Monitoring Of Neuromuscular Function Research Articles

Residual neuromuscular block in elderly patients after surgical procedures under general anaesthesia with rocuronium

Incomplete recovery of neuromuscular function following the administration of medium-acting, non- -depolarising agents is one of the most feared complications in anaesthesia. We assessed the incidence of postoperative residual curarisation (PORC) after general anaesthesia with rocuronium in elderly and young patients, and we evaluated possible complications of postoperative residual curarisation. This observational study included 415 patients (ASA physical status I-III) who were undergoing different surgical procedures: 184 patients were aged ≥ 65 (range: 65-89) years, and 231 patients were aged 19-57 years. No patients had renal or hepatic disorders. Patients received rocuronium for relaxation. Neuromuscular monitoring was not used intraoperatively. Neuromuscular function recovery was spontaneous. Patients were transferred to the post-anaesthesia care unit (PACU) after anaesthesia. During the first ten minutes in the post-anaesthesia care unit, the presence of postoperative residual curarisation was assessed by acceleromyography and train-of-four (TOF) stimulation. Patient well-being was monitored continuously. During hospitalisation, patient medical documentation was assessed for postoperative residual curarisation-related complications. TOF ratios were < 0.7 in 31% of all patients, whereas the block was clinically completely recovered in all patients. Postoperative residual curarisation was more frequent in elderly (44%) than younger patients (20%) (P < 0.05). Only 73 patients (21 elderly, 52 younger patients) had TOF ratios ≥ 0.9. Hypoxia was more frequent in elderly patients in the PACU: 17.9% vs. 8.2% (P < 0.05). Postoperative residual curarisation-related pneumonia was observed in one elderly patient. Residual paralysis remains a major problem in geriatric clinical anaesthesia. Neuromuscular function monitoring is obligatory, and pharmacological reversal of relaxation should be advised in geriatric patients after using relaxants for general anaesthesia.

Low-dose Sugammadex Reversal

Low-dose Sugammadex Reversal

A Survey of the Management of Neuromuscular Blockade Monitoring in Australia and New Zealand

This survey of anaesthetists in Australia and New Zealand aimed to investigate their attitudes and practice relating to the management of neuromuscular blockade monitoring. All medical practitioner members (3188) of the Australian and New Zealand Societies of Anaesthetists were invited to complete an anonymous survey, which was available online for two months. A total of 678 survey questionnaires were completed (response rate 21%). Most respondents (71.4%) underestimated the incidence of residual neuromuscular blockade and 63.2% believed this to be a significant clinical problem. Objective monitoring of neuromuscular function was used routinely only by 17% of respondents, although 70% believed routine monitoring would reduce the incidence of residual neuromuscular blockade. Only 25% of respondents correctly indicated that quantitative train-of-four counts of greater than 90% were the accepted criteria for safe extubation, with 52% using clinical judgement only. Only 29% of respondents believed neuromuscular function monitors should be part of minimum monitoring standards; quantitative neuromuscular function monitors were not available in 42% of the hospitals in which the respondents practiced. Despite the low response rate, the large sample size and heterogeneity of respondents make the findings of this survey concerning. There is a need for more education, availability of appropriate monitoring equipment and evidence-based guidelines for management of neuromuscular blockade in Australia and New Zealand.

A survey of the current use of neuromuscular blocking drugs among the Middle Eastern anesthesiologists

