Pretreatment of rocuronium reduces the frequency and severity of etomidate-induced myoclonus

Efficacy of Granisetron versus Sufentanil on Reducing Myoclonic Movements Following Etomidate: Double-blind, randomised clinical trial

Objectives

This study aimed to reduce the intensity of myoclonus movements by comparing the effectiveness of granisetron and sufentanil in reducing the intensity of etomidate-induced myoclonic movements. Etomidate-induced myoclonus occurs in up to 85% of patients under general anaesthesia. This type of myoclonus can induce significant clinical and economic problems in patients with special conditions.

Methods

This double-blind randomised clinical trial study consisted of 96 adult patients recruited between January and July 2021 from Mashhad University of Medical Sciences, Mashhad, Iran. Using block randomisation, subjects were divided into three groups of 32 patients: the group receiving granisetron 40 μg/kg (group G), the group receiving sufentanil 0.2 μg/kg (group S) and the control group who did not receive the pretreatment (group C). Patients received these medications as pretreatments 120 seconds before induction with etomidate. After the injection of etomidate with a dose of 0.3 mg/kg, the incidence of myoclonus was evaluated. After evaluating the myoclonus, the full dose of narcotics (fentanyl 1 μg/kg) and muscle relaxants (atracurium 0.5 mg/kg) were administered to patients and a suitable airway was established for them.

Results

The findings indicated that granisetron reduced the intensity and incidence of myoclonic movements more than sufentanil. In addition, myoclonic movements were observed at a significantly higher intensity in the control group (P = 0.001).

Conclusion

The results obtained from the current study indicate that granisetron and sufentanil as pretreatments are effective for reducing myoclonus in patients.

Comparison of the Effectiveness of Various Drug Interventions to Prevent Etomidate-Induced Myoclonus: A Bayesian Network Meta-Analysis

Background

Myoclonic movement is a very common but undesirable phenomenon during the induction of general anesthesia using etomidate. Such movement may cause unnecessary problems. Currently, there is an increasing number of drugs for preventing etomidate-induced myoclonus (EM). However, direct comparisons of various drugs are lacking, and this interferes with clinical decision-making. Our network meta-analysis (NMA) aimed to compare the efficacy of different drugs for the prevention of moderate-to-severe general myoclonus.

Methods

Using several biomedical databases, randomized controlled trials (RCTs) published in English from inception to August 22, 2021 were searched. Among the various interventions, we selected nine types of intervention drugs (dexmedetomidine, etomidate, lidocaine, NMDA receptor antagonist, κ opioid receptor agonist, μ opioid receptor agonist, muscle relaxant, gabapentin, and midazolam) for comparison, according to the number of studies. Bayesian NMA was performed using STATA16 and R softwares. The relative risk of EM was assessed using risk ratios (RRs) and the corresponding 95% confidence intervals (CI).

Results

A total of 31 RCTs (3209 patients) were included. NMA results showed that, compared with a placebo, etomidate (RR 4.0, 95%CI 2.1–7.8), κ opioid receptor agonist (RR 2.9, 95%CI 1.9–4.6), μ opioid receptor agonist (RR 3.1, 95%CI 2.3–4.3), NMDA receptor antagonist (RR 1.7, 95%CI 1.0–2.8), dexmedetomidine (RR 2.4, 95%CI 1.5–3.9), lidocaine (RR 2.1, 95%CI 1.2–3.9), and midazolam (RR 2.2, 95%CI 1.5–3.2) can significantly reduce the risk of EM. In contrast, the effects of muscle relaxants (RR 2.1, 95%CI 0.81–5.3) and gabapentin (RR 2.8, 95%CI 0.92–9.3) were inconclusive. Further subgroup analyses showed that preoperative low-dose etomidate, μ-opioid receptor agonist, and κ-opioid receptor agonist were significantly better than other interventions in the prevention of moderate to severe EM.

Conclusion

Preoperative use of small doses of etomidate or opioids may be the most effective way to avoid EM, especially moderate and severe EM, which makes anesthesia induction safer, more stable, and aligns better with the requirements of comfortable medicine.

