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Rocuronium is increasingly used as a first-line neuromuscular blocker (NMB) in rapid sequence intubation by transport teams. Prior work has shown that rocuronium is associated with a delay in postintubation sedation compared with intubation with succinylcholine.Boston MedFlight is a consortium-based transport organization. In 2017, the intubation protocol and formulary for Boston MedFlight was changed to replace succinylcholine with rocuronium. We performed a retrospective review of patients intubated by the critical care transport teams from January 2017 through December 2019.We analyzed data for 264 intubations, 92 with succinylcholine and 172 with rocuronium. Ketamine and etomidate were the most common induction agents. The mean time from NMB administration to the first dose of sedation was 9.2 minutes (95% confidence interval, 5.4-23.7) for the succinylcholine cohort and 14.8 minutes (95% confidence interval, 8.4-38.0; P.001) for the rocuronium cohort. After neuromuscular blockade, the total hourly weight-adjusted fentanyl dose was significantly lower for patients intubated with rocuronium compared with succinylcholine.Intubation with rocuronium was associated with a longer time until the administration of sedation and decreased postneuromuscular blockade fentanyl administration compared with intubation with succinylcholine. These findings suggest opportunities for improvement in sedation and analgesia practices after rocuronium rapid sequence intubation.

Background New therapies are created to address specific problems and enjoy popularity as they enter widespread clinical use. Broader use can reveal unknown adverse effects and impact the life cycle significantly. Succinylcholine, a depolarizing neuromuscular blocker, was the product of decades of research surrounding the ancient compound, curare. It was introduced into practice in the 1950s by Burroughs Wellcome and Company (BW Co) and was welcomed due to its rapidly acting muscle relaxation effects. Global clinical use revealed adverse effects, both minor and major, in particular, hyperkalemia and malignant hyperthermia. We investigated when practitioners and the manufacturer became aware of these adverse effects, how information about these side effects was disseminated, and whether the manufacturer met the regulatory requirements of the time, specifically regarding the timely reporting of adverse effects. Sources Primary literature search using online and archived documents was conducted at the Wood Library-Museum of Anesthesiology, Schaumburg, IL. We consulted documents submitted by BW Co to federal authorities, through the Freedom of Information Act (FOIA), Food and Drug Administration (FDA) reports, promotional advertisements, package inserts, published articles, and textbooks. Results Initial clinical testing in humans in 1952 found no adverse effects on cardiovascular or respiratory systems. Fasciculations and myalgia were early side effects described in case reports in 1952. Large-scale clinical trials in 1953 found abnormally long recovery times among some patients; the discovery of abnormal pseudocholinesterase enzyme activity was not fully demonstrated until the early 1960s. Bradycardia was first reported in 1957 in children, and in 1959 in adults. In 1960, animal studies reported a transient increase in plasma potassium; further experiments in 1969 clearly demonstrated succinylcholine-induced hyperkalemia in burn patients. Malignant hyperthermia was first described in 1966. Similar cases of elevated temperatures and muscle rigidity were described globally but the underlying mechanism was not elucidated until the 1990s. Standard anesthesia textbooks did not report major side effects of succinylcholine until 1960 and included newly documented side effects with each edition. BW Co's packaging contained warnings as early as the 1950s but were later updated in 1962 and beyond to reflect the newly discovered hyperkalemia and malignant hyperthermia. Conclusion Particularly given the regulatory environment of the time, BW Co appropriately reported the adverse effects of succinylcholine after market entry; it updated promotional and packaging material in a timely manner to reflect newly discovered adverse effects. The toxicity, though alarming and put clinicians on alert, did not seem to heavily impact succinylcholine's use, given its various desirable properties. It is still a choice muscle relaxant used today, although there are efforts to develop superior agents to replace succinylcholine.

Objective Nondepolarizing neuromuscular blocking agents (NMBAs) are associated with perioperative complications in noncardiac surgery; however, little is known about their effect on cardiac surgery. This study assessed the effect of neuromuscular blockade (NMB) on the incidence of postoperative pulmonary complications (PPCs) after cardiac surgery and operating conditions. Design Prospective, randomized clinical trial with blinded outcomes assessment. Setting University hospital, single institution. Participants Adult patients having cardiac surgery requiring cardiopulmonary bypass. Interventions One hundred patients were randomized to receive succinylcholine (group SUX) for intubation with no further NMB administered or cisatracurium (group CIS) for intubation and maintenance NMB. The primary outcome was a composite incidence of PPCs in the 72 hours after elective cardiac surgery. PPCs included failure to extubate within 24 hours, need for reintubation, pneumonia, aspiration, unanticipated need for noninvasive respiratory support, acute respiratory distress, and mortality from respiratory arrest. The secondary outcome was the adequacy of operating conditions as assessed by blinded surgeon survey (including a rating of surgical conditions on a Likert scale from 1 = poor to 5 = excellent), anesthesiologist report, and patient questionnaire. Measurements and Main Results The composite incidence of PPCs did not differ between groups (8 of 50 patients in both groups; 16%). Mean surgeon rating of surgical conditions was lower in the SUX group (4.65 ± 0.85 v 4.96 ± 0.20, p = 0.02). Conclusion Although avoiding nondepolarizing NMBA is feasible, doing so worsened operating conditions and did not reduce the incidence of postoperative pulmonary complications.

Objective The aim of this study was to evaluate the difference in the time to postintubation sedation between patients receiving etomidate and either succinylcholine or rocuronium in the prehospital setting. Setting: Patients who received rapid sequence intubation medications from transport service personnel and were subsequently intubated were included. The critical care transport agency operates 8 helicopter- and 3 ground-based emergency medical service units. Methods This retrospective cohort study compared the time to the first sedative in patients intubated with etomidate and succinylcholine versus etomidate and rocuronium. Enrollment of 64 patients per arm was needed to achieve 80% power with a 2-tailed alpha of 0.05. Results Sixty-four and 38 patients received succinylcholine or rocuronium, respectively. The median time to postetomidate sedation was 10 (range, 5.0-16.0) and 13.5 (range, 7.0-20.8) minutes for succinylcholine and rocuronium patients, respectively (P = .13). Given the average duration of effect of etomidate, succinylcholine, and rocuronium, 0 (0%) succinylcholine versus 33 (86.8%) rocuronium patients were found to be at risk of wakeful paralysis. Conclusions This study suggests rocuronium's long duration of effect puts patients at risk for wakeful paralysis once the short effects of etomidate have subsided.

