Caution for psychiatrists: malignant hyperthermia risks with the anesthetic agent succinylcholine (Suxamethonium) during electroconvulsive therapy.

BACKGROUND: Malignant hyperthermia is a potentially lethal condition triggered by specific anesthetic drugs, especially a depolarizing muscle relaxant of succinylcholine (Suxamethonium). Despite the frequent use of succinylcholine with electroconvulsive therapy (ECT), there has been no reported case of potentially lethal malignant hyperthermia following ECT. In addition, the time interval between the administration of succinylcholine and the onset of malignant hyperthermia has not been outlined in the context of ECT. CASE PRESENTATION: We present the case of a 79-year-old woman suffering from severe depression, who experienced severe malignant hyperthermia due to succinylcholine administration during an ECT session. She presented with a high fever of 40.2 °C, tachycardia of 140/min, hypertension with a blood pressure exceeding 200 mmHg, significant muscle rigidity, and impaired consciousness. These symptoms emerged two hours after ECT, which occurred in a psychiatric ward rather than an operating room, and reached their peak in less than 24 h. She was given 60 mg of dantrolene, which quickly reduced the muscular rigidity. Subsequently, she received two additional doses of 20 mg and 60 mg of dantrolene, which brought her fever down to 36.2 °C and completely eased her muscle rigidity within two days after ECT. CONCLUSIONS: This is the first reported case of potentially lethal malignant hyperthermia after ECT. In addition, it highlights the delayed onset of malignant hyperthermia following an ECT procedure, emphasizing the necessity for psychiatrists to recognize its onset even after the treatment. In the light of potentially lethal consequences of malignant hyperthermia, it is critically important for psychiatrists to closely monitor both intraoperative and postoperative patient's vital signs and characteristic physical presentations, promptly identify any symptomatic emergence, and treat it immediately with dantrolene.

Navigating Anesthesia: Muscle Relaxants and Reversal Agents in Patients with Renal Impairment.

This comprehensive review explores the interaction between neuromuscular blocking agents, reversal agents, and renal function, focusing on various drugs commonly used in anesthesia and their effects on kidney health. Succinylcholine, commonly used for anesthesia induction, can trigger elevated potassium levels in patients with specific medical conditions, leading to serious cardiac complications. While studies suggest the use of succinylcholine in patients with renal failure is safe, cases of postoperative hyperkalemia warrant further investigation. Some agents, such as atracurium and mivacurium, are minimally affected by impaired kidney function, whereas others, such as cisatracurium and rocuronium, can have altered clearance, necessitating dose adjustments in patients with renal failure. The reversal agents neostigmine and sugammadex affect renal markers, while cystatin C levels remain relatively stable with sugammadex use, indicating its milder impact on glomerular function, compared with neostigmine. Notably, the combination of rocuronium and sugammadex in rat studies shows potential nephrotoxic effects, cautioning against the simultaneous use of these agents. In conclusion, understanding the interplay between neuromuscular blocking agents and renal function is crucial for optimizing patient care during anesthesia. While some agents can be used safely in patients with renal failure, others can require careful dosing and monitoring. Further research is needed to comprehensively assess the long-term impact of these agents on kidney health, especially in high-risk patient populations. This article aims to review the use of muscle relaxants and reversal for anesthesia in patients with impaired renal function.

[Update: Neuromuscular Blockade during General Anesthesia]. / Update: Muskelrelaxierung in der Anästhesie.

The correct use of muscle relaxants and neuromuscular monitoring during anesthesia has been subject of controversial discussions for decades. Particularly important in clinical practice are identification and management of residual neuromuscular blockages and avoidance of associated complications. Despite the differences in the molecular mechanisms of action between depolarizing and non-depolarizing muscle relaxants the blockade of the postsynaptic nicotinic acetylcholine receptor remains a common ending pathway. Due to its unfavorable side effect profile, succinylcholine should only be used in justified exceptional cases. The use of muscle relaxants generally reduces the complication rate in airway management. However, even the single use of muscle relaxants increases the likelihood of postoperative pulmonary complications. These complications associated with the use of muscle relaxants, such as residual neuromuscular blockade, must be anticipated. The application of guideline-based approaches, including continuous neuromuscular monitoring and the application of muscle relaxant reversal agents, may significantly reduce the rate of adverse events associated with the use of muscle relaxants.

