using DBS or TOF stimulation. Neuromuscular transmission was monitored mechanomyographically. Alternating sequences of 4 DBS and 6 TOF stimulations were applied during the phase of spontaneous recovery. Repeatability, bias (accuracy) and limits of agreement were calculated as proposed by Bland and Altman [11]. RESULTS: The repeatability coefficients before any neuromuscular blocking agent was given were 3.4 and 7.7% for T1 and D1, respectively (P < 0.05), and 3.8 and 3.5% for TOF ratio and DBS ratio, respectively (P > 0.05). The mean difference between duplicated DBS and TOF measurements during recovery (repeatability) differed from zero due to the ongoing recovery process. It was therefore not possible to calculate the repeatability coefficients. The DBS ratio bias decreased from 6.69 to 3.51% (P < 0.05) during recovery. The limits of agreement between the DBS and TOF ratios increased from -2.07 to 15.45%, to -11.93 to 18.95% during recovery, while the limits of agreement between the DBS and TOF twitch heights increased from -5.02 to 10.68%, to -21.02 to 25.26%. CONCLUSION: The limits of agreement between DBS and TOF responses were so wide that DBS and TOF can not be used interchangeably.

Adult↗

PubMed1984

Hypocarbia and spontaneous recovery from vecuronium neuromuscular blockade in anesthetized patients.

The effect of hypocarbia on the recovery from the neuromuscular blockade produced by vecuronium was studied in 20 anesthetized patients. Vecuronium was administered until twitch tension was reduced to between 0-15% of control. Neuromuscular function was then allowed to spontaneously recover during continued normocarbia (end-tidal PCO2 5.5 kPa [41 mm Hg]) in half the patients, and in the other half of the patients hyperventilation producing hypocarbia (mean end-tidal PCO2 of 3.1 +/- 0.4 kPa SD [23 +/- 3 mm Hg] at the completion of twitch force recovery) was initiated at the beginning of spontaneous recovery from neuromuscular blockade. The mean vecuronium recovery index (time for spontaneous recovery from 25-75% of control twitch tension) was slightly but not significantly shorter in the hyperventilated patients (8.4 +/- 1.8 min SD) than in the normally ventilated patients (10.4 +/- 3.4 min SD). We conclude the vecuronium recovery index in anesthetized patients is not significantly changed by hyperventilation with hypocarbia when induced at the beginning of recovery from neuromuscular blockade.

Adult↗

PubMed2006

Residual neuromuscular blockade: incidence, assessment, and relevance in the postoperative period.

The residual effects of neuromuscular blocking agents may persist into the early postoperative recovery period, even when neuromuscular blockade is carefully monitored and reversed in the operating room. Recent data suggest that mild degrees of residual paresis (train-of-four TOF ratios of 0.7-0.9) may be associated with significant impairment of respiratory and pharyngeal muscle function. Therefore, the new gold standard reflecting acceptable neuromuscular recovery is a TOF ratio > or =0.9. Several investigations have demonstrated that many patients continue to arrive in the postanesthesia care unit with TOF ratios <0.7-0.9. Several techniques may be used to reduce the risk of postoperative residual paresis, which include avoidance of long-acting muscle relaxants, use of neuromuscular monitoring in the operating room, routine reversal of neuromuscular blockade at a TOF count of 2-3, and early administration of reversal agents. Careful management of neuromuscular blockade may limit the occurrence of adverse events associated with residual postoperative paralysis. Large-scale outcome studies are needed to clearly define the impact of residual neuromuscular block on major morbidity and mortality in surgical patients.

Anesthesia↗

PubMed1985

[Atracurium: neuromuscular blockade in repeated administration].