Purpose Characterize medication practices during and immediately after rapid sequence intubation (RSI) by provider/location and evaluate adverse drug events. Materials and methods This was a multicenter, observational, cross-sectional study of adult and pediatric intensive care unit and emergency department patients over a 24-h period surrounding first intubation. Results A total of 404 patients from 34 geographically diverse institutions were included (mean age 58 ± 22 years, males 59%, pediatric 8%). During RSI, 21%, 87%, and 77% received pre-induction, induction, and paralysis, respectively. Significant differences in medication use by provider type were seen. Etomidate was administered to 58% with sepsis, but was not associated with adrenal insufficiency. Ketamine was associated with hypotension post-RSI [RR = 1.78 (1.36–2.35)] and use was low with traumatic brain injury/stroke (1.5%). Succinylcholine was given to 67% of patients with baseline bradycardia and was significantly associated with bradycardia post-RSI [RR = 1.81 (1.11–2.94)]. An additional 13% given succinylcholine had contraindications. Sedation practices post-RSI were not consistent with current practice guidelines and most receiving a non-depolarizing paralytic did not receive adequate sedation post-RSI. Conclusions Medication practices during RSI vary amongst provider and medications are often used inappropriately. There is opportunity for optimization of medication use during RSI.

We report a case of acute rhabdomyolysis following general anesthesia for strabismus surgery in a previously healthy 11-year-old girl. The patient received a depolarizing muscle relaxant (succinylcholine) and halogenated volatile anesthetic agent (sevoflurane) during surgery. In rare cases, these classes of drugs can trigger malignant hyperthermia (MH) or anesthesia-induced rhabdomyolysis (AIR), which can cause significant morbidity and mortality if not recognized and treated promptly. Pathophysiology, early recognition, and special considerations in strabismus patients are discussed.

Succinylcholine chloride (SCC) is a common poison that threatens human life. At present, there is a lack of research on its on-site rapid detection methods. In this work, the use of gold nanorods as an enhanced substrate based on the high affinity between the quaternary ammonium salt structure can achieve rapid SERS detection of SCC in plasma. The long alkane chain structure of cetyltrimethylammonium bromide (CTAB) and the quaternary ammonium salt structure of SCC have a high molecular affinity, so that the target molecule can show a strong and obvious characteristic signal of SERS. Combined with a simple pretreatment method, acetonitrile is used as a protein precipitation agent to effectively remove matrix interference. The constructed SERS substrate can achieve the sensitive detection of 2 × 10-8 M level of SCC in plasma samples and has high detection reproducibility. The entire pre-processing and testing process can be completed within 7 min, which can be used as an important technical basis for the preliminary identification of on-site SCC-related drug cases. The research results provide an effective solution for the establishment of SCC analysis strategies in complex matrices, and can provide new ideas for solving the problems of difficult identification of common poisons in the field and the lack of rapid detection methods on site.

ResumoJustificativa e objetivosA ação epidural de agentes bloqueadores neuromusculares pode ser explicada à luz de suas características físico‐químicas e propriedades do espaço epidural. Na literatura existem poucos casos sobre a administração acidental em espaço epidural de agente neuromuscular que se manifesta principalmente com a instituição de bloqueio neuromuscular ou fasciculações.Relato de casoRelatamos um caso de administração acidental de succinilcolina como uma dose teste epidural em uma paciente submetida à laparotomia programada, sob anestesia combinada geral e peridural. Aproximadamente dois minutos após a injeção de succinilcolina, a paciente queixou‐se de falta de ar, enquanto fasciculações leves apareceram em seu tronco e rosto, tratadas com a instituição imediata de anestesia geral. Exceto pela duração relativamente longa do bloqueio neuromuscular em comparação com a administração intravenosa, sequelas neurológicas ou cardiovasculares ou outros sintomas de toxicidade local ou sistêmica não foram observados.ConclusõesA administração oral de diazepam parece diminuir os efeitos adversos da administração epidural acidental de succinilcolina. A meticulosidade e discriminação dos rótulos das seringas, bem como os cuidados persistentes mantidos durante todos os procedimentos de anestesia, continuam a ser de importância crucial.AbstractBackground and objectivesEpidural action of neuromuscular blocking agents could be explained under the light of their physicochemical characteristics and epidural space properties. In the literature there are few cases of accidental neuromuscular agent's epidural administration, manifesting mainly with neuromuscular blockade institution or fasciculations.Case reportWe report a case of accidental succinylcholine administration as an epidural test dose, in a female patient undergoing scheduled laparotomy, under combined general and epidural anesthesia. Approximately 2min after the succinylcholine injection the patient complained for shortness of breath, while mild fasciculations appeared in her trunk and face, managed by immediate general anesthesia institution. With the exception of a relatively longer duration of neuromuscular blockade compared with intravenous administration, no neurological or cardiovascular sequelae or other symptoms of local or systemic toxicity were observed.ConclusionsOral administration of diazepam seems to lessen the adverse effects from accidental epidural administration of succinylcholine. The meticulous and discriminative labeling of syringes, as well as keeping persistent cautions during all anesthesia procedures remains of crucial importance.

Study objective Malignant hyperthermia (MH) is a rare yet potentially fatal pharmacogenetic disorder triggered by exposure to inhalational anesthetics and the depolarizing neuromuscular blocking agent succinylcholine. Epidemiologic data on the geographic variation in MH prevalence is scant. The objective of this study is to examine the prevalence of recorded MH diagnosis in patients discharged from hospitals in four states in the United States. Design Observational study. Setting Healthcare Cost and Utilization Project (HCUP) State Inpatient Database (SID) for California (2011), Florida (2011), New York (2012) and Wisconsin (2012). Patients A total of 164 hospital discharges that had a recorded diagnosis of MH using the International Classification of Disease, 9th Revision, Clinical Modification code 995.86. Methods MH prevalence was assessed by patient demographic and clinical characteristics. Main results The prevalence of MH per 100,000 hospital discharges ranged from 1.23 (95% Confidence Interval [CI], 0.80–1.66) in New York to 1.91 (95% CI, 1.48–2.34) in California, and the prevalence of MH per 100,000 surgical discharges ranged from 1.47 (95% CI, 0.93–2.02) in New York to 2.86 (95% CI, 2.00–3.71) in Florida. The prevalence of MH in male patients was more than twice the prevalence in female patients. Of the 164 patients with MH diagnosis, 11% were dead on discharge. Conclusions There exists a modest variation in the prevalence of recorded MH diagnosis in hospital discharges in California, Florida, New York and Wisconsin. Epidemiologic patterns of MH diagnosis in hospital discharges appear to be similar across the four states. Further research is needed to better understand the geographic variation and contributing factors of MH in different populations.

