Prevention of etomidate-induced myoclonus: which is superior: Fentanyl, midazolam, or a combination? A Retrospective comparative study

Comparative assessment of dexmedetomidine and butorphanol for attenuation of etomidate-induced myoclonus: A double-blind, randomised controlled study

Background and Aims

Etomidate is a popular induction agent, but its use is associated with myoclonus in 50%-80% of non-premedicated patients. This study aims to compare dexmedetomidine and butorphanol for their relative efficacy in preventing etomidate-induced myoclonus.

Methods

This randomised study was conducted after obtaining institutional ethical committee clearance and written informed consent from sixty American Society of Anesthesiologists (ASA) I or II consenting patients between 18 and 60 years of age of either sex who had been scheduled for elective surgeries under general anaesthesia. Patients were randomly allocated to dexmedetomidine 0.5 μg/kg (Group D) or butorphanol 0.015 mg/kg (Group B). Both the drugs were given as an infusion over a period of 10 min before induction of anaesthesia. The primary outcome was the incidence of myoclonic movements after etomidate, and the secondary outcomes were the severity of myoclonus, changes in the haemodynamic parameters and incidence of airway complications. Normally distributed variables were compared using Student's t-test, and non-normally distributed variables were compared using Mann-Whitney U test. Qualitative data were analysed using Chi-square/Fisher's exact test. A P-value <0.05 was considered significant.

Results

The incidence of etomidate-induced myoclonus was significantly higher in group B compared to group D (P = 0.035). The median (interquartile range [IQR]) of myoclonus grade in patients of group D was 0.00 (0.00-3.00), and group B was 2.50 (0.00-3.00) (P = 0.035). Haemodynamics and airway-related complications were comparable between the groups.

Conclusion

Dexmedetomidine was more effective than butorphanol in preventing 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.

Pharmacotherapy optimization for rapid sequence intubation in the emergency department

PURPOSE

Rapid-sequence intubation (RSI) is the process of administering a sedative and neuromuscular blocking agent (NMBA) in rapid succession to facilitate endotracheal intubation. It is the most common and preferred method for intubation of patients presenting to the emergency department (ED). The selection and use of medications to facilitate RSI is critical for success. The purpose of this review is to describe pharmacotherapies used during the RSI process, discuss current clinical controversies in RSI medication selection, and review pharmacotherapy considerations for alternative intubation methods.

SUMMARY

There are several steps to the intubation process requiring medication considerations, including pretreatment, induction, paralysis, and post-intubation sedation and analgesia. Pretreatment medications include atropine, lidocaine, and fentanyl; but use of these agents in clinical practice has fallen out of favor as there is limited evidence for their use outside of select clinical scenarios. There are several options for induction agents, though etomidate and ketamine are the most used due to their more favorable hemodynamic profiles. Currently there is retrospective evidence that etomidate may produce less hypotension than ketamine in patients presenting with shock or sepsis. Succinylcholine and rocuronium are the preferred neuromuscular blocking agents, and the literature suggests minimal differences between succinylcholine and high dose rocuronium in first-pass success rates. Selection between the two is based on patient specific factors, half-life and adverse effect profiles. Finally, medication-assisted preoxygenation and awake intubation are less common methods for intubation in the ED but require different considerations for medication use.

AREAS FOR FUTURE RESEARCH

The optimal selection, dosing, and administration of RSI medications is complicated, and further research is needed in several areas. Additional prospective studies are needed to determine optimal induction agent selection and dosing in patients presenting with shock or sepsis. Controversy exists over optimal medication administration order (paralytic first vs induction first) and medication dosing in obese patients, but there is insufficient evidence to significantly alter current practices regarding medication dosing and administration. Further research examining awareness with paralysis during RSI is needed before definitive and widespread practice changes to medication use during RSI can be made.

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 the influence of low dose etomidate and propofol as priming dose on the incidence of etomidate induced myoclonus: a randomised, double-blind clinical trial

BACKGROUND

Though hemodynamically stable, etomidate is known for its myoclonus side effect following induction. The main aim of this study is an effective attempt to decrease the incidence of myoclonus with a priming agent.

