Residual curarization in the recovery room after vecuronium

Residual neuromuscular block in the postanaesthesia care unit: a single-centre prospective observational study and systematic review

BACKGROUND

Concerns regarding residual neuromuscular block (RNMB) have persisted since the introduction of neuromuscular blocking agents, with reported incidences in the 21st century up to 50%. Advances in neuromuscular transmission (NMT) monitoring and the introduction of sugammadex have addressed this issue, but the impact of these developments remains unclear.

METHODS

This prospective observational study evaluated RNMB in 500 surgical patients in a large Dutch teaching hospital with readily available quantitative NMT monitoring and reversal agents. The anaesthetic technique and intraoperative NMT monitoring were independently chosen by the attending anaesthesiologist. Acceleromyography was performed upon arrival in the PACU for patients who received nondepolarising neuromuscular blocking agents. RNMB was defined as a train-of-four ratio (TOFR) <0.9. A systematic review was conducted to analyse trends in RNMB in contemporary practice.

RESULTS

Out of 500 patients, 11 (2.2%) had a TOFR <0.9. Intraoperative NMT monitoring was performed in 77.6% of patients, and sugammadex was administered to 38% of patients. No patient received neostigmine. The only difference was an automatically recorded TOFR ≥0.9 at the end of surgery in 61.1% in the non-RNMB group compared with 18.2% in the RNMB group (P=0.009). Our systematic review identified incidences ranging from 3.5% to 53.3% since 2000, with a decreasing trend in Europe and North America.

CONCLUSIONS

The incidence of residual neuromuscular block in the PACU was 2.2%. This suggests significant improvement in the prevention of residual neuromuscular block and stresses the importance of rigorous neuromuscular transmission monitoring and adequate use of reversal agents.

Comparison of Postoperative Muscle Strength Recovery Between Cisatracurium and Rocuronium

Background Neuromuscular blocking agents are crucial for anesthesia but can cause reversible paralysis, leading to risks like postoperative residual dysfunction. Undetected paralysis in the post-anesthesia care unit (PACU) jeopardizes patient safety by impairing airway function and increasing complications. Effective reversal, assessed clinically or via nerve stimulation, is critical to prevent residual postoperative curarization (RPOC), which is linked to significant morbidity and mortality. Evaluating agents like rocuronium and cisatracurium helps optimize anesthesia outcomes and patient recovery. Methodology The study included 100 American Society of Anaesthesiologists (ASA) I and II patients approved by the Institutional Review Board of Kasturba Medical College, Mangalore, India. Patients were briefed about the study, provided written informed consent, and underwent pre-anesthetic evaluations, including discussions on anesthetic procedures and associated risks. They were instructed to fast overnight after consenting. Results The study compared 100 ASA I and II patients receiving rocuronium or cisatracurium during anesthesia, analyzing age distribution (p=0.429), gender (p=0.839), ASA status (p=0.228), and physical characteristics (height, weight, BMI, p>0.05). Recovery parameters such as hand grip, sustained head lift, and double burst stimulation (DBS) twitch response showed no significant differences between groups (p=0.538 for hand grip and sustained head lift; p=0.220 for DBS. Late recovery rates at 15 minutes were observed with 16% for hand grip, 14% for sustained head lift, and 26% for DBS in the rocuronium group; compared to 14%, 10%, and 16%, respectively, in the cisatracurium group. Conclusion The study found significant postoperative residual curarization in both groups, emphasizing the need for intraoperative and PACU peripheral nerve stimulation for effective assessment. Further research on intraoperative variables could improve understanding of residual paralysis in PACU, guiding better anesthesia management.