The neuromuscular blocking action of repeated injections of atracurium and vecuronium was studied in 74 surgical patients during balanced anaesthesia (methohexitone or etomidate, intubation after suxamethonium, fentanyl, droperidol, N2O). The initial bolus dose (ID) of atracurium was 0.25 mg/kg and of vecuronium 0.05 mg/kg followed by repeated increments (RD) of atracurium 0.1 mg/kg and vecuronium 0.0125 mg/kg when neuromuscular function (EMG) had recovered to about 30% of pre-relaxant control. Dose-response relationships revealed atracurium to be about 1/5 as potent as vecuronium; the ED50 of atracurium was 0.13 +/- 0.03 mg/kg and of vecuronium 0.023 +/- 0.007 mg/kg. The ID of both relaxants produced a neuromuscular blockade of about 90% within 4 min. The duration from the time of injection to 30% recovery was slightly longer in atracurium 26 +/- 9 min. In all patients the RD produced within 3.5 min satisfactory muscle relaxation with a neuromuscular block of about 85%. The mean duration of atracurium (18 min) was 5-10 min longer than of vecuronium (12 min). To maintain good surgical relaxation (more than 70% blockade) atracurium 0.32 mg/kg X h and vecuronium 0.056 mg/kg X h were required. No cumulation could be measured after repeated injections. The recovery time of atracurium and vecuronium at the end of anaesthesia was 10-12 min. Neither cardiovascular side-effects nor signs of histamine release were observed after both relaxants in our particular dose range. It is concluded, that atracurium is a favourable blocker for anaesthetic practice: The time of onset is approximately the same compared with vecuronium. The duration of action, however, is slightly longer but still truly intermediate long.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, General↗

PubMed2002

Cisatracurium infusion for neuromuscular blockade in the pediatric intensive care unit: A dose-finding study.

OBJECTIVE: To evaluate the safety and efficacy of cisatracurium besylate, a neuromuscular blocking agent in infants zero to 2 yrs of age. DESIGN: An open-label study to evaluate efficacy and safety of cisatracurium as a continuous infusion in infants. SETTING: A tertiary pediatric intensive care unit. PATIENTS: Eleven children, 0-2 yrs of age, requiring prolonged neuromuscular blockade. INTERVENTIONS: Cisatracurium besylate, 0.1 mg/kg, was administered as an intravenous bolus dose and repeated if necessary until a >90% neuromuscular blockade, as determined by train-of-four response, was achieved. Patients were allowed to recover to 90% blockade (I/IV twitch) after the initial bolus and were administered continuous infusion at 2 &mgr;g/kg/min. The continuous infusion rate was adjusted to maintain a train-of-four response of 0-I/IV, with an increase in the rate preceded by a bolus dose of cisatracurium besylate. An electromyographic monitor was used to measure recovery at the end of infusion, when possible. Heart rate and blood pressure were recorded after the initial bolus dose and after changes in infusion rates. Blood samples were drawn at steady-state during cisatracurium infusion at several different times during the study and at the end of infusion for measurement of plasma cisatracurium and laudanosine concentrations. MEASUREMENTS AND MAIN RESULTS: The mean infusion rate of cisatracurium besylate required to maintain train-of-four response of 0-I/iv was 5.4 +/- 3.0 &mgr;g/kg/min. The mean total duration of infusion was 64.5 +/- 36 hrs. Ten percent and complete neuromuscular recovery occurred at 26.6 +/- 10.4 and 74.8 +/- 32 mins, respectively, after discontinuation of infusion. Mean cisatracurium and laudanosine concentrations were 342.5 +/- 169 and 163.3 +/- 116 ng/mL, respectively. Four (37%) patients had undetectable (<5 ng/mL) cisatracurium concentrations at the time of 100% neuromuscular recovery (train-of-four response of IV/IV or no fade at 50 mA on the electromyogram). No significant hemodynamic changes were observed during treatment with cisatracurium besylate (p <.05). CONCLUSIONS: A longer period of recovery from neuromuscular blockade was observed compared with reports of older children. Recovery from neuromuscular blockade after long-term use was not associated with any adverse events in the immediate postinfusion period. Cisatracurium besylate is a safe and effective neuromuscular blocking agent for children 0-2 yrs of age.

Journal Article↗

PubMed1989

[Succinylcholine neuromuscular blockade in a case of pseudocholinesterase variant].

