Extreme variability in succinylcholine dose for muscle relaxation in electroconvulsive therapy.

OBJECTIVES: To determine what dose of succinylcholine falls outside the range of 2 SD above or below the mean optimal dose of 0.9 mg/kg used for electroconvulsive therapy (ECT). METHODS: In this retrospective chart review, for all patients who received ECT at our institution within the 5-year study period, the initial dose of succinylcholine in milligrams per kilogram was compared with subsequent doses after adjustments were made for individual patient responses. Mean and SD were calculated using the dose of succinylcholine, once the optimal dose for each patient had been determined, based on clinical response. RESULTS: Five hundred patients treated during the 5-year period met inclusion criteria, 180 (36%) of whom required an adjustment of the succinylcholine dosing either above (119 patients) or below (61 patients) the 0.9 mg/kg standard after their first treatment. CONCLUSIONS: In those patients who required an adjustment of 2 SD either above or below the mean dose of succinylcholine (29 patients, 5.8%), adequate neuromuscular blockade was only achieved with either an increased dose of up to 2.10 mg/kg or a decreased dose as low as 0.29 mg/kg.

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.

[Anterior dislocation of a Incarcerated Retroverted Uterus at 21 weeks of amenorrhea : Case Report. ]. / Luxation antérieure d'un utérus rétroversé incarcéré à 21 semaines d'aménorrhée : à propos d'un cas.

BACKGROUND: An incarcerated uterus refers to the retroversion of a pregnant uterus within the pelvis due to the absence of a forward tilt at the end of the first trimester. An incarcerated uterus that is overlooked or only discovered perpartum can cause severe obstetrical complications. Several authors have shared their experience with uterine incarceration management at 12, 14, and 16 weeks of amenorrhea. CASE: Our report concerns a case of uterine incarceration management at 21 weeks of amenorrhea, achieved by way of a specific anesthesia protocol and the positioning of the patient, which allowed the disimpaction of the uterus with the help of external maneuvers. No recurrence was observed. CONCLUSION: Uterine incarceration management is possible beyond 16 weeks of amenorrhea.

Background: An incarcerated uterus refers to the retroversion of a pregnant uterus within the pelvis due to the absence of a forward tilt at the end of the first trimester. An incarcerated uterus that is overlooked or only discovered perpartum can cause severe obstetrical complications. Several authors have shared their experience with uterine incarceration management at 12, 14, and 16 weeks of amenorrhea. Case: Our report concerns a case of uterine incarceration management at 21 weeks of amenorrhea, achieved by way of a specific anesthesia protocol and the positioning of the patient, which allowed the disimpaction of the uterus with the help of external maneuvers. No recurrence was observed. Conclusion: Uterine incarceration management is possible beyond 16 weeks of amenorrhea.

Leech on the eye in a child.

PURPOSE: to present the case of a 4-year-old girl with leech infestation of the ocular surface. DESIGN: observational case report. RESULTS: a 4-year-old girl presented with a two-day history of bleeding from the left eye. Examination under anesthesia revealed a leech adhering to the cornea and bulbar conjunctiva. Irrigation with normal saline released the leech from the conjunctiva. Detaching from the cornea was successful after injection of suxamethonium 50 mg/ml into the worm. CONCLUSIONS: The possibility of leech infestation need to be considered in the differential diagnosis of open-globe injury with prolapse of uveal tissue. The use of a muscle relaxant for leech removal was not previously documented.

Airway management in trauma.

Maintenance of a patent and prevention of aspiration are essential for the management of the trauma patient, that requires experienced physicians in airway control techniques. Difficulties of the airway control in the trauma setting are increased by the vital failures, the risk of aspiration, the potential cervical spine injury, the combative patient, and the obvious risk of difficult tracheal intubation related to specific injury related to the trauma. Endotracheal intubation remains the gold standard in trauma patient airway management and should be performed via the oral route with a rapid sequence induction and a manual in-line stabilization maneuver, to decrease the risks previously mentioned. Different techniques to control the airway in trauma patients are presented: improvement of the laryngoscopic vision, lighted stylet tracheal intubation, retrograde technique for orotracheal intubation, the laryngeal mask and the intubating laryngeal mask airways, the combitube and cricothyroidotomy. Management of the airway in trauma patients requires regular training in these techniques and the knowledge of complementary techniques allowing tracheal intubation or oxygenation to overcome difficult intubation and to prevent major complications as hypoxemia and aspiration.