Objective Transportation by air exposes drugs used in emergency medical services to vibrations. The aim of the study was to determine whether or not vibrations caused by a helicopter induce the degradation of 5 drugs used in this setting. Methods A longitudinal study in an operating medical helicopter along with a worst case was conducted. The studied drugs were 3 drugs labeled for refrigeration (cisatracurium, lorazepam, and succinylcholine) and 2 albumin solutions (human albumin 4% and 20%). These drugs were stored for 4 months according to the following conditions: inside a helicopter, worst case with exposure to extreme vibrations, at room temperature, and according to manufacturers’ recommendations. Samples were analyzed with validated high-performance liquid chromatography assay methods. A drug was considered stable if the remaining drug content was above 90% of the label claim. Except for the albumin solutions, visual inspection was used to determine instability by the formation of aggregates. Results Only the samples stored at room temperature became unstable after 4 months. No difference in extreme foaming was observed in the albumin solutions. Conclusions These data suggest that the effect of degradation of drugs caused by vibrations is negligible. Temperature was observed as the main cause of drug degradation.

Study Objective Inclusion body myositis is a painless inflammatory myopathy affecting older adults. It manifests as progressive muscle atrophy and weakness, typically affecting proximal lower extremity muscles initially but insidiously progressing to affect other muscles, including bulbar (oropharyngeal) muscles and the diaphragm, and leading to dysphagia and respiratory insufficiency. This study reviews the perioperative outcomes of patients with inclusion body myositis who received general anesthesia. Design Observational retrospective study. Setting Academic tertiary referral center. Patients Patients with inclusion body myositis from October 1, 2009, to September 30, 2015, undergoing procedures requiring general anesthesia. Interventions Perioperative health records were reviewed. Measurements Perioperative outcomes and complications were assessed, with emphasis on respiratory complications and unexpected reactions to succinylcholine and nondepolarizing neuromuscular blocking drugs. Main Results Sixteen patients with inclusion body myositis underwent 18 procedures requiring general anesthesia. Succinylcholine was used during induction in 6 cases (33.3%) and nondepolarizing neuromuscular blocking drugs in 11 cases (61.1%). For 13 patients (72.2%), the trachea was extubated at the end of surgery, and none had postoperative respiratory complications. The 5 patients who continued to have tracheal intubation were expected to require continuous mechanical ventilation postoperatively. Three patients died within 30 days of surgery. One patient underwent a tracheostomy for planned long-term mechanical ventilation but life support was withdrawn after 22 days, and 2 severely deconditioned patients died at 11 and 15 days following general anesthesia for endoscopic procedures. Conclusions Our patients with inclusion body myositis had uneventful perioperative outcomes following general anesthesia with depolarizing and nondepolarizing muscle relaxants. The small patient cohort in our series precludes a definitive conclusion regarding the safety of anesthetic agents in this patient population.

Rapid sequence intubation (RSI) involves a rapidly acting sedative plus a neuromuscular blocking agent (NMBA) to facilitate endotracheal intubation. Rocuronium and succinylcholine are NMBAs commonly used in RSI with drastically different durations of action.Evaluate whether patients receiving RSI with a longer-acting NMBA had a greater delay in sedation or analgesia than patients that received a short-acting NMBA.This was a retrospective review of patients presenting to the emergency department requiring endotracheal intubation. Exclusions included age18 years, pregnancy, prior intubation, and contraindication to sedation and analgesia. Primary endpoint was time to continuous sedation or analgesia after RSI in patients receiving rocuronium or succinylcholine. Secondary endpoints included hospital length of stay (HLOS), intensive care unit length of stay (ICU LOS), and impact of an emergency medicine pharmacist (EPh).A total 106 patients met inclusion criteria, 76 patients receiving rocuronium and 30 receiving succinylcholine. Mean time to sedation or analgesia was longer in the rocuronium group when compared to the succinylcholine group at 34 ± 36 min vs. 16 ± 21 min (p = 0.002). In the presence of an EPh, the mean time to sedation or analgesia was 20 ± 21 min, vs. 49 ± 45 min (p0.001). Time spent on ventilator, HLOS, and ICU LOS were not significantly different between groups.Patients receiving rocuronium in RSI had a significantly longer time to sedation or analgesia when compared to patients receiving succinylcholine. The presence of an EPh significantly decreased the time to administration of sedation or analgesia after RSI.

The bispectral index (BIS) monitor is a quantitative electroencephalographic (EEG) device that is widely used to assess the hypnotic component of anaesthesia, especially when neuromuscular blocking drugs are used. It has been shown that the BIS is sensitive to changes in electromyogram (EMG) activity in anaesthetized patients. A single study using an earlier version of the BIS showed that decreased EMG activity caused the BIS to decrease even in awake subjects, to levels that suggested deep sedation and anaesthesia.We administered suxamethonium and rocuronium to 10 volunteers who were fully awake, to determine whether the BIS decreased in response to neuromuscular block alone. An isolated forearm technique was used for communication during the experiment. Two versions of the BIS monitor were used, both of which are in current use. Sugammadex was used to antagonise the neuromuscular block attributable to rocuronium.The BIS decreased after the onset of neuromuscular block in both monitors, to values as low as 44 and 47, and did not return to pre-test levels until after the return of movement. The BIS showed a two-stage decrease, with an immediate reduction to values around 80, and then several minutes later, a sharp decrease to lower values. In some subjects, there were periods where the BIS was60 for several minutes. The response was similar for both suxamethonium and rocuronium. Neither monitor was consistently superior in reporting the true state of awareness.These results suggest that the BIS monitor requires muscle activity, in addition to an awake EEG, in order to generate values indicating that the subject is awake. Consequently, BIS may be an unreliable indicator of awareness in patients who have received neuromuscular blocking drugs.ACTRN12613000587707.

The compound crossbow can be used to eject syringe-like dart loaded with poisonous solution. Succinylcholine (Sch) is a short-acting neuromuscular blocker medically used to achieve complete relaxation of muscle for a good intubation condition. Without the help of an artificial respirator, intramuscular injection of a large dose of Sch can paralyze the respiratory muscle and result in the receiver's death. In this paper, we present the homicide case of a young male killed by Sch from a syringe-like dart ejected by a compound crossbow. The subcutaneous and muscular hemorrhages observed around the entry were more severe than that caused by a medical injection. Additionally, other autopsy results showed the external appearance of a pinhole, general asphyxia signs and pathological findings which were not characteristic. The discovery of a syringe-like dart at the scene is the critical clue and reason for analyzing for Sch, which is commonly used to load syringe-like dart to paralyze and steal dog in the countryside of China.