Background:This survey aimed to assess the extent of practice of the Middle Eastern anesthesiologists in the use of neuromuscular blocking agents (NMB) in 2012.Methods:We distributed an electronic survey among 577 members of the Triple-M Middle Eastern Yahoo anesthesia group, enquiring about their practice in the use of neuromuscular blocking agents. Questions concerned the routine first choice use of NMB, choice for tracheal intubation, the use of neuromuscular monitoring (NMT), type of NMB used in difficult airway, frequency of using suxamethonium, cisatracurium, rocuronium and sugammadex, observed side effects of rocuronium, residual curarization, and the reversal of residual curarization of rocuronium.Results:A total of 71 responses from 22 Middle Eastern institutions were collected. Most of the Middle Eastern anesthesiologists were using cisatracurium and rocuronium frequently for tracheal intubation (39% and 35%, respectively). From the respondents, 2/3 were using suxamethonium for tracheal intubation in difficult airway, 1/3 were using rocuronium routinely and 17% have observed hypersensitivity reactions to rocuronium, 54% reported residual curarization from rocuronium, 78% were routinely using neostigmine to reverse the rocuronium, 21% used sugammadex occasionally, and 35% were using NMT routinely during the use of NMB.Conclusions:We believe that more could be done to increase the awareness of the Middle Eastern anesthesiologists about the high incidence of PROC (>20%) and the need for routine monitoring of neuromuscular function. This could be accomplished with by developing formal training programs and providing official guidelines.

Clinical variability of vecuronium. Experience at an institution in Colombia

ObjectiveTo establish the variability of vecuronium (lag-time, latency duration, clinical duration and complete recovery), original molecule, in a group of patients who received the agent prior to surgery under general anesthesia with endotracheal intubation. Materials and methodsObservational, prospective study including 20 adult patients – ASAI or II classification – selected on the basis of suitability, who received general anesthesia and vecuronium as neuromuscular relaxant. Remifentanyl and propofol were the induction agents. The neuromuscular activity was quantified using a TOF-WATCH SX® stimulator, establishing lag-time, duration of latency, clinical duration and complete recovery. The data were analyzed using STATA 10. ResultsThe data on lag-time to complete recovery are given as medians: lag-time: 32.5seconds; latency time: 240seconds; clinical length 25: 43.5min; clinical length 50: 57.5min; clinical length 75: 58.5min; clinical length 100: 55min; complete recovery: 87min; need for reversion: 55%; adverse effects: none. ConclusionsThe results obtained suggest a broad variability between the time of administration of vecuronium, its clinical effect and duration of action, all of which were above the levels recorded in the literature. This suggests that the agent is long-acting and highly unpredictable. We recommend neuromuscular function monitoring as an indispensable routine and preferably quantitative.