A case of catatonia resembling frontotemporal dementia and resolved with electroconvulsive therapy.

We describe a case of catatonia in a 51-year-old man in whom the catatonic symptoms could not be distinguished from symptoms of frontotemporal dementia (FTD) until they were resolved with electroconvulsive therapy (ECT). When it is difficult to distinguish between catatonia and FTD in patients with frontal dysfunction associated with frontal lobe atrophy, we believe that sequential administration of benzodiazepines and ECT is important for therapeutic diagnosis because the risk of missing a diagnosis of catatonia outweighs the risks associated with administration of benzodiazepines and/or ECT.

[Neuromuscular monitoring: methods and machines]. / Uberwachung der neuromuskulären Blockade - Methoden und Geräte.

Muscle relaxing agents are clinically in use for general anaesthesia to optimize the conditions to the endotracheal intubation as well as the surgical conditions. Therefore different musclerelaxants with specific pharmacological characteristics are available. Many factors that depend on the condition of the patient and the used musclerelaxant agent influence the duration of the neuromuscular blockade. Rapid reversal of their effects, particularly in cases of profound blockades, proved to be difficult. In cases of postoperative residual paralysis hypoxic complications because of failure of the ventilation increase the morbidity and mortality of the perioperative period. To avoid these complications in cause of postoperative residual neuromuscular blockade it seems to be necessary to evaluate the status of the muscle function. For the tactile or visual assessment or the objective measurement of stimulation the train-of-four (TOF), double-burst (DBS) or tetanus-stimulation of peripheral nerves like the ulnar nerve may be used. Established methods for the objective monitoring of neuromuscular function is the mechanomyography (MMG), the acceleromyography (AMG), the electromyography (EMG), the kinemyography (KMG) and the phonomyography (PMG). A sufficient recovery of the neuromuscular transmission is reached to a TOF-ratio of 0,9 and should be aimed before the extubation at the end of surgery. No subjective evaluation of the neuromuscular recovery is able to identify residual paralysis above a TOF-ratio of 0,5. Recent studies suggest that objective methods should be used to monitor neuromuscular function to avoid postoperative residual blockades.

Skin reactions to intradermal neuromuscular blocking agent injections: a randomized multicenter trial in healthy volunteers.

BACKGROUND: Numerous reports confirm the performance of intradermal tests for the diagnosis of anaphylaxis during anesthesia; however, there is controversy over their diagnostic value regarding the newer neuromuscular blocking agents (NMBAs). METHODS: One hundred eleven healthy volunteers were randomly assigned to receive intradermal injections of two NMBAs, at five increasing concentrations. A concentration was considered as a reactive concentration when it led to a positive reaction in more than 5% of the subjects. These concentrations were compared with the maximal concentration recommended for the diagnosis of sensitization to NMBAs. RESULTS: The maximal nonreactive concentrations were 10 m for suxamethonium; 10 m for pancuronium, vecuronium, rocuronium, and cisatracurium; and 10 m for atracurium and mivacurium. Except for mivacurium, these nonreactive concentrations were close to the maximal concentrations used for the diagnosis of sensitization against NMBAs. For mivacurium, the nonreactive concentrations were higher than the maximal concentration currently recommended in clinical practice. CONCLUSION: The aminosteroidal NMBAs pancuronium, vecuronium, and rocuronium and the benzylisoquinoline cisatracurium have a similar potency to induce a nonspecific skin reactivity. If the criteria for positivity and the maximal concentrations of the commercially available compounds recommended by French practice guidelines are used, the risk of false-positive results is limited, and only minor modifications of these recommendations could be suggested. A slight reduction in the maximal concentration used for rocuronium from 1:100 to 1:200 and an increase from 1:1,000 to 1:200 for mivacurium can be proposed.

Effects of remifentanil and alfentanil on seizure duration, stimulus amplitudes and recovery parameters during ECT.