Objective There are limited data regarding appropriateness of sedative and paralytic dosing of obese patients undergoing rapid sequence intubation (RSI) in the emergency department. The goal of this study was to compare rates of appropriate succinylcholine and etomidate doses in obese and nonobese patients. Methods Retrospective review using a database of endotracheally intubated patients using RSI in an urban, tertiary care academic emergency department, from November 2009 to June 2011. Dosing for succinylcholine and etomidate was calculated as milligrams per kilogram of total body weight (TBW) for each patient, defining appropriate dosing as succinylcholine 1-1.5 mg/kg TBW and etomidate 0.2-0.4 mg/kg TBW. Logistic regression analysis was used to estimate the association between appropriate dosing and World Health Organization body mass index classification. Results A total of 440 patients were included in the study, 311 (70.7%) classified as nonobese and 129 (29.3%) as obese. two hundred thirty-three (56%) received an inappropriate succinylcholine dose and 107 (24%) received an inappropriate etomidate dose. Obese patients were more likely to be underdosed with succinylcholine (odds ratio [OR], 63.7; 95% confidence interval [CI], 17.8-228.1) and etomidate (OR, 178.3; 95% CI, 37.6-844.7). Nonobese patients were more likely to be overdosed with succinylcholine (OR, 62.5; 95% CI, 17.9-250) and etomidate (OR, 166.7; 95% CI, 37.0-1000). Conclusion Obese patients were more likely to be underdosed during RSI compared with nonobese patients, whereas nonobese patients were more likely to be overdosed with RSI medications. Most obese and nonobese patients were inappropriately dosed with RSI medications, suggesting that physicians are not dosing these medications based on weight.

Butyrylcholinesterase deficiency is characterized by prolonged apnea after the use of muscle relaxants (suxamethonium or mivarcurium) in patients who have mutations in the BCHE gene. Here, we report a case of prolonged neuromuscular block after administration of mivacurium leading to the discovery of a novel BCHE variant (c.185C>T, p.Ala34Val). Inhibition studies, kinetic analysis and molecular dynamics were undertaken to understand how this mutation remote from the active center determines the “silent” phenotype. Low activity of patient plasma butyrylcholinesterase with butyrylthiocholine (BTC) and benzoylcholine, and values of dibucaine and fluoride numbers fit with a heterozygous enzyme of type atypical/silent. Kinetic analysis with succinyldithiocholine (SCdTC) as the substrate showed that Ala34Val BChE was inactive against this substrate. However, with BTC, the mutant enzyme was active, displaying an unexpected activation by excess substrate. Competitive inhibition of BTC by mivacurium gave a K i = 1.35 mM consistent with the lack of activity with the related substrate SCdTC, and with the clinical data. Molecular dynamic simulations revealed the mechanism by which mutation Ala34Val determines the silent phenotype: a chain of intramolecular events leads to disruption of the catalytic triad, so that His438 no longer interacts with Ser198, but instead forms hydrogen bonds either with residues Glu197 and Trp82, or peripheral site residue Tyr332. However, at high BTC concentration, initial binding of substrate to the peripheral site triggers restoration of a functional catalytic triad, and activity with BTC.

The use of succinylcholine and rocuronium are reportedly feasible during intraoperative neuromonitoring (IONM) of the recurrent laryngeal nerve (RLN) in thyroid surgery. This study aimed to investigate and compare the recovery profiles of succinylcholine and rocuronium on the laryngeal muscle during IONM of the RLN in a porcine model. Nine male Duroc-Landrace piglets were anesthetized with thiamylal and underwent tracheal intubation without neuromuscular blocking agents (NMBAs). Needle electrodes were inserted into the vocalis muscles through the cricothyroid ligament. The RLN was exposed and stimulated. Electromyographic (EMG) signals were obtained before and after the intravenous administration of a NMBA. The EMG amplitudes were measured before and after (at 1-minute intervals) the administration of the study drug until complete recovery. The study NMBA regimen included succinylcholine (1 mg/kg), low-dose rocuronium (0.3 mg/kg), and standard dose rocuronium (0.6 mg/kg). The maximal neuromuscular blockade and 80% recovery (i.e., duration) of the control responses were recorded and analyzed. The 80% recovery of the control response for succinylcholine (1 mg/kg) was 19.7 ± 1.5 minutes; low-dose rocuronium (0.3 mg/kg), 16.3 ± 2.5 minutes; and standard dose rocuronium (0.6 mg/kg), 29.3 ± 5.7 minutes. Succinylcholine (1 mg/kg) and low-dose rocuronium (0.3 mg/kg) had significantly shorter durations than standard dose rocuronium (0.6 mg/kg). The EMG signal recovery returned to baseline within 30 minutes in the succinylcholine and low-dose rocuronium groups, but it did not return to baseline until 1 hour after surgery in the rocuronium (0.6 mg/kg) group. In this study, succinylcholine (1 mg/kg) and low-dose rocuronium (0.3 mg/kg) had favorable recovery profiles on the laryngeal muscle. It is recommended that low-dose rocuronium may replace succinylcholine for the induction of general anesthesia during IONM of the RLN in thyroid surgery.

In the present study, we characterized the neural regulation of esophageal striated muscle in Suncus murinus (a house musk shrew; “suncus” used as a laboratory name), which was compared with that in the rat. The tunica muscularis consists of striated muscle in the suncus esophagus. An isolated segment of the suncus esophagus was placed in an organ bath and the contractile responses were recorded using a force transducer. Electrical stimulations to vagus nerves induced contractile responses in the esophageal segment. Treatment with α-bungarotoxin, a blocker of nicotinic acetylcholine receptors, blocked the vagally mediated contractions of the suncus esophagus. d -tubocurarine and succinylcholine, typical antagonists of nicotinic acetylcholine receptors, also inhibited the suncus esophageal contractions, while higher concentrations of the agents were required rather than concentrations for producing an equivalent block in the rat. We used capsaicin, a stimulator of small-caliber afferent neurons, for activating the peripheral neural network. The reagent inhibited the vagally mediated twitch contractions of striated muscle in the suncus esophagus, which was reversed by pretreatment with a nitric oxide synthase inhibitor, N G -nitro- l -arginine methyl ester. Application of a nitric oxide donor, diethylamine NONOate diethylammonium salt, mimicked capsaicin-induced inhibition. The results suggest that motility of the suncus esophagus, which consists of striated muscles, is regulated by vagal cholinergic neurons. The local neural network including capsaicin-sensitive neurons and intrinsic nitrergic neurons can modify the vagally mediated motility in the suncus esophagus. In addition, nicotinic acetylcholine receptors of the suncus esophagus might be pharmacologically distinct from those of rodent esophagi.