Monitoring in Anesthesia and Perioperative Care

Edited by David L. Reich, M.D., Ronald Kahn, M.D., Andrew B. Leibowitz, M.D., Alexander J. C. Mittnacht, M.D., Marc E. Stone, M.D., James B. Eisenkraft, M.D. New York, Cambridge University Press, 2011. Pages: 432. Price: $125.00.Patient safety has improved tremendously since the first public demonstration of anesthesia in the Ether Dome in 1846. The evolution of anesthesia care from a clinical art to a systematic, modern science has been led, in large part, by dramatic advancements in our ability to monitor patients. Accordingly, much of the significant decline in anesthesia-related morbidity and mortality (especially in the last 40 yr) can be directly attributed to improved patient monitoring during the perioperative period.Monitoring in Anesthesia and Perioperative Care aims to describe not only the historical art but also the modern science and technology that form the basis of perioperative patient monitoring. It chronicles monitoring from its conception by such visionaries as Harvey Cushing and Arthur Guedel through modern-day investigational modalities not yet used in clinical practice. It describes a wide range of monitoring options and offers advice from leading experts regarding the risks, benefits, and applicability of each modality.The book is generally organized into three sections. The first four chapters deal with historical developments, medicolegal implications, and educational concerns related to monitoring in general. This is followed by the bulk of the text, which is organized into chapter-by-chapter reviews of physiologic and biochemical monitoring modalities. Whenever possible, each of these chapters is organized around six themes: technical concepts, parameters measured, evidence of utility, complications, credentialing and standards, and practice guidelines. The final chapters address various scales and schemata used to assess perioperative and critical-care patients beyond routine vital sign assessment. The text concludes with a chapter on the convergence of clinical monitoring with electronic medical records, highlighting the coming of age of anesthesia information management systems.As one would expect, the text educates the reader on commonly used monitors, such as those required by the American Society of Anesthesiologists. It also serves as a primer for less common and investigational techniques, including the use of near-infrared spectroscopy to assess regional tissue perfusion. The chapter on perioperative monitoring of neuromuscular function is particularly valuable as it provides poignant insight into a topic of ongoing debate in the literature. The book also includes multiple chapters that discuss ancillary monitoring modalities, such as fetal heart rate monitoring and neurophysiologic monitoring. At the end of the second section, the authors include several chapters relating to perioperative laboratory assessment, such as assessment of coagulation status and cardiac biomarkers.We applaud the authors' attempts to synthesize multiple aspects of perioperative monitoring into a comprehensive, yet approachable text. However, there are several notable shortcomings. Although individual chapters are well organized, the overall flow of the text does not seem to follow a logical order. The chapter on gastric tonometry, for example, appears in the text several hundred pages before the discussions of pulse oximetry and temperature measurement. By beginning with the American Society of Anesthesiologists' standard monitors, and following with chapters based on organ systems, the text would likely flow better. However, a concise table of contents and a thorough index do help to ameliorate this concern.In addition, the mostly black-and-white (and often low-resolution) photos are not what one would expect from an expensive and otherwise high-quality medical text. Finally, although there is an inevitable time lag between the writing and publication of any textbook, this is even more apparent in this text, which chronicles a rapidly changing technological landscape.Overall, Monitoring in Anesthesia and Perioperative Care is a thorough and well written resource for clinicians seeking an improved understanding of modern anesthesia monitoring practices. With the ever-increasing quantity and sophistication of monitoring modalities, the potential exists for a concomitant rise in the hazards of such a complex system. Fortunately, Monitoring in Anesthesia and Perioperative Care provides the reader with a solid foundation for seeking an optimal balance between improved patient care and “monitoring overload.”

Variabilidad clínica del vecuronio. Experiencia en una institución en Colombia

ObjectiveTo establish the variability of vecuronium (lag-time, latency duration, clinical duration and complete recovery), original molecule, in a group of patients that received the agent prior to surgery under general anesthesia with endotracheal intubation. Materials and methodsObservational, prospective study including 20 adult patients - ASAI or II classification — selected on the basis of suitability, who received general anesthesia and vencuronium as neuromuscular relaxant. Remifentanyl and propofol were the induction agents. The neuromuscular activity was quantified using a TOF-WATCH SX® stimulator, establishing lag-time, duration of latency, clinical duration and complete recovery. The data were analyzed using STATA 10. ResultsThe data on lag-time to complete recovery, are given as medians: lag-time: 32.5seconds; latency time: 240seconds; clinical length 25: 43.5min; clinical length 50: 57.5min; clinical length 75: 58.5min; clinical length 100: 55min. Complete recovery: 87min. Need for reversion: 55%. Adverse effects: none. ConclusionsThe results obtained suggest a broad variability between the time of administration of vecuronium, its clinical effect and duration of action, all of which were above the levels recorded in the literature. This suggests that the agent is long-acting and highly unpredictable. We recommend neuromuscular function monitoring as an indispensable routine and preferably quantitative.

