Comparison of succinylcholine with two doses of rocuronium using a new method of monitoring neuromuscular block at the laryngeal muscles by surface laryngeal electromyography

Rocuronium versus succinylcholine for rapid sequence induction intubation

BACKGROUND

Patients often require a rapid sequence induction (RSI) endotracheal intubation technique during emergencies or electively to protect against aspiration, increased intracranial pressure, or to facilitate intubation. Traditionally succinylcholine has been the most commonly used muscle relaxant for this purpose because of its fast onset and short duration; unfortunately, it can have serious side effects. Rocuronium has been suggested as an alternative to succinylcholine for intubation. This is an update of our Cochrane review published first in 2003 and then updated in 2008 and now in 2015.

OBJECTIVES

To determine whether rocuronium creates intubating conditions comparable to those of succinylcholine during RSI intubation.

SEARCH METHODS

In our initial review we searched all databases until March 2000, followed by an update to June 2007. This latest update included searching the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 2), MEDLINE (1966 to February Week 2 2015), and EMBASE (1988 to February 14 2015 ) for randomized controlled trials (RCTs) or controlled clinical trials (CCTs) relating to the use of rocuronium and succinylcholine. We included foreign language journals and handsearched the references of identified studies for additional citations.

SELECTION CRITERIA

We included any RCT or CCT that reported intubating conditions in comparing the use of rocuronium and succinylcholine for RSI or modified RSI in any age group or clinical setting. The dose of rocuronium was at least 0.6 mg/kg and succinylcholine was at least 1 mg/kg.

DATA COLLECTION AND ANALYSIS

Two authors (EN and DT) independently extracted data and assessed methodological quality for the 'Risk of bias' tables. We combined the outcomes in Review Manager 5 using a risk ratio (RR) with a random-effects model.

MAIN RESULTS

The previous update (2008) had identified 53 potential studies and included 37 combined for meta-analysis. In this latest update we identified a further 13 studies and included 11, summarizing the results of 50 trials including 4151 participants. Overall, succinylcholine was superior to rocuronium for achieving excellent intubating conditions: RR 0.86 (95% confidence interval (CI) 0.81 to 0.92; n = 4151) and clinically acceptable intubation conditions (RR 0.97, 95% CI 0.95 to 0.99; n = 3992, 48 trials). A high incidence of detection bias amongst the trials coupled with significant heterogeneity provides moderate-quality evidence for these conclusions, which are unchanged from the previous update. Succinylcholine was more likely to produce excellent intubating conditions when using thiopental as the induction agent: RR 0.81 (95% CI: 0.73 to 0.88; n = 2302, 28 trials). In the previous update, we had concluded that propofol was the superior induction agent with succinylcholine. There were no reported incidences of severe adverse outcomes. We found no statistical difference in intubation conditions when succinylcholine was compared to 1.2 mg/kg rocuronium; however, succinylcholine was clinically superior as it has a shorter duration of action.

AUTHORS' CONCLUSIONS

Succinylcholine created superior intubation conditions to rocuronium in achieving excellent and clinically acceptable intubating conditions.

Rocuronium versus succinylcholine for rapid sequence induction intubation

BACKGROUND

Patients requiring emergency endotracheal intubation often require a rapid sequence induction (RSI) intubation technique to protect against aspiration or increased intracranial pressure, or to facilitate intubation. Succinylcholine is the most commonly used muscle relaxant because of its fast onset and short duration; unfortunately, it can have serious side effects. Rocuronium has been suggested as an alternative to succinylcholine for intubation. This meta-analysis is an update since our initial Cochrane systematic review in 2003.

OBJECTIVES

To determine if rocuronium creates comparable intubating conditions to succinylcholine during RSI intubation. Comparisons were made based on dose of rocuronium, narcotic use, emergency versus elective intubation, age and induction agent. The primary outcome was excellent intubation conditions. The secondary outcome was acceptable conditions.

SEARCH STRATEGY

In our initial systematic review we searched all databases until March 2000. We have updated that search and searched the Cochrane Central Register of Controlled Trials (The Cochrane Library, 2007 issue 3), MEDLINE (1966 to June Week 3 2007), EMBASE (1988 to 2007 Week 26) for randomized controlled trials or controlled clinical trials relating to the use of rocuronium and succinylcholine. We included foreign language journals and handsearched the references of identified studies for additional citations.

SELECTION CRITERIA

We included all trials meeting the inclusion criteria (comparison of rocuronium and succinylcholine, main outcomes of intubation conditions).