METHODS

A prospective, double-blind study was carried out on 50 adults posted for elective surgery. After premedication, priming was done with etomidate 0.03 mg.kg-1 (Group E) and propofol 0.2 mg.kg-1 (Group P), i.e., 1/10th of induction dose. After 60 seconds of priming, patients were induced with etomidate by titrating dose over 60 seconds until loss of verbal command and eyelash reflex. The grading of myoclonus, induction dosage, and hemodynamics for 10 minutes post induction were recorded.

RESULTS

In the study, only 4 cases had myoclonus. Grade 1 myoclonus was encountered in three cases of etomidate group, while only one case in the propofol group had grade 2 myoclonus which was not statistically significant (p-value: 0.12). There was a significant reduction in the etomidate induction dosage in both groups.

CONCLUSION

Priming with etomidate and propofol is equally effective in reducing myoclonus with the added benefit of hemodynamic stability and reduction of an induction dose of etomidate (> 50%).

Etomidate and its Analogs: A Review of Pharmacokinetics and Pharmacodynamics

Etomidate is a hypnotic agent that is used for the induction of anesthesia. It produces its effect by acting as a positive allosteric modulator on the γ-aminobutyric acid type A receptor and thus enhancing the effect of the inhibitory neurotransmitter γ-aminobutyric acid. Etomidate stands out among other anesthetic agents by having a remarkably stable cardiorespiratory profile, producing no cardiovascular or respiratory depression. However, etomidate suppresses the adrenocortical axis by the inhibition of the enzyme 11β-hydroxylase. This makes the drug unsuitable for administration by a prolonged infusion. It also makes the drug unsuitable for administration to critically ill patients. Etomidate has relatively large volumes of distributions and is rapidly metabolized by hepatic esterases into an inactive carboxylic acid through hydrolyzation. Because of the decrease in popularity of etomidate, few modern extensive pharmacokinetic or pharmacodynamic studies exist. Over the last decade, several analogs of etomidate have been developed, with the aim of retaining its stable cardiorespiratory profile, whilst eliminating its suppressive effect on the adrenocortical axis. One of these molecules, ABP-700, was studied in extensive phase I clinical trials. These found that ABP-700 is characterized by small volumes of distribution and rapid clearance. ABP-700 is metabolized similarly to etomidate, by hydrolyzation into an inactive carboxylic acid. Furthermore, ABP-700 showed a rapid onset and offset of clinical effect. One side effect observed with both etomidate and ABP-700 is the occurrence of involuntary muscle movements. The origin of these movements is unclear and warrants further research.

Acute Movement Disorders in Childhood

Acute-onset movement disorders (MDs) are an increasingly recognized neurological emergency in both adults and children. The spectrum of possible causes is wide, and diagnostic work-up is challenging. In their acute presentation, MDs may represent the prominent symptom or an important diagnostic clue in a broader constellation of neurological and extraneurological signs. The diagnostic approach relies on the definition of the overall clinical syndrome and on the recognition of the prominent MD phenomenology. The recognition of the underlying disorder is crucial since many causes are treatable. In this review, we summarize common and uncommon causes of acute-onset movement disorders, focusing on clinical presentation and appropriate diagnostic investigations. Both acquired (immune-mediated, infectious, vascular, toxic, metabolic) and genetic disorders causing acute MDs are reviewed, in order to provide a useful clinician’s guide to this expanding field of pediatric neurology.

Effect of Pre-Treatment with a Combination of Fentanyl and Midazolam for Prevention of Etomidate-Induced Myoclonus

Objective

Pre-treatment with either fentanyl or midazolam has previously been used to prevent etomidate-induced myoclonus (EIM). The aim of the present study was to determine the effect of pre-treatment with a combination of midazolam and fentanyl in reducing the incidence and severity of EIM.

Methods

This prospective, randomised, double-blind study was conducted on 210 surgical patients allocated to three study groups. Group F patients received fentanyl 2 μg kg^-1 and 5 mL saline. Group M patients received midazolam 0.03 mg kg^-1 and 5 mL saline. Group FM patients received fentanyl 2 μg kg^-1 plus midazolam 0.03 mg kg^-1. The study drugs were administered intravenously over 30 s. Five minutes after study drug administration, etomidate 0.3 mg kg^-1 was administered over 60 s. Patients were observed for 1 min for occurrence and severity of EIM.