Systematic Review Registration

[https://www.crd.york.ac.uk/prospero/], [CRD4202127706].

Comparison of Premedication with Low-Dose Midazolam Versus Etomidate for Reduction of Etomidate-Induced Myoclonus During General Anesthesia for Electroconvulsive Therapy: A Randomized Clinical Trial

Background

A variety of anesthetics including methohexital, thiopental sodium, propofol, ketamine, and etomidate are used for electroconvulsive therapy (ECT), each accompanied by adverse effects that can cause unpleasant experiences for patients. Etomidate-induced myoclonus is among the adverse effects. We attempted to assess the effect of premedication with low-dose midazolam compared to etomidate on the reduction of this complication.

Objectives

This study was designed to compare the effectiveness of low-dose etomidate and low- dose midazolam to suppress etomidate-induced myoclonus in ECT.

Methods

This randomized double-blinded clinical trial was conducted on 132 patients who were candidates for ECT. They were divided into three groups of 44 patients to receive 0.015 mg/kg midazolam, 0.03 mg/kg etomidate, or placebo. Independent t-test and chi-square test were used for comparison of variables.

Results

The frequency of myoclonic movements during anesthesia was different between the three groups (P value < 0.001). Myoclonic movements were significantly lower in the midazolam group than in the placebo (P value < 0.001) and etomidate (P value = 0.002) groups. In addition, the intensity of myoclonic movements was significantly higher in the midazolam group than in the placebo and etomidate groups (P value < 0.001).

Conclusions

Low-dose midazolam (0.015 mg/kg) before anesthesia induction with etomidate was accompanied with significantly lower incidence and intensity of myoclonus than low-dose etomidate (0.03 mg/kg).

Comparison of the efficacy and safety of remifentanil versus different pharmacological approaches on prevention of etomidate-induced myoclonus: a meta-analysis of randomized controlled trials

Objective: Myoclonus was considered as one conundrum in etomidate induction, which led to multiple risks during clinical anesthesia. The present study was conducted to compare the efficacy of pretreatment with remifentanil to different pharmacological approaches on reducing etomidate-induced myoclonus.

Methods: We searched PubMed, Embase, Cochrane Library, and China National Knowledge Infrastructure from the inception to October 2018. Randomized controlled trials comparing remifentanil versus other pharmacological approaches in reducing etomidate-induced myoclonus were eligible to be analyzed.

Results: Overall, 13 trials with 1,392 patients met with the inclusion criteria. 1) Pretreatment with remifentanil could reduce the incidence of etomidate-induced myoclonus compared to placebo and fentanyl; few differences were found between the use of remifentanil and the use of midazolam: (incidence of myoclonus: 5.56% with remifentanil vs 71.65% with saline, RR=0.08, with 95% CI [0.05, 0.12], P<0.0001; 3.80% with remifentanil vs 13.33% with fentanyl, RR with 95% 0.31 [0.11, 0.86], P=0.02; 46.00% with remifentanil vs 55.45% with midazolam, RR=0.82, with 95% CI [0.64, 1.06], P=0.13). 2) Compared with placebo, pretreatment with remifentanil could reduce the incidence of mild, moderate, and severe myoclonus; compared with midazolam, patients receiving remifentanil experienced lower occurrence of severe myoclonus; compared with fentanyl, pretreatment with remifentanil associated with significant low occurrence of moderate and severe myoclonus. 3) The outcomes also indicated that pretreatment with remifentanil could prevent excessive hemodynamic changes after endotracheal intubation compared to fentanyl.

Conclusions: Pretreatment with remifentanil could be considered as one operative option to reduce both incidence and severity of etomidate-induced myoclonus. Compared with fentanyl, it also provides efficacy in preventing excessive hemodynamic changes after endotracheal intubation. However, the best treatment and the proper prophylactic dosage calls for more high quality evidence with large sample size.

Effect of Fentanyl and Nalbuphine for Prevention of Etomidate-Induced Myoclonus

BACKGROUND

Etomidate is a potent intravenous inducing agent with known undesirable side effects such as myoclonus and pain on injection in nonpremedicated patients.

