There are hundreds of publications in the area of neuromuscular blocking agents and neuromuscular monitoring. For the past decade, results of investigations continue to document that residual neuromuscular weakness is a patient safety concern, and call for publication of guidelines that will support the use of neuromuscular monitors in all patients who receive neuromuscular blocking agents. In line with our mission to improve patient outcomes and reduce hospital costs, we have summarized a few of these articles in an attempt to educate about this recurring and avoidable complication. The library is updated continuously. We encourage your comments, and request that you send us new articles that may be helpful to other clinicians and patients.
Consensus Statement on Perioperative Use of Neuromuscular Monitoring.
Naguib, Mohamed MB BCh, MSc, FCARCSI, MD; Brull, Sorin J. MD, FCARCSI (Hon); Kopman, Aaron F. MD; Hunter, Jennifer M. MBE, MB ChB, PhD, FRCA, FCARCSI (Hon); Fülesdi, Béla MD, PhD, DSci; Arkes, Hal R. BA, PhD; Elstein, Arthur PhD; Todd, Michael M. MD; Johnson, Ken B. MD Anesthesia & Analgesia: Post Author Corrections: November 30, 2017 Link
Reversal of residual neuromuscular block: complications associated with perioperative management of muscle relaxation.
J. M. Hunter, University of Liverpool, Institute of Ageing and Chronic Disease, Liverpool L69 3GA, UK. Link
Abstract, “Examining Awake Volunteer Pain Scores and Operator Ease of Use of a Novel Neuromuscular Blockade Monitor” is to be presented at the International Anesthesia Research Society (IARS) meeting in Washington, DC Link
Postoperative pulmonary complications
BJA: British Journal of Anaesthesia, Volume 118, Issue 3, 1 March 2017, Pages 317–334. Link
Conceptual and technical insights into the basis of neuromuscular monitoring.
Anaesthesia. 2017 Jan;72 Suppl 1:16-37. doi: 10.1111/anae.13738. Link
Residual neuromuscular blockade in the postanesthesia care unit.
Observational cross-sectional study of amulticenter cohort. Errando CL.et al. Minerva Anestesiol. Link
Hidden universality of residual neuromuscular block
An editorial yet again concluding the needs for guidelines and the use of objective neuromuscular monitors.
Eikermann M. Br. J. Anaesth. (2016) 116 (3):435-436 February 2016. Link
Survey of postoperative residual curarization, acute respiratory events and approach of anesthesiologists
An oberservational study including 415 patients who received general anesthesia and NMBAs in Turkey. The incidence of PORC among the 415 patients in the study was 43% and 11% of the patients showed Critical Respiratory Event symptoms in the PACU, and this despite the use of neostigmine for reversal in 66% of the patients. The researchers conclude that routine objective neuromuscular monitoring is recommended to enhance patient safety.
Aytac I et al. Rev Bras Anestesiol. 2016;66(1):55-62. Published January 2016. Link
A Strategy for managing neuromuscular blockade – Wiley Online Library
Recommendations for standards of monitoring during anaesthesia and recovery 2015 : Association of Anaesthetists of Great Britain and Ireland
The Association of Anaesthetists of Great Britain and Ireland (AAGBI) issues new guidance on the minimum standards for physiological monitoring of any patient undergoing anaesthesia. The new guidelines include a recommendation to use a quantitative peripheral nerve stimulator whenever neuromuscular blocking drugs are given.
Checketts MR et al. Anaesthesia. December 2015. Link
Incidence of postoperative residual neuromuscular blockade after general anesthesia: A prospective, multicenter, anesthetists-blind, observational study.
In this blinded multicenter study, 1,571 adults undergoing surgery in 32 hospitals across China were monitored for neuromuscular blockade (NMB) using acceleromyography. NMB was reversed with neostigmine in 78% of patients. The overall incidence of residual NMB (rNMB) at extubation was 57.8%. This study demonstrates that the overall incidence of rNMB at the time of endotracheal extubation is high in Chinese patients undergoing abdominal procedures, which necessitates appropriate management in current real-life practice.
Buwei Y et al. Curr Med Res Opin. October 2015 – Issue 9. Pages 1-24. Link
Residual Neuromuscular Block in the Elderly: Incidence and Clinical Implications
Data were prospectively collected on 150 younger and 150 elderly patients. Train-of-four ratios were measured on arrival to the postanesthesia care unit (PACU).