Residual Neuromuscular Block Remains a Safety Concern for Perioperative Healthcare Professionals: A Comprehensive Review

Residual neuromuscular block (RNMB) remains a significant safety concern for patients throughout the perioperative period and is still widely under-recognized by perioperative healthcare professionals. Current literature suggests an association between RNMB and an increased risk of postoperative pulmonary complications, a prolonged length of stay in the post anesthesia care unit (PACU), and decreased patient satisfaction. The 2023 American Society of Anesthesiologists Practice Guidelines for Monitoring and Antagonism of Neuromuscular Blockade provide guidance for the use of quantitative neuromuscular monitoring coupled with neuromuscular reversal to recognize and reduce the incidence of RNMB. Using sugammadex for the reversal of neuromuscular block as well as quantitative neuromuscular monitoring to quantify the degree of neuromuscular block may significantly reduce the risk of RNMB among patients undergoing general anesthesia. Studies are forthcoming to investigate how using neuromuscular blocking agent reversal with quantitative monitoring of the neuromuscular block may further improve perioperative patient safety.

Residual Neuromuscular Blockade and Postoperative Pulmonary Complications in the Post-anesthesia Care Unit: A Prospective Observational Study

Background Neuromuscular blocking agents (NMBAs) are employed during general anesthesia induction for endotracheal intubation and to facilitate specific surgeries requiring muscle relaxation. However, residual neuromuscular blockade (RNMB) can lead to respiratory complications in post-anesthesia care units (PACUs). This study investigates RNMB incidence in PACUs and its association with postoperative airway and respiratory issues. Methods A prospective observational study on patients undergoing general anesthesia with NMBAs was conducted at the Department of Anesthesia, Salmaniya Medical Complex, Bahrain, over six months (April to September 2023). Train-of-four (TOF) ratios were calculated using an acceleromyograph upon PACU arrival. Data on demographics, perioperative variables, and postoperative complications were recorded. Results Among 82 patients, 30 (36.6%) had RNMB upon PACU arrival. RNMB incidence declined: 17.1% at 10 minutes, 6.1% at 20 minutes, and 2.4% at 30 minutes, resolving by 40 minutes. Demographics and procedure duration showed no correlation with RNMB. Postoperative respiratory complications affected 23.2% of patients, notably higher in those with RNMB (p = 0.001). Among patients with TOF <90% at PACU arrival, 46.7% experienced complications compared to 9.6% with TOF ≥90% (p<0.001). Participants without RNMB had a significantly higher weight (p = 0.046). Airway support was required for 30% of patients, all with TOF <90% (p<0.001). Conclusion This study emphasizes the importance of assessing and monitoring neuromuscular function to detect and prevent RNMB in PACUs. RNMB presence correlated with an increased susceptibility to postoperative respiratory complications. Regular quantitative neuromuscular monitoring is advisable in clinical practice to proactively mitigate RNMB incidence and its complications.

Efficacy and safety of sugammadex sodium in reversing rocuronium-induced neuromuscular blockade in children: An updated systematic review and meta-analysis

Objective

In response to the differences in pharmacodynamic and pharmacokinetic characteristics of neuromuscular blocking agents between children and adults and limited studies which existing meta-analyses included, this study will update the safety and efficacy of sugammadex (Sug) sodium in reversing rocuronium-induced neuromuscular blockade in children.

Methods

Five electronic databases were searched for clinical trials on the safety and efficacy of Sug sodium in reversing rocuronium-induced neuromuscular block in children. A random-effects model was used to calculate the standardized mean difference (SMD) for primary outcomes. The relative risk (RR) was calculated for secondary outcomes.

Results

As of 2022-11-03, 18 out of 236 studies included 724 children in the intervention group and 478 children in the control group for meta-analysis. The results showed that compared with the control group, the time required for Train-of-Four Ratio (TOFR) to return to 0.9 and the extubation time were shortened in both 2 mg/kg and 4 mg/kg of Sug sodium, with statistically significant differences (TOFR ≥0.9: 2 mg/kg: SMD = -2.90; 95%CI: -3.75, -2.04; 4 mg/kg: -3.31; -4.79, -1.84; extubation time: 2 mg/kg: -2.95; -4.04, -1.85; 4 mg/kg: -1.57; -1.90, -1.23). Compared with the control group, the total incidence of adverse effects in the Sug group was lower (RR = 0.44; 0.24,0.82).