Neuromuscular monitoring and its importance in neuromuscular blockade

IntroductionThe incorporation of new guidelines or strategies as part of good practices in the use of muscle relaxants is not a requirement at present in the practice of anesthesia. There are only action recommendations designed to persuade clinicians of the fact that neuromuscular monitoring is a very useful tool for the rational use of muscle relaxants. MethodologyComplications occur, and residual paralysis is a significant event. For this reason, the authors advocate that monitoring neuromuscular block may be a determining factor in improving patient care and reducing morbidity and mortality. This review and its methodology based on the experience of the authors is designed to present, in a simple format, the knowledge that is considered fundamental for the systematic use of neuromuscular monitoring in every day practice. Results and conclusionsThis update describes the fundamental principles of the methods available at present, emphasizing quantitative recording measurements. It then describes the different ways in which muscles respond to the effect of neuromuscular blockade, as these are critical fundamental principles that have to be known. Neuromuscular monitoring is a practice that should be implemented every time a neuromuscular block is required. We are aware of the difficulty of generating an explicit recommendation, but our enthusiasm is derived from the benefits we have personally experienced when applying these methods that have been known for a long time. Due to the potential morbidity associated with residual muscle relaxation, perioperative monitoring of neuromuscular function is essential.

La monitorización neuromuscular y su importancia en el uso de los bloqueantes neuromusculares

IntroductionThe incorporation of new guidelines or strategies as part of good practices in the use of muscle relaxants is not a requirement at present in the practice of anesthesia. There are only action recommendations designed to persuade clinicians of the fact that neuromuscular monitoring is a very useful tool for the rational use of muscle relaxants. MethodologyComplications occur, and residual paralysis is a significant event. For this reason, the authors advocate that monitoring neuromuscular block may be a determining factor in improving patient care and reducing morbidity and mortality. This review and its methodology based on the experience of the authors is designed to present, in a simple format, the knowledge that considered fundamental for the systematic use of neuromuscular monitoring in every day practice. Results and conclusionsThis update describes the fundamental principles of the methods available at present, emphasizing quantitative recording measurements. It then describes the different ways in which muscles respond to the effect of neuromuscular blockade, as these are critical fundamental principles that have to be known. Neuromuscular monitoring is a practice that should be implemented every time a neuromuscular block is required. We are aware of the difficulty of generating an explicit recommendation, but our enthusiasm is derived from the benefits we have personally experienced when applying these methods that have been known for a long time. Due to the potential morbidity associated with residual muscle relaxation, perioperative monitoring of neuromuscular function is essential.

Avaliação do bloqueio neuromuscular em crianças no momento da reversão do bloqueio e da retirada da cânula endotraqueal

JUSTIFICATIVA E OBJETIVOS: Estudos evidenciam a importância da monitoração da função neuromuscular na prevenção do bloqueio residual. No entanto, a maioria dos anestesistas em sua prática diária se abaliza em dados clínicos para avaliar a recuperação da função neuromuscular. O objetivo deste estudo foi avaliar o grau de bloqueio neuromuscular em crianças submetidas à anestesia geral no momento da reversão do bloqueio e da retirada da cânula endotraqueal. MÉTODO: Foram avaliadas crianças entre 3 meses e 12 anos, submetidas à anestesia geral com uso de atracúrio ou rocurônio. A monitoração foi iniciada no momento da reversão do bloqueio neuromuscular e/ou retirada da cânula endotraqueal. O anestesiologista não era informado sobre o valor de T4/T1; apenas era alertado quando o momento era inadequado para a retirada da cânula endotraqueal. Houve registro do grau de bloqueio neuromuscular desde o início da monitoração, bem como do intervalo para a recuperação da relação T4/T1 > 0,9, doses de bloqueador e neostigmina utilizadas, fração expirada do agente inalatório, duração da anestesia, temperatura central e periférica. RESULTADOS: O bloqueio neuromuscular foi revertido em 80% das crianças no Grupo Rocurônio e 64,5% no Grupo Atracúrio. A reversão foi incorreta em 45,8 % do Grupo Rocurônio e 25% do Grupo Atracúrio. A incidência de T4/T1 < 0,9 no momento da retirada da cânula endotraqueal foi de 10% em ambos os grupos. CONCLUSÕES: Na decisão de retirada da cânula endotraqueal, com base em critérios clínicos, 10% das crianças apresentavam T4/T1 < 0,9, independentemente do bloqueador recebido. Um número considerável de pacientes teve o bloqueio neuromuscular revertido de maneira incorreta, quando o bloqueio ainda era profundo demais ou mesmo já estava recuperado.