Results

The incidence of EIM was 34/70 (48.6%), 55/70 (78.6%) and 11/70 (15.7%) in groups F, M and FM, respectively (p=0.001). Myoclonus of moderate or severe grade occurred in 23/70 (32.9%), 45/70 (64.3%) and 6/70 (8.6%) in groups F, M and FM, respectively (p=0.001). Patients who experienced myoclonus exhibited a significantly higher percentage change in post-induction heart rate (p=0.02), systolic blood pressure (p=0.001) and mean blood pressure (p=0.001) from pre-induction values than those who did not.

Conclusion

Pre-treatment with a combination of fentanyl and midazolam is more effective than that with fentanyl or midazolam alone in reducing the incidence and severity of EIM. Myoclonus is associated with a higher post-induction haemodynamic variation.

Descriptive assessment of adverse events associated with midazolam-etomidate versus saline-etomidate in healthy hydromorphone premedicated dogs

OBJECTIVES

To determine the frequency, severity and duration of adverse events including myoclonus, pain on injection, hypersalivation, regurgitation and apnoea after administration of midazolam or saline followed by etomidate in hydromorphone premedicated dogs.

MATERIALS AND METHODS

Dogs undergoing elective dental prophylaxis or soft tissue surgeries were enrolled in this randomised trial. Dogs were premedicated with hydromorphone 0.1 mg/kg IV. Sixty seconds later, midazolam 0.3 mg/kg or saline at an equivalent volume was administered IV. Sixty seconds after that, etomidate 1.5 mg/kg IV was administered over 60 seconds. Additional doses of 0.5 mg/kg etomidate were administered until endotracheal intubation was successful. Observers were blinded to the treatment. Frequency, duration and a severity score of 0 to 3 were recorded for myoclonus, pain on injection, hypersalivation and regurgitation. Duration of apnoea and frequency of any additional complications was recorded.

RESULTS

Forty variable breed healthy dogs were enrolled in the study. Myoclonus, pain on injection, regurgitation, hypersalivation, gagging, tachypnoea and pigmenturia occurred, respectively, in 10%, 40%, 0%, 15%, 35%, 25% and 5% of dogs in the saline group and 0%, 65%, 0%, 10%, 45%, 15% and 5% of dogs in the midazolam group. Apnoea occurred for 115 seconds (range 0 to 660 seconds) and 160 seconds (range 0 to 600 seconds) in the saline and midazolam groups, respectively. Two dogs developed pigmenturia. The trial was stopped early due to the occurrence of pigmenturia.

CLINICAL SIGNIFICANCE

Due to early stopping of the trial, the predefined sample size was not reached. Further investigation is needed to determine if midazolam reduced the incidence of adverse events or improved the induction quality when combined with hydromorphone and etomidate.

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).

Effect of dexmedetomidine on etomidate-induced myoclonus: a randomized, double-blind controlled trial

Background: Etomidate used for the induction of general anesthesia can result in myoclonus. We tested the hypothesis that pretreatment with dexmedetomidine (Dex) reduces the incidence of etomidate-induced myoclonus during the induction of general anesthesia.

Materials and methods: One hundred patients who were scheduled for selective operations under general anesthesia were included in this randomized, double-blind controlled trial. Patients were randomized to receive either Dex 0.5 µg/kg in 20 mL of normal saline or the same volume of normal saline as pretreatment agents 15 mins before the injection of etomidate 0.3 mg/kg. The primary endpoint was the incidence of etomidate-induced myoclonus. Secondary endpoints were the severity of etomidate-induced myoclonus and the incidence of adverse effects from the onset of action of Dex or normal saline to the injection of etomidate, such as dizziness, respiratory depression, bradycardia, hypotension and nausea/vomiting.

Results: All of the 100 patients completed the trial. Dex resulted in a significant 38% reduction in the number of patients who experienced etomidate-induced myoclonus: 13 (26%) vs 32 (64%) (P=0.0001). Additionally, the severity of myoclonus was also reduced in the Dex group than that in the placebo group (P=0.02). Incidence of dizziness, respiratory depression, bradycardia, hypotension and nausea/vomiting was similar in both groups.

Conclusions: Pretreatment with Dex 0.5 µg/kg 15 mins before the induction of general anesthesia not only resulted in a 38% reduction in the incidence of etomidate-induced myoclonus, but also reduced the severity of myoclonus, without inducing any adverse effects.

Effect of butorphanol on etomidate-induced myoclonus: a systematic review and meta-analysis

Objective: To evaluate the effect of butorphanol on the prevention of myoclonus induced by etomidate.