DATA COLLECTION AND ANALYSIS

Two authors (JP, JL or VS) independently extracted data and assessed methodological quality for allocation concealment. We combined the outcomes in RevMan using relative risk (RR) with a random-effects model.

MAIN RESULTS

In our initial systematic review we identified 40 studies and included 26. In this update we identified a further 18 studies and included 11. In total, we identified 58 potential studies; 37 were combined for meta-analysis. Overall, succinylcholine was superior to rocuronium, RR 0.86 (95% confidence interval (95% CI) 0.80 to 0.92) (n = 2690). In the group that used propofol for induction, the intubation conditions were superior with succinylcholine (RR 0.88, 95% CI 0.80 to 0.97) (n = 1183). This is contrary to our previous meta-analysis results where we reported that intubation conditions were superior in the rocuronium group when propofol was used. We found no statistical difference in intubation conditions when succinylcholine was compared to 1.2mg/kg rocuronium; however, succinylcholine was clinically superior as it has a shorter duration of action.

AUTHORS' CONCLUSIONS

Succinylcholine created superior intubation conditions to rocuronium when comparing both excellent and clinically acceptable intubating conditions.

The optimal pediatric induction dose of propofol in combination with reduced-dose rocuronium and alfentanil for day-case tonsillectomy in children

OBJECTIVE

Tonsillectomy in children may be performed on a day-case basis. To achieve quality anesthesia and successful, fast recovery with minimal morbidity without the use of volatile anesthetic, the choice of drug combination has to be centered on one rapid- and short-acting hypnotic, opioid and non-depolarizing muscle relaxant. The aim of our study was to determine the optimal pediatric induction dose of propofol that by means of alfentanil and reduced-dose rocuronium allows the highest percentage of excellent intubating conditions.

METHODS

One hundred and eleven children were randomized in three equal groups and included in prospective, double blind study. Anesthesia was induced with 2.0 (Group A), 2.5 (Group B) or 3.0 mg kg(-1) (Group C) of propofol proceeded by alfentanil (0.02 mg kg(-1)). Muscle relaxation was achieved with reduced-dose rocuronium (1.5x ED(95)) (0.45 mg kg(-1)). The intubating conditions were assessed using the four-point scoring system based on the difficulty of laryngoscopy, presence of vocal cord movement and the intensity of coughing. Neuromuscular transmission was monitored by means of acceleromyography with supramaximal train-of-four stimulation of the ulnar nerve by the frequency of 1Hz.

RESULTS

Adequate intubating conditions were achieved in high percentages in all study groups (A = 94%, B = 95%, C = 98%) (P = 0.352). Significant higher differences of excellent and good intubating conditions, attributed to quality of laryngoscopy, movement of the vocal cords and intensity of coughing were observed in Group C (excellent = 94%, good = 4%) (B = excellent 80%, good = 18% and A = excellent 47%, good = 47%) (P = 0.0001). MAP decrease of 12% from the baseline occurred immediately only after 3.0 mg kg(-1) induction dose of propofol (80+/-7 mm Hg; A = 92 +/- 6, B = 88 +/- 9) (P = 0.005).

CONCLUSIONS

Induction dose of 2.5 mg kg(-1) of propofol preceded by 0.02 mg kg(-1) of alfentanil in addition to reduced-dose rocuronium (0.45 mg kg(-1)) is the optimal pediatric induction dose of propofol for improving the most excellent intubating conditions without significant hemodynamic changes.

Update on neuromuscular pharmacology

Since the introduction of d-tubocurarine into clinical practice, neuromuscular relaxants have been widely used in anaesthesia. Although their clinical use is easy, several points still require further attention and research. There is still a need for a drug with the clinical profile of succinylcholine but fewer unwanted side-effects. A better understanding of the effects of muscle relaxants on different muscles could help in their clinical use during the perioperative period. Much knowledge is needed about residual neuromuscular block and its detection in order to improve the quality of recovery from neuromuscular blockade. If some questions remain to be answered, several recent articles have increased our knowledge and should improve our clinical practice.

Brief review: Neuromuscular monitoring: an update for the clinician

PURPOSE

To review established techniques and to provide an update on new methods for clinical monitoring of neuromuscular function relevant to anesthesia.

SOURCE

A PubMed search of relevant article for the period 1985-2005 was undertaken, and bibliographies were scanned for additional sources.