An unanticipated difficult airway may arise during rapid sequence induction and intubation (RSII). The aim of the trial was to assess how rapidly spontaneous ventilation could be re-established after RSII. We hypothesized that the time period from tracheal intubation to spontaneous ventilation would be shorter with rocuronium-sugammadex than with succinylcholine.This randomized and patient- and observer-blinded trial was approved by the regional Ethics Committee and the Danish Medicines Agency. We included elective surgical patients undergoing general anaesthesia for RSII using alfentanil (10 µg kg(-1)), propofol (2 mg kg(-1)), and either succinylcholine (1 mg kg(-1)) or rocuronium (1 mg kg(-1)). Sugammadex (16 mg kg(-1)) was given in the rocuronium group after tracheal intubation. The primary endpoint was the time from correct placement of the tracheal tube to spontaneous ventilation, defined as a respiratory rate of more than 8 bpm and a tidal volume of at least 3 ml kg(-1) for 30 s.We included 61 patients; of whom, 55 were evaluated for the primary endpoint. The median time from tracheal intubation to spontaneous ventilation was 406 s with succinylcholine and 216 s with rocuronium-sugammadex (P = 0.002). The median time from tracheal intubation to 90% recovery of the first twitch in train-of-four (T(1) 90%) was 518 s with succinylcholine and 168 s with rocuronium-sugammadex (P0.0001). Intubation conditions and time to tracheal intubation were not significantly different.RSII with rocuronium followed by reversal with sugammadex allowed earlier re-establishment of spontaneous ventilation than with succinylcholine.

A 14 month old, 19 kg female infant with aminotic band syndrome and severe craniofacial malformations presented for placement of an open gastrostomy tube. Spontaneous ventilation was maintained while an "awake look" was performed with the video laryngoscope using intravenous propofol (30 mg total) for sedation. A Grade I Cormack-Lehane score was obtained on the monitor. Succinylcholine was then administered intravenously and orotracheal intubation was performed on the first attempt with a size 4.5 endotracheal tube.

Victims of nerve agents basically require antidotal treatment. There is need for novel antidotes and for therapeutic procedures that are specifically adapted to these patients. To cope with this challenge, in vitro test systems which are easy to handle and allow for conducting long-term studies would be of great benefit. The present work introduces co-cultures of spinal cord and muscle tissue as ex vivo testing systems meeting these criteria. Cell cultures in which functional neuromuscular synapses formed ex vivo were prepared from embryonic mice. Spontaneous muscle activity was recorded by video microscopy. Muscle contractions involved intact neuromuscular transmission as indicated by the effect of succinylcholine, a muscle relaxant that completely abolished muscle activity. At a concentration of 0.75 μM the nerve agent VX reduced the frequency of spontaneous muscle contractions by about 75%. Subsequent application of obidoxime re-established muscle movements. After 24 h of antidotal treatment, muscle activity approached the level of sham-treated cultures and remained stable over the following week. In summary, co-cultures of spinal cord and muscle tissue are promising tools for evaluating the success of antidotal treatment following organophosphate intoxication over a period of at least seven days.

Over the past 50 yr, many drugs have been implicated as triggers of malignant hyperthermia (MH), a potentially fatal pharmacogenetic disorder of skeletal muscle calcium regulation. This review discusses the potent inhalation agents as the principal triggers and evidence that the modern agents, desflurane, sevoflurane, and isoflurane, can cause florid MH reactions in the same way as halothane but also are associated with reactions whose onset is delayed for several hours into anaesthesia. There is evidence that the triggering of MH by drugs is dose-dependent but the minimum dose that will trigger the condition is unknown. This has implications for the preparation of anaesthetic machines when used for known or suspected MH patients. While succinylcholine enhances the response of potent inhalation anaesthetics, its role as an inherent trigger of the condition is controversial. Non-depolarizing neuromuscular blocking drugs appear to protect against the development of MH and this may be by blocking excitation-coupled calcium entry-a recently described route of skeletal muscle calcium entry that may also explain the mechanism of the effect of succinylcholine in MH. Another mechanism for extracellular calcium influx, store-operated calcium entry, is activated in MH muscle and may explain how a triggered reaction is sustained. Finally, reports of drugs that have been implicated as additional triggers of MH over the past 10 yr are discussed.

Doubts concerning the applicability of succinylmonocholine (SMC) as a succinylcholine (SUX) marker have been issued. A comparative analysis of previously discussed tissues, i.e. brain, liver and kidney, was conducted to further elucidate this question by searching for diagnostically useful differences in analyte content in samples of SUX- versus non-SUX-associated fatalities. Furthermore, possible advantages of vitreous humor as a novel and promising target matrix for SUX analytics were assessed. Sample material of SUX-negative controls as well as the fatal SUX-intoxication was derived from frozen archive material and current autopsies. Samples were analyzed according to a modified protocol of a previously published and validated method employing ion-pairing solid-phase extraction and subsequent HPLC-MS/MS analysis. Standard addition was employed for quantification as well as an estimation of the analytical limits of the method. In all tested matrices, the method was proven to be sufficiently sensitive for the intended application. No indication of native SMC was found in controls of fresh tissues, nor in fresh or frozen vitreous humor. However, most of the samples were found to be positive for a previously reported interference with SMC's main ion transition, thereby falsely suggesting an SMC content of up to 139 ng/g, 126 ng/g, 165 ng/g and 93 ng/ml in brain, liver, kidney and vitreous humor, respectively. Contrasting the results for fresh sample material, SMC was detectable in some of the initially non-putrefied liver samples after long-term storage, as well as in massively decomposed SUX-negative control bodies. In this context, a microbial origin of the analyte may be assumed. All tissues as well as the vitreous humor of the fatal SUX-intoxication were negative for SUX and SMC. Just like serum, tissue and vitreous humor samples therefore do not allow a reliable diagnosis of a SUX-intoxication: in tissues this is due to the pronounced instability of both target analytes in these esterase-containing matrices, for vitreous humor an additional reason could be their insufficient incorporation into this medium.