Suspected Pseudocholinesterase Deficiency During Left Thyroid Lobectomy and Isthmusectomy: A Case Report.

BACKGROUND: Pseudocholinesterase (butyrylcholinesterase) deficiency is an acquired or inherited condition in which decreased plasma levels of the pseudocholinesterase enzyme lead to an inability to metabolize the neuromuscular blocking agents succinylcholine and mivacurium, prolonging their paralytic effects. This often results in delayed extubation and additional intensive care requirements in the postoperative period. CASE DESCRIPTION: We describe a case of suspected pseudocholinesterase deficiency in a previously healthy 59-year-old female who underwent a left thyroid lobectomy and isthmusectomy. The patient received 120 mg of succinylcholine chloride before intubation. The patient did not meet extubation criteria following the completion of the procedure approximately two hours after receiving succinylcholine chloride. The patient was transferred to the ICU for respiratory support and for the medication to clear from the patient's system. The patient regained muscle control approximately four hours after receiving succinylcholine chloride and was extubated without complication. The patient shared post-extubation that she had a blood relative with the diagnosis of pseudocholinesterase deficiency. CONCLUSION: Pseudocholinesterase deficiency is rare but can result in potentially serious complications following the administration of succinylcholine chloride, mivacurium, or ester local anesthetics due to reduced metabolism and subsequently increased pharmacodynamic effects. Given the widespread use of succinylcholine chloride as a neuromuscular blocking agent, such as in this case, providers must be aware of the presentation, pathophysiology, diagnosis, and management. Additionally, this case demonstrates the importance of thoroughly inquiring about any personal or family history of anesthetic complications during a preoperative assessment.

Traumatic brain injury and RSI is rocuronium or succinylcholine preferred?

PURPOSE OF REVIEW: Traumatic brain injury is widespread and has significant morbidity and mortality. Patients with severe traumatic brain injury often necessitate intubation. The paralytic for rapid sequence induction and intubation for the patient with traumatic brain injury has not been standardized. RECENT FINDINGS: Rapid sequence induction is the standard of care for patients with traumatic brain injury. Historically, succinylcholine has been the agent of choice due to its fast onset and short duration of action, but it has numerous adverse effects such as increased intracranial pressure and hyperkalemia. Rocuronium, when dosed appropriately, provides neuromuscular blockade as quickly and effectively as succinylcholine but was previously avoided due to its prolonged duration of action which precluded neurologic examination. However, with the widespread availability of sugammadex, rocuronium is able to be reversed in a timely manner. SUMMARY: In patients with traumatic brain injury necessitating intubation, rocuronium appears to be safer than succinylcholine.

Acute myotonic reaction during succinylcholine anaesthesia.

A 21-year-old woman developed an acute myotonic reaction while undergoing anaesthesia using succinylcholine. Examination later showed she had shoulder, neck and calf hypertrophy, bilateral symmetrical ptosis and eyelid, handgrip and percussion myotonia. Peripheral neurophysiology studies identified significant, continuous myotonic discharges in both upper and lower limbs. Genetic analysis identified a c.3917G>A (p.Gly1306Glu) mutation in the SCN4A gene, confirming a diagnosis of sodium channel myotonia. Succinylcholine and other depolarising agents can precipitate life-threatening acute myotonic reactions when given to patients with myotonia. Patients with neuromuscular disorders are at an increased risk of perioperative anaesthetic complications. We report a woman who developed an acute myotonic reaction whilst undergoing anaesthesia, in the context of an unrecognised myotonic disorder. We then discuss an approach to the diagnosis of myotonic disorders.

Age-Specific Clinical Features of Pediatric Malignant Hyperthermia: A Review of 187 Cases Over 60 Years in Japan.