AIMS

The aim of this study is to compare the effect of fentanyl and nalbuphine in the prevention of etomidate-induced myoclonus.

SETTINGS AND DESIGN

Randomized double-blind, placebo-controlled, and prospective comparative study.

MATERIALS AND METHODS

A total of 120 patients were randomly allocated to one of the three groups containing 40 patients each for intravenous administration of fentanyl 2 μg/kg diluted in 10 mL normal saline (NS) (Group 1), nalbuphine 0.3 mg/kg diluted in 10 mL NS (Group 2), and only 10 mL NS (Group 3) over 10 min. All groups subsequently received 0.3 mg/kg etomidate by intravenous bolus injection over 15-20 s and were assessed for the severity of pain using Grade IV pain scale and observed for myoclonus for 2 min and graded according to clinical severity. Serum creatinine phosphokinase (CPK) levels were obtained prior and postetomidate injection.

STATISTICAL ANALYSIS

Statistical analysis was performed by the SPSS program version 17.0 for Windows. Tests used are Shaipro-Wilk test, ANOVA, Tukey's multiple comparison test, Tamhane's T2, and the Chi-square test. For all statistical tests, P < 0.05 was considered statistically significant with 5% level of significance (α).

RESULTS

The incidence of myoclonus in Group 1 and 2 was 52.5% and 17.5%, respectively, whereas it was 92.45% in Group 3. There was no pain observed in 70%, 92.5%, and 50% of patients in Group 1, 2, and 3, respectively. There was a statistically significant difference in mean CPK level after induction among three groups (P < 0.001).

CONCLUSION

Nalbuphine is more effective than fentanyl in the prevention of etomidate-induced myoclonus and pain with the minimum rise in CPK levels.

Effects of transcutaneous acupoint electrical stimulation combined with low-dose sufentanil pretreatment on the incidence and severity of etomidate-induced myoclonus: A randomized controlled trial

BACKGROUND

Myoclonus is an undesirable phenomenon that occurs after induction of general anesthesia using etomidate. Opioids such as sufentanil are considered effective pretreatment drugs for myoclonus inhibition, although high doses are required. Transcutaneous acupoint electrical stimulation (TAES), a noninvasive technique involving electrical stimulation of the skin at the acupuncture points, exhibits analgesic effects, promotes anesthetic effects, decreases the dose of anesthetic drugs, and increases endogenous opioid peptide levels. In the present study, we investigated the effects of TAES combined with low-dose sufentanil pretreatment on the incidence and severity of etomidate-induced myoclonus in patients undergoing elective hysteroscopy.

METHODS

In a double-blind manner, 172 patients (American Society of Anesthesiologists class I-II; age, 20-55 years) scheduled to undergo elective hysteroscopy were randomized into the following groups (n = 43 each): control (false TAES followed by saline injection after 30 min), TAES (TAES followed by saline injection after 30 minutes), sufentanil [false TAES followed by low-dose sufentanil (0.1 μg/kg) injection after 30 minutes], and sufentanil plus TAES (TAES followed by low-dose sufentanil injection after 30 minutes). In all groups, general anesthesia was induced by etomidate 0.3 mg/kg after sufentanil or saline injection. The incidence and severity of myoclonus were assessed for 2 minutes after etomidate administration. The visual analogue scale (VAS) scores for pain at 1 hour after surgery were recorded. The heart rate (HR), mean arterial pressure (MAP), and peripheral capillary oxygen saturation (SPO2) were recorded before premedication, after etomidate injection, after uterus expansion, and after recovery from anesthesia.

RESULTS

The incidence of myoclonus was highest in the control group (88.3%), followed by TAES (74.4%), sufentanil (60.4%), and TAES plus sufentanil (48.8%) groups. Thus, the incidence was significantly higher in the control and TAES groups than in the sufentanil and TAES plus sufentanil groups. Grade 3 myoclonus occurred in 30.2%, 9.3%, 11.6%, and 9.3% patients in the control, TAES, sufentanil, and TAES plus sufentanil groups, respectively, with significant differences between the control group and the other 3 groups. Furthermore, the postoperative VAS scores for pain were significantly lower in the TAES, sufentanil, and TAES plus sufentanil groups compared with those in the control group. There were no significant differences in any other parameters among groups.