PRINCIPAL FINDINGS

There is no substitute for objective neuromuscular monitoring; for research purposes, mechanomyography (MMG) is the gold standard; however, the most versatile method in the clinical setting is acceleromyography since it can be applied at various muscles and has a long track record of clinical utility. Kinemyography is valid to monitor recovery of neuromuscular transmission at the adductor pollicis muscle (AP), whereas phonomyography is easy to apply to various muscles and shows promising agreement with MMG. Monitoring of the corrugator supercilii muscle (CS) may be used to determine the earliest time for tracheal intubation as it reflects laryngeal relaxation better than monitoring at the AP. Recovery of neuromuscular transmission is best monitored at the AP, since it is the last muscle to recover from neuromuscular blockade (NMB). If train-of-four (TOF) stimulation is used, a TOF-ratio > 0.9 should be the target before awakening the patient. If surgery or the type of anesthesia necessitates NMB of a certain degree, e.g., TOF-ratio = 0.25, monitoring of muscles which best reflect the degree of NMB at the surgical site is preferable.

CONCLUSION

Objective methods should be used to monitor neuromuscular function in clinical anesthesia. Acceleromyography offers the best compromise with respect to ease of use, practicality, versatility, precision and applicability at various muscles. The CS is the optimal muscle to determine the earliest time for intubation, e.g., for rapid sequence induction.

Succinylcholine or rocuronium? A meta-analysis of the effects on intubation conditions

This meta-analysis was undertaken to compare the effects of succinylcholine (SCH) and rocuronium (RCR) on endotracheal intubation (ETI) conditions. Eligible randomised controlled trials (RCTs) were identified via medline and a manual search of references. The frequencies of excellent and unacceptable ETI conditions in subjects receiving SCH 1.0-1.5 mg/kg and RCR 0.6-1.2 mg/kg were determined using standard statistical methods. Inclusion criteria were met by 16 RCTs, representing 1362 subjects. SCH was associated with a 17.7% increase (95% CI = 13-22) in the frequency of excellent ETI conditions and a 5.1% decrease (95% CI = -7.3 to -2.9) in the frequency of unacceptable ETI conditions, when compared with RCR. In the subgroup undergoing true rapid sequence intubation, SCH was associated with a 19.1% increase (95% CI = 13.7-24.5) in the frequency of excellent ETI conditions. SCH appears to be superior to RCR in creating excellent ETI conditions and avoiding unacceptable ETI conditions.

An external monitoring site at the neck cannot be used to measure neuromuscular blockade of the larynx

Using phonomyography, a new monitoring technique of neuromuscular blockade (NMB), we compared NMB after mivacurium 0.1 mg/kg at the lateral cricoarytenoid muscle (LCA) with a possible external monitoring site of the larynx. In 12 patients, data were obtained at both sites using phonomyography. Anesthesia was induced with remifentanil 0.25-0.5 microg . kg(-1) . min(-1) followed by propofol 2-3 mg/kg. A small piezo-electric microphone was positioned beside the vocal cords into the muscular process at the base of the arytenoid cartilage to record acoustic signals from the contraction of the LCA. A second microphone was positioned at an external site, lateral to the trachea, just below the thyroid notch. The recurrent laryngeal nerve was stimulated supramaximally using train-of-four (TOF) stimulation every 12 s. Onset, maximum effect, and offset of NMB were measured and compared. Peak effect, time to reach (T) 25%, 75%, and 90% of control twitch response, and TOF recovery to TOF ratios 0.5-0.8 were significantly longer at the external site. The onset time was not significantly different between the two sites. We used phonomyography with a microphone placed at the neck to evaluate the possibility to externally monitor NMB at the larynx. When compared with LCA, we found a more pronounced peak effect and longer offset of NMB. The acoustic signals recorded at this external site are unlikely to stem from laryngeal muscle contraction but are rather a result of contraction of the strap muscles of the neck.

Influence of muscle relaxation on neuromonitoring of the recurrent laryngeal nerve during thyroid surgery

BACKGROUND

The influence of muscle relaxation on the intra-operative neuromonitoring of the recurrent laryngeal nerve during thyroid surgery is unclear.

METHODS

In a prospective study involving 200 patients undergoing elective thyroid surgery, the influence of muscle relaxation on neuromonitoring of the recurrent laryngeal nerve was investigated. The patients received balanced anaesthesia with oxygen-nitrous oxide-isoflurane, and rocuronium bromide was used as the non-depolarizing neuromuscular blocking agent. The degree of relaxation was monitored continuously by accelerometry [twitch (% TW)]. Summed action potentials (SAcP) obtained from the vocalis muscle were characterized by the area under the electromyographic curve expressed in millivolt seconds.

