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.

[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.

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.

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.

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.

Malignant Hyperthermia.

Malignant Hyperthermia (MH) is a life-threatening pharmacogenetic disorder which results from exposure to volatile anesthetic agents and depolarizing muscle relaxants. It manifests as a hypermetabolic response resulting in tachycardia, tachypnea, hyperthermia, hypercapnia, acidosis, muscle rigidity and rhabdomyolysis. An increase in the end-tidal carbon dioxide is one of the earliest diagnostic signs. Dantrolene sodium is effective in the management of MH, and should be available whenever general anesthesia is administered. This review also aims to highlight the genetics and pathology of MH, along with its association with various inherited myopathy syndromes like central core disease, multi-mini core disease, Native-American myopathy, and King-Denborough syndrome.

Succinylcholine for Emergency Airway Rescue in Class B Ambulatory Facilities: The Society for Ambulatory Anesthesia Position Statement.

Procedures in class B ambulatory facilities are performed exclusively with oral or IV sedative-hypnotics and/or analgesics. These facilities typically do not stock dantrolene because no known triggers of malignant hyperthermia (ie, inhaled anesthetics and succinylcholine) are available. This article argues that, in the absence of succinylcholine, the morbidity and mortality from laryngospasm can be significant, indeed, higher than the unlikely scenario of succinylcholine-triggered malignant hyperthermia. The Society for Ambulatory Anesthesia (SAMBA) position statement for the use of succinylcholine for emergency airway management is presented.

Rocuronium is more hepatotoxic than succinylcholine in vitro.

BACKGROUND: The development of liver failure is a major problem in critically ill patients. The hepatotoxicity of many drugs, as one important reason for liver failure, is poorly screened for in human models. Rocuronium and succinylcholine are neuromuscular blocking agents used for tracheal intubation and for rapid-sequence induction. OBJECTIVE: We used an in-vitro test with a permanent cell line and compared rocuronium and succinylcholine for hepatotoxicity. DESIGN: In-vitro study. SETTING: A basic science laboratory, University Hospital Rostock, Germany. MATERIAL/(PATIENTS): The basic test compound is the permanent human liver cell line HepG2/C3A. In a standardised microtitre plate assay the toxicity of different concentrations of rocuronium, succinylcholine and plasma control was tested. INTERVENTIONS: After two incubation periods of 3 days, the viability of cells (XTT test, lactate dehydrogenase release and trypan blue staining), micro-albumin synthesis and the cytochrome 1A2 activity (metabolism of ethoxyresorufin) were measured. MAIN OUTCOME MEASURES: Differences between rocuronium and succinylcholine were assessed using the Kruskal-Wallis one-way test and two-tailed Mann-Whitney U test. RESULTS: Rocuronium, but not succinylcholine, led to a significant dose-dependent decrease of viability, albumin synthesis and cytochrome 1A2 activity of test cells. CONCLUSION: An in-vitro test with a cell line showed hepatotoxicity of rocuronium that was dose-dependent. Further studies are needed to investigate the underlying mechanisms of the effects of rocuronium on hepatic cellular integrity. TRIAL REGISTRATION: Not suitable.

Pharmacological and non-pharmacological interventions for reducing rocuronium bromide induced pain on injection in children and adults.