CONCLUSION

Our results suggest that TAES combined with low-dose opioids such as sufentanil can decrease the incidence and severity of etomidate-induced myoclonus.

Pretreatment with Oxycodone Simultaneously Reduces Etomidate-Induced Myoclonus and Rocuronium-Induced Withdrawal Movements During Rapid-Sequence Induction

Background

Etomidate and rocuronium are often paired in rapid-sequence anesthesia induction. However, the effect of pretreatment with oxycodone on myoclonic and withdrawal movements has not been previously investigated.

The aim of this study was to evaluate the effects of oxycodone on the incidence and severity of etomidate-induced myoclonus and rocuronium-induced nociceptive withdrawal movements during rapidsequence anesthesia induction.

Material/Methods

We randomly divided 120 patients into the saline group (group S) and the oxycodone group (group O) (n=60 in each group). Patients received 0.05 mg/kg oxycodone or saline intravenously 2 min before administration of 0.3 mg/kg etomidate. The occurrence and severity of myoclonus were assessed after administration of etomidate, then rocuronium was injected, followed by evaluation of withdrawal movements.

Results

The total frequency of involuntary movements following sequential administration of etomidate and rocuronium was significantly lower in Group O than in Group S (28.3% vs. 90%, p<0.001). The total frequency and grade 3 severity of myoclonus following etomidate injection in Group O was significantly lower than in Group S (25.0% vs. 63.3% for total frequency; 0 vs. 10 for grade 3 severity, P<0.001). The total frequency and grade 3 intensity of withdrawal movements were significantly less in Group O than in Group S (6.7% vs. 73.3% for total frequency; 0 vs. 11 for grade 3 intensity, P<0.001).

Conclusions

Oxycodone is effective for simultaneously preventing etomidate-induced myoclonus and rocuronium-induced withdrawal movements during general anesthesia induction.

Etomidate versus propofol sedation for complex upper endoscopic procedures: a prospective double-blinded randomized controlled trial

BACKGROUND AND AIMS

Although a growing body of evidence demonstrates that propofol-induced deep sedation can be effective and performed safely, cardiopulmonary adverse events have been observed frequently. Etomidate is a new emerging drug that provides hemodynamic and respiratory stability, even in high-risk patient groups. The objective of this study was to compare safety and efficacy profiles of etomidate and propofol for endoscopic sedation.

METHODS

A total of 128 patients undergoing EUS were randomized to receive either etomidate or propofol blinded administered by a registered nurse. The primary outcome was the proportion of patients with any cardiopulmonary adverse events.

RESULTS

Overall cardiopulmonary adverse events were identified in 22 patients (34.38%) of the etomidate group and 33 patients (51.56%) of the propofol group, without significant difference (P = .074). However, the incidence of oxygen desaturation (4/64 [6.25%] vs 20/64 [31.25%]; P =.001) and respiratory depression (5/64 [7.81%] vs 21/64 [32.81%]; P =.001) was significantly lower in the etomidate group than in the propofol group. The frequency of myoclonus was significantly higher in the etomidate group (22/64 [34.37%]) compared with the propofol group (8/64 [12.50%]) (P =.012). Repeated measure analysis of variance revealed significant effects of sedation group and time on systolic blood pressure (etomidate group greater than propofol group). Physician satisfaction was greater in the etomidate group than in the propofol group.

CONCLUSIONS

Etomidate administration resulted in fewer respiratory depression events and had a better sedative efficacy than propofol; however, it was more frequently associated with myoclonus and increased blood pressure during endoscopic procedures. (Clinical trial registration number: KCT0001701.).

Propofol decreases etomidate-related myoclonus in gastroscopy

OBJECTIVE

Myoclonus, a common complication during intravenous induction with etomidate, is bothersome to both anesthesiologists and patients. This study explored the preventive effect of pretreatment with propofol on etomidate-related myoclonus.