Assessment of Neuromuscular Blockade in Children at the Time of Block Reversal and the Removal of the Endotracheal Tube

Studies show the importance of monitoring neuromuscular function in preventing the residual block. However, most anesthesiologists in their daily practice base their evaluation of the recovery of neuromuscular function on clinical data. The aim of this study was to assess the degree of neuromuscular blockade in children undergoing general anesthesia at the time of block reversal and the removal of the endotracheal tube. We evaluated children between 3 months and 12 years of age undergoing general anesthesia with the use of atracurium or rocuronium. Monitoring was initiated at the time of reversal of neuromuscular blockade and/or removal of the endotracheal tube. The anesthesiologist was not informed about the T₄/T₁ value; he/she was only alerted when the time was inadequate for the removal of the endotracheal tube. Since the start of the monitoring process, the degree of neuromuscular blockade was registered, as well as the interval of recovery of the T(4)/T₁ ≥ 0.9 ratio, the doses of neostigmine and blocker used, the expired fraction of the inhalational agent, the duration of the anesthesia, and core and peripheral temperatures. Neuromuscular blockade was reversed in 80% of the children of the Rocuronium Group and in 64.5% of the Atracurium Group. The reversal was incorrect in 45.8% of the Rocuronium Group and in 25% of the Atracurium Group. The incidence of T₄/T₁ < 0.9 at the time of the removal of the endotracheal tube was 10% in both groups. When deciding to remove the endotracheal tube based on clinical criteria, 10% of children had T₄/T₁ < 0.9 regardless the blocker received. A considerable number of patients had the neuromuscular blockade incorrectly reversed when the blockade was still too deep or even already recovered.

Evidence-Based Management of Neuromuscular Block

experts. Basically, European experts have advocated that objective neuromuscular monitoring should be a standard of care, whereas at least some experts from the U.S. have been more reluctant to accept this. The argument against is that it has never been convincingly documented that intraoperative neuromuscular monitoring actually decreases the incidence of residual paralysis. 3,5,6 Some of this disagreement may be caused by confusion between the two words intraoperative and perioperative. Intraoperative, strictly speaking, includes only the time of the operation itself. The perioperative period includes the time before, during, and immediately after the surgery, before the patient is transferred to the postoperative care unit. It is correct that there is no convincing evidence in the literature that intraoperative monitoring of neuromuscular function, whether subjective (visual or tactile evaluation of the response to nerve stimulation) or objective (mechanomyography, acceleromyography, kinemyography, or electromyography), decreases the incidence of potentially clinically significant postoperative residual paralysis. 3,5,6 However, monitoring does obviously make the evaluation and the management of the neuromuscular block during the operation easier. In this respect it is not critical whether the clinician is using subjective or objective monitoring. The level of block can easily be quantified by tactile evaluation of the response to posttetanic count stimulation for intense and deep block, and TOF stimulation for moderate block. 7 In contrast, during the recovery phase of the neuromuscular block, it is not possible with certainty to quantify the degree of block manually or visually when the TOF ratio is 0.40. 3 There

Sugammadex for the reversal of muscle relaxation in general anaesthesia: a systematic review and economic assessment

