Laudanosine, an atracurium and cisatracurium metabolite:

Cisatracurium dosing in a patient with hyperthermia

PURPOSE

A case report involving varying cisatracurium dosing requirements in a hyperthermic patient undergoing prone ventilation who subsequently received active cooling as part of targeted temperature management is presented.

SUMMARY

Cisatracurium is known to be primarily metabolized via pH- and temperature-dependent Hofmann elimination. Previous reports in the literature described cases of decreased dosing requirements for both cisatracurium and its parent compound, atracurium, for patients in hypothermic states. While augmented atracurium dosing requirements in hyperthermic states have been reported, a literature search found no such reports concerning cisatracurium administration. In the case described here, a patient was initiated on cisatracurium for treatment of symptoms suggestive of acute respiratory distress syndrome (ARDS) and septic shock. An initial dosing requirement of 12 µg/kg/min (adjusted to a goal of 2-4 twitches per train-of-four monitoring) was needed to achieve adequate paralysis while the patient remained hyperthermic (a bladder temperature of 40.1°C). This cisatracurium infusion rate exceeded maximum reported and maximum institutional infusion rates (10 µg/kg/min). After initiation of cooling and lowering of the bladder temperature to 37.8°C, the cisatracurium rate requirement decreased to 5 µg/kg/min.

CONCLUSION

A hyperthermic patient thought to have ARDS and septic shock required a high rate of cisatracurium infusion for adequate paralysis during mechanical ventilation. The cisatracurium did not appear to cause prolonged neuromuscular blockade.

Neuromuscular blocking agents for acute respiratory distress syndrome: an updated meta-analysis of randomized controlled trials

Backgrounds

The aim of this study is investigating the benefits and harms of neuromuscular blocking agents (NMBAs) in patients with acute respiratory distress syndrome (ARDS).

Methods

We comprehensively searched PubMed, EMBASE, and Cochrane library for randomized controlled trials comparing NMBAs to any other comparator. We pooled data using relative risk (RR) for dichotomous outcomes and weighted mean difference (WMD) for continuous outcomes, with 95% confidence intervals. We assessed the quality of included studies using the Cochrane tool and levels of evidence using the GRADE method.

Results

Finally, six RCTs (n = 1557 patients) were eligible for analysis. The results showed NMBAs use was not associated with reduced 28 days mortality (RR 0.78; 95% CI, 0.58 to 1.06; P = 0.11), 90 days mortality (RR, 0.92; 95% CI, 0.81 to 1.04; P = 0.16), and intensive care unit (ICU) mortality (RR, 0.90; 95% CI, 0.79 to 1.03; P = 0.13) in patients with ARDS. However, 21–28 days mortality was slightly lower in patients received NMBAs (RR 0.73; 95% CI, 0.54 to 0.99; P = 0.04; I² = 53%). Besides, NMBAs use could improve the PaO₂/FiO₂ ratio at 48 and 72 h, decrease plateau pressure and PEEP at 72 h. Additionally, NMBAs had no significant effects on days free of ventilation at day 28 (WMD, 0.55; 95% CI, − 0.46 to 1.57; P = 0.29), days not in ICU at day 28 (WMD, 0.12; 95% CI, − 0.85 to 1.08; P = 0.82), ICU-acquired weakness (RR, 1.23; 95% CI, 0.99 to 1.93; P = 0.06). Finally, NMBAs use was associated with a lower risk of barotrauma (RR, 0.55; 95% CI, 0.35 to 0.85; P = 0.007).

Conclusion

In patients with respiratory distress syndrome, NMBAs may be beneficial in reverse refractory hypoxemia and may be associated with reduced short-term mortality and incidence of barotrauma. However, there is no significant effects of NMBAs on mid-term and long-term mortality, and further studies are required.

Retrospective evaluation of clinical use of cis-atracurium in horses

Background

To the authors’ knowledge, there are no reports describing the use of cis-atracurium in the horse.

Objective

To describe the onset time and the duration of the neuromuscular blockade (NMB) of three different doses of cis-atracurium in horses and to determine the appropriate dose needed maintain a NMB.

Study design

Retrospective study.