METHODS

This was a prospective, double-blind, clinical, randomized controlled study. Totally, 363 patients who were scheduled for a short-duration, painless gastrointestinal endoscopy were divided into 5 groups. Four groups received 0 mg/kg (E group), 0.25 mg/kg (LPE group), 0.50 mg/kg (MPE group), or 0.75 mg/kg (HPE group) propofol pretreatment before etomidate anesthesia. Another group only received 1 to 2 mg/kg of propofol (P group) as anesthesia. The incidence and severity of myoclonus, patient circulation and respiratory status, and intraoperative and postoperative complications were recorded.

RESULTS

The incidence of myoclonus in the LPE group (26.8%), MPE group (16.4%), HPE group (14.9%), and P group (0) was lower than the E group (48.6%, P < .05). The incidence of grade 1, 2, and 3 of myoclonus in the LPE group, MPE group, HPE group, and P group was significantly lower than the E group, and that in the P group was lower than the LPE group (P < .05). The incidence of hypoxemia in the P group was higher than the E group, and the incidence of adverse events in the HPE group and P group was lower than the E group (P < .05).

DISCUSSION

Pretreatment with propofol was feasible for preventing etomidate-related myoclonus. Furthermore, as propofol dosage increased, its effect on reducing the incidence and severity of myoclonic movements induced by etomidate increased.

Comparison of the Effects of Low-Dose Midazolam, Magnesium Sulfate, Remifentanil and Low-Dose Etomidate on Prevention of Etomidate-Induced Myoclonus in Orthopedic Surgeries

BACKGROUND

Etomidate is a potent hypnotic agent with several desirable advantages such as providing a stable cardiovascular profile with minimal respiratory adverse effects and better hemodynamic stability compared with other induction agents. This drug is associated, however, with myoclonic movements which is characterized by a sudden, brief muscle contractions as a disturbing side-effect.

OBJECTIVES

The present study was designed to compare the effectiveness of low- dose midazolam, magnesium sulfate, remifentanil and low-dose etomidate to suppress etomidate-induced myoclonus in orthopedic surgery.

PATIENTS AND METHODS

A double-blind clinical trial study was conducted in an academic hospital from September 2014 to August 2015. Two hundred and eighty-four eligible patients, American society of anesthesiologists class I - II, scheduled for elective orthopedic surgery were randomly allocated into four equal groups (n = 71). They received premedication with intravenous low-dose midazolam 0.015 mg/kg, magnesium sulfate 30 mg/kg, remifentanil 1 μg/kg and low-dose etomidate 0.03 mg/kg two minutes before induction of anesthesia with 0.3 mg/kg intravenous etomidate. Then the incidence and intensity of myoclonus were evaluated on a scale of 0 - 3; 0 = no myoclonus; 1 = mild (movement at wrist); 2 = moderate (movement at arm only, elbow or shoulder); and 3 = severe, generalized response or movement in more than one extremity, within ninety seconds. Any adverse effect due to these premedication agents was recorded.

RESULTS

The incidence and intensity of myoclonus were significantly lower in the low-dose etomidate group. The incidence rates of myoclonus were 51 (71.85%), 61 (85.9%), 30 (42.3%) and 41 (57.7%), and the percentages of patients who experienced grade III of myoclonus were 30 (58.8%), 32 (52.5%), 9 (30%) and 14 (34.1%) in the midazolam, magnesium sulfate, etomidate and remifentanil groups, respectively. The incidence and intensity of myoclonus were significantly lower in the low-dose etomidate group (P = 0.0001). No notable adverse effect was detected in our patients during the study period.

CONCLUSIONS

Intravenous etomidate 0.03 mg/kg prior to induction can effectively reduce the incidence and severity of myoclonus linked to etomidate.