BACKGROUND: Malignant hyperthermia (MH) is an inherited muscle disorder induced by volatile anesthetics and depolarizing muscle relaxants. While the incidence of MH is high in young, there are few reports on the clinical features of pediatric MH. In this study, we selected pediatric cases from an MH database and analyzed the clinical findings by age group. We hypothesized that there would be age-related differences in the clinical characteristics. METHODS: A retrospective analysis of MH data collected in our database during 1960 to 2020 was performed to identify pediatric subjects (≤18 years) with a Clinical Grading Scale of ≥35, indicating "very likely" or "almost certain" MH. We compared clinical characteristics among the 0 to 24 month, 2 to 12 year, and 13 to 18 year (youngest, middle, and oldest, respectively) age groups. RESULTS: Data were available for 187 patients: 15 in the youngest age group, 123 in the middle-aged group, and 49 in the oldest age group. Of these, 55 patients (29.4%) had undergone muscle biopsy and muscle contracture test. The mortality rates during the study period were 13.3%, 13.8%, 20.4%, and 15.5% in the youngest, middle, and oldest cohorts and overall, respectively. In contrast, the overall mortality rate from 2000 to 2020 was 8.8%. The most frequent initial symptoms of MH were elevated temperature (46.7%) and generalized muscular rigidity (26.7%) in the youngest cohort, masseter spasm (35.0%) and generalized muscular rigidity (19.5%) in the middle cohort, and elevated end-tidal carbon dioxide (26.5%) and tachycardia (22.4%) in the oldest cohort. Physical examination revealed that elevated temperature, sinus tachycardia, and respiratory acidosis occurred frequently in all groups. The middle cohort had high frequencies of masseter spasm (58.4%; P = .02) and dark urine (75.5%; P = .01) compared to those in the oldest groups, and had a higher peak creatine kinase level compared to those in the 3 groups. Skeletal muscle symptoms tended to be more common in patients administered succinylcholine (generalized muscular rigidity, P = .053; masseter spasm, P < .0001; dark urine, P < .0001). In particular, masseter spasm and dark urine were more common in the middle cohort when succinylcholine was administered (masseter spasm: versus youngest cohort, P = .06, versus oldest cohort, P = .027; dark urine: versus youngest cohort, P = .0072, versus oldest cohort, P = .0015). CONCLUSIONS: The clinical characteristics of pediatric patients with MH vary according to age group. The difference in initial symptoms of MH depending on age group is noteworthy information for the early diagnosis of MH.

Incidence, Complications, and Factors Associated with Out-of-Hospital First Attempt Intubation Failure in Adult Patients: A Secondary Analysis of the CURASMUR Trial Data.

Objectives: The objectives of this study were to evaluate first attempt intubation failure rate, its associated factors, and its related complications in out-of-hospital emergency setting, when emergency physicians perform standardized airway management using rapid sequence intubation in adult patients. Material and methods: The present study was a substudy of the Succinylcholine versus Rocuronium for out-of-hospital Emergency Intubation (CURASMUR) Trial, which compared Succinylcholine and Rocuronium used for Rapid sequence intubation. First attempt Intubation failure rate and early intubation related complications were recorded. We used multivariable logistic regression analysis to determine first intubation failure associated factors. Results: A total of 1230 patients were included with mean age of 55.9 +/- 19 years. First attempt intubation failure was recorded in 285 (23.2%) patients. The occurrence of a first attempt intubation failure was independently associated with history of ear, nose, and throat neoplasia (OR 2.20, CI 95% 1.06-4.60). Early intubation related complications were more frequent in case of first attempt intubation failure: 80 of 285 (28.4%) in patients with first attempt intubation failure and 185 of 945 (19.6%) in patients with successful first attempt intubation [OR 1.44; CI 95%, 1.11-1.87]. Conclusion: Based on a large multicenter study on out-of-hospital tracheal intubation of adult patients, we found that first attempt intubation failure rate was high and that history of ear, nose, and throat (ENT) neoplasia was an independent associated factor. Failure in first intubation attempt was associated with significantly more intubation related complications.

Mapping the current evidence on the anesthetic management of adult patients with neuromuscular disorders-a scoping review.