To evaluate the efficacy of a manual jet ventilation device for bronchoscopic removal of foreign bodies in children.360 children aged from 10 months to 12 years old undergoing rigid bronchoscopy for airway foreign body (FB) removal from February 2005 to June 2009 were included in the study. Patients were randomly divided into three groups of 120 patients per group (S, P and J). In group S, anesthesia was induced with propofol and γ-hydroxybutyrate sodium and maintained by intermittent bolus administration of propofol; the patients were breathing spontaneously throughout the procedure. In group P, anesthesia was induced with propofol (4-5 mg/kg), fentanyl (1-2 μg/kg) and succinylcholine (2 mg/kg). Mechanical ventilation was performed through the side arm of the rigid bronchoscope. In group J, the patient received propofol, fentanyl and succinylcholine as the same doses administered in group P, and manual jet ventilation was performed by using the Manujet III device. Condition for insertion of bronchoscope, occurrence of hypoxemia, successful rate of FB removal, the duration of the operation, the time of emergence and recovery from anesthesia, and perioperative complications (adverse events) were recorded.Groups P and J had significantly higher rates of successful bronchoscope insertion (P0.05), significantly higher success rates for FB removal (P0.05), and lower incidences of hypoxemia during intra- and post-operative periods when compared with group S. Perioperative complications were lower (P0.05), duration of operation was shorter, and emergence from anesthesia was faster (P0.05) in groups P and J when compared with group S. Incidences of hypoxemia were lower in Group J when compared with Group P (P0.05).This study confirmed the safety and efficacy of performing manual jet ventilation with Manujet III in foreign body removal by rigid bronchoscopy in children.

Objective: Several drugs have been used to prevent or attenuate succinylcholineinduced muscle fasciculations. There are possible advantages to succinylcholine pretreatment. We designed the present study to compare the effectiveness of atracurium versus ”mini-dose” (5 mg) succinylcholine pretreatment for the prevention of muscle fasciculations. Methods: Under standard monitoring, 79 patients were randomly assigned to three groups after premedication: Group 1 (n=26) received normal saline as a placebo, Group 2 (n=27) received 0.03mg/kg atracurium, and Group 3 (n=26) received 5 mg succinylcholine. Thiopental (4 mg/kg) was administered intravenously 90 seconds after pretreatment, followed by intravenous administration of 1.5 mg/kg succinylcholine. An anesthesiologist graded fasciculations based on a four-point scale, from 0 (none) to 3 (severe). All patients were evaluated on the first postoperative day for the presence of postoperative myalgia (POM), the severity of which was graded on a four-point scale, from 0=no myalgia to 3=generalized, severe discomfort. Results: There were no statistical differences among the three groups with respect to sex, weight or age. In Group 1, 3.8% of the patients showed no fasciculations, while 30.8% had mild, 53.8% had moderate and 11.5% had vigorous fasciculations. In Group 2, fasciculations were absent in 74.1% of the patients, while 25.9% of the patients had mild fasciculations. In Group 3, 23.1% patients had no fasciculations, while 42.3%, 30.8% and 3.8% of the patients showed mild, moderate and vigorous fasciculations, respectively, with succinylcholine pretreatment. There was no difference in the presence or severity of myalgia between Groups 1 and 3. Furthermore, the presence of fasciculations was not correlated with POM in Groups 1 and 3, but a significant correlation was found in Group 2. Conclusion: Our results showed that the incidence and severity of fasciculations were significantly decreased by atracurium pretreatment but not by pretreatment with succinylcholine or placebo (p＜0.0001 and p=0.0003 respectively). However, atracurium did not exert significant effects on POM.

Idiopathic acute transverse myelitis is a rare focal inflammatory disorder of the spinal cord causing motor, sensory and autonomic dysfunction. We report the successful use of general anaesthesia for caesarean section in a patient with this disease. Potential anaesthetic concerns include autonomic dysreflexia and hyperkalaemia following the use of suxamethonium. Further complicating issues with this patient included psychotic depression and new-onset neuropathic pain on a background of chronic pain symptoms.

Background: Two methods of paralysis are available for rapid sequence intubation (RSI) in the emergency department (ED): depolarizing agents such as succinylcholine, and non-depolarizing drugs such as rocuronium. Rocuronium is a useful alternative when succinylcholine is contraindicated. Contraindications to succinylcholine include allergy, history of malignant hyperthermia, denervation syndromes, and patients who are 24–48 h post burn or crush injury. Non-depolarizing drugs have the advantage of causing less pain due to post-paralysis myalgias. Clinical Question: Can rocuronium replace succinylcholine as the paralytic of choice for RSI in the ED? Evidence Review: Four relevant studies were selected from an evidence search and a structured review performed. Results: For the outcomes of clinically acceptable intubation conditions and time to onset, the two agents were not statistically significantly different. Succinylcholine seems to produce conditions that have higher satisfaction scores. Conclusion: Succinylcholine remains the drug of choice for ED RSI unless there is a contraindication to its usage.

Traditionally anaesthetic drugs for obstetrics are prepared as a contingency and stored until they are required for emergency use or have expired. Expiry is based on presumed reduction in sterility and efficacy although evidence for this is inconsistent. Preparation in advance introduces the risk of error and potential for tampering by a third party. Discarding and re-preparing drugs daily represents significant wastage with associated cost implications. We predicted that practice of drug preparation would differ widely across the UK, so conducted a national survey.A postal questionnaire was sent to lead consultant obstetric anaesthetists at each of the 223 consultant-led UK obstetric units enquiring about the preparation of anaesthetic drugs for obstetric emergencies.The response rate was 75%; 87% of units routinely draw up emergency drugs, most commonly thiopental and succinylcholine. Only 10% routinely use commercially-prepared succinylcholine syringes, although a further 8% would use them if available. Thiopental is prepared by anaesthetists in 78% of units, operating department practitioners in 8% and pharmacy in7% of cases. Drugs are changed every 24h in 80% of units and weekly in 6%. With one exception, all units changing drugs weekly use pharmacy-prepared thiopental.The majority of UK obstetric units routinely draw up emergency drugs every 24h. With conflicting evidence regarding sterility and efficacy this represents tremendous wastage and potential for drug error and tampering. We propose that nationwide introduction of commercially- and pharmacy-prepared drugs with long shelf lives would improve safety and cost effectiveness.

The role of prehospital endotracheal intubation (ETI) remains controversial, with significant national variability in practice. The purpose of this project was to evaluate ETI management in a system of advanced life support (ALS) providers experienced in ETI and other advanced airway techniques, and describe management and outcomes of patients with a "difficult airway." Data were collected prospectively for all ETIs performed by the fire department over a 4-year period (2001-2005), and included demographics, number of laryngoscopy attempts, airway procedures, complications, and outcomes. Of 80,501 ALS patient contacts, 4091 (5.1%) underwent attempted oral ETI, with a 96.8% success rate in four or fewer attempts. The difficult airway cohort included 130 patients (3.2%), whose airway management consisted of oral ETI after more than four attempts (46%), bag-valve-mask ventilation (33%), cricothyroidotomy (8%), retrograde ETI (5%), and digital ETI (1%). Procedural success rates ranged from 14% (digital ETI) to 91% (cricothyroidotomy). Nine patients (7%) had failed airway management, of whom 5 were found in cardiac arrest. The two most common reasons subjectively reported by ALS providers for airway difficulty were anterior trachea (39%) and small mouth (30%). Overall mortality for the difficult airway cohort was 44%. Prehospital ETI can be performed with a high success rate by experienced ALS providers, but may still require advanced airway techniques in a small subset of patients. Patient anatomy is a primary factor in failed ETI. Among the advanced procedures, cricothyroidotomy had the highest success rate and should not be delayed by other interventions.