Methods

Horses which received cis-atracurium as part of a balanced anaesthetic protocol at the Equine Teaching Hospital of the University of Liège between March 2014 and June 2017 were included in this study. A train-of-four (TOF) stimulation pattern was used to assess the NMB. The cis-atracurium induction dose, the onset and duration of action (when TOF count was under three twitches) of the first bolus, the number of supplementary boluses of cis-atracurium and the total dose of cis-atracurium administered per horse, the total duration of the NMB and the recovery time were recorded and analysed. Also the use of an antidote and any side effects produced by cis-atracurium were recorded.

Results

From 37 horses that received cis-atracurium during this period, only 23 had a complete records and were included in the study. Three different doses of cis-atracurium were used to induce NMB: 100 μg/kg (n = 8) 75 μg/kg (n = 3) and 50 μg/kg (n = 12). Cis-atracurium 50 μg/kg failed to induce NMB in 3 horses. The onset of action was not significantly different between the three doses (5 minutes). The duration of the NMB was dose-dependent. The calculated dose of cis-atracurium necessary to maintain a NMB was 2.3 μg/kg/minute based on the sum of the induction dose and the supplementary boluses divided by the duration of the NMB.

Main limitations

A further prospective study is needed to confirm the results.

Conclusions

Cis-atracurium can be an alternative to other NMBA in horses.

Neuromuscular blocking agents for acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is an acute inflammatory process that impairs the ability of the lungs to oxygenate thereby resulting in respiratory failure. Treatment of ARDS is often a multimodal approach using both nonpharmacologic and pharmacologic treatment strategies in addition to trying to reverse the underlying cause of ARDS. Neuromuscular blocking agents (NMBAs) have been prescribed to patients with ARDS as they are thought to decrease inflammation, oxygen consumption, and cardiac output and help facilitate ventilator synchrony. NMBAs have only been evaluated in patients with early, severe ARDS in three multicenter, randomized, controlled trials (n = 432), but have resulted in decreased inflammation and improved oxygenation, ventilator-free days, and mortality. Despite reports of NMBAs being associated with adverse effects like postparalytic quadriparesis, myopathy, and prolonged recovery, these effects have not been seen in patients receiving short courses of NMBAs for ARDS. A large multicenter, prospective, randomized, placebo-controlled trial is ongoing to confirm benefit of NMBAs in early, severe ARDS when adjusting for limitations of the previous studies. The current available literature suggests that 48 h of NMBA therapy in patients with early, severe ARDS improves mortality, without resulting in additional patient harm.

Effect of creatine phosphate sodium on bispectral index and recovery quality during the general anaesthesia emergence period in elderly patients: A randomized, double-blind, placebo-controlled trial

Objective

To evaluate the effect of creatine phosphate sodium on bispectral index (BIS) and recovery quality during the general anaesthesia emergence period in elderly patients.

Methods

This randomized, double-blind, placebo-controlled study enrolled patients undergoing transabdominal cholecystectomy under general anaesthesia. Patients were randomly assigned to receive either creatine phosphate sodium (1.0 g/100 ml 0.9% saline; group P) or 100 ml 0.9% saline (group C) over 30 minutes during surgical incision. The BIS values were recorded at anaesthesia induction (T₀), skin incision (T₁), cutting the gallbladder (T₂), suturing the peritoneum (T₃), skin closure (T₄), sputum suction (T₅), extubation (T₆) and 1 min (T₇), 5 min (T₈), 10 min (T₉), and 15 min (T₁₀) after extubation. The anaesthesia duration, operation time, waking time, extubation time, consciousness recovery time, time in the postanaesthesia care unit (PACU), and the Steward recovery scores at T₇, T₈, T₉ and T₁₀ were recorded.

Results

A total of 120 elderly patients were randomized equally to the two groups. Compared with group C, the BIS values were significantly higher in group P at T₅, T₆, T₇ and T₈; and the Steward recovery scores at T₇ and T₈ were significantly higher in group P. The waking time, extubation time, consciousness recovery time and time in the PACU were significantly shorter in group P compared with group C.

Conclusion

Creatine phosphate sodium administered during transabdominal cholecystectomy can improve BIS values and recovery following general anaesthesia in elderly patients.