Since there is little or no pseudocholinesterase at the motor end plate, the neuromuscular blockade by succinylcholine is terminated by its diffusion away from the end-plate into extracellular fluid. Pseudocholinesterase (ChE), therefore, influences the duration of action of succinylcholine (SCC) by controlling the rate of hydrolysis before it reaches the end-plate. SCC neuromuscular blockade can be prolonged in the presence of an atypical form of ChE. A 37 year old male with the deficiency of ChE activity underwent pancreatico-duodenectomy under neuroleptanesthesia. The mode, duration and treatments of neuromuscular blockade following succinylcholine (SCC) were studied using train-of-four (TOF). SCC was administered 6 times (total 170 mg) during the operation. Prolonged apnea was noted after the first intravenous injection of SCC (60 mg, 1 mg.kg-1). It was found that spontaneous resolution of the neuromuscular block had four phases and there was a pronounced fade of the TOF response. After the second injection of SCC (30 mg), a remarkable fade of the TOF was detected and the character of the block was considered to be a desensitizing block (phase II block). The block was treated by intravenous infusion of fresh frozen plasma (FFP) (400 ml) which contained ChE, at the rate of 231 +/- 56 IU/l/37 degrees C begun shortly after the fifth injection of SCC (20mg). The duration of the block was remarkably shortened but the recovery curves were almost unchanged, indicating the diffusion of SCC away from the end-plate and/or that receptor-channel is presumably slow. The neuromuscular blockade was fully reversed by additional injection of FFP (400 ml) before extubation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1982

Antagonism of org NC 45 (vecuronium) and pancuronium neuromuscular blockade by neostigmine.

The antagonism, by neostigmine, of neuromuscular blockade produced by either Org NC 45 or pancuronium was studied in 29 anaesthetized patients during a continuous infusion of the myoneural blocker. The ED50 of neostigmine (dose which produced a 50% antagonism) when antagonizing Org NC 45 and pancuronium was 0.011 mg kg-1 and 0.010 mg kg-1 respectively. The dose-response relationships for the antagonism of Org NC 45 and pancuronium neuromuscular blockades were not significantly different. The duration of the effect of neostigmine was not different when antagonizing an Org NC 45- or pancuronium-induced blockade. We concluded that Org NC 45 and pancuronium are effectively and equally (independent of pharmacokinetics) antagonized by neostigmine in man.

Adult↗

PubMed1991

The onset and duration of neuromuscular blockade using combinations of atracurium and vecuronium.

The effect of atracurium-vecuronium combinations on the onset and duration of neuromuscular blockade was investigated in 30 adult patients undergoing general anaesthesia for elective surgery. The patients were randomized to receive either atracurium 0.6 mg.kg-1, vecuronium 0.1 mg.kg-1, or quarter-dose, half-dose, or full-dose combinations of the two drugs. Neuromuscular blockade was assessed by measuring the evoked electromyographic response of the abductor digiti minimi to transcutaneous stimulation of the ulnar nerve. It was found that half-dose combinations of atracurium and vecuronium did not produce a shorter onset time, but did result in a longer duration of neuromuscular blockade than full-doses of either drug alone (P less than 0.01). The quarter-dose combinations did not reduce onset time or increase duration. The full-dose combinations produced both a shorter onset time (P less than 0.01) and a longer duration (P less than 0.001). The results indicate that atracurium-vecuronium combinations are supra-additive in terms of the duration of the neuromuscular blockade produced. However, the inability of atracurium-vecuronium combinations to reduce onset time without increasing duration suggests that there is little advantage in combining the two drugs in clinical practice.

Adult↗

PubMed1992

[Can nicardipine potentiate vecuronium induced neuromuscular blockade?].