Efficacy and Safety of Opioids for the Prevention of Etomidate-Induced Myoclonus: A Meta-Analysis

Etomidate is a widely used hypnotic drug for induction of general anesthesia and sedation, especially in elderly patients and hemodynamically unstable patients. Myoclonus, however, is the most prominent problem during induction of anesthesia with etomidate. Many agents have been used to prevent it and opioid is one of them. This meta-analysis was to evaluate effects of opioids pretreatment for preventing etomidate-induced myoclonus. We searched the PubMed, EMBASE, and the Cochrane Library databases and published studies in English updated to September 2015. Randomized controlled trials of opioids versus placebo/control in patients were included. We evaluated the prophylactic effect of opioids on etomidate-induced myoclonus. All statistical analysis was performed using RevMan 5.2 software. Nine randomized controlled trials involving 604 participants were included. The results indicated that compared with placebo/control, opioids allow more patients to experience no myoclonic movements after etomidate injection [risk ratio (RR) 2.76, 95% confidence interval (CI) 1.75-4.37, P < 0.0001]. The numbers of patients with mild myoclonus [(RR) 0.53, 95% (CI) 0.36-0.78, P = 0.001], moderate myoclonus [(RR) 0.36, 95% (CI) 0.23-0.55, P < 0.00001], and severe myoclonus [(RR) 0.20, 95% (CI) 0.08-0.52, P = 0.0009] after etomidate injection were significantly decreased with the pretreatment of opioids. This meta-analysis suggests that pretreatment with opioids before injecting etomidate was effective for preventing etomidate-induced myoclonus and can reduce the intensity of myoclonus without any adverse effects.

Low-Dose Ketamine Pretreatment Reduces the Incidence and Severity of Myoclonus Induced by Etomidate: A Randomized, Double-Blinded, Controlled Clinical Trial

Myoclonic movement induced by etomidate is a common but undesirable problem during general anesthesia induction. To investigate the influence of pretreatment with low-dose ketamine on the incidence and severity of myoclonus induced by etomidate, 104 patients were randomized allocated to 1 of 2 equally sized groups (n = 52) to receive either intravenous low-dose ketamine 0.5 mg/kg (group K) or an equal volume of normal saline (group S) 1 minute before induction of anesthesia with 0.3-mg/kg etomidate. The incidence and severity of myoclonus were assessed for 2 minutes after administration of etomidate. Here, we found that the incidence and intensity of myoclonus were both significantly reduced in low-dose ketamine-treated group compared with saline-treated group. The incidence of adverse effects was low and similar between groups. These results demonstrate that intravenous infusion of low-dose ketamine 0.5 mg/kg 1 minute prior to etomidate administration is effective in relieving etomidate-induced myoclonic movements during general anesthesia induction.

Comparison of orbital muscle akinesia caused by rocuronium versus hyaluronidase mixed to the local anesthetic in single injection peribulbar block for cataract surgery

Background:

The aim of this study was to compare orbital muscle akinesia caused by rocuronium versus hyaluronidase when mixed with the local anesthetic in single-injection peribulbar anesthesia (PBA).

Patients and Methods:

Sixty patients were included in the study and subjected to cataract extraction using phacoemulsification technique with intraocular lens implantation. Group I received peribulbar block with 5 ml mixture of 30 IU/ml hyaluronidase and 2% lidocaine. Group II received peribulbar block with 5 ml mixture of rocuronium 5 mg and 2% lidocaine. The onset and duration of akinesia were assessed; the akinesia score at 2, 5, and 10 min was measured after injection. The need for supplementary injection was also recorded.

Results and Conclusion:

PBA using a mixture of rocuronium and lidocaine provides optimal globe akinesia and faster establishment of suitable conditions to start eye surgery and shortens the block onset time as compared with the addition of hyaluronidase to lidocaine.

Effect of gabapentin pretreatment on myoclonus after etomidate: a randomized, double-blind, placebo-controlled study

AIM

To evaluate the effects of three different doses of gabapentin pretreatment on the incidence and severity of myoclonic movements linked to etomidate injection.

METHOD

One hundered patients, between 18 and 60 years of age and risk category American Society of Anesthesiologists I-II, with planned elective surgery under general anesthetic were included in the study. The patients were randomly divided into four groups and 2h before the operation were given oral capsules of placebo (Group P, n=25), 400mg gabapentin (Group G400, n=25), 800mg gabapentin (Group G800, n=25) or 1200mg gabapentin (Group G1200, n=25). Side effects before the operation were recorded. After preoxygenation for anesthesia induction 0.3mgkg(-1) etomidate was administered for 10s. A single anesthetist with no knowledge of the study medication evaluated sedation and myoclonic movements on a scale between 0 and 3. Two minutes after induction, 2μgkg(-1) fentanyl and 0.8mgkg(-1) rocuronium were administered for tracheal intubation.