The incidence of postoperative residual neuromuscular block (PRNB) was 57.7% in elderly and 30.0% in younger patients. Airway obstruction, hypoxemic events, signs and symptoms of muscle weakness, postoperative pulmonary complications, and increased PACU and hospital lengths of stay were observed more frequently in the elderly.
The research team concluded that the elderly are at increased risk for PRNB and associated adverse outcomes.
Murphy GS et al. Anesthesiology. October 2015. Link
Can residual paralysis be avoided?: A critical appraisal of the use of Sugammadex
An excellent editorial summarizing the case for Sugamadex as a reversal agent. The author references several key studies concluding the essential need for objective neuromuscular monitoring when using Sugammadex.
Esteves S. European Journal of Anesthesiology. October 2015 – Volume 32 – Issue 10 – p 663–665. Link
The Implementation of Quantitative Electromyographic Neuromuscular Monitoring in an Academic Anesthesia Department: Follow-Up Observations
The letter to editor reports on the progress on the introduction of EMG-based neuromuscular monitoring of 843 patients in an Academic Hospital.
The clinicans report “Since the introduction of department-wide quantitative neuromuscular blockade monitoring, we have seen no PACU reintubations in appropriately monitored patients. The continued failure by some of our providers to use the available technology also reinforces our comments regarding the difficulties in changing long-held, but dangerously erroneous, beliefs that such monitoring is unnecessary and/or that qualitative assessment of reversal is sufficient.”
Todd M. et al. Anesthesia & Analgesia. Volume 121. Sept 2015. Pages 836-838. Link
Postoperative Residual Neuromuscular Paralysis at an Australian Tertiary Children’s Hospital
The prospective study aimed to investigate the incidence and severity of Residual neuromuscular blockade (RNMB) at an Australian tertiary pediatric center.
64 children receiving neuromuscular blocking agents (NMBA) during anesthesia were included and directly prior to tracheal extubation, the train-of-four (TOF) ratio was assessed quantitatively.
The incidence of RNMB (TOF < 0.9) was 28.1% overall. Severe RNMB (TOF ratio < 0.7) was found in 6.5% of the patients.The researchers conclude that the lack of utilization of routine neuromuscular monitoring and poor understanding regarding the consequences of RNMB demonstrate a need for better education to increase greater awareness regarding this issue.
Ledowski T et al. Anesthesiology Research and Practice. Volume 2015, article ID 41024. Link
Incidence of residual neuromuscular block in Spain
The researchers conducted the first prospective, multicenter study of a cohort of patients receiving NMBA in Spain, with a reiew of 763 patients at 26 hospitals. The study concludes an incidence of residual neuromuscular block of 29,8 % among female patients in Spain which is similar to that published in other settings and countries.
Almenara Almenara N. et al of the Spanish Research Group on Residual Neuromuscular Blockade (RNMB). Abstract 1AP20-11 presented at the ESA meeting June 2015.
Reversal of Neuromuscular Blockade. “Identification Friend or Foe”
Another great editorial discussing the need to monitor the depth of NMBA block and adequacy of pharmacologic reversal, and questions why monitoring is still not used routinely across the world.
Objective measurement of neuromuscular function should be mandatory. The depth of block cannot be guessed, inferred, or “assessed” by subjective means, regardless of one’s vast clinical experience—in other words, we should always use objective monitoring technology to identify NMBAs (and for that matter, neostigmine) as either “friend or foe.”
Brull SJ et al. Anesthesiology. 2015 Jun;122(6):1183-1185. Link
Neuromuscular blockade: using quantitative monitoring to get it just right
An excellent infographic describing the rationale for quantitative monitoring. Check out the link here.
Wanderer JP et al. Anesthesiology. 2015 Jun;122(6):A23
Dose-dependent Association between Intermediate-acting Neuromuscular-blocking Agents and Postoperative Respiratory Complications.
In a hospital-based registry study on 48,499 patients who received neuromuscular-blocking agents, the authors tested the primary hypothesis that neuromuscular-blocking agents are dose dependently associated with the risk of postoperative respiratory complications.
In the secondary analysis, the authors evaluated the association between neostigmine dose given for reversal of neuromuscular-blocking agents and respiratory complications.
The reseachers concluded that the use of neuromuscular-blocking agents was dose dependently associated with increased risk of postoperative respiratory complications. Neostigmine reversal was also associated with a dose-dependent increase in the risk of respiratory complications.