The effects of intravenous nicardipine on the neuromuscular blockade produced by single bolus injection of vecuronium were studied in surgical patients undergoing tracheal intubation. We measured the mechanical response of the abductor pollicis muscle to stimulation of the ulnar nerve in a train-of-four sequence at 2 Hz and recorded the amplitudes of the first response (T1). Anesthesia was induced with thiopental 5 mg.kg-1 with or without nicardipine 10 micrograms.kg-1 followed by injection of vecuronium in a dose of either 0.1 or 0.15 mg.kg-1. Onset and duration of neuromuscular blockade were judged by percent depression of T1. The time intervals for 90% and 100% depression in T1 seen in patients who had received vecuronium 0.1 mg.kg-1 with nicardipine (n = 10) were 157.0 +/- 30.8 sec and 192.3 +/- 31.2 sec (mean +/- SD), respectively. These values were significantly shorter than those observed in patients without nicardipine administration (n = 10, P less than 0.05), and were not significantly different from the values in patients who had received vecuronium 0.15 mg.kg-1 (n = 10). On the other hand, the time for 25% recovery in T1 was uninfluenced by nicardipine. Present study indicates that nicardipine pretreatment possibly shortens the onset time after minor or moderate dose of vecuronium.

Adult↗

PubMedDate not supplied

[Post-tetanic count after 50 and 100 Hz tetanic stimulation for monitoring deep neuromuscular blockade with vecuronium].

For monitoring of vecuronium profound neuromuscular blockade post-tetanic count (PTC) following tetanic stimulation at frequency of 50 and 100 Hz was employed in 25 ASA I-II patients submitted to elective surgery, to evaluate the differences between the two patterns of stimulation and the possible clinical utility of the latter pattern of stimulation. The drugs employed for anaesthesia were: diazepam 0.15 mg kg-1 in premedication, thiopental 4-5 mg kg-1 for induction, suxamethonium 1.5 mg kg-1 for tracheal intubation. Anaesthesia was maintained with N2 + O2 (2:1). Analgesia was obtained with fentanyl at usual doses, and muscular relaxation with vecuronium. The ulnar nerve was stimulated at the wrist with Digistim III Plus and the responses evaluated by tactile method. The pattern of stimulation used was a cyclic one, as described by Howardy Hansen et al. The first dose of vecuronium (0.06 mg kg-1) was administered at recovery from suxamethonium (clinically evaluated) and the other doses (0.06 mg kg-1) when the third response to a train of four appeared. The results show that the PTC following 100 Hz tetanus was greater than the PTC following 50 Hz tetanic stimulation (P < 0.01). The results also show that PTC following 100 Hz tetanus leads to underestimate neuromuscular blockade; yet maybe it has any clinical employment in selected surgical situations such as middle ear and eye surgery, microvascular surgery, neurosurgery.

Adolescent↗

PubMed1980

Antagonism of Org NC 45 neuromuscular blockade by neostigmine, pyridostigmine, and 4-aminopyridine.

The antagonism of Org NC 45 neuromuscular blockade by neostigmine, pyridostigmine, 4-aminopyridine, and their combinations was studied in the in vivo rat sciatic nerve anterior tibialis preparation using the constant infusion of Org NC 45 technique. The ED50 (dose of drug which produced a 50% antagonism) of neostigmine, pyridostigmine, and 4-aminopyridine were 14.5, 75, and 466 micrograms/kg, respectively. The addition of 100 microgram/kg of 4-aminopyridine, which produced no antagonism by itself, decreased neostigmine ED50 to 9.8 micrograms/kg. The addition of 200 micrograms/kg of 4-aminopyridine, which produced a 14.8% antagonism by itself, decreased the ED50 of pyridostigmine to 17.5 micrograms/kg. We concluded that neostigmine, pyridostigmine, and 4-aminopyridine effectively antagonize an Org NC 45 neuromuscular blockade. Neostigmine and pyridostigmine interact with 4-aminopyridine in a synergistic manner. The doses of antagonists were very similar to those required to antagonize a pancuronium neuromuscular blockade.

Aminopyridines↗

PubMed1990

Reversal of intense neuromuscular blockade following infusion of atracurium.