BACKGROUND AND OBJECTIVE: Propofol may decrease seizure duration in electroconvulsive therapy. Although not proven, prolonged seizures may be more efficacious. The goal of this study was to evaluate and compare effects of alfentanil and remifentanil on seizure duration, recovery parameters and degree of stimulus amplitude in patients undergoing electroconvulsive therapy. METHODS: Twenty-four ASA I-II patients enrolled in this prospective, randomized trial, each receiving a total of seven electroconvulsive therapies. Patients were randomized to receive only Propofol, group P (0.75 mg kg-1, n=8), Propofol with alfentanil, group A (10 microg kg-1 alfentanil+0.5 mg kg-1 Propofol, n=8) and Propofol with remifentanil, group R (1 microg kg-1 remifentanil +0.5 mg kg-1 propofol, n=8) via an iv route. Supplemental doses of propofol were given as required to achieve loss of consciousness. Succinylcholine 0.5 mg kg-1 iv was given to all groups for muscular paralysis. We recorded hemodynamic parameters, cortical and motor seizure durations, and recovery parameters. RESULTS: Mean motor seizure duration was found to be significantly longer in patients receiving propofol-remifentanil anesthesia (53.3+/-13.6 s) and propofol-alfentanil anesthesia (52.2+/-0.4 s) compared with propofol anesthesia (37.6+/-9.2 s) (P=0.001). Recovery parameters and stimulus amplitudes were similar in groups A and R; significantly different from group P (P=0.001). CONCLUSIONS: Adding 10 microg kg-1 alfentanil or 1 microg kg-1 remifentanil to reduced doses of propofol provided unconsciousness and increased seizure durations. For patients who need higher stimulus amplitudes for longer seizure durations, combining low-dose propofol with alfentanil or remifentanil may be good alternative regimens for ECT.

Tracheal intubation without muscle relaxant--a technique using sevoflurane vital capacity induction and alfentanil.

This randomized controlled study examined intubating conditions and haemodynamic changes following sevoflurane nitrous oxide induction in four groups: three different doses of alfentanil compared with low-dose alfentanil and suxamethonium. All patients received atropine 0.3 mg i.v. before induction of anaesthesia with vital capacity breaths of sevoflurane 8% (more than 7% in the inspiratory gas) in 60% nitrous oxide and oxygen. Patients were allocated randomly to four groups of intravenous supplements: group SA20, alfentanil 20 microg x kg(-1); group SA25, alfentanil 25 microg x kg(-1); group SA30, alfentanil 30 microg x kg(-1); group SSA, alfentanil 10 microg x kg(-1) and suxamethonium 1 mg x kg(-1). Orotracheal intubation and assessment of intubating conditions was performed by one of the investigators who was blinded to the subject's group. Intubating conditions were satisfactory or excellent in 83%, 80%, 92% and 96% of patients in groups SA20, SA25, SA30 and SSA respectively. These differences were not statistically significant. The increase in heart rate associated with laryngoscopy and tracheal intubation was effectively attenuated in all groups. Mean arterial pressure decreased significantly and similarly after induction in all groups. Two minutes after intubation the mean arterial pressure was increased significantly (P<0.05) compared to the post-induction value in group SSA. The intubating conditions obtained with sevoflurane plus alfentanil 30 microg x kg(-1) were comparable to those provided by the sevoflurane, suxamethonium and alfentanil 10 microg x kg(-1) combination.

Choice of the muscle relaxant for rapid-sequence induction.

Muscle relaxants are given as part of a rapid-sequence induction to facilitate tracheal intubation. Among all the muscle relaxants available, succinylcholine is the only one with a fast (approximately equal to 1 min) onset and a fast recovery. Therefore it is still the most frequently used muscle relaxant for rapid-sequence induction despite its well-known side-effects. The short duration of action of succinylcholine is, however, no substitute for aggressive airway management in the case of an unexpectedly difficult intubation in order to prevent life-threatening hypoxia. A preoperative assessment of the airway is mandatory in any patient and may indicate the need for using intubation techniques without a muscle relaxant. Rocuronium in large doses (i.e. > or = 1 mg kg-1) is an alternative to succinylcholine in a classical rapid-sequence setting under relatively light anaesthesia. With respect to rapid tracheal intubation, the timing and priming principles offer little advantage over the use of rocuronium in doses of 0.6 mg kg-1 in combination with an appropriate induction technique (i.e. including an opioid) or over the use of larger doses of rocuronium (> or = 1.0 mg kg-1) under relatively light anaesthesia, and may even be potentially harmful. In contrast to rocuronium, the use of rapacuronium in a rapid-sequence setting has been associated with dose-dependent respiratory side-effects that limit its usefulness in doses higher than 1.5 mg kg-1 for this indication.