Materials and methods: We searched the PubMed, Embase, Cochrane Library, and China National Knowledge Infrastructure databases to collect relevant randomized controlled trials (RCTs) evaluating the effect of butorphanol on etomidate-induced myoclonus in January 2019 without any language restrictions. The primary outcome was the incidence of etomidate-induced myoclonus. Secondary outcomes included the incidence of myoclonus at various degrees and the incidence of adverse effects. Risk ratios (RRs) were calculated for binary outcomes. All statistical analysis were performed by using RevMan 5.3 software.

Results: We identified 6 RCTs involving a total of 608 patients who reported the incidence of etomidate-induced myoclonus. In pooled analyses, the incidence of etomidate-induced myoclonus in the butorphanol group was significantly lower than that in the control group (RR =0.15, 95% CI [0.10, 0.22], P<0.00001). Subgroup analyses showed that butorphanol significantly decreased the numbers of patients with mild myoclonus (RR =0.41, 95% CI [0.25, 0.68], P=0.0005), moderate myoclonus (RR =0.18, 95% CI [0.09, 0.34], P<0.00001), and severe myoclonus (RR =0.04, 95% CI [0.01, 0.10], P<0.00001). Additionally, butorphanol did not increase the incidence of postoperative nausea/vomiting (RR =3.0, 95% CI [0.32, 28.42], P=0.34) or dizziness (RR =6.79, 95% CI [0.84, 54.84], P=0.07) associated with etomidate.

Conclusion: Our findings suggest that butorphanol can effectively prevent the incidence of etomidate-induced myoclonus and alleviate the intensity of etomidate-induced myoclonus, without inducing postoperative nausea/vomiting and dizziness.

Butorphanol effectively prevents etomidate-induced myoclonus: a pooled analysis of 788 patients

OBJECTIVE

To evaluate the efficacy of pre-injection of butorphanol on etomidate-induced myoclonus during anesthesia induction.

METHODS

Randomized controlled trials (RCTs) of the ability of butorphanol to prevent etomidate-induced myoclonus were collected by searching PubMed, Cochrane Library, CNKI, and WanFang databases, from the day of database establishment until May 2017. The literature was screened independently by two evaluators, and the data were then extracted and independently evaluated. Finally, meta-analysis was performed by using RevMan 5.2 software.

RESULTS

Eight RCTs were analyzed. The results of meta-analysis showed that: 1. compared with the control group, butorphanol was effective in preventing etomidate-induced myoclonus [RR = 0.15, 95% CI: 0.11, 0.21]; 2. butorphanol was effective in preventing mild, moderate, and severe etomidate-induced myoclonus [RR = 0.40, 95% CI: 0.25, 0.63; RR = 0.15, 95% CI: 0.08, 0.27; and RR = 0.04, 95% CI: 0.01, 0.09]; 3. butorphanol did not increase the incidence of dizziness and nausea associated with etomidate.

CONCLUSIONS

Butorphanol could reduce the incidence and degree of etomidate-induced myoclonus. Notably, it did not increase the incidence of dizziness and nausea associated with etomidate.

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.

[Etomidate for intravenous induction of anaesthesia]

The pharmacological and historical knowledge about the currently available intravenous induction hypnotics form the basis for the daily work of anesthetists. Side effects of using hypnotic induction agents must be anticipated and adequately treated. Decades of experience with using intravenous induction hypnotics have led to theoretical requirements for an ideal narcotic agent with a best possible side effect profile. In the absence of this optimal hypnotic induction agent, a careful selection of one or a combination of narcotic drugs is necessary to meet the needs of the respective risk constellation of the patient. While propofol enjoyed increasing frequency of use over the last three decades and is currently regarded as the gold standard in numerous clinics, thiopental is a noteworthy alternative apart from its elimination kinetics. Furthermore, substances with favorable hemodynamic profiles are available with etomidate and ketamine. Midazolam as a short-acting benzodiazepine rounds off the spectrum.

Comparison of priming versus slow injection for reducing etomidate-induced myoclonus: a randomized controlled study

Background

Etomidate injection is often associated with myoclonus. Etomidate injection technique influences the incidence of myoclonus. This study was designed to clarify which of the two injection techniques—slow injection or priming with etomidate—is more effective in reducing myoclonus.