MacLean DJ et al. Anesthesiology. 2015 Jun;122(6):1201-13
Uncovering residual paralysis in the PACU: a pilot study
At a major academic hospital not using objective monitoring of NMBA, a pilot study was conducted to measure the TOF ratio using the TOF-Watch (Merck, Organon) on postoperative surgical patients upon arrival in the PACU. All patients had received non-depolarizing neuromuscular blocking drugs and reversal with neostigmine.
TOF ratio measurement was successful in 77% of patients, with failure to determine the TOF ratio due to inadequate twitch height, inconsistent readings, and patient discomfort. 26% of patients had residual paralysis. One patient with residual paralysis required immediate interventions to relieve upper airway obstruction.
The researchers concluded that despite nearly universal administration of reversal agent, one quarter of patients still had residual paralysis. Contributing factors may include inadequate dosing of reversal, inadequate time from reversal to extubation, and reliance on clinical signs and qualitative nerve twitch monitors for determining adequacy of recovery.
Wolf F A et al. Abstract S-247 presented at the IARS 2015 meeting and published online in the March 2015 edition of Anesthesia & Analgesia
Risk factors for unplanned tracheal intubations in general and vascular surgery patients
Unplanned tracheal intubations (re-intubation) after planned extubation in the operating room are a major contributor to postoperative morbidity and mortality. Re-intubation requiring unplanned admission to the intensive care unit has been associated with a 90-fold higher risk of dying in the hospital.
The researchers sought to determine the factors associated with re-intubations. Data were analyzed on 557,592 patients in the Premiere database. Re-intubations occurred in 7,152 patients (1.3%). The failure to use a neuromuscular reversal agent appeared to have the strongest impact on early risk for re-intubation.
Murphy G et al. Abstract S-304 presented at the IARS 2015 meeting and published online in the March 2015 edition of Anesthesia & Analgesia
Comparison of neostigmine induced reversal of vecuronium in normal weight, overweight and obese female patients
Obese patients are more vulnerable to residual neuromuscular block and its associated complications in the post-operative period. In this study the researchers aimed to compare neostigmine induced reversal of vecuronium in normal weight, overweight and obese female patients, objectively using neuromuscular monitoring. The results showed that recovery of TOF to 0.9 was significantly delayed in both overweight (12.18 ± 4.29 min) and obese patients (13.78 ± 4.30 min).
It was concluded that in overweight and obese patients, recovery of neuromuscular blockers is delayed in late phases (TOF 0.7–0.9), which may result in vulnerability for associated complications of incomplete recovery. Ensuring safe recovery thus requires objective NM monitoring.
Joshi SB et al. Indian J Anaesth 2015;59:165-70.
Neuromuscular Monitoring, Muscle Relaxant Use, and Reversal at a Tertiary Teaching Hospital 2.5 Years after Introduction of Sugammadex: Changes in Opinions and Clinical Practice
Sugammadex was introduced to Royal Perth Hospital in early 2011 without access restriction. Departmental audits were undertaken to investigate the change of beliefs and clinical practice related to the use of neuromuscular blocking agents at the Royal Perth Hospital since this introduction.
The researchers found that, in the 2.5 years since introduction of Sugammadex, more anesthetists (69.5 versus 38%) utilized neuromuscular monitoring, and aminosteroidal neuromuscular blocking agents were used in 94.3% of cases (versus 77% in 2011).
Ledowski T, et al. Anesthesiology Research and Practice Volume 2015, Article ID 367937. Link
Prevalence and Risk Factors of Postoperative Residual Curarization in Patients Arriving at Postanesthesia Care Unit after General Anesthesia: A Prospective Cohort Study
A total of 542 patients were included in the study conducted at the Peking University First Hospital. Patients who were admitted to PACU after general anesthesia were enrolled. Neuromuscular function was monitored using acceleromyography and train-of-four (TOF) stimulation. A TOF ratio of less than 0.9 was defined as having Postoperative Residual Curarization (PORC).