Decreased mivacurium constant infusion requirements with defasciculating doses of pancuronium.

This study was designed to verify a technique in which the pharmacologic profile of mivacurium infusions could be altered by small doses of pancuronium to reduce the infusion requirement without altering the subsequent recovery kinetics. Thirty ASA physical status I or II patients were randomized into two groups in a blinded fashion. One group was administered pancuronium 10 micrograms/kg followed by pancuronium 2.5 micrograms.kg-1.h-1 thereafter. The control group was given identical volumes of saline. Subsequently, all patients were given an initial bolus of mivacurium, and anesthesia was maintained using a nitrous oxide/ alfentanil technique. When the thenar electromyogram response to supramaximal train-of-four stimulation returned to 5% of baseline, a mivacurium infusion was begun in both groups, and the infusion rate required to maintain the electromyographic response at 1%-10% of baseline was determined. At the conclusion of the procedure, the infusion was terminated and the recovery profile ascertained. The mivacurium infusion requirement for the group receiving the pancuronium supplementation was 2.77 +/- 1.38 micrograms.kg-1.min-1 (mean +/- SD), which represented a 49% decrease compared with the group that used mivacurium alone which required an infusion rate of 5.43 +/- 1.85 micrograms.kg-1.min-1. No statistically significant difference was found in the recovery profiles of the two groups when the infusion was terminated. We conclude that the addition of a small amount of pancuronium decreased the required mivacurium infusion rate by nearly 50% without affecting the spontaneous recovery when terminating the infusion.

Combinations of high-dose vecuronium and mivacurium provide similar paralysis and intubation conditions to succinylcholine in paediatric patients.

This randomized blinded study tested the hypothesis that equipotent doses of vecuronium and mivacurium given in combination could achieve onset times to 90% neuromuscular block (B90) and intubation scores similar to succinylcholine. Thirty children were randomly assigned to one of three groups as follows. Group Sux received a single dose (1 mg.kg-1) of succinylcholine followed by normal saline. Group V1M1 received 0.08 mg.kg-1 of vecuronium followed by 0.1 mg.kg-1 of mivacurium. Group V2M2 received 0.16 mg.kg-1 of vecuronium followed by 0.2 mg.kg-1 of mivacurium. Anaesthesia consisted of propofol, fentanyl, and nitrous oxide. Neuromuscular response was monitored by adductor pollicis electromyography (Datex NMT). Sixty s after administration of the first injection, the laryngoscopy began, with the anaesthesiologist scoring the ease of intubation on a four category scale as excellent, good, poor, or inadequate. Time from injection to B90 was 39 (2.6)s after succinylcholine, which was not significantly different from 48 (3.5)s after vecuronium 0.16 mg.kg-1 and mivacurium 0.2 mg.kg-1 (V2M2). Mean time to B90 for group V1M1 was 64 (4.7)s, which was significantly different from that in group Sux. The intubation score was 'excellent' for all patients in groups Sux and V2M2 and for only seven of ten patients in group V1M1. Only combination of vecuronium (0.16 mg.kg-1) and mivacurium (0.2 mg.kg-1) provided rapid onset of neuromuscular blockade and excellent intubating conditions comparable to succinylcholine 1 mg.kg-1. This combination did result in prolonged recovery times.

Central nervous system effects of intrathecal muscle relaxants in rats.