Methods

This prospective randomized controlled study was conducted on 189 surgical patients allocated to three study groups. Control group (Group C, n = 63) received 0.3 mg/kg etomidate (induction dose) over 20 s. Priming group (Group P, n = 63) received pretreatment with 0.03 mg/kg etomidate, followed after 1 min by an etomidate induction dose over 20 s. Slow injection group (Group S, n = 63) received etomidate (2 mg/ml) induction dose over 2 min. The patients were observed for occurrence and severity of myoclonus for 3 min from the start of injection of the induction dose.

Results

The incidence of myoclonus in Group P (38/63 [60.3%], 95% CI: 48.0–71.5) was significantly lower than in Group C (53/63 [84.1%], 95% CI: 72.9–91.3, P = 0.003) and Group S (49/63 [77.8%], 95% CI: 66.0–86.4, P = 0.034). Myoclonus of moderate or severe grade occurred in significantly more patients in Group C (68.3%) than in Group P (36.5%, P < 0.001) and Group S (50.8%, P = 0.046), but the difference between Groups P and S was not significant (P = 0.106).

Conclusions

Priming is more effective than slow injection in reducing the incidence of myoclonus, but their effects on the severity of myoclonus are comparable.

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.

Comparison of different doses of intravenous lignocaine on etomidate-induced myoclonus: A prospective randomised and placebo-controlled study

Background and Aims

Etomidate-induced myoclonus (EM) is observed in 50%-80% of unpremedicated patients. Low-dose lignocaine has been shown to attenuate but not abolish the EM. The aim of this prospective, randomised controlled study was to compare the different doses of lignocaine on the incidence and severity of EM.

Methods

Two hundred adult patients were randomly assigned into four groups to receive saline placebo (Group I) or IV lignocaine 0.5 mg/kg (Group II), 1 mg/kg (Group III) or 1.5 mg/kg (Group IV) 2 min before injection etomidate 0.3 mg/kg IV. The patients were assessed for the EM using a four-point intensity scoring system. Our primary outcome was the incidence of myoclonus at 2 min (EM2). The incidence of myoclonus at 1 min (EM1) and severity of myoclonus constituted the secondary outcomes. ANOVA and Pearson Chi-square test were used for statistical analysis and P < 0.05 was considered as statistically significant.

Results

The incidence of EM was significantly reduced in Groups III [(EM1: 32% vs. 60%, P = 0.009); (EM2: 42% vs. 76%, P = 0.001)] and IV (EM2: 54% vs. 76%, P = 0.035) compared with Group I. Lignocaine 1 mg/kg and 1.5 mg/kg significantly reduced the incidence of severe myoclonus at 2 min (14% each) compared to Groups I (42%, P = 0.003) and II (32%, P = 0.032).

Conclusion

Lignocaine 1 mg/kg and 1.5 mg/kg IV pretreatment significantly reduces the incidence of EM, with maximum attenuation observed with 1 mg/kg.

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.

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.

Clinical effects of intravenous anesthesia with etomidate plus propofol for subpyloric endoscopic ultrasonography

AIM

To investigate the clinical effects of intravenous anesthesia with etomidate plus propofol for deep sedation during subpyloric endoscopic ultrasonography (EUS).

METHODS

We recruited 60 patients who would undergo subpyloric EUS examination. They were randomly allocated into three groups to receive intravenous etomidate alone (group E, n = 20), intravenous propofol alone (group P, n = 20) and etomidate combined with propofol (group EP, n = 20), respectively. The change of patients' vital signs, examination duration, time to awakening, and adverse effects were observed.

RESULTS

There was no significant difference in the onset time of anesthesia, examination duration or time to awakening among all groups (P > 0.05). There was a significant circulatory fluctuation in group E and group P. In group E, 7 cases had myoclonus and a total of 15 cases developed adverse effects, and the rates of myoclonus and overall adverse effects were significantly higher than those in the other two groups (P < 0.05).

CONCLUSION

Intravenous anesthesia with etomidate plus propofol can be safely and effectively applied to ubpyloric EUS with few adverse effects.

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.

Drug-induced movement disorders

INTRODUCTION

Drug-induced movement disorders (DIMDs) can be elicited by several kinds of pharmaceutical agents. The major groups of offending drugs include antidepressants, antipsychotics, antiepileptics, antimicrobials, antiarrhythmics, mood stabilisers and gastrointestinal drugs among others.