In order to evaluate reversal time from very intense neuromuscular blockade caused by a continuous infusion of atracurium, the time course of neostigmine induced reversal from different levels of neuromuscular blockade was evaluated using the post-tetanic count (PTC) and the train-of-four (TOF) in 30 patients anesthetized with nitrous oxide, fentanyl, and thiopental. Reversal time (time from administration of neostigmine at different PTC levels to a TOF ratio of 0.7) was found to depend upon the degree of blockade at the time of reversal. Median reversal time from a PTC of 1-2, 3-4, 5-6, 7-8, 9-10, 11-12, and greater than 13 (but less than 10% twitch height) to a TOF ratio of 0.7 was 31, 23, 19, 18, 14, and 13 min, respectively. Spontaneous recovery from PTC level of 1-2, when atracurium infusion was stopped, to a PTC level at which antagonism was induced and reversal time were both correlated to the square root of the PTC. Total recovery time (spontaneous recovery plus reversal time) was not shortened by an early injection of neostigmine. It is concluded that neostigmine administration during intense neuromuscular blockade following atracurium infusion does not shorten total recovery time and offers no clinical advantages.

Adult↗

PubMed1981

Neomycin-induced neuromuscular blockade.

The unusual complication of neuromuscular blockade secondary to neomycin absorption is described. The syndrome characterized by acute muscle flaccidity, diaphragmatic breathing, and central nervous system depression presents a potentially fatal situation. Appropriate treatment of this complication includes respiratory assistance and calcium gluconate administration (IV). A review of the pediatric literature reveals 12 previous cases, of which 2 were secondary to urologic procedures.

Calcium Gluconate↗

PubMed1986

Interaction of verapamil with gallamine and pancuronium and reversal of combined neuromuscular blockade with neostigmine and edrophonium.

In this in vitro study, the effects and interactions of verapamil with gallamine and pancuronium and reversal by edrophonium and neostigmine of combined neuromuscular blockade, produced by the muscle relaxants and verapamil, were studied in an avian skeletal muscle. The results show that verapamil reduced the amplitude of indirectly-elicited twitch tension and potentiated the neuromuscular blockade produce by the two muscle relaxants. Edrophonium and neostigmine reversed the neuromuscular blockade produce by the muscle relaxants alone, and in combination with verapamil. Edrophonium was more potent than neostigmine in reversing the combined neuromuscular blockade produced by the muscle relaxants with and without verapamil.

Animals↗

PubMed1989

[Neuromuscular blockade using vecuronium in dermatomyositis].

The significant features of neuromuscular blockade with vecuronium in a patient with dermatomyositis are described: vecuronium 0.08 mg/kg resulted in 90%, 0.12 mg/kg in 100% neuromuscular blockade. In contrast to claims made in some previous publications, dermatomyositis did not produce increased sensitivity to vecuronium. Onset time and duration of action were also within normal limits in our patient. Time of spontaneous recovery until antagonism with neostigmine was markedly prolonged, but the dermatomyositis was only one of various possible explanations. Although there are potential hazards in the use of neostigmine in patients with dermatomyositis, antagonism of the neuromuscular block with 2 mg neostigmine was without problems in our patient. Our data support recent suggestions to reconsider the implications of dermatomyositis for anesthesia.

Aged↗

PubMed1991

Model-based adaptive closed-loop feedback control of atracurium-induced neuromuscular blockade.

Closed-loop control of atracurium-induced neuromuscular blockade by a model-based adaptive feedback algorithm is described. Mean offsets (+/- s.d.) from setpoints at 50, 70 and 90% neuromuscular blocks using the Relaxograph were 1.1 +/- 1.3, 0.2 +/- 0.7 and 0.1 +/- 0.4%, respectively. Correspondingly, the mean steady-state rates of infusion of atracurium were 0.20 +/- 0.06, 0.25 +/- 0.03 and 0.39 +/- 0.10 mg.kg-1.h-1. The described controller provides reasonable control of atracurium dosing at different degrees of neuromuscular blockade. It gives a solution to the problem of adapting pharmacokinetic and pharmacodynamic data to individuals when using population mean data as starting values for drug therapy.

Algorithms↗