Objectives The purpose of this study was to: (1) assess the effectiveness of galantamine in the prevention of cognitive impairments during ECT treatment and (2) to explore the safety and tolerability of galantamine during ECT treatment. Methods Nine consecutive ECT patients were given galantamine 4 mg bid throughout the course of their ECT treatments followed by a second cohort of eight consecutive ECT patients who did not receive galantamine. Objective measures of cognitive functioning and depression severity were performed pre-ECT and post-ECT. Subjective ratings of depression, confusion, and side effects were obtained weekly. Results The two groups were similar in age, gender and admission Global Assessment Functioning (GAF) scores. There were no significant between group differences found with regards to mean seizure duration, energy administered to induce seizures, blood pressure, or heart rate during and post-ECT treatment. None of the patients discontinued galantamine due to side effects and there were no severe adverse drug reactions. Patients receiving galantamine performed significantly better on delayed memory and abstract reasoning following ECT. The galantamine group showed a greater but non-significant mood improvement (repeated measure ANOVA). Conclusions Our data support the hypothesis that galantamine may reduce cognitive impairment during ECT, especially with regards to new learning. In addition, galantamine may also enhance the antidepressant action of ECT. Galantamine was both safe and well tolerated during ECT.

Succinylcholine is still recommended for some situations in open globe injuries. However, the use of succinylcholine is associated with an increase in intraocular pressure (IOP). This may be deleterious in open globe injuries. No method has previously been shown to abolish completely this rise in the IOP. We investigated whether dexmedetomidine, an alpha-2 agonist, could attenuate this increase in the IOP after succinylcholine and intubation.Forty patients with no pre-existing eye disease undergoing general anaesthesia were randomly premedicated by i.v. dexmedetomidine 0.6 microg kg(-1), or saline. Heart rate (HR), mean arterial pressure (MAP), and IOP (using Schioetz tonometer) were measured before, after the premedication, after thiopental, after succinylcholine, immediately after intubation, and then every 2 min for 6 min.Succinylcholine and intubation increased IOP in both groups. However, in the dexmedetomidine group, the IOP rise was not different from the baseline value (P=0.65) and was significantly lower than in the saline group (P=0.003). After intubation, the MAP in the control group was higher than that in the dexmedetomidine group (P=0.041) and exceeded the baseline value (P0.001). The HR also showed less fluctuation in the dexmedetomidine group than in the saline group.We conclude that dexmedetomidine could be a beneficial premedication in open globe injuries.

Malignant hyperthermia is a rare anesthetic-related disorder. We present a case with unusual presentation. A boy aged 3 years and 9 months who was scheduled for Hotz's operation presented normally before the operation. Anesthesia was induced by atropine, thiopental and sevoflurane. Trachea intubation was facilitated by succinylcholine. Jaw stiffness was first noted although trachea was intubated without difficulty. The following tachycardia, hypercapnia and hyperthermia led to the diagnosis of malignant hyperthermia. Symptoms were relieved dramatically after the discontinuation of sevoflurane. Molecular genetic testing identified a novel ryanodine receptor (RYR1) mutation in exon 39, which confirmed malignant hyperthermia susceptibility in this patient.

The best known clinical application of serum BChE assay is to predict abnormally prolonged apnea following the application of the muscle relaxant succinylcholine. The aim of the present study was to assess the frequency of BChE phenotypes and to predict the risk of apnea for those receiving succinylcholine among the residents in western Iran.We examined the frequency of nine BChE phenotypes in 1548 volunteers including 816 males and 732 females with the mean age of 35+/-15 years from an apparently healthy group living in western Iran. The frequencies of BChE phenotypes were determined using BChE activity measurements and by inhibition with dibucaine, fluoride, and the compound Ro2-0683 (Hoffman-La-Roche).The reference range for serum total BChE activity was 4600-14000 U/L (using butyrylthiocholine iodide as substrate). The mean value obtained for men (9030 U/L) was significantly (p0.05) higher than that for women (8550 U/L). The frequencies of four alleles U, A, F, S were calculated to be 0.9826, 0.0165, 0.008 and 0.001, respectively. The frequency of phenotypes of BChE was as follows: normal phenotype (UU) 95.5%, moderate sensitive to succinylcholine including UA,US,UF phenotypes was 3.9% and hypersensitive to succinylcholine (AA, AF, AS, FF, SS) was 0.58%.This study indicates that the population of western Iran has a medium frequency of succinylcholine-sensitive individuals compared to other populations. We suggest that determination of BChE activity and phenotype by the micro automated method is well suited to pre-operative screening and detection of at-risk of prolonged apnea in persons receiving succinylcholine in the healthy population of western Iran.

Posterior reversible encephalopathy syndrome refers to a neuroradiologic disorder in which seizure activity (multiple seizures are more common than single events) is commonly the initial presenting symptom. We describe a case of posterior reversible encephalopathy syndrome in a previously healthy parturient who presented to the labor and delivery suite with generalized tonic-clonic seizures. Prompt recognition and treatment of this potentially catastrophic disease may avert injury to the patient and neonate.

The tetrameric glycoprotein butyrylcholinesterase (BChE; EC 3.1.1.8) is one of two enzymes that hydrolyze choline esters. The controlling gene (BCHE) is comprised of four coding exons and is located on chromosome 3q26. Based on BChE activity measurements in the presence and absence of dibucaine, usual (designated U) and atypical (designated A) gene products have been distinguished. Homozygotes for the A gene product are at risk for prolonged apnea following exposure to the surgical anesthetics succinylcholine or mivacurium. In this report, we detail biochemical and molecular investigations of succinylcholine sensitivity in a prairie Hutterite kindred. Our results establish that BChE activities in the family members are impacted by two distinct BCHE mutations, namely, c.209A>G p. D70G and c.1615G>A p. A539T. However, homozygotes for the c.209A>G mutation (i.e., atypical or A) are the only individuals whose BChE activity could lead to adverse reactions to succinylcholine. Interestingly, haplotype analysis of the chromosomal region containing BCHE indicates that the c.209A>G mutation is carried on a unique haplotype, suggesting that it was likely introduced into the population only once. Conversely, the c.1615G>A mutation is carried on various haplotypes and was likely introduced into the population more than once.