PURPOSE: Patients with neuromuscular disorders (NMDs) are at increased risk of perioperative complications. The objective of this scoping review was to examine emerging evidence from published studies, case reports, and review articles on anesthetic management of patients with NMDs, following the methodological frame for scoping reviews. SOURCES: We searched PubMed and EMBASE for articles published between 1 January 2000 and 14 July 2021. PRINCIPAL FINDINGS: Three prospective and 21 retrospective studies on altered pharmacokinetics and pharmacodynamics of neuromuscular blocking agents (NMBA) in NMD patients were included. Furthermore, 168 case reports/series reporting 212 anesthetics in 197 patients were included. These studies showed that preanesthetic neuromuscular monitoring can be used for precise NMBA dosing in myasthenia gravis patients. Sugammadex was associated with fewer postoperative myasthenic crises. Perioperative complications were not associated with specific anesthetic agents. Case reports/series showed that in 32% (67/212) of anesthetics, at least one complication was reported. Unexpected intensive care unit admission was a frequently reported complication. Patients with a complicated disease course may have had a higher use of succinylcholine (unadjusted relative risk, 0.13; 95% confidence interval [CI], 0.20 to 0.86) and volatile anesthetics (adjusted odds ratio [OR], 0.38; 95% CI, 0.20 to 0.73; P = 0.004). CONCLUSION: Evidence on the anesthetic management and perioperative complications of patients with NMDs is mainly based on small retrospective studies and case reports. Further clinical trials or large retrospective studies are required to investigate the choice of safe anesthetic agents. Main areas of interest are the potential benefits of neuromuscular monitoring and sugammadex and the risks possibly associated with volatile anesthetics and succinylcholine.

RéSUMé: OBJECTIF: Les patients atteints de maladies neuromusculaires (MNM) courent un risque accru de développer des complications périopératoires. L'objectif de cette étude de portée est de résumer les connaissances émergentes tirées des études, présentations de cas et comptes rendus publiés portant sur l'anesthésie des patients atteints de MNM, tout en suivant le cadre méthodologique d'une étude de portée. CONSTATATIONS PRINCIPALES: ont été incluses trois études prospectives et 21 études rétrospectives comprenant des patients atteints de MNM chez lesquels les myorelaxants ont eu des propriétés pharmacocinétiques et pharmacodynamiques modifiées. En outre, 168 présentations / séries de cas portant sur 212 gestes d'anesthésie chez 197 patients ont été incluses. Ces études ont démontré qu'un suivi neuromusculaire peut être utilisé en pré-anesthésie pour ajuster les doses de myorelaxant chez les patients atteints de myasthénie grave. En postopératoire, un taux plus faible de crises de myasthénie grave a été observé avec le sugammadex. Aucune relation entre les anesthésiques et les complications périopératoires n'a été détectée. Dans les présentations / séries de cas, les patients ayant eu au moins une complication représentaient 67 (32 %) des cas. L'admission non programmée en réanimation est une complication fréquemment rapportée. Les patients dont la maladie s'est dégradée plus rapidement ont possiblement reçu des doses plus fortes de succinylcholine (risque relatif non ajusté 0,13, intervalle de confiance [IC] 95 %, 0,20 à 0,86) et d'agents volatils (rapport de cotes [RC] ajusté, 0,38 (IC 95 %, 0,20 à 0,73), P = 0.004). SOURCES: Les articles sont issus des bases de données PubMed et EMBASE (articles publiés entre le 1er janvier 2000 et le 14 juillet 2021). CONCLUSION: Les données probantes sur la prise en charge anesthésique et les complications périopératoires affectant les patients atteints de MNM sont principalement fondées sur de petites études rétrospectives et des cas cliniques. Des études cliniques ou rétrospectives d'envergure sont nécessaires pour orienter le choix de la technique d'anesthésie optimale. Les principaux domaines d'intérêt sont les bienfaits potentiels du monitorage neuromusculaire et de l'utilisation de sugammadex ainsi que les effets indésirables possibles des anesthésiques volatils et de la succinylcholine.

Impact of duloxetine on succinylcholine-induced postoperative myalgia after direct microlaryngoscopic surgeries: Randomized controlled double-blind study.