PORC occurred in 30.6% of patients. Increasing age, combined use of two different non-depolarizing NMBDs during surgery and hypothermia at PACU arrival were associated with increased risk of PORC. Patients with PORC at PACU arrival had 20% prolonged PACU stay and increased occurrence of adverse events during PACU stay
Xie et al. Journal of Anesthesia and Perioperative Medicine, Nov, 2014 Volume 1 Issue 2. Link
Effects of Neostigmine Reversal of Nondepolarizing Neuromuscular Blocking Agents on Postoperative Respiratory Outcomes – A Prospective Study
3,000 patients at the Massachusetts General Hospital, Boston, MA, were enrolled in this prospective, observer-blinded, observational study. 78% of the patients received Neostigmine for reversal.
Approximately 20% of all the patients proved to have postoperative residual neuromuscular blockade at PACU admission. There was no significant difference in the incidence of postoperative residual neuromuscular blockade between patients who received neostigmine reversal and those who did not.
The researchers concluded that high-dose neostigmine was a strong predictor of atelectasis and was associated with longer postoperative hospital length of stay. Unwarranted use of neostigmine without appropriate guidance from neuromuscular monitoring, was associated with increased respiratory morbidity.
Sasaki et al. Anesthesiology 121;959-68.
Post-Operative Outcomes Associated with Residual Block (RECITE-U.S.)
A post-hoc analysis of a prospective, multi-site study of adult patients undergoing elective open or laparoscopic abdominal surgery lasting ≤4 hours. 255 patients were included with valid TOF measurements at tracheal extubation. The anesthesia providers and PACU nurses were blinded to these values.
The overall incidence of residual neuromuscular blockade (rNMB) at tracheal extubation was 65%. Patients with rNMB at tracheal extubation had statistically significantly greater odds of having an unanticipated hospital procedure as well as needing respiratory therapy.
The researchers concluded that although sample size was limited, the results suggest that rNMB at tracheal extubation can have a significant impact on some post-operative clinical outcomes and healthcare resource use.
Saager et al. Abstract presented at the 2014 American Society of Anesthesiologists meeting. Link
Current recommendations for monitoring depth of neuromuscular blockade.
The article offers an excellent review where the authors summarize that residual neuromuscular block is a relatively frequent occurrence and is associated with postoperative pulmonary complications, including aspiration, pneumonia and hypoxia, impaired hypoxic ventilatory drive and decreased patient satisfaction.
Without the use of nerve stimulators, dosing of neuromuscular blocking agents and anticholinesterases is often inappropriate and adequacy of recovery of neuromuscular function upon tracheal extubation cannot be guaranteed. Use of peripheral nerve stimulators allows clinicians to administer neuromuscular blocking and reversal agents in a rational manner. Routine use of quantitative monitors of depth of neuromuscular blockade is the best guarantee of the adequacy of recovery of postoperative muscle strength.
Lien CA, Kopman AF. Curr Opin Anaesthesiol. 2014 Sep 23. Link
Management of neuromuscular blockade in ambulatory patients
This review summarizes recent developments in neuromuscular blockade, neuromuscular monitoring, and reversal with a special reference to day case surgery.
The author concludes that there could be an increased request for a more intense neuromuscular block during laparoscopic surgery. Therefore, the use of quantitative neuromuscular monitoring and selective reversal binding agents may gain more importance in the future.
“The management of neuromuscular blocks in day case surgery…should include an adequate dosing of the muscle relaxant, quantitative objective monitoring, and a sufficient and appropriate reversal.”
Schreiber JU. Curr Opin Anaesthesiol. 2014 Sep 23.
Residual Paralysis: Does it Influence Outcome After Ambulatory Surgery?
In the USA, it is estimated that over 60 % of surgical and non-surgical procedures are now performed as day-cases with approximately 40 % of these occurring in free-standing ambulatory surgery centers. Research has shown that residual paralysis occurs less frequently in ambulatory surgery, however the proportion of patients affected is still significant at 38%. In the USA alone, it is estimated that postoperative pulmonary complications lead to an additional 92,000 ICU admissions and incur a cost of $3.42 billion each year.
The authors conclude the review stating that outcomes can be improved by employing techniques to minimize the risk of residual paralysis such as neuromuscular transmission monitoring and judicious use of low-dose neuromuscular blocking drugs.
Farhan, Eikermann et al. Curr Anesthesiol Rep. DOI 10.1007/s40140-014-0073-6. Link
The implementation of quantitative electromyographic neuromuscular monitoring in an academic anesthesia department.
In response to a number of incidents of postoperative respiratory failure resulting in reintubation in the PACU, quantitative TOF-monitoring was made available in all ORs at the University of Iowa Carver College of Medicine, Iowa City, Iowa.