Taylor et al. [Taylor, A., Durbaba, R., Rodgers, J.F., 1992a. The classification of afferents from muscle spindles of the jaw-closing muscles of the cat. J Physiol 456, 609-628] developed a method to classify muscle spindle afferents using succinylcholine (Sch) and ramp and hold stretches. They demonstrated that cat jaw muscle spindle afferents show high proportion of intermediate responses to ramp and hold jaw stretch. Together with observations on the responses to Sch their data suggests that the majority of jaw muscle spindle afferents are influenced by a combination of nuclear bag(2) and nuclear chain fibres. Relatively few are influenced solely by nuclear bag(1) fibres. The purpose of this study was to categorize jaw muscle spindle afferent in rodents in response to ramp and hold stretches. Several measures were used to classify spindle afferents including (1) conduction velocity, (2) coefficient of variation (C.V.) of the interspike interval during jaw opening, and (3) the dynamic sensitivity and the initial discharge of spindle afferents before and after succinylcholine infusion (Sch, 100mg/kg, i.v.). Consistent with observations in the cat jaw muscles, the distribution of the conduction velocity and the C.V. of Vmes masseter afferents were unimodal. Therefore, these parameters were of little value in functional classification of spindle innervation. Succinylcholine injection either markedly increased the dynamic sensitivity or produced no change in Vmes afferents. Unlike cat jaw muscle spindle afferents, the effect of Sch on the initial discharge was not clearly separable from those responding or not responding to Sch. These results suggest that rat jaw muscle spindle afferents, have physiological properties that are primarily intermediate in nature and are likely to reflect a predominance of influence from nuclear bag(2) and chain fibres. However, the distinction between bag(2) and chain fibres influences is not as clearly defined in the rat compared to the cat.

Background In a randomized, double-blind clinical trial, we studied the effect of different i.v. induction drugs on tracheal intubation conditions and apnoea time after small-dose (0.6 mg kg−1) succinylcholine used to facilitate orotracheal intubation at an urban, university-affiliated community medical centre. Methods One hundred and seventy-five ASA I and II adult patients scheduled to undergo surgical procedures requiring general anaesthesia and tracheal intubation were allocated to one of five groups according to i.v. anaesthetic induction drug used. General anaesthesia was induced by i.v. administration of lidocaine 30 mg and propofol 2.5 mg kg−1 (Group 1), thiopental 5 mg kg−1 (Group 2), lidocaine 30 mg and thiopental 5 mg kg−1 (Group 3), etomidate 0.3 mg kg−1 (Group 4), or lidocaine 30 mg and etomidate 0.3 mg kg−1 (Group 5). After loss of consciousness, succinylcholine 0.6 mg kg−1 was given i.v. followed by direct laryngoscopy and tracheal intubation after 60 s. Measurements included intubation conditions recorded during laryngoscopy 60 s after succinylcholine administration, and apnoea time. Results Overall, clinically acceptable intubation conditions were met in 168 out of the 175 patients studied (96%). They were met in 35/35 patients in Group 1, 33/35 patients in Group 2, 34/35 patients in Group 3, 33/35 patients in Group 4, and 33/35 patients in Group 5. Mean ( sd ) apnoea time was 4.0 (0.4), 4.2 (0.3), 4.2 (0.6), 4.1 (0.2) and 4.1 (0.2) min respectively in Groups 1–5. There were no differences in the intubation conditions or apnoea times between the groups. Conclusions The use of succinylcholine 0.6 mg kg−1 produced the same favourable intubation conditions and a short apnoea time regardless of the induction drug used.

Pulmonary aspiration is a cause of anesthesia-related morbidity and mortality, with little change in incidence over the past 20 years. Rapid sequence induction is a common procedure in obese patients, who appear to be more at risk for both pulmonary gastric aspiration and difficult airways, and is required in obese and sleep apnea syndrome patients with symptomatic gastroesophageal reflux or other predisposing conditions. In the elective obese or sleep apnea patient with no other risk factors for pulmonary aspiration, the risks and benefits of rapid sequence induction and cricoid pressure should be weighed. If rapid sequence induction is required, succinylcholine remains the neuromuscular blocking agent of choice, if there are no contraindications.

We report the case of a 20-year-old woman who developed masseter spasm after receiving succinylcholine for rapid sequence intubation. Sometimes referred to as "jaws of steel," masseter spasm secondary to anesthetic administration may progress to malignant hyperthermia. Although succinylcholine-induced masseter spasm is uncommon, it is important to be prepared to deal with this entity when administering succinylcholine.

A patient with unrecognized atypical pseudocholinesterase was given succinylcholine and then vecuronium before neuromuscular monitoring was instituted. Subsequently, when neostigmine and glycopyrrolate were given to reverse what was thought to be a nondepolarizing block, the patient became further relaxed, and his trachea could not be extubated for more than 10 hours. In this report, we discuss drug interactions, phase II block, and the importance of timely neuromuscular monitoring.

Within the last several years, the poultry industry has seen a dramatic increase in the occurrence of pale, soft, and exudative (PSE) meat. This problem is known to be associated with a rapid decline in postmortem (PM) muscle pH, which results in inferior protein functionality similar to that found in PSE pork. Many factors such as seasonal changes have been known to influence the occurrence of PSE meat in poultry and swine. Halothane and succinylcholine have been used within the pork industry to identify animals susceptible to stress and prone to developing PSE meat. The mechanism for the triggering of the PSE gene in poultry has not been fully understood. Therefore, a study was conducted to determine the effectiveness of screening broilers with halothane to identify those prone to developing PSE meat. Succinylcholine was used before slaughter to serve as a triggering agent for the PSE condition. At 4 wk of age, broilers from 4 commercial strains (n = 1,000) were subjected to 3% halothane gas and classified as either halothane positive (HAL+) or negative (HAL-) based on muscle rigidity within the legs. Although halothane sensitivity varied slightly among the strains, approximately 14% of the birds overall were classified as HAL+. All HAL- birds (n = 163) and an equal number of HAL-birds (n = 163) in each strain were grown to market age (7 wk) and were commercially processed. At the time of processing, half of the HAL+ and HAL- birds were injected intravenously with succinylcholine and were slaughtered at 0.25 h postinjection. Pectoralis muscle samples were collected at 0.25, 2, 5, and 24 h PM for the evaluation of rigor development (muscle pH) and meat quality (L* value, moisture, drip loss, and cook loss). Halothane sensitivity had no effect on rigor development, muscle color, or water-holding capacity in the 4 broiler strains. Although birds exhibited reactions to the halothane gas, the halothane sensitivity, along with the use of succinylcholine, was not able to identify birds prone to developing PSE meat.