BACKGROUND: Succinylcholine is a preferred muscle relaxant for rapid sequence intubation. Postoperative myalgia (POM) is one of its commonest adverse effects with unknown pathogenesis. Various modalities were examined to reduce POM. We hypothesized that duloxetine may reduce the incidence and severity of fasciculation or succinylcholine-induced POM in outpatient surgeries. METHODS: This randomized double-blinded trial involved controlled 70 adult participants scheduled for elective direct microlaryngoscopic surgeries. Before induction of general anesthesia by 2 h, 35 patients received duloxetine 30 mg orally (group D) and 35 patients received similar oral starch placebo capsules (group C). Fasciculations, POM, sedation score, time to first rescue analgesia, total analgesic consumption 24 h after surgery, patients' satisfaction, and adverse effects were recorded. RESULTS: Incidence of fasciculation was 77.1% and 94.3% in groups D and C (p value = 0.04), whereas its severity was not significant between groups (p value = 0.09). Incidence and severity of POM were significantly lower in group D (p values = 0.004 and 0.021). Positive correlation was recorded between fasciculations and POM scores (r = 0.732 and p < 0.001). Time required for first analgesia was prolonged in group D (p value < 0.001) with less total analgesic consumption (p value = 0.039). The potassium and creatine kinase levels showed significant differences between both groups after 30 min and 24 h, respectively (p value < 0.05). Sedation scores and patients' satisfaction were better in duloxetine group (p value < 0.05) with no severe complications. CONCLUSIONS: Preoperative oral duloxetine 30 mg administration decreased incidence and severity of succinylcholine-related muscle POM and fasciculations. It was also effective in reducing postoperative rescue analgesic requirement with better patients' satisfaction and no serious adverse effects.

Characterization of four BCHE mutations associated with prolonged effect of suxamethonium.

Butyrylcholinesterase (BChE) deficiency is characterized by prolonged apnea after the use of muscle relaxants (suxamethonium or mivacurium) in patients who have mutations in the BCHE gene. Here, we report the characterization of four BCHE mutations associated with prolonged effect of suxamethonium (amino acid numbering based on the matured enzyme): p.20delValPheGlyGlyThrValThr, p.Leu88His, p.Ile140del and p.Arg386Cys. Expression of recombinant BCHE mutants, kinetic analysis and molecular dynamics were undertaken to understand how these mutations induce BChE deficiency. Three of the mutations studied (p.20delValPheGlyGlyThrValThr, p.Ile140del and p.Arg386Cys) lead to a "silent" BChE phenotype. Recombinant BCHE expression studies for these mutants revealed BChE activity levels comparable to untransfected cells. Only the last one (hBChE-L88H) presented BChE activity in the transfected cell culture medium. This BChE mutant (p.Leu88His) is associated with a lower kcat value compare to the wild-type enzyme. Molecular dynamics simulations analyses suggest that a destabilization of a structure implicated in enzyme activity (Ω-loop) can explain the modification of the kinetic parameter of the mutated protein.

Rapid Sequence Induction With a Standard Intubation Dose of Rocuronium After Magnesium Pretreatment Compared With Succinylcholine: A Randomized Clinical Trial.