RESULTS

Evoked potentials were obtainable in all patients and at all time points. With decreasing neuromuscular blockade a significant increase in the potentials evoked at the vocalis muscle was observed. At 0% TW SAcP was 1.27 (SD 1.02) mV s. An increase in TW to 10% was accompanied by an increase in SAcP to 2.68 (2.01) mV s (P<0.01). At a TW of 25%, mean SAcPs of 5.08 mV s were recorded.

CONCLUSIONS

There was a significant difference in the degree of relaxation of the adductor pollicis muscle and the vocalis muscle. The laryngeal muscles exhibited a shorter response time than the adductor pollicis and recovered more quickly. These results confirm the feasibility of intra-operative neuromonitoring of the recurrent laryngeal nerve during neuromuscular blockade.

Prolonged paralysis related to mivacurium: A case study

Pseudocholinesterase deficiency is usually identified when an anesthetized patient has prolonged paralysis after receiving neuromuscular blocking agents dependent on pseudocholinesterase enzymes for hydrolysis. This rare complication, most frequently associated with succinylcholine, can occur with the use of mivacurium, one of the newer nondepolarizing muscle relaxants also hydrolyzed by pseudocholinesterase. Prolonged paralysis has occurred 3 times in the past 2 years at this pediatric hospital after administration of mivacurium. The following case study describes causality and interventions for a patient with prolonged paralysis after receiving mivacurium.

A priming technique accelerates onset of neuromuscular blockade at the laryngeal adductor muscles

PURPOSE

Priming is a known technique to accelerate onset of neuromuscular blockade (NMB). Its effect on NMB of the larynx has not been studied yet.

METHODS

We compared a priming technique with a bolus application of rocuronium on the onset of NMB at the laryngeal adductor and the adductor pollicis muscles (AP). In 30 female patients, after induction of anesthesia a tube with a surface electrode was placed into the trachea prior to the administration of any neuromuscular blocking agent to monitor electromyography (EMG) of the laryngeal adductor muscles. Neuromuscular monitoring consisted of EMG of the laryngeal adductor muscles and the left AP. Patients were randomized into two groups. After transcutaneous stimulation of the recurrent laryngeal nerve and ulnar nerve, a bolus of rocuronium 0.6 mg x kg(-1) (Bolus group) or a priming dose of rocuronium 0.06 mg x kg(-1) followed by rocuronium 0.54 mg x kg(-1) three minutes later (Priming group) were injected. Lag time, onset 90%, onset time and peak effect of NMB were recorded and compared; a P < 0.05 was considered significant.

RESULTS

The onset 90% and onset time measured at the laryngeal adductor muscles (onset: 44.7 +/- 7.4 vs 74.0 +/- 23.8 sec) and at the AP (onset: 105.4 +/- 29.9 vs 139.2 +/- 51.5 sec) were significantly shorter in the Priming group than in the Bolus group. Within groups, the onset times were significantly shorter at the laryngeal muscles in comparison to AP.

CONCLUSION

Our results indicate that a priming technique with rocuronium significantly accelerates the onset of NMB at the laryngeal adductor muscles. Our results further support the use of rocuronium as an alternative to succinylcholine for rapid sequence induction.

Simultaneous Determination of Neuromuscular Blockade at the Adducting and Abducting Laryngeal Muscles Using Phonomyography

Phonomyography (PMG) is a new method for measuring neuromuscular blockade (NMB) at the larynx. In this study, we used PMG to compare NMB at the posterior cricoarytenoid (PCA) and the lateral cricoarytenoid muscle (LCA) in humans. Twelve patients were included in this study. Endotracheal intubation was performed without aid of neuromuscular blocking drugs. One small condenser microphone was inserted beside the vocal cords into the muscular process at the base of the arytenoid cartilage to record acoustic responses of the LCA (vocal cord adduction), and a second microphone was placed behind the larynx to measure NMB of the PCA (vocal cord abduction). Stimulation of the recurrent laryngeal nerve was performed using superficial electrodes placed at the neck (midline between jugular notch and cricoid cartilage) using train-of-four (TOF) stimulation every 12 s. After supramaximal stimulation, mivacurium 0.1 mg/kg was injected and onset, peak effect, and offset of NMB measured and compared using t-test (P < 0.05). The data are presented as mean (SD). Peak effect, onset time, and early recovery to 25% of control twitch height were not significantly different between PCA and LCA at 86% (13) versus 78% (16), 2.3 min (0.45) versus 2.3 min (1.0), and 9.55 min (3.05) versus 8.5 min (4.7), respectively. However, recovery to 75%, 90% of control twitch height, and recovery to a TOF ratio of 0.8 were significantly longer at the PCA than at the LCA at 14 min (4) versus 11 min (5), 17 min (5) versus 11.8 min (5.6), and 17.5 min (5.6) versus 12.3 min (5.5), respectively. The authors conclude that recovery of NMB at the PCA takes longer than at the LCA in humans after mivacurium.