When given for a sufficient time and dose intravenously, neuromuscular blocking drugs eventually can enter the cerebrospinal fluid (CSF). To study the potential pharmacologic consequences of neuromuscular blocking drugs in the CSF, a model was developed in the rat by using an intrathecal infusion of these drugs. A cannula was stereotaxically implanted in a lateral cerebral ventricle of anesthetized male Sprague-Dawley rats (250-300 g). Several days later, the effects of an intraventricular infusion (5 microL/min) of atracurium (0.804 mumol/mL), pancuronium (0.172 mumol/mL), and vecuronium (21.978 mumol/mL) were studied in unanesthetized rats. These rats (n = 6 in each group) exhibited dose-dependent hyperexcitability, during drug infusion, with seizures occurring at threshold doses of (mean), 0.12, 0.26, and 0.065 +/- 0.010 and 3.32 mumol/kg of atracurium, pancuronium, and vecuronium, respectively. The neuromuscular ED50 (intravenous dose required to produce a 50% depression of twitch tension) in rats determined by other investigators are 0.408, 0.115, and 0.352 mumol/kg for atracurium, pancuronium, and vecuronium, respectively. Therefore, seizure threshold doses were not related to the potencies of these drugs as neuromuscular blocking drugs. Based on these data, central nervous system effects were studied over the subseizure dose range approximating 1/100, 1/10, and 1/5 of the cumulative dose causing seizures for each drug (n = 5 for each dose). At 1/100 of seizure dose, decreased locomotor activity and piloerection occurred. At 1/10 to 1/5 of seizure dose, agitation, shivering, splayed limbs, and whole body shaking resulted.(ABSTRACT TRUNCATED AT 250 WORDS)

Accelerated onset and delayed recovery of neuromuscular block induced by mivacurium preceded by pancuronium in children.

The goal of this study was to describe a technique which could shorten the time from mivacurium administration to peak neuromuscular block (NMB) after administration of the maximum recommended dose of mivacurium. Forty-eight pediatric patients were randomized into three groups and studied during nitrous oxide-alfentanil-thiopental anesthesia. Every patient received two blinded injections 3 min apart: either 15 micrograms/kg of pancuronium in 1 mL of saline followed by 170 or 200 micrograms/kg of mivacurium or saline followed by 200 micrograms/kg of mivacurium. Intravenous induction of anesthesia followed the first injection. Thenar electromyogram response to supramaximum train-of-four stimulation of the ulnar nerve at 10-s intervals was used for neuromuscular monitoring. Pretreatment with pancuronium significantly shortened the time to NMB and prolonged spontaneous recovery from NMB in comparison to the temporal course of NMB after administration of 200 micrograms/kg of mivacurium. Time from injection to 90% NMB averaged 116 (SEM 11) s after administration of 200 micrograms/kg of mivacurium, and 71 (7) s and 94 (11) s when 200 micrograms/kg or 170 micrograms/kg of mivacurium, respectively, was preceded by pancuronium (P = 0.0095). Mean times from injection to recovery of neuromuscular function to > 25% of baseline (T25) and to train-of-four ratio of 0.75 were 9.1 (0.7) and 15.8 (1.2) min, respectively, after administration of 200 micrograms/kg of mivacurium alone. T25 and train-of-four of 0.75 occurred significantly later at 21.9 (1.8) and 35.0 (2.8) min, respectively (P = 0.0001), when 200 micrograms/kg of mivacurium was preceded by 15 micrograms/kg of pancuronium.(ABSTRACT TRUNCATED AT 250 WORDS)

Degeneration of rat thalamic reticular neurons following intrathalamic domoic acid injection.

Domoic acid (DA), an analog of kainic acid, produces attentional deficits in humans who have ingested shell fish contaminated with this excitotoxin. The thalamic reticular nucleus (RT), by virtue of its location, connections and intrinsic properties, has been implicated in attentional processes. This study demonstrated the vulnerability of RT neurons following intrathalamic DA injections in rats. Lesions were characterized by almost total neuronal loss throughout the RT and sparing of adjacent populations of relay neurons in the VL and VPL. Los of RT neurons may underlie some types of attentional deficits observed in humans following DA poisoning.

[Pymadine, a new type of non-depolarizing muscle-relaxant antagonist]. / Pymadine, un nou tip de antagonist al miorelaxantelor nedepolarizante.

The paper presents the author's experience in post-anesthetic decurarization with a new antagonist of competitive curare. Presented for the first time in 1970, 4-amino-pyridine was found o tbe a substance with a different mode of action than that of reversible inhibitors of cholinesterase, without parasympaticomimetic effects, and without untoward effects on the cardio-circulatory function. It also has a central analeptic effect. This is why the authors consider the new drug as a powerful means for reversing the competitive neuromuscular blockage.