BACKGROUND: Succinylcholine remains the muscle relaxant of choice for rapid sequence induction (RSI) but has many adverse effects. High-dose rocuronium bromide may be an alternative to succinylcholine for RSI but recovery times are nearly doubled compared with a standard intubating dose of rocuronium. Magnesium sulfate significantly shortens the onset time of a standard intubating dose of rocuronium. We set out to investigate whether intravenous (IV) pretreatment with MgSO4 followed by a standard intubating dose of rocuronium achieved superior intubation conditions compared with succinylcholine. METHODS: Adults were randomized to receive a 15-minute IV infusion of MgSO4 (60 mg·kg-1) immediately before RSI with propofol 2 mg·kg-1, sufentanil 0.2 µg·kg-1 and rocuronium 0.6 mg·kg-1, or a matching 15-minute IV infusion of saline immediately before an identical RSI, but with succinylcholine 1 mg·kg-1. Primary end point was the rate of excellent intubating conditions 60 seconds after administration of the neuromuscular blocking agent and compared between groups using multivariable log-binomial regression model. Secondary end points were blood pressure and heart rate before induction, before and after intubation, and adverse events up to 24 hours postoperatively. RESULTS: Among 280 randomized patients, intubating conditions could be analyzed in 259 (133 MgSO4-rocuronium and 126 saline-succinylcholine). The rate of excellent intubating conditions was 46% with MgSO4-rocuronium and 45% with saline-succinylcholine. The analysis adjusted for gender and center showed no superiority of MgSO4-rocuronium compared with saline-succinylcholine (relative risk [RR] 1.06, 95% confidence interval [CI], 0.81-1.39, P = .659). The rate of excellent intubating conditions was higher in women (54% [70 of 130]) compared with men (37% [48 of 129]; adjusted RR 1.42, 95% CI, 1.07-1.91, P = .017). No significant difference between groups was observed for systolic and diastolic blood pressures. Mean heart rate was significantly higher in the MgSO4-rocuronium group. The percentage of patients with at least 1 adverse event was lower with MgSO4-rocuronium (11%) compared with saline-succinylcholine (28%) (RR 0.38, 95% CI, 0.22-0.66, P < .001). With saline-succinylcholine, adverse events consisted mainly of postoperative muscle pain (n = 26 [19%]) and signs of histamine release (n = 13 [9%]). With MgSO4-rocuronium, few patients had pain on injection, nausea and vomiting, or skin rash during the MgSO4-infusion (n = 5 [4%]). CONCLUSIONS: IV pretreatment with MgSO4 followed by a standard intubating dose of rocuronium did not provide superior intubation conditions to succinylcholine but had fewer adverse effects.

Prolonged apnea after ECT in organophosphorus poisoning - the need to redefine norms.

BACKGROUND: Poisoning and deaths by organo-phosphorous (OP) compounds are one of the major causes of death in developing and poor countries, and a common admission in the emergency ward and the ICU. OP compounds act by irreversibly binding to pseudocholinesterase enzyme and hence prolong the apnea in patients being given suxamethonium. We present a unusual case of OP poisoning (OPP) in which prolonged apnea ensued in a patient of severe depression following MECT (modified electroconvulsive therapy) in which suxamethonium was used as muscle relaxant, in whom we were cautious of the side-effect of prior organophosphorus poisoning. Since the cases of OPP are very high worldwide, a thorough knowledge of the interaction of the action of the drug and the receptors on which it acts takes pride of place. This article highlights the nuances in the field of psychiatry and anaesthesia in diagnosis and management of prolonged apnea after ECT. CASE PRESENTATION: A 53/F patient consumed OP 38 days prior to MECT. Since existing literature recommend a delay of 4 weeks and a subminimal dose of suxamethonium to prevent prolonged apnea, both these points were taken into consideration. Despite 38 days post exposure to OP, and a dose of succinylcholine of < 0.3 mg/kg, the patient remained apneic for 3 h. Suxamethionum apnea was managed with elective ventilation. After recovery, patient had no residual effect. Subsequently her pseudocholinesterase levels were done which were found to be very low. CONCLUSION: This case is being presented to emphasize that behaviour of post synaptic receptors cannot be relied upon after OP poisoning and pseudocholinesterase levels needs to be mandatorily checked, irrespective of duration post-exposure. In strong suspects dibucaine number and fluoride number also needs to be estimated.

Comparison of Rocuronium with Succinylcholine for Rapid Sequence Induction Intubation in the Emergency Department: A Retrospective Study at a Single Center in China.

BACKGROUND This retrospective study was conducted at a single center in China and aimed to compare rocuronium with succinylcholine for rapid sequence induction intubation in the Emergency Department of a hospital. MATERIAL AND METHODS An orotracheal intubation procedure was performed in a total of 267 patients by direct laryngoscopy using an intravenous bolus injection of 1 mg/kg of succinylcholine (n=141; SY group) or 1.2 mg/kg of rocuronium (n=126; RM group) for a rapid sequence induction in the emergency department. The success of orotracheal intubation was evaluated by a capnography curve. The modified Cormack-Lehane score was used to grade the direct laryngoscopy. RESULTS There was no statistically significant difference in numbers of patients with successful first-attempt orotracheal intubation between the groups (112 vs. 87, P=0.067). Fewer intubation failures under direct laryngoscopy were reported in the SY group than in the RM group (23 [16%] vs. 34 [27%], P=0.037). The number of intubation attempts was higher in the RM group than in the SY group (1.52±0.87 per patient vs. 1.27±0.60 per patient, P=0.032). CONCLUSIONS The findings from this study support results from previous studies, showing that even in the Emergency Department setting, rocuronium was equivalent to succinylcholine in achieving rapid sequence induction intubation, when the dose was appropriate. However, as current clinical guidelines highlight, succinylcholine has more contraindications and adverse effects, including hyperkalemia, which should be monitored, and rocuronium has a longer duration of action.