Conclusions

This review and meta-analysis suggest that Sug sodium is more effective and safer in reversing rocuronium-induced neuromuscular blockade in children than traditional antagonistic regimens or placebos.

2023 American Society of Anesthesiologists Practice Guidelines for Monitoring and Antagonism of Neuromuscular Blockade: A Report by the American Society of Anesthesiologists Task Force on Neuromuscular Blockade

These practice guidelines provide evidence-based recommendations on the management of neuromuscular monitoring and antagonism of neuromuscular blocking agents during and after general anesthesia. The guidance focuses primarily on the type and site of monitoring and the process of antagonizing neuromuscular blockade to reduce residual neuromuscular blockade.

Neuromuscular block in patients 80 years and older: a prospective, controlled study

Background

An increasing number of patients older than 80 years are undergoing anesthesia, but little information is available regarding pharmacodynamic effects of myorelaxants in this population. This study aims to compare the time course of rocuronium neuromuscular block in patients ≥ 80 years with those of younger adults.

Methods

Under total intravenous anesthesia with propofol and sufentanil, time course of a bolus of rocuronium 0.6 mg/kg neuromuscular block was assessed with acceleromyography in patients ≥ 80 and in patients 20–50 years old. Onset time, clinical duration, duration until 90% and 100% recovery of baseline were determined.

Results

Data from 32 patients were analyzed, 16 were ≥ 80 years and 16 were 20–50 years old. Demographic data are shown in Table 1. In the group ≥ 80, onset time was 190 s ± 46 s compared to 123 s ± 40 s in the group 20–50, P < 0.001 and the clinical duration was 52 [48–69.5] min and 36 [34–41] min, respectively, P < 0.001. Duration to 90% recovery of baseline was 77.5 [71–88.5] min and duration to 100% recovery of baseline was 91.2 [82.2–98] min in patients ≥ 80 years and the corresponding values in the patients 20–50 years old were 53.5 [49–55.5] min and 59.5 [56.5–70.25] min, respectively, P < 0.001.

Conclusion

Compared to younger adults rocuronium shifted in patients ≥ 80 years from a rapid onset, intermediate acting compound to a slower onset, long-acting compound.

Trial registration

ClinicalTrials.gov identifier: NCT03551652 (29/05/2018).

Quantitative Neuromuscular Monitoring With Train-of-Four Ratio During Elective Surgery: A Prospective, Observational Study

OBJECTIVES

Postoperative residual neuromuscular block (PRNB) is a serious problem that can cause death after surgery. It was aimed to evaluate the adequacy of neuromuscular block (NMB) during endotracheal intubation and the adequacy of neuromuscular recovery during clinically extubation decision and follow-up with the train-of-four ratio (TOFR) using quantitative monitoring.

METHODS

This study has a prospective-observational single-blind study design. A total of 205 adult patients who underwent elective surgery, who had American Society of Anesthesiologists physical statuses I to III, and who were intubated with neuromuscular blocking agent under general anesthesia were included in the study. Train-of-four ratio measurements were provided single-blindly by another anesthesiologist outside the team. The TOFRs were measured at the time of intubation (TOFRind), before reversal agent administration (TOFRpre-rev) and after (TOFRpost-rev), at the time of extubation (TOFRext), and on admission to the postoperative care unit (TOFRPACU). If clinical signs of PRNB appeared, the recovery protocol was applied and then TOFRrec was measured. Postoperative respiratory complications were also evaluated for the first 24 hours after surgery.

RESULTS

Endotracheal intubation was performed in 41.5% of the patients (n = 85) without adequate NMB. In 48.8% (n = 100) of the patients, adequate recovery (TOFRext ˂0.9) was not available at the time of extubation. Adequate TOFRPACU rate was found to be significantly higher in those who did not receive additional neuromuscular blocking agent doses (P < 0.001). In the recovery protocol, low-dose sugammadex administered to patients with clinical signs of PRNB significantly increased the TOFRrec rate compared with neostigmine (P ˂ 0.001). The first 24 hours, postoperative respiratory complication rate was 5.4% (n = 11), and the most common hypoxemia was observed.