The report describes the institutions successful efforts to implement quantitative monitoring. The effort resulted in a significant reduction in the incidence of incompletely reversed patients in the PACU.
Todd MM et al.Anesth Analg 2014 Jun; 119(2):323-31. Link
Residual Neuromuscular Block Should, and Can, Be a “Never Event”
”We therefore urge universal adoption of objective (quantitative) monitoring of neuromuscular transmission as a standard guiding tracheal extubation (TE) decision.”
”…we ask all anesthesia societies (national and international) to urgently create practice guidelines/ standards governing the clinical management and monitoring of neuromuscular blockade. Until such guidelines are published and implemented, the incidence of adverse events related to RNMB in the PACU will continue to surpass all other PACU anesthetic-related morbidities.”
El-Orbany M et al. Anesth Analg. 2014 Mar;118(3):691. Link
Why Are We Using Pulse Oximetry but Not Neuromuscular Monitoring Routinely: The Real World Scenario?
An excellent editorial where the authors question why pulse oximetry is part of global practice guidelines and why not yet neuromuscular monitoring. They conclude ”…recommending that neuromuscular monitoring equipment should be available and used for every patient in whom neuromuscular blocking drugs are used.”
de Boer et al. Anesthesia & Analgesia. Volume 118, Issue 3, Editorial, p 690. Link.
The Incidence of Insufficient Neuromuscular Block: A Registry Analysis
Neuromuscular blocking agents (NMBA’s) facilitate intubation, ventilation, and optimization of surgical conditions. In certain procedures, such as neurovascular, abdominal and laparoscopic surgeries, maintenance of adequate muscle relaxation is essential.
Intraoperative electronic anesthesia records of 48,315 adults having non-cardiac surgery 2005-2013 at the Cleveland Clinic were studied. These records were queried using ten search strategies to identify cases of insufficient intraoperative neuromuscular block.
A total of 13,573 cases or 28% were identified to have insufficient block.
The researchers conclude ”our results suggest that insufficient block is relatively common, even in operations that are generally thought to require muscle relaxation.”
Hesler et al. Abstract presented at the 2013 American Society of Anesthesiologists meeting. Link
Reversal with sugammadex in the absence of monitoring did not preclude residual neuromuscular block.
The researchers demonstrated that the risk of TOFR <0.9 after tracheal extubation after sugammadex remains as high as 9.4% in a clinical setting in which neuromuscular monitoring (objective or subjective) was not used. Our finding underscores the importance of neuromuscular monitoring even when sugammadex is used for antagonism of rocuronium-induced neuromuscular block.
Kotake Y et al. Anesth Analg. 2013 Aug;117(2):345-51. Link
Cohort study of cases with prolonged tracheal extubation times to examine the relationship with duration of workday
An elegant study showing that prolonged extubation times, i.e. the required time to reverse neuromuscular block and remove the endotracheal tube, can be very costly, because most delays result in variable cost increases, not in fixed costs.
Knowing the depth of relaxation intraoperatively and appropriate reversal using objective monitors is likely to avoid these expensive delays.
The authors conclude that prolonged tracheal extubation times should not be treated as fixed costs but as resulting in proportionally increased OR variable costs.
Epstein et al. Can J Anesth/J Can Anesth (2013) 60:1070–1076. Link
Residual neuromuscular block in elderly patients after surgical procedures under general anaesthesia with rocuronium.
The authors conclude that ”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”
Pietraszewski P et al. Anaesthesiol Intensive Ther. 2013 Apr-Jun;45(2):77-81. Link
Neuromuscular monitoring, residual blockade, and reversal: Time for re-evaluation of our clinical practice
The Editorial summarizes some published explanations to why the use of neuromuscular monitors is not adopted in a higher extent despite the clinical evidence in favor. Reasons include lack of equipment, absence of technical support in the field, reliability and the need to improve ease-of-use of monitors.
The author concludes: ”We should revisit and put into practice the fundamental aspects of neuromuscular management, and in particular, methods to avoid residual blockade as well as methods for the safe administration of reversal agents. Let us implement this important aspect of knowledge translation into our daily routine clinical practice. Yes indeed, it is now time for another re-evaluation of current practice of monitoring and reversal.”
Plaud. Can J Anesth/J Can Anesth (2013) 60:634–640. Link
Residual neuromuscular block as a risk factor for critical respiratory events in the post anesthesia care unit.