BET 2: Is the use of long-acting neuromuscular blocking agents for intubation associated with reduced provision of postintubation sedation?

A short cut review was conducted to assess if the use of rocuronium in the ED was associated with a decrease in the provision of postintubation sedation. Four papers were identified that presented the best evidence to answer the question. Again the studies, relevant outcomes, results and weaknesses are tabulated. All the identified studies were retrospective and there was a plethora of outcome measures used. When compared with suxamethonium, rocuronium was associated with a delayed initiation and reduced dose of postintubation sedation.

Malignant Hyperthermia-Associated Rhabdomyolysis After Succinylcholine: A Case Report.

Malignant hyperthermia-associated rhabdomyolysis is a condition that lies on the spectrum of malignant hyperthermia (MH). Unlike MH, malignant-hyperthermia-associated rhabdomyolysis is a condition which most commonly is recognized in the postoperative period by the development of discolored brown urine with notably absent rigidity, tachypnea, tachycardia, and hyperthermia. The presented case describes the subtle onset of malignant hyperthermia-associated rhabdomyolysis, along with a review of relevant literature.

Succinylcholine and postoperative pulmonary complications: a retrospective cohort study using registry data from two hospital networks.

BACKGROUND: Neuromuscular blocking agents (NMBAs) with a non-depolarising mechanism of action carry the risk of postoperative residual paralysis and are associated with postoperative pulmonary complications (POPC). Owing to the shorter duration of action, the depolarising NMBA succinylcholine may be associated with less postoperative residual paralysis, and hence fewer POPC. We tested the association of succinylcholine administration during anaesthesia and POPC. METHODS: In a retrospective cohort study of registry data from two large US academic medical centres, 244 850 adult noncardiac surgical patients undergoing general anaesthesia were included. The primary outcome was POPC, defined as post-extubation haemoglobin oxygen de-saturation to <90%, or re-intubation requiring intensive care unit admission within 7 days after surgery. The association between succinylcholine and POPC and its dose-dependency were tested in a hierarchical fashion using a multivariable logistic regression model. RESULTS: A total of 13 206 patients (5.4%) experienced POPC. Use of succinylcholine was associated with increased risk of POPC (adjusted odds ratio [ORAdj]=1.11; 95% confidence interval [CI], 1.06-1.16; P<0.001; adjusted risk=5.18%; 95% CI, 5.06-5.30 without and 5.69%; 95% CI, 5.53-5.85 with succinylcholine), with a dose-dependent relationship (ORAdj=1.08; 95% CI, 1.05-1.11 per mg kg-1; P<0.001). In patients receiving non-depolarising NMBAs, succinylcholine further increased the risk of POPC (ORAdj=1.08; 95% CI, 1.03-1.14; P=0.001). The association between succinylcholine and POPC was modified (P=0.03 for interaction) by the duration of surgery with higher odds of POPC in patients undergoing surgeries of <2 vs ≥2 h (ORAdj=1.24; 95% CI, 1.15-1.33 and 1.05; 95% CI, 1.00-1.10, respectively). CONCLUSIONS: In contrast to our prediction, succinylcholine administration was associated with an increased risk of POPC. This association was dose-dependent and magnified in surgeries of shorter duration.

The Effect of Pregabalin on the Prevention of Succinylcholine-Induced Fasciculation and Myalgia.