Clinical Practice Guidelines for Sustained Neuromuscular Blockade in the Adult Critically Ill Patient

OBJECTIVE

To update the 2002 version of "Clinical practice guidelines for sustained neuromuscular blockade in the adult critically ill patient."

DESIGN

A Task Force comprising 17 members of the Society of Critical Medicine with particular expertise in the use of neuromuscular-blocking agents; a Grading of Recommendations Assessment, Development, and Evaluation expert; and a medical writer met via teleconference and three face-to-face meetings and communicated via e-mail to examine the evidence and develop these practice guidelines. Annually, all members completed conflict of interest statements; no conflicts were identified. This activity was funded by the Society for Critical Care Medicine, and no industry support was provided.

METHODS

Using the Grading of Recommendations Assessment, Development, and Evaluation system, the Grading of Recommendations Assessment, Development, and Evaluation expert on the Task Force created profiles for the evidence related to six of the 21 questions and assigned quality-of-evidence scores to these and the additional 15 questions for which insufficient evidence was available to create a profile. Task Force members reviewed this material and all available evidence and provided recommendations, suggestions, or good practice statements for these 21 questions.

RESULTS

The Task Force developed a single strong recommendation: we recommend scheduled eye care that includes lubricating drops or gel and eyelid closure for patients receiving continuous infusions of neuromuscular-blocking agents. The Task Force developed 10 weak recommendations. 1) We suggest that a neuromuscular-blocking agent be administered by continuous intravenous infusion early in the course of acute respiratory distress syndrome for patients with a PaO2/FIO2 less than 150. 2) We suggest against the routine administration of an neuromuscular-blocking agents to mechanically ventilated patients with status asthmaticus. 3) We suggest a trial of a neuromuscular-blocking agents in life-threatening situations associated with profound hypoxemia, respiratory acidosis, or hemodynamic compromise. 4) We suggest that neuromuscular-blocking agents may be used to manage overt shivering in therapeutic hypothermia. 5) We suggest that peripheral nerve stimulation with train-of-four monitoring may be a useful tool for monitoring the depth of neuromuscular blockade but only if it is incorporated into a more inclusive assessment of the patient that includes clinical assessment. 6) We suggest against the use of peripheral nerve stimulation with train of four alone for monitoring the depth of neuromuscular blockade in patients receiving continuous infusion of neuromuscular-blocking agents. 7) We suggest that patients receiving a continuous infusion of neuromuscular-blocking agent receive a structured physiotherapy regimen. 8) We suggest that clinicians target a blood glucose level of less than 180 mg/dL in patients receiving neuromuscular-blocking agents. 9) We suggest that clinicians not use actual body weight and instead use a consistent weight (ideal body weight or adjusted body weight) when calculating neuromuscular-blocking agents doses for obese patients. 10) We suggest that neuromuscular-blocking agents be discontinued at the end of life or when life support is withdrawn. In situations in which evidence was lacking or insufficient and the study results were equivocal or optimal clinical practice varies, the Task Force made no recommendations for nine of the topics. 1) We make no recommendation as to whether neuromuscular blockade is beneficial or harmful when used in patients with acute brain injury and raised intracranial pressure. 2) We make no recommendation on the routine use of neuromuscular-blocking agents for patients undergoing therapeutic hypothermia following cardiac arrest. 3) We make no recommendation on the use of peripheral nerve stimulation to monitor degree of block in patients undergoing therapeutic hypothermia. 4) We make no recommendation on the use of neuromuscular blockade to improve the accuracy of intravascular-volume assessment in mechanically ventilated patients. 5) We make no recommendation concerning the use of electroencephalogram-derived parameters as a measure of sedation during continuous administration of neuromuscular-blocking agents. 6) We make no recommendation regarding nutritional requirements specific to patients receiving infusions of neuromuscular-blocking agents. 7) We make no recommendation concerning the use of one measure of consistent weight over another when calculating neuromuscular-blocking agent doses in obese patients. 8) We make no recommendation on the use of neuromuscular-blocking agents in pregnant patients. 9) We make no recommendation on which muscle group should be monitored in patients with myasthenia gravis receiving neuromuscular-blocking agents. Finally, in situations in which evidence was lacking or insufficient but expert consensus was unanimous, the Task Force developed six good practice statements. 1) If peripheral nerve stimulation is used, optimal clinical practice suggests that it should be done in conjunction with assessment of other clinical findings (e.g., triggering of the ventilator and degree of shivering) to assess the degree of neuromuscular blockade in patients undergoing therapeutic hypothermia. 2) Optimal clinical practice suggests that a protocol should include guidance on neuromuscular-blocking agent administration in patients undergoing therapeutic hypothermia. 3) Optimal clinical practice suggests that analgesic and sedative drugs should be used prior to and during neuromuscular blockade, with the goal of achieving deep sedation. 4) Optimal clinical practice suggests that clinicians at the bedside implement measure to attenuate the risk of unintended extubation in patients receiving neuromuscular-blocking agents. 5) Optimal clinical practice suggests that a reduced dose of an neuromuscular-blocking agent be used for patients with myasthenia gravis and that the dose should be based on peripheral nerve stimulation with train-of-four monitoring. 6) Optimal clinical practice suggests that neuromuscular-blocking agents be discontinued prior to the clinical determination of brain death.