BACKGROUND: Rocuronium bromide is a routinely used muscle relaxant in anaesthetic practice. Its use, however, is associated with intense pain on injection. While it is well established that rocuronium bromide injection causes pain in awake patients, anaesthetized patients also tend to show withdrawal movements of the limbs when this muscle relaxant is administered. Various strategies, both pharmacological and non-pharmacological, have been studied to reduce the incidence and severity of pain on rocuronium bromide injection. We wanted to find out which of the existing modalities was best to reduce pain on rocuronium injection. OBJECTIVES: The objectives of this review were to assess the ability of both pharmacological and non-pharmacological interventions to reduce or eliminate the pain that accompanies rocuronium bromide administration. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2013, Issue 7), MEDLINE via Ovid SP (1966 to July 2013) and EMBASE via Ovid SP (1980 to July 2013). We also searched specific websites. We reran the searches in February 2015 and will deal with the 11 studies of interest found through this search when we update the review. SELECTION CRITERIA: We included all randomized controlled trials (RCTs) that compared the use of any drug or a non-pharmacological method with control patients, or those receiving no treatment to reduce the severity of pain with rocuronium injection. Our primary outcome was pain on rocuronium bromide injection measured by a pain score assessment. Our secondary outcomes were rise in heart rate and blood pressure following administration of rocuronium and adverse events related to the interventions. DATA COLLECTION AND ANALYSIS: We used the standardized methods for conducting a systematic review as described in the Cochrane Handbook for Systematic Reviews of Interventions. Two authors independently extracted details of trial methodology and outcome data from reports of all trials considered eligible for inclusion. We made all analyses on an intention-to-treat basis. We used a fixed-effect model where there was no evidence of significant heterogeneity between studies and a random-effects model if heterogeneity was likely. MAIN RESULTS: We included 66 studies with 7840 participants in the review, though most analyses were based on data from fewer participants. In total there are 17 studies awaiting classification. No studies were at a low risk of bias. We noted substantial statistical and clinical heterogeneity between trials. Most of the studies reported the primary outcome pain as assessed by verbal response from participants in an awake state but some trials reported withdrawal of the injected limb as a proxy for pain after induction of anaesthesia in response to rocuronium administration. Few studies reported adverse events and no study reported heart rate and blood pressure changes after administration of rocuronium. Lidocaine was the most commonly studied intervention drug, used in 29 trials with 2256 participants. The risk ratio (RR) of pain on injection if given lidocaine compared to placebo was 0.23 (95% confidence interval (CI) 0.17 to 0.31; I² = 65%, low quality of evidence). The RR of pain on injection if fentanyl and remifentanil were given compared to placebo was 0.42 (95% CI 0.26 to 0.70; I² = 79%, low quality of evidence) and (RR 0.10, 95% CI 0.04 to 0.26; I² = 74%, low quality of evidence), respectively. Pain on injection of intervention drugs was reported with the use of lidocaine and acetaminophen in one study. Cough was reported with the use of fentanyl (one study), remifentanil (five studies, low quality evidence) and alfentanil (one study). Breath holding and chest tightness were reported with the use of remifentanil in two studies (very low quality evidence) and one study (very low quality evidence), respectively. The overall rate of complications was low. AUTHORS' CONCLUSIONS: The evidence to suggest that the most commonly investigated pharmacological interventions reduce pain on injection of rocuronium is of low quality due to risk of bias and inconsistency. There is low or very low quality evidence for adverse events, due to risk of bias, inconsistency and imprecision of effect. We did not compare the various interventions with one another and so cannot comment on the superiority of one intervention over another. Complications were reported more often with use of opioids.

A cardiac arrest following the administration of succinylcholine.

A twenty-three year old woman, admitted to the intensive care unit (ICU) with a diagnosis of menin- gitis and associated lower limb ischemia suffered a car- diac arrest, due to extreme hyperkalemia, following the administration of succinylcholine in order to replace an endo-tracheal tube. After prolonged cardiopulmonary resuscitation (CPR) lasting 45 minutes, during which 8 mg of epinephrine was administered, cardiac output was restored. Four weeks later the patient left intensive care, having made a full recovery with no neurological deficit. The following case highlights the risks of succinylcholine in the septic patient and that prolonged resuscitation can have a succesfiil outcome.

Prolonged Paralysis Following Emergent Cesarean Section with Succinylcholine Despite Normal Dibucaine Number.

Prolonged paralysis due to a quantitative or qualitative deficiency of pseudocholinesterase activity is an uncommon but known side effect of succinylcholine. We describe a patient who experienced prolonged paralysis following administration of succinylcholine for general anesthesia and endotracheal intubation for an emergent cesarean section despite laboratory evidence of normal enzyme function. The patient required mechanical ventilation in the intensive care unit for several hours following surgery. The patient was extubated following return of full muscle strength and had a good outcome. The enzyme responsible for the metabolism of succinylcholine, pseudocholinesterase, was determined to be low in quantity in this patient but was functionally normal. This low level, by itself, was unlikely to be solely responsible for the prolonged paralysis. The patient likely had an abnormal pseudocholinesterase enzyme variant that is undetectable by standard laboratory tests.

Do we foresee new emerging drugs to treat malignant hyperthermia?

Malignant hyperthermia (MH) is a life-threatening genetic sensitivity of skeletal muscles to volatile anesthetics and depolarizing neuromuscular blocking drugs occurring during or after anesthesia. Mortality of MH has been significantly reduced by using the skeletal muscle relaxant dantrolene. However, pharmacological disadvantages are known. By approval of a nanocrystalline dantrolene sodium suspension (DSS), a new product enters the market. DSS is a promising substance, but clinical data are lacking up to now. Especially with regard to newer knowledge on MH and its associated clinical presentations, there might be an increasing interest on DSS.