Sugammadex (Bridion) is a newly developed agent for the reversal of neuromuscular blockade (NMB) induced by rocuronium or vecuronium. Sugammadex can reverse profound blockade and can be given for immediate reversal and its use would avoid the potentially serious adverse effects of the currently used agent, succinylcholine. Also, sugammadex can reverse NMB more quickly and predictably than existing agents. To determine the clinical effectiveness and cost-effectiveness of sugammadex for the reversal of muscle relaxation after general anaesthesia in UK practice following routine or rapid induction of NMB. Medical databases [including MEDLINE, EMBASE, CINAHL, Science Citation Index, BIOSIS and Cochrane Central Register of Controlled Trials (CENTRAL), conference proceedings, internet sites and clinical trials registers] were searched to identify published and unpublished studies. The main searches were carried out in May 2008 and supplemented by current awareness updates up until November 2008. For the clinical effectiveness review, randomised controlled trials of sugammadex against placebo or an active comparator (neostigmine + glycopyrrolate) for the reversal of moderate or profound NMB and for immediate reversal (spontaneous recovery from succinylcholine-induced blockade) were included. The primary effectiveness outcome was speed of recovery from NMB, as measured by objective monitoring of neuromuscular function. For the cost-effectiveness review, a de novo economic assessment considered the routine induction of NMB and the rapid induction and/or reversal of NMB, and threshold analyses were carried out on a series of pairwise comparisons to establish how effective sugammadex needs to be to justify its cost. The review of clinical effectiveness included four randomised active-control trials of sugammadex, nine randomised placebo-controlled trials and five studies in special populations. A total of 2132 titles and abstracts and 265 full-text publications were screened. The included trials indicated that sugammadex produces more rapid recovery from moderate or profound NMB than placebo or neostigmine. Median time to recovery from moderate blockade was 1.3-1.7 minutes for rocuronium + sugammadex, 21-86 minutes for rocuronium + placebo and 17.6 minutes for rocuronium + neostigmine. In profound blockade, median time to recovery was 2.7 minutes for rocuronium + sugammadex, 30 to > 90 minutes for rocuronium + placebo, and 49 minutes for rocuronium + neostigmine. Results for vecuronium were similar. In addition, recovery from NMB was faster with rocuronium reversed by sugammadex 16 mg/kg after 3 minutes (immediate reversal) than with succinylcholine followed by spontaneous recovery (median time to primary outcome 4.2 versus 7.1 minutes). The evidence base for modelling cost-effectiveness is very limited. However, assuming that the reductions in recovery times seen in the trials can be achieved in routine practice and can be used productively, sugammadex [2 mg/kg (4 mg/kg)] is potentially cost-effective at its current list price for the routine reversal of rocuronium-induced moderate (profound) blockade, if each minute of recovery time saved can be valued at approximately 2.40 pounds (1.75 pounds) or more. This is more likely to be achieved if any reductions in recovery time are in the operating room (estimated value of 4.44 pounds per minute saved) rather than the recovery room (estimated value of 0.33 pounds per minute saved). The results were broadly similar for rocuronium- and vecuronium-induced blockade. For rapid reversal of NMB it appeared that any reduction in morbidity from adopting sugammadex is unlikely to result in significant cost savings. The evidence base was not large and many of the published trials were dose-finding and safety studies with very small sample sizes. Also, some relevant outcomes, in particular patient experience/quality of life and resources/costs used, were either not investigated or not reported. In addition, it is likely that the patients included in the efficacy trials were relatively young and in good general health compared with the overall surgical population. Regarding the economic evaluation, there appears to be no evidence linking measures of clinical efficacy to patients' health-related quality of life and mortality risks. Sugammadex may be a cost-effective option compared with neostigmine + glycopyrrolate for reversal of moderate NMB and also provides the facility to recover patients from profound blockade. Rocuronium + sugammadex could be considered as a replacement for succinylcholine for rapid induction (and reversal) of NMB, although this may not be a cost-effective option in some types of patient at current list prices for sugammadex. Considerable uncertainties remain about whether the full benefits of sugammadex can be realised in clinical practice.

Bloqueo fase II después de una dosis subclínica de succinilcolina. Importancia de la monitorización neuromuscular

Neuromuscular monitoring is not a routine practice in clinical settings worldwide. The little interest expressed is mainly because clinicians lack information and documentation, even though the literature on the subject is vast and experts agree that routine monitoring reduces morbidity related to the use of neuromuscular blockers. We report a case of an unusual phase II neuromuscular block from a subclinical dose of succinylcholine. The blockade lasted longer than expected in a patient with diminished plasma cholinesterase activity. We emphasize that monitoring neuromuscular function aided diagnosis and observation of the block during emergency surgery.