RESULTS

Demographic data were similar. Incidence and severity of myoclonus in Group G1200 and Group G800 were significantly lower than in Group P; sedation incidence and level were appreciably higher compared to Group P and Group G400. While there was no difference in the incidence of myoclonus between Group P and Group G400, the severity of myoclonus in Group G400 was lower than in the placebo group. In the two-hour period before induction other than sedation none of the side effects related to gabapentin were observed in any patient.

CONCLUSION

Pretreatment with 800mg and 1200mg gabapentin 2h before the operation increased the level of sedation and reduced the incidence and severity of myoclonic movements due to etomidate.

Prevention of etomidate-induced myoclonus during anesthetic induction by pretreatment with dexmedetomidine

Myoclonus induced by etomidate during induction of general anesthesia is undesirable. This study evaluated the effect of dexmedetomidine (DEX) pretreatment on the incidence and severity of etomidate-induced myoclonus. Ninety patients undergoing elective surgical procedures were randomly allocated to three groups (n=30 each) for intravenous administration of 10 mL isotonic saline (group I), 0.5 µg/kg DEX in 10 mL isotonic saline (group II), or 1.0 µg/kg DEX in 10 mL isotonic saline (group III) over 10 min. All groups subsequently received 0.3 mg/kg etomidate by intravenous push injection. The incidence and severity of myoclonus were recorded for 1 min after etomidate administration and the incidence of cardiovascular adverse events that occurred between the administration of the DEX infusion and 1 min after tracheal intubation was recorded. The incidence of myoclonus was significantly reduced in groups II and III (30.0 and 36.7%), compared with group I (63.3%). The incidence of severe sinus bradycardia was significantly increased in group III compared with group I (P<0.05), but there was no significant difference in heart rate in groups I and II. There were no significant differences in the incidence of low blood pressure among the 3 groups. Pretreatment with 0.5 and 1.0 µg/kg DEX significantly reduced the incidence of etomidate-induced myoclonus during anesthetic induction; however, 0.5 µg/kg DEX is recommended because it had fewer side effects.

Intravenous dezocine pretreatment reduces the incidence and intensity of myoclonus induced by etomidate

To evaluate the suppressive effect of intravenous dezocine on the incidence and severity of myoclonic movements induced by etomidate, a total of 80 patients, American Society of Anesthesiologists physical status I-II, were randomized into two equally sized groups (n = 40). These two groups were assigned to give either intravenous dezocine 0.1 mg/kg or a matching placebo (equal volume of 0.9% saline) 30 s before administration of etomidate. For anesthesia induction, 0.3 mg/kg etomidate was injected over a period of 1 min. One minute after etomidate administration, the severity of myoclonus was assessed. Pretreatment with dezocine significantly reduced both the incidence and intensity of myoclonus. These results demonstrate that intravenous dezocine 0.1 mg/kg 30 s prior to induction was effective in suppressing myoclonic movements in our patients.

Priming with atracurium efficiently suppresses etomidate-induced myoclonus

INTRODUCTION

Etomidate is a hypnotic drug widely used as an intravenous anesthetic induction agent. The incidence of etomidate-induced myoclonus has been reported as much as 50-80% after induction making it an undesirable drug for induction.

OBJECTIVE

Our aim is to use a priming dose of atracurium to suppress etomidate-induced myoclonus during induction of anesthesia.

METHODS

In a double-blinded clinical trial 80 patients were randomly given either atracurium (20% of ED95 × kg) or saline as a priming agent. Then, induction of anesthesia was performed using 0.4 mg/kg etomidate. Age, weight, body mass index, bispectral index (BIS) monitor, and duration and grade of myoclonus were recorded.

RESULTS

The demographic characteristics, age, body mass index, BIS score, and weight were not significantly different between the atracurium (ATRA) priming group and control groups. The binomial regression model showed that BMI was an independent predictor variable for myoclonus (OR: 2.1, CI 95%: 1.7-7.5, p = 0.032). In this model, adjusted odds ratios (OR) of myoclonus (multivariate logistic regression analysis) in the control group was 6.6 (95% CI: 1.5-9.7, p = 0.013).