Receptor analysis of differential sensitivity change to succinylcholine induced by nerve injury in rat gastrocnemius.

BACKGROUND: Urgent tracheal intubation is common in intensive care units and the emergency room, and succinylcholine is a first-line neuromuscular blocker used in these situations. Paraplegic or critically ill patients may be at a high risk of receiving succinylcholine because the denervation stage changes nicotinic receptors, which affect the efficacy and safety of succinylcholine. The objective of this study was to determine the receptor subtypes associated with changes in the pharmacodynamics of succinylcholine and its time-line trend. METHODS: Denervated gastrocnemius was collected from tibial nerve transected rats. To determine the 50% effective dose of succinylcholine and rocuronium at 0 (control), 1, 3, 7, 14, and 28 d after denervation, action potential amplitude was monitored by an intracellular recording method. Subunits α1, α7, ε, and γ of the acetylcholine receptor (AChR) were quantified by real-time polymerase chain reaction. Receptor amount and pharmacodynamic changes were analyzed by correlation and regression analysis. RESULTS: The pharmacodynamic change in succinylcholine was a dynamic process, and at the same time α7, ε, and γ-nicotinic AChR genes in denervated muscle were significantly changed but only α7 was closely correlated with the action of succinylcholine. Subunit γ and α7 were related to pharmacodynamic change in the nondepolarizing neuromuscular agent, rocuronium. CONCLUSIONS: Nerve injury may alter nicotinic AChR subtypes in skeletal muscle at different stages, which probably affected the pharmacodynamics of neuromuscular blockers in different ways. Denervation time and stage and the type of neuromuscular blocker and dosage should be taken into consideration when using these drugs in patients with nerve injury.

Rocuronium versus succinylcholine for rapid sequence induction intubation.

BACKGROUND: Patients often require a rapid sequence induction (RSI) endotracheal intubation technique during emergencies or electively to protect against aspiration, increased intracranial pressure, or to facilitate intubation. Traditionally succinylcholine has been the most commonly used muscle relaxant for this purpose because of its fast onset and short duration; unfortunately, it can have serious side effects. Rocuronium has been suggested as an alternative to succinylcholine for intubation. This is an update of our Cochrane review published first in 2003 and then updated in 2008 and now in 2015. OBJECTIVES: To determine whether rocuronium creates intubating conditions comparable to those of succinylcholine during RSI intubation. SEARCH METHODS: In our initial review we searched all databases until March 2000, followed by an update to June 2007. This latest update included searching the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 2), MEDLINE (1966 to February Week 2 2015), and EMBASE (1988 to February 14 2015 ) for randomized controlled trials (RCTs) or controlled clinical trials (CCTs) relating to the use of rocuronium and succinylcholine. We included foreign language journals and handsearched the references of identified studies for additional citations. SELECTION CRITERIA: We included any RCT or CCT that reported intubating conditions in comparing the use of rocuronium and succinylcholine for RSI or modified RSI in any age group or clinical setting. The dose of rocuronium was at least 0.6 mg/kg and succinylcholine was at least 1 mg/kg. DATA COLLECTION AND ANALYSIS: Two authors (EN and DT) independently extracted data and assessed methodological quality for the 'Risk of bias' tables. We combined the outcomes in Review Manager 5 using a risk ratio (RR) with a random-effects model. MAIN RESULTS: The previous update (2008) had identified 53 potential studies and included 37 combined for meta-analysis. In this latest update we identified a further 13 studies and included 11, summarizing the results of 50 trials including 4151 participants. Overall, succinylcholine was superior to rocuronium for achieving excellent intubating conditions: RR 0.86 (95% confidence interval (CI) 0.81 to 0.92; n = 4151) and clinically acceptable intubation conditions (RR 0.97, 95% CI 0.95 to 0.99; n = 3992, 48 trials). A high incidence of detection bias amongst the trials coupled with significant heterogeneity provides moderate-quality evidence for these conclusions, which are unchanged from the previous update. Succinylcholine was more likely to produce excellent intubating conditions when using thiopental as the induction agent: RR 0.81 (95% CI: 0.73 to 0.88; n = 2302, 28 trials). In the previous update, we had concluded that propofol was the superior induction agent with succinylcholine. There were no reported incidences of severe adverse outcomes. We found no statistical difference in intubation conditions when succinylcholine was compared to 1.2 mg/kg rocuronium; however, succinylcholine was clinically superior as it has a shorter duration of action. AUTHORS' CONCLUSIONS: Succinylcholine created superior intubation conditions to rocuronium in achieving excellent and clinically acceptable intubating conditions.