Incidence et risques de la curarisation résiduelle postopératoire

A 0.9 train-of-four ratio, measured at the thumb, is currently considered to reflect adequate recovery of neuromuscular block. Recent studies have documented that a train-of-four ratio <0.9 is associated with a decrease in chemoreceptor sensitivity to hypoxia and with a functional impairment of the pharyngeal muscles. These residual effects of neuromuscular blocking agents promote insufficient ventilatory response to hypoxia and regurgitation/aspiration. As a result, the incidence of pulmonary complications have been found to be higher in both early and late postoperative périod in patients with residual curarisation. Clinical tests such as the head lift test and visual or tactile evaluation of the response to peripheral nerve stimulation are no longer sufficient to exclude postoperative residual curarisation. Residual curarisation is still present at the time of extubation despite the use of subjectif monitoring of neuromuscular function, clinical tests and/or reversal of neuromuscular blocking agents. In contrast, acceloromyographic monitoring provides a valuable tool to avoid residual curarisation and to reduce the related-side effects.

A reply

We appreciate the interest of Naguib and Kopman in our recent review article on monitoring neuromuscular transmission [1]. They express concerns regarding methodological criticism of their meta-analysis. In this meta-analysis Naguib et al. [2] could not demonstrate that the use of an intraoperative neuromuscular function monitoring decreased the incidence of postoperative residual cuarisation. This result was surprising and raised methodological concerns [3]. In the mean time a remarkably well conducted meta-analysis confirmed, that contrary to Naguib et al.’s principle conclusion, objective acceleromyographic monitoring might reduce the incidence of postoperative residual paralysis [4]. Finally, Murphy et al. [5] determined the impact on acceleromyography on postoperative residual paralysis in 185 patients randomised to intra-operative acceleromyography monitoring or conventional train of four monitoring. This paper confirmed that the incidence, severity and duration of clinical manifestations of residual paralysis such as hypoxia and airway obstruction were significantly less in the acceleromyography group compared to the conventional neuromuscular monitoring group. Ultimately, an argument should be considered as false if it has been proven to be false. Thus, after all we have to conclude: can objective neuromuscular monitoring reduce residual paralysis? Yes it can!

Increased sensitivity to a nondepolarizing muscle relaxant in a patient with acquired neuromyotonia

Neuromyotonia is a disorder of hyperexcitability of the peripheral nerve. It has electromyographic features of spontaneous, continuous, irregularly occurring doublets, or multiplets of motor unit potential discharges. Neuromyotonia is characterized by both myokymic and neuromyotonic discharges. To our knowledge, this is the first report in the literature to assess the sensitivity of skeletal muscle to a nondepolarizing muscle relaxant drug, rocuronium, in a woman with acquired neuromyotonia. She had a past medical history notable for prolonged postoperative paralysis following anesthesia. The patient showed increased sensitivity to the neuromuscular effects of rocuronium. This increase in sensitivity may be explained by downregulation of acetylcholine receptors in response to chronic high agonist (acetylcholine) concentrations. If patients with neuromyotonia receive anesthesia, we recommend that smaller doses of a nondepolarizing muscle relaxant be administered, accompanied by monitoring of neuromuscular function, so as to provide optimal muscle relaxation while avoiding overdose and prolonged postoperative recovery.

Neuromuscular function monitoring: An equal concern among anaesthesiologistʼs professional associations?

Neuromuscular function monitoring: An equal concern among anaesthesiologistʼs professional associations?

Überwachung 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.

Recovery from neuromuscular blockade and routine monitoring of neuromuscular function

Recovery from neuromuscular blockade and routine monitoring of neuromuscular function