CONCLUSION

Low-dose atracurium priming could effectively suppress etomidate-induced myoclonus.

Effects of etomidate on bispectral index scale and spectral entropy during induction of anesthesia by means of the raw electroencephalographic and electromyographic characteristics

BACKGROUND

Etomidate frequently induces myoclonus, so it may affect electromyographics (EMG). And EMG commonly has an effect on the bispectral index scale (BIS) and spectral entropy. This study was performed to compare the effect of etomidate on BIS, response entropy (RE) and state entropy (SE) during induction of anesthesia.

METHODS

Fifty patients (ASA I or II) scheduled for elective surgery were included in this study. Anesthesia was induced with etomidate (0.3 mg/kg) and rocuronium (0.6 mg/kg). Patients also inhaled 4 vol% sevoflurane and 100% oxygen and, then intubated. BIS, RE, SE and Modified Observer's Assessment of Alertness/Sedation Scale (MOAA/S) were measured 4 times (before injection of etomidate [T0], at loss of eyelash reflex [T1], 90 seconds after rocuronium injection [T2], and after intubation [T3]). We also checked whether myoclonus occurred.

RESULTS

Baseline values (T0) were 93.1 ± 4.7 for BIS, 95.8 ± 3.7 for RE and, 87.3 ± 3.5 for SE. In comparison with T0, there were significantly differences in BIS (50.2 ± 16.3), RE (76.8 ± 18.5) and SE (66.3 ± 17.4) at T1 (all P < 0.05). There were no significant differences at T2 and T3. Thirty one patients had myoclonus. At the occurrence of myoclonus, RE and SE values significantly increased but not BIS (P < 0.05).

CONCLUSIONS

In patients with myoclonus, at the loss of consciousness, spectral entropy did not decrease where as BIS did, suggesting that BIS may evaluate hypnotic levels better than spectral entropy during induction of anesthesia with etomidate.

The proper effect site concentration of remifentanil for prevention of myoclonus after etomidate injection

BACKGROUND

Etomidate frequently induces myoclonus when administered intravenously with bolus injection during anesthetic induction. This can be bothersome for the anesthesiologist. The dose of remifentanil appropriate for preventing myoclonus without side effects was investigated.

METHODS

All patients with American Society of Anesthesiologists (ASA) physical status I-III were divided into three groups (n = 33 per group) according to the pretreatment effect site concentration of remifentanil (Ultiva, Glaxo-Wellcome, München, Germany) of 0, 2 or 4 ng/ml (Group N: 0 ng/ml, Group R: 2 ng/ml, Group Q: 4 ng/ml) by a target controlled infusion (TCI) system. After a 0.3 mg/kg dose of etomidate was injected intravenously for over 1 minute for anesthetic induction, myoclonus was observed. Before the etomidate injection, the patients were pretreated with remifentanil and their side effects were monitored.

RESULTS

The number of patients showing myoclonus was significantly different among the groups. The incidence of myoclonus was 81%, 12% and 0% (groups N, R, and Q, respectively, P < 0.01). Side effects including bradycardia and hypotension did not occur in either Group R or Q. Chest wall rigidity occured in 45% of patients in Group Q.

CONCLUSIONS

Administration with a 2 ng/ml effect site concentration of remifentanil could reduce the incidence of myoclonus caused by etomidate bolus injection without chest wall rigidity.

Lidocaine pretreatment reduces the frequency and severity of myoclonus induced by etomidate

The objective of this study was to assess the effects of lidocaine on the incidence and severity of myoclonic movements induced by etomidate. Sixty patients were randomly assigned to receive either 20 mg lidocaine or saline (n = 30, each), 30 s before administration of etomidate (0.3 mg/kg). One minute after etomidate administration we assessed severity of myoclonus. Pretreatment with lidocaine significantly reduced both the incidence and severity of myoclonic movements. As a conclusion, lidocaine is an effective and safe drug to reduce the etomidate-induced myoclonus without significant side effects.