CONCLUSIONS

Approximately half of the patients are intubated without sufficient NMB and extubated without sufficient neuromuscular recovery. This suggests that routine use of quantitative neuromuscular monitoring is necessary for patient safety.

Vigilance: the behavioral impact of quantitative monitoring on administration and antagonism of neuromuscular blocking agents

PURPOSE

The aim of this study was to determine whether use of acceleromyography (1) changes dosing of neuromuscular blocking agents (NMBAs), and (2) increases the time between neostigmine administration and extubation, when compared with subjective assessment of neuromuscular blockade.

METHODS

For this retrospective study, data were collected from patient electronic medical records. Patients were included if they had received an NMBA as part of a general anesthetic in 2013 and 2014. Data were analyzed by category of monitoring device: quantitative monitor (acceleromyograph [AMG]) or subjective device (peripheral nerve stimulator [PNS]). Outcomes measured were the total dose of NMBA administered and, the timing of the last dose of NMBA and anticholinesterase relative to tracheal extubation.

RESULTS

Results from multivariate models showed that use of acceleromyography was not associated with a change in the total dose of NMBA administered. In contrast, the number of times any monitor was used, as determined by the frequency with which the train-of-four count (TOFC) was recorded, correlated with the administration of greater amounts of rocuronium (P < 0.01) and vecuronium (P < 0.01). The use of acceleromyography did not prolong the time interval between neostigmine administration and tracheal extubation. The number of times any monitor was used during an anesthetic was associated with a decrease in this time interval. The interval decreased an average of 2.7 min each successive time the TOFC was recorded (P < 0.01).

CONCLUSIONS

The data presented provides insight about the behavioral engineering inherent to the practice of anesthesiology. Introduction of neuromuscular blockade assessment appeared to increase provider vigilance in dosing of NMBAs-regardless of assessment method. The frequency of intraoperative monitoring (quantitative or subjective) was associated with an increased total dose of NMBA administered and decreased time interval between the last dose of neostigmine and extubation.

Comparison of sugammadex and pyridostigmine bromide for reversal of rocuronium-induced neuromuscular blockade in short-term pediatric surgery: A prospective randomized study

BACKGROUND

Sugammadex reverses rocuronium-induced neuromuscular blockade quickly and effectively. This study compared efficacy of sugammadex and pyridostigmine for reversal of rocuronium-induced light block or minimal block in children scheduled for elective entropion surgery.

METHODS

A prospective randomized study was conducted on 60 pediatric patients aged 1 to 11 years and scheduled for entropion surgery under sevoflurane anesthesia. Neuromuscular blockade was achieved by administration of 0.6 mg/kg rocuronium and assessed using train-of-four (TOF) ulnar nerve stimulation. Patients were randomly assigned to 2 groups receiving sugammadex 2 mg/kg or pyridostigmine 0.2 mg/kg plus glycopyrrolate 0.01 mg/kg. Primary outcomes were time from reversal agents administration to TOF ratio 0.9 and time from reversal agent administration to TOF ratio 1.0. Time from TOF ratio 0.9 to extubation, time from TOF ratio 1.0 to extubation, and postoperative adverse events were also recorded.

RESULTS

There were no substantial differences in demographic variables. Time from reversal agents administration to TOF ratio 0.9 and time from reversal agents to TOF ratio 1.0 were significantly faster in sugammadex group: 1.30 ± 0.84 versus 3.53 ± 2.73 minutes (P < .001) and 2.75 ± 1.00 versus 5.73 ± 2.83 minutes (P < .001). Extubation time was shorter in sugammadex group. Incidence of skin rash, nausea, vomiting, and postoperative residual neuromuscular blockade (airway obstruction) was not statistically different between groups. Incidence of patients agitation in recovery room was lower in sugammadex group.