Anesthesia for Patients with Concomitant Cardiac and Renal Dysfunction

Renal disease and cardiovascular disease are commonly encountered in the same patient. The dynamic interactions between renal disease and cardiovascular disease have an impact on perioperative management. Renal failure is an independent risk factor for cardiovascular disease and the link between the two disease states remains to be fully elucidated.

Highlights in muscle relaxants

The aim of this article is to provide an overview on neuromuscular blocking agents and a rational selection of the most appropriate agents, along with pharmacological and pharmacoeconomic considerations on neuromuscular blockers and their antagonists. Neuromuscular blocking agents are used during anesthesia to facilitate endotracheal intubation and provide surgically required paralysis. There is continuing development in the field of neuromuscular blocking agents, with new products appearing at regular intervals. All new agents come at increased costs. The proportion of anesthesia-related drug costs on a per-patient basis are small and vary from country to country, but account for no more than 12% of hospital drug budgets. However, given the large number of anesthetics performed over time, the total cost is significant. Moreover, such costs should be put into the perspective of the operating theater and patient admission costs. Appropriate selection of neuromuscular blocking agents can help not only to reduce biological costs secondary to complications, but also to make operating lists proceed smoothly and without incident. The paucity of outcome studies in relation to anesthetic drugs is not surprising given that anesthesia is used to facilitate the provision of therapy rather than being therapeutic in its own right. Accordingly, the assessment of anesthetic drugs has a different priority to therapeutic drugs. As anesthetic drugs are nontherapeutic, it is also difficult to determine the best choice of agent. However, new neuromuscular blocking agents are marketed on the basis of improvements in the frequency of side effects, safety, reliability, duration, reversibility and undesirable hemodynamic effects.

Epilepsy and anesthesia

BACKGROUND AND OBJECTIVES

Epilepsy is one of the most frequent chronic neurological diseases. Although anesthesia for epilepsy patients is more common in neurosurgery, this group of patients needs, just as the general population, anesthesia for different diagnostic and therapeutic procedures. This article aims to address the issues of greatest interest to the anesthesiologist in the perioperative management of epileptic patients undergoing anesthesia for non-neurosurgical procedures.

CONTENT

We discuss relevant aspects of pathophysiology, classification and diagnosis of epilepsy; anticonvulsant therapy and interactions with anesthetic drugs; surgery and the ketogenic diet; pro-and anticonvulsant effects of drugs used in anesthesia; preoperative evaluation, intra- and postoperative conduct in epileptic patients, as well as the diagnosis and treatment of perioperative seizures.

CONCLUSIONS

In the perioperative management of epileptic patients is important for anesthesiologists to identify the type of epilepsy, the frequency, severity and the factors triggering the epileptogenic crises; the use of anticonvulsant drugs and possible interactions with drugs used in anesthesia; the presence of ketogenic diet and stimulatory of the vagus nerve, and its implications in anesthetic techniques. It is essential the understanding of pro- and anticonvulsant properties of drugs used in anesthesia, minimizing the risk of seizure activity in the intra- and postoperative. Finally, it is important to outline the diagnosis and initiate treatment of seizures, perioperative, which offers lower both morbidity and mortality.

Perinatal neuroprotection by muscle relaxants against hypoxic-ischemic lesions: Is it a possible hypothesis?