PURPOSE: This study evaluates the effect of pregabalin on fasciculation and myalgia after using succinylcholine. DESIGN: This randomized double-blind prospective study was conducted among 100 patients aged 20 to 60 years old. METHODS: Pregabalin (300 mg) and placebo (in capsule form) were placed in similar containers. The results were analyzed by SPSS 23 software, and statistical analysis consisted of χ2 test and t test, and a P value less than .05 was considered significant. FINDINGS: The mean pain score in the group receiving pregabalin was lower than the placebo group. According to the χ2 test, there was a significant difference between the two groups in the frequency of fasciculation (P = .003). Mean fasciculation severity in the pregabalin group was lower than placebo group. According to t test, there was a significant difference in the mean fasciculation severity between the two groups (P = .002). CONCLUSIONS: This study showed that 300 mg of pregabalin was effective in reducing postoperative fasciculation and myalgia in patients treated with succinylcholine.

Suspected Succinylcholine-Induced Masseter Muscle Rigidity During Rapid Sequence Intubation in the Air Medical Setting.

Trismus, or masseter muscle rigidity, is a rare but previously described complication of succinylcholine-induced neuromuscular blockade. We present a case report that details unique aspects of suspected masseter muscle rigidity in the prehospital setting air medical setting after attempted rapid sequence intubation with succinylcholine. We then discuss the need for knowledge base of this life-threatening and rarely described syndrome as well as the importance of working through a differential diagnosis and specific trismus-focused airway algorithm. Trismus, or masseter muscle rigidity (MMR), is a rare but previously described complication of succinylcholine-induced neuromuscular blockade. It has been cited in anesthesia and emergency medicine literature as a potentially life-threatening complication and requires prompt intervention. This case report details a unique case of suspected MMR in the prehospital setting after attempted rapid sequence intubation (RSI) with succinylcholine performed by an experienced aeromedical flight crew.

Succinylcholine Use and Dantrolene Availability for Malignant Hyperthermia Treatment: Database Analyses and Systematic Review.

BACKGROUND: Although dantrolene effectively treats malignant hyperthermia (MH), discrepant recommendations exist concerning dantrolene availability. Whereas Malignant Hyperthermia Association of the United States guidelines state dantrolene must be available within 10 min of the decision to treat MH wherever volatile anesthetics or succinylcholine are administered, a Society for Ambulatory Anesthesia protocol permits Class B ambulatory facilities to stock succinylcholine for airway rescue without dantrolene. The authors investigated (1) succinylcholine use rates, including for airway rescue, in anesthetizing/sedating locations; (2) whether succinylcholine without volatile anesthetics triggers MH warranting dantrolene; and (3) the relationship between dantrolene administration and MH morbidity/mortality. METHODS: The authors performed focused analyses of the Multicenter Perioperative Outcomes Group (2005 through 2016), North American MH Registry (2013 through 2016), and Anesthesia Closed Claims Project (1970 through 2014) databases, as well as a systematic literature review (1987 through 2017). The authors used difficult mask ventilation (grades III and IV) as a surrogate for airway rescue. MH experts judged dantrolene treatment. For MH morbidity/mortality analyses, the authors included U.S. and Canadian cases that were fulminant or scored 20 or higher on the clinical grading scale and in which volatile anesthetics or succinylcholine were given. RESULTS: Among 6,368,356 queried outcomes cases, 246,904 (3.9%) received succinylcholine without volatile agents. Succinylcholine was used in 46% (n = 710) of grade IV mask ventilation cases (median dose, 100 mg, 1.2 mg/kg). Succinylcholine without volatile anesthetics triggered 24 MH cases, 13 requiring dantrolene. Among 310 anesthetic-triggered MH cases, morbidity was 20 to 37%. Treatment delay increased complications every 10 min, reaching 100% with a 50-min delay. Overall mortality was 1 to 10%; 15 U.S. patients died, including 4 after anesthetics in freestanding facilities. CONCLUSIONS: Providers use succinylcholine commonly, including during difficult mask ventilation. Succinylcholine administered without volatile anesthetics may trigger MH events requiring dantrolene. Delayed dantrolene treatment increases the likelihood of MH complications. The data reported herein support stocking dantrolene wherever succinylcholine or volatile anesthetics may be used.