The researchers conclude that the incidence of residual neuromuscular in the post-anesthesia care unit was 29.7%. Patients with residual neuromuscular block had more frequently overall critical respiratory events (51%), This study suggests that residual neuromuscular block is common in the PACU and is associated with more frequent critical respiratory events.
Norton M et al. Rev Esp Anestesiol Reanim. 2013 Apr;60(4):190-6. Link
Residual neuromuscular block as a risk factor for critical respiratory events in the post anesthesia care unit
The researchers studied a total of 202 patients admitted to the PACU during a three-week period. On arrival in the PACU, 61 patients or 29.7% were found to have neuromuscular residual block. A total of 51 patients had Critical Respiratory Events (CREs) and the incidence of CREs was significantly higher in the group with TOF-values <0.9 as compared to the group with TOF-values ≥0.9. The researchers conclude that residual neuromuscular block is common in the PACU and is associated with more frequent critical respiratory events.
Norton, Xará et al. Rev Esp Anestesiol Reanim. 2013;60(4):190-196. Link
Postoperative residual neuromuscular blockade is associated with impaired clinical recovery.
The researchers sought to sought to determine the association between objective evidence of residual neuromuscular blockade (train-of-four [TOF] ratio;0.9) and the type, incidence, and severity of subjective symptoms of muscle weakness in the postanesthesia care unit (PACU).
It was concluded that the incidence of symptoms of muscle weakness was significantly higher in the TOF <0.9 group at all times (P < 0.001), as was the median (range) number of symptoms from PACU arrival.
Murphy GS et al. Anesth Analg. 2013 Jul;117(1):133-41. Link
Intermediate acting non-depolarizing neuromuscular blocking agents and risk of postoperative respiratory complications: prospective propensity score matched cohort study
In this large study, 18 579 surgical patients who received intermediate acting neuromuscular blocking agents (NMBAs) during surgery were matched by propensity score to 18 579 reference patients who did not receive such agents. The objective was to determine whether use of intermediate acting NMBAs during general anesthesia increases the incidence of postoperative respiratory complications.
The researchers conclude that use of intermediate NMBAs during anesthesia was associated with an increased risk of clinically meaningful respiratory complications. Qualitative monitoring of neuromuscular transmission did not did not help prevent postoperative respiratory complications. The clinical strategies used in the trial to prevent residual postoperative neuromuscular blockade should be revisited.
Furthermore, the researchers conclude that in the United States, treatment of critically ill patients represents nearly 1% of the gross domestic product and 25% of a typical hospital budget. Therefore, all efforts should be undertaken to reduce factors that contribute to unplanned admissions to an intensive care unit.
Grosse-Sundrup et al. BMJ 2012;345:e6329 doi: 10.1136/bmj.e6329 Link
Monitoring and Pharmacologic Reversal of a Nondepolarizing Neuromuscular Blockade Should Be Routine
The authors conclude that ”evidence and logic dictate that strong consideration be given to routine monitoring of NMB and pharmacologic antagonism (i.e., reversal) of a nondepolarizing NMB. This combination offers the anesthesiologist the best opportunity to attenuate the occurrence, but probably not eliminate residual NMB in the immediate postoperative period.”
Miller et al. International Anesthesia Research Society. July 2010, Volume 111, Number 1. Link
Evidence-Based Management of Neuromuscular Block
The authors conclude in the Editorial that ”Good evidence-based practice dictates that the anesthesiologist, preferably perioperatively but at least before sending the patients to the recovery ward, should ensure that the TOF ratio is 0.90 or more by using an objective monitor.”
Viby-Mogensen et al. Anesth Analg 111;1-2. Link
Residual Neuromuscular Block: Lessons Unlearned.
Part I: Definitions, Incidence, and Adverse Physiologic Effects of Residual Neuromuscular Block
Part II: Methods to Reduce the Risk of Residual Weakness
These review articles summarize the clinical implications of residual neuromuscular block as well as the optimal neuromuscular management strategies that can be used by clinicians to reduce the risk of residual paralysis in the early postoperative period. The authors conclude that there is strong evidence that quantitative monitoring improves detection and risk of residual blockade. Data suggest that residual neuromuscular block is a common complication in the postanesthesia care unit, with approximately 40% of patients exhibiting a train-of-four ratio <0.9.