AREAS COVERED

This paper reviews literature covering each movement disorder induced by commercially available pharmaceuticals. Considering the magnitude of the topic, only the most prominent examples of offending agents were reported in each paragraph paying a special attention to the brief description of the pathomechanism and therapeutic options if available.

EXPERT OPINION

As the treatment of some DIMDs is quite challenging, a preventive approach is preferable. Accordingly, the use of the offending agents should be strictly limited to appropriate indications and they should be applied in as low doses and as short duration as the patient's condition allows. As most of DIMDs are related to an unspecific adverse action of medications in the basal ganglia and the cerebellum, future research should focus on better characterisation of the neurochemical profile of the affected functional systems, in addition to the development of drugs with higher selectivity and better side-effect profile.

Haemodynamic Responses to Tracheal Intubation Using Propofol, Etomidate and Etomidate-Propofol Combination in Anaesthesia Induction

Introduction: The aim of this study was to measure the haemodynamic responses to a etomidate-propofol combination used for anaesthesia induction and to compare the haemodynamic responses with the separate use of each drug.

Methods: The patients were randomly divided into three groups as group P (n = 30, propofol 2.5 mg kg^-1), group E (n = 30, etomidate 0.3 mg kg^-1) and group PE (n = 30, propofol 1.25 mg kg^-1 + etomidate 0.15 mg kg^-1). For each patient, the times of measurement of the heart rate (HR) and mean arterial pressure values were defined as baseline, after the induction, before the intubation, immediately after the intubation and 1, 2, 3, 4, 5 and 10 minutes after the intubation.

Results: In all 3 groups, a significant decrease in MAP values were seen at T2 and T3 compared to the baseline values, and this decrease was greater in group P compared to that in group E and PE (P < 0.001, P < 0.01). A significant increase was seen in all 3 groups in the mean arterial pressure (MAP) value at T4 after the intubation. When the groups were compared with each other, this increase was greater in group E than in the other two groups (with group P, P < 0.001; with group PE, P < 0.01).

Conclusion: Etomidate-propofol combination may be a valuable alternative when extremes of hypotensive and hypertensive responses due to propofol and etomidate are best to be avoided.

Hemodynamic Responses to Two Different Anesthesia Regimens in Compromised Left Ventricular Function Patients Undergoing Coronary Artery Bypass Graft Surgery: Etomidate-Midazolam Versus Propofol-Ketamine

Background:

Various methods have been suggested to prevent hemodynamic instability caused by propofol and adverse effects caused by etomidate induction. The current study evaluated hemodynamic effects of propofol-ketamine mixture in comparison to etomidate-midazolam mixture during anesthesia induction.

Objectives:

The aim of this study was to evaluate the hemodynamic effects of etomidate-midazolam by comparing it with propofol-ketamine for the induction of anesthesia in patients with left ventricular dysfunction undergoing coronary artery bypass graft surgery.

Patients and Methods:

One-hundred patients aged between 40 and 65 with coronary artery disease and low ejection fraction scheduled for elective coronary artery bypass surgery participated in this study. The patients were randomly allotted to one of the two groups to receive either propofol-ketamine or etomidate-midazolam combination. Two groups were compared for pain on injection and myoclonus, Heart Rate (HR), Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), Mean Arterial Pressure (MAP), Cardiac Index (CI) and Systemic Vascular Resistance (SVR), before and one minute after induction of anesthesia, and one, three and five minutes after intubation.

Results:

Incidence of pain on injection (2 - 4%) and myoclonus (10%) was less in both groups. The hemodynamic response was similar in the two groups for all variables over the time interval, except for CI at one and three minutes after intubation (P = 0.024 and P = 0.048, respectively), and SVR in five minutes after intubation (P = 0.009), with differences being statistically significant.

Conclusions:

Both anesthetic regimens were acceptable for induction in patients with coronary artery disease and left ventricular dysfunction undergoing coronary artery bypass graft surgery.

Magnesium sulfate versus Lidocaine pretreatment for prevention of pain on etomidate injection: A randomized, double-blinded placebo controlled trial

Objective:

Etomidate is an imidazole derivative and formulated in 35% propylene glycol. When given without a rapid lidocaine injection, etomidate is associated with pain after injection. Magnesium (Mg) is a calcium channel blocker and influences the N-methyl-D-aspartate receptor ion channel. The aim of the study is to evaluate the efficiency of preemptive injection of magnesium sulfate and lidocaine on pain alleviation on etomidate intravenous injection.