IMPLICATIONS

After neuromuscular blockade in humans, the recovery of the ability to open the vocal cords takes longer than the ability to close the vocal cords.

Neuromuscular blockade at the larynx, the diaphragm and the corrugator supercilii muscle: a review

PURPOSE

To review recent findings concerning neuromuscular blockade and monitoring at the larynx, the diaphragm, and the corrugator supercilii muscle.

SOURCE

This narrative review is based on recent publications.

PRINCIPAL FINDINGS

Neuromuscular blockade at the larynx and the diaphragm is less intense than at the adductor pollicis muscle; the onset and offset of neuromuscular blockade is more rapid. The corrugator supercilii muscle reflects better the time course of neuromuscular blockade of the larynx than the adductor pollicis muscle, is better suited to monitor the onset of neuromuscular blockade for intubation, and should give a better reflection of the time course and degree of neuromuscular blockade of the larynx or the diaphragm. Recovery of neuromuscular function at the end of any procedure is best reflected at the adductor pollicis muscle where neuromuscular transmission is last restored. Clinical monitoring of the larynx or the diaphragm is still limited by the absence of a simple method. Acceleromyography of the corrugator supercilii muscle is prone to artifacts that do not occur during monitoring of the adductor pollicis muscle. Phonomyography, a new method of monitoring that is currently being tested, is based on the phenomenon that muscle contraction creates low-frequency sound waves, which can be detected using special microphones to quantify neuromuscular blockade. This method seems promising because it can be easily used on all muscles of interest.

CONCLUSION

Research during the last 15 years has greatly enhanced our knowledge about how muscles react differently to muscle relaxants and has enabled us to achieve better surgical conditions with safer use of muscle relaxants. Interesting technologies have been developed to reliably monitor neuromuscular blockade at the larynx and the diaphragm, but are currently restricted to research settings. Our increased understanding should help us in ongoing efforts to develop the "ideal" muscle relaxant and the "ideal" method of neuromuscular monitoring.

Neuromuscular monitoring

This review summarizes recent reports on the techniques and the use of methods for monitoring neuromuscular function during anaesthesia. The latest news on the use of acceleromyography in the face and hand, on laryngeal and diaphragmal surface electromyography, on acoustic myography, on evaluation of intense neuromuscular block, and on postoperative residual curarization is presented and discussed. It is concluded that available evidence suggests that more attention should be paid by the anaesthetist to the problems of residual curarization and hence to proper monitoring of neuromuscular function using objective methods.

Simultaneous determination of neuromuscular block at the larynx, diaphragm, adductor pollicis, orbicularis oculi and corrugator supercilii muscles

We simultaneously determined the neuromuscular blocking effect of mivacurium 0.2 mg kg(-1) at five muscles in 20 women undergoing gynaecological surgery. Evoked electromyographic responses were obtained using surface electromyography (EMG) at the adducting laryngeal muscles, the diaphragm (lateral to vertebrae T12/L1 or L1/L2) and the adductor pollicis muscle and acceleromyographic (AMG) responses were measured at the orbicularis oculi and the corrugator supercilii muscle. Onset time and times for the first twitch response (T1/T0) to return to 25, 75 and 90% at the adducting laryngeal muscles and the diaphragm were significantly (P<0.005) shorter than at the adductor pollicis, the corrugator supercilii or the orbicularis oculi muscles (mean (SD) onset time: 89 (26) s and 78 (17) s to 202 (45) s, 152 (41) s, 194 (40) s; T1/T0=25%: 10.4 (1.5) and 11.4 (1.2) min versus 20.5 (3.9), 15.9 (3.3), 16.3 (3.7) min; T1/T0=90%: 15.5 (1.6) and 16.1 (1.6) min versus 27.4 (4.6), 21.5 (3.8), 23.3 (5.1) min). Onsetand clinical duration of neuromuscular block at the larynx and the diaphragm after mivacurium 0.2 mg kg(-1) are shorter than in the peripheral muscles. Monitoring of neuromuscular block in the diaphragm was successfully used in all patients.