Managing Neuromuscular Block: Where are the Guidelines?
A great editorial summarizing: ”…I firmly believe that some policy statement from the ASA regarding the management of neuromuscular block is long overdue.”
Kopman A. Anesthesia & Analgesia. July 2010 – Volume 111 – Issue 1 – p 9–10. Link
Neuromuscular Monitoring: What Evidence Do We Need to Be Convinced?
Yet another excellent editorial summarizing: ”Objective monitoring should be one of the key strategies used by anesthesiologists to avoid the consequences of neuromuscular blockade.”
Donati F. Anesthesia & Analgesia. July 2010 – Volume 111 – Issue 1 – p 6–8. Link
Postoperative residual curarization from intermediate-acting neuromuscular blocking agents delays recovery room discharge
A very interesting study where the researchers studied 248 patients arriving to the PACU of the Massachusetts General Hospital, US, after receiving NMBDs as part of surgical anaesthesia.
PACU length of stay was significantly longer (33%) in patients with a TOF <0.9 as compared with patients with adequate recovery of neuromuscular transmission. Age and diagnosis of TOF-level, but not the type of neuromuscular blocking agent, were independently associated with PACU length of stay. Delayed discharge significantly increases the chances of patients having to wait to enter the PACU. The authors conclude that Postoperative residual curarization is associated with a delayed PACU discharge. The magnitude of the effect is clinically significant.
The authors recommend increased use of neuromuscular monitoring.
Butterly et al. British Journal of Anaesthesia 105 (3): 304–9 (2010). Link
Neuromuscular monitoring: Old issues, new controversies
An excellent review article where Professor Kopman concludes that objective TOF-monitors should be available in any modern anesthetizing location where neuromuscular blocking drugs are administered.
Kopman. Journal of Critical Care (2009) 24, 11–20. Link
Postoperative residual neuromuscular block: a survey of management
This study aimed to evaluate changes of perioperative neuromuscular block management over a 10 year period at a French hospital that introduced objective TOF-monitoring in the mid 1990’s.
It was concluded that the use of intraoperative monitoring of neuromuscular function rose from 2% to 60% and reversal of residual antagonism increased from 6% to 42% of cases.
As a result of the changes in clinical practice, the incidence of PORC decreased from 62% to less than 4%. The study confirms the positive impact of neuromuscular monitoring and reversal of neuromuscular block in routine anaesthetic practice.
Baillard et. al. British Journal of Anaesthesia 95 (5): 622–6. Link
Residual Paralysis at the Time of Tracheal Extubation
120 patients were enrolled at the Northwestern University Feinberg School of Medicine in Chicago aiming to investigate TOF ratios immediately before tracheal extubation, when clinicians had determined that full recovery of neuromuscular function had occurred using standard clinical criteria.
It was concluded that significant residual paralysis was present in the majority of patients at the anticipated time of tracheal extubation. Despite the use of a protocol directing strict monitoring and reversal of an intermediate-acting muscle relaxant, and the performance of a careful clinical examination for signs of muscle weakness, clinicians were consistently unable to achieve acceptable levels of neuromuscular recovery in the OR.
In order for anesthesiologists to be assured that neuromuscular recovery is complete and that respiratory and pharyngeal muscle function has returned to normal, quantitative neuromuscular monitoring is required.
The authors conlcude that complete recovery from neuromuscular blockade is rarely present at the time of tracheal extubation.
Murphy G. et al. Anesth Analg 2005;100:1840–5. Link
Evidence-based Practice and Neuromuscular Monitoring
Another excellent editorial authored by Prof Lars Eriksson of the Karolinska Hospital, Stockholm. He concludes:
”The message is short and clear — it is time to move from discussion to action and introduce objective neuromuscular monitoring in all operating rooms, not just those occupied by researchers and aficionados of muscle relaxants. I believe that objective neuromuscular monitoring is an evidence-based practice and should consequently be used whenever a nondepolarizing neuromuscular blocking agent is administered. Such monitoring is noninvasive and has little risk, and there are strong reasons to believe that its use can improve patient outcome.”
Anesthesiology 2003; 98:1037–9.
Quantative Assesment of Residual Antidepolarizing Block
This the first of a series of landmark studies by HH Ali et al. introducing the Train-of-Four (TOF) to measure the degree of neuromuscular block in man.
Ali HH, Br J Anaesth 42;967. Link