CONCLUSION

Sugammadex provided more rapid reversal of rocuronium-induced neuromuscular blockade in pediatric patients undergoing surgery lasting 30 to 60 minutes than did pyridostigmine plus glycopyrrolate, with no differences in incidence of adverse events between groups.

Effect of Cricoid Pressure Compared With a Sham Procedure in the Rapid Sequence Induction of Anesthesia: The IRIS Randomized Clinical Trial

Importance

The use of cricoid pressure (Sellick maneuver) during rapid sequence induction (RSI) of anesthesia remains controversial in the absence of a large randomized trial.

Objective

To test the hypothesis that the incidence of pulmonary aspiration is not increased when cricoid pressure is not performed.

Design, Setting, and Participants

Randomized, double-blind, noninferiority trial conducted in 10 academic centers. Patients undergoing anesthesia with RSI were enrolled from February 2014 until February 2017 and followed up for 28 days or until hospital discharge (last follow-up, February 8, 2017).

Interventions

Patients were assigned to a cricoid pressure (Sellick group) or a sham procedure group.

Main Outcomes and Measures

Primary end point was the incidence of pulmonary aspiration (at the glottis level during laryngoscopy or by tracheal aspiration after intubation). It was hypothesized that the sham procedure would not be inferior to the cricoid pressure. The secondary end points were related to pulmonary aspiration, difficult tracheal intubation, and traumatic complications owing to the tracheal intubation or cricoid pressure.

Results

Of 3472 patients randomized, mean (SD) age was 51 (19) years and 1777 (51%) were men. The primary end point, pulmonary aspiration, occurred in 10 patients (0.6%) in the Sellick group and in 9 patients (0.5%) in the sham group. The upper limit of the 1-sided 95% CI of relative risk was 2.00, exceeding 1.50, failing to demonstrate noninferiority (P = .14). The risk difference was -0.06% (2-sided 95% CI, -0.57 to 0.42) in the intent-to-treat population and -0.06% (2-sided 95% CI, -0.56 to 0.43) in the per protocol population. Secondary end points were not significantly different among the 2 groups (pneumonia, length of stay, and mortality), although the comparison of the Cormack and Lehane grade (Grades 3 and 4, 10% vs 5%; P <.001) and the longer intubation time (Intubation time >30 seconds, 47% vs 40%; P <.001) suggest an increased difficulty of tracheal intubation in the Sellick group.

Conclusions and Relevance

This large randomized clinical trial performed in patients undergoing anesthesia with RSI failed to demonstrate the noninferiority of the sham procedure in preventing pulmonary aspiration. Further studies are required in pregnant women and outside the operating room.

Trial Registration

ClinicalTrials.gov Identifier: NCT02080754.

Survey of neuromuscular monitoring and assessment of postoperative residual neuromuscular block in a postoperative anaesthetic care unit

INTRODUCTION

The use of neuromuscular blocking agents (NMBAs) is common during general anaesthesia. Neuromuscular monitoring with a peripheral nerve stimulator (PNS) is essential to prevent postoperative residual neuromuscular block (PRNB), defined as a train-of-four (TOF) ratio < 0.9. PRNB remains a common complication and may contribute to morbidity in the postoperative anaesthetic care unit (PACU).

METHODS

An online survey was sent to anaesthesiologists in our department to assess their knowledge and clinical practices related to neuromuscular blockade. Next, a study was conducted on adult patients scheduled for elective surgery under general anaesthesia requiring NMBAs. Upon admission to the PACU, TOF monitoring was performed.

RESULTS

A large proportion of anaesthesiologists showed a lack of knowledge of neuromuscular blockade or non-adherence to the best clinical practices associated with it. The majority (98.7%) stated that they did not routinely use PNS monitoring. In the clinical study, TOF monitoring was only used in 17.9% of the 335 patients who were assessed. The prevalence of PRNB was 33.4% and was associated with the elderly (age ≥ 65 years), a higher dose of NMBA used, a shorter duration of surgery, and a shorter duration between the last dose of NMBA and measurement of PRNB in the PACU. The incidence of adverse symptoms in the PACU was observed to