The incidence of neurological disabilities ascribable to hypoxia-ischemia in the perinatal period (HIPP) is rising. Glutamate plays a key role in the development of cerebral damage related to HIPP: it triggers the excitotoxic cascade by overactivating N-methyl-D-aspartate receptors (NMDA), implicated as important mediators of both learning and neuronal development. Laudanosine is the metabolite of the neuromuscular blocking drugs, atracurium and cisatracurium, administered as part of obstetric general anesthesia. In elective cesarean section, laudanosine may be found in the fetus with a mean umbilical vein concentration of 26 (range 6-60) ng ml(-1). At nM concentrations, laudanosine can activate alpha4beta2 nACh subtype receptors. Activation of alpha4beta2 nAChRs provided neuroprotection against NMDA excitotoxic cascade in a neonatal model. Taken together, experimental and clinical data widely indicate a potential neuroprotective role for laudanosine against perinatal brain lesions of hypoxic-ischemic origin. The clinical relevance is that administration of the neuromuscular blocking drugs atracurium and cisatracurium, administered as part of general anesthesia for cesarean section, could be potentially therapeutic in obstetric anesthesia. Therefore, we find laudanosine to be an attractive proposal for further studies in the prevention of neurological disabilities ascribable to perinatal injury related to hypoxia and ischemia.

Xylazine Premedication does not Modify the Onset and Duration of Cisatracurium Blockade in Anaesthetized Dogs

The purpose of this study was to evaluate the effect of xylazine as premedication on the onset time and duration of cisatracurium neuromuscular blockade in anaesthetized dogs. This study was carried out on 12 healthy dogs aged 0.5-6 years and weighing 9-26 kg undergoing various elective surgical procedures. The dogs were randomly divided into two groups of t (test) and c (control), with six dogs each. In group t, premedication was conducted using acepromazine maleate 0.3 mg kg(-1) and xylazine 0.3 mg kg(-1) and in group c only acepromazine (same dose) was injected intramuscularly 20 min before general anaesthesia. After induction with thiopental, anaesthesia was maintained with halothane in oxygen to deliver an end-tidal halothane concentration of 1.1%. Neuromuscular blockade was induced with cisatracurium 0.2 mg kg(-1) and monitored using the train-of-four (TOF) stimulation pattern applied at the ulnar nerve. The onset time of cisatracurium blockade was 195 +/- 85.44 s in test and 153.3 +/- 38.16 s in control group. The duration of neuromuscular blockade was 24.8 +/- 4.79 min in t and 28.3 +/- 5.46 min in the c group. Statistical analysis of the data showed no significant difference between groups in terms of onset and duration of neuromuscular blockade.

Acute motor axonal polyneuropathy after a cisatracurium infusion and concomitant corticosteroid therapy

A 40-yr-old male was admitted to the intensive care unit following blunt chest trauma. He had multiple rib fractures, bilateral pneumothoraces, and acute respiratory failure requiring mechanical ventilation. Sedation was achieved with midazolam and morphine, and later with propofol. The patient was paralysed with a continuous infusion of cisatracurium 1.42-5.75 micro g kg(-1) min(-1). Methylprednisolone 125 mg i.v. every 12 h was also started. After discontinuation of the cisatracurium infusion 7 days later, the patient manifested a flaccid quadriplegia with absence of deep-tendon reflexes. No sensory deficits were observed. Electromyography (EMG), repetitive nerve stimulation testing, and single fibre EMG (SFEMG) were performed at regular intervals after stopping cisatracurium. Clinical symptoms and electrophysiological examinations supported the diagnosis of acute motor axonal polyneuropathy related to concomitant administration of cisatracurium and corticosteroid therapy.

β-Phenylethylamines and the isoquinoline alkaloids

This review covers beta-phenylethylamines and isoquinoline alkaloids derived from them, including further products of oxidation. condensation with formaldehyde and rearrangement, some of which do not contain an isoquinoline system, together with naphthylisoquinoline alkaloids, which have a different biogenetic origin. The occurrence of the alkaloids, with the structures of new bases, together with their reactions, syntheses and biological activities are reported. The literature from July 2002 to June 2003 is reviewed, with 568 references cited.