PSEUDOCHOLINESTERASE DEFICIENCY IN A OCTOGENARIAN UNDERGOING TOTAL INTRAVENOUS ANESTHESIA; IMPLICATIONS FOR NEUROMONITORING.

Pseudocholinesterase deficiency manifests as prolonged motor blockade after the administration of succinylcholine. A previously unknown homozygous form of the disease, became apparent during a lumbar laminectomy seriously limiting the ability to monitor motor evoked potentials and perform electromyelography (EMG). Moreover, concerns were raised as to how the enzyme deficiency would affect the metabolism of remifentanil and other esters during a total intravenous anesthetic. We present the perioperative management of the patient and a literature review of the syndrome. The patient provided written permission for the authors to publish this report. At our institution, IRB review and approval is not required for a single case report.

Use of neuromuscular monitoring to detect prolonged effect of succinylcholine or mivacurium: three case reports.

Mutations in the butyrylcholinesterase gene can lead to a prolonged effect of the neuromuscular blocking agents, succinylcholine and mivacurium. If the anaesthesiologist is not aware of this condition, it may result in insufficient respiration after tracheal extubation. However, this can be avoided with the use of objective neuromuscular monitoring if used adequately. Three case reports of prolonged effect of succinylcholine or mivacurium were presented to illustrate the importance of neuromuscular monitoring during anaesthesia. In the first case, continuous intraoperative neuromuscular monitoring allowed a prolonged neuromuscular blockade to be discovered prior to tracheal extubation of the patient. The patient was extubated after successful reversal of the neuromuscular blockade. On the contrary, neuromuscular monitoring was not used during anaesthesia in the second patient; hence, the prolonged effect of the neuromuscular blocking agent was not discovered until after extubation. In the third patient, the lack of response to nerve stimulation was interpreted as a technical failure and the prolonged effect of succinylcholine was discovered when general anaesthesia was terminated. Both patients had insufficient respiration. They were therefore re-sedated, transferred to the intensive care unit and the tracheas were extubated after full recovery from neuromuscular blockade. We recommend the use of monitoring every time these agents are used, even with short-acting drugs like succinylcholine and mivacurium.

The increases in potassium concentrations are greater with succinylcholine than with rocuronium-sugammadex in outpatient surgery: a randomized, multicentre trial.

BACKGROUND: Succinylcholine provides rapid onset of neuromuscular blockade and short duration of action, but its administration may be associated with hyperkalemia. Rocuronium is not known to increase potassium concentration, has fast onset of activity, and can be rapidly reversed by sugammadex. This study evaluated changes in plasma potassium concentrations in patients randomized either to rocuronium followed by sugammadex reversal or to succinylcholine in ambulatory surgery. METHODS: In this multicentre randomized active-controlled study, adult patients undergoing short surgical procedures in an outpatient setting received either rocuronium 0.6 mg·kg(-1) for intubation with sugammadex 4.0 mg·kg(-1) for reversal (n = 70) or succinylcholine 1.0 mg·kg(-1) with spontaneous recovery (n = 80). Blood potassium concentrations were assessed at baseline (before study drug administration) and at intervals up to 15 min after rocuronium, sugammadex, and succinylcholine. RESULTS: At the primary endpoint, five minutes post-administration, the changes in potassium concentrations from baseline were significantly smaller in patients treated with rocuronium than in those given succinylcholine [mean (SD): -0.06 (0.32) vs 0.30 (0.34) mmol·L(-1), respectively; P < 0.0001]. At baseline, potassium concentrations were similar in both groups, but they were greater at two, five, ten, and 15 min after succinylcholine than after rocuronium (P < 0.0001) for all time points. After sugammadex administration, there were no significant changes in mean potassium concentration from the pre-rocuronium baseline. No adverse effects related to hyperkalemia were observed. CONCLUSION: Succinylcholine was associated with a modest increase in potassium concentration; these changes were not seen after rocuronium or sugammadex ( CLINICAL TRIAL REGISTRATION NUMBER: NCT00751179).