Methods:

In a randomized, double-blinded trial study, 135 adult patients scheduled for elective outpatient or inpatient surgery were divided into three groups. Group M received 620 mg magnesium sulfate, Group L received 3 ml lidocaine 1% and Group S received normal saline, all in a volume of 5 mL followed by a maximal dose of 0.3 mg/kg of 1% etomidate. Pain was assessed on a four-point scale: 0 = no pain, 1 = mild pain, 2 = moderate pain and 3 = severe pain at the time of pretreatment and etomidate injection.

Findings:

About 60% of patients in the control group had pain during etomidate injection as compared to 22.2% and 40% in the lidocaine and magnesium sulfate groups, respectively. There was difference in induction pain score between three treatment groups, significantly (P = 0.01) and observed differences in pain scores between “normal saline and lidocaine group” (P < 0.001) and “normal saline and magnesium sulfate groups” were statistically meaningful (P = 0.044).

Conclusion:

Intravenous magnesium sulfate and lidocaine injection are comparably effective in reducing etomidate-induced pain.

Sedation and analgesia with fentanyl and etomidate for intrathecal injection in childhood leukemia patients

In this study, we tried to find a safe as well as fast effective treatment for sedation and analgesia for intrathecal injection in childhood leukemia patients, relieving treatment difficulties and pain, increasing the success rate of single intrathecal injection.The patients were divided into the experimental group (fentanyl combined with etomidate) and the control group (lidocaine only) randomly. The experimental group was given fentanyl 1 to 2 μg/kg intravenously first, then etomidate 0.1 to 0.3 mg/kg intravenously after the pipe washed. The patients younger than 1.5 years or who did not achieve satisfied sedative and analgesic situation received an additional time of etomidate (0.1-0.3 mg/kg). The patients were given oxygen at the rate of 4-5 L/min during the whole operation, and the finger pulse oximeter was used simultaneously to detect the changes in heart rate (HR) and blood oxygen saturation (SpO2). The doctors who performed the procedures assessed the quality of sedation and analgesia.In the experimental group, the patients' HR increased slightly after given fentanyl combined with etomidate. The patients' SpO2 was stable. Most patients achieved a good sedative and analgesic state within 1 to 2 minutes, and no case of respiration depression or cardiac arrhythmias occurred during the whole operation. The wake-up time was 55.42 ± 20.62 min. In the control group, the patients were not very cooperative during the intrathecal injection, which made the procedures very difficult.During intrathecal injection, pain obviously reduced and the success rate of single lumbar puncture increased. It is safe and effective to apply fentanyl combined with etomidate for sedation and analgesia.

Etomidate-remifentanil is more suitable for monitored anesthesia care during gastroscopy in older patients than propofol-remifentanil

Background

This prospective and randomized study was designed to compare safety, potential complications, and patient and examiner satisfaction of 2 anesthetic combinations – etomidate-remifentanil and propofol-remifentanil – in elderly patients undergoing diagnostic gastroscopy.

Material/Methods

A group of 720 patients, aged 60–80 years, scheduled for diagnostic gastroscopy under sedation were prospectively randomized. After 0.4–0.6 μg kg⁻¹ of remifentanil was infused, etomidate or propofol was administered. Patients in the etomidate group received doses of etomidate at 0.1–0.15 mg kg⁻¹ followed by 4–6 mg. Patients in the propofol group received doses of propofol at 1–2 mg kg⁻¹ followed by 20–40 mg. Physiological indexes were evaluated for the 715 of 720 patients that completed the treatment. The onset time, duration time, and discharge time were recorded. Physicians, anesthetists, and patients were surveyed to assess their satisfaction.

Results

Systolic pressure and diastolic pressure decreased significantly after the procedure in the propofol group (P<0.001). The average heart rate was significantly lower in the propofol group (P<0.05). No periods of desaturation (SpO₂ <95%) were observed in either group. The onset time was earlier in the etomidate group (P=0.00). All adverse events, with the exception of myoclonus, were greater in the propofol group, and physician and patient satisfaction in both groups was similar.

Conclusions

Etomidate-remifentanil administration for sedation and analgesia during gastroscopy resulted in more stable hemodynamic responses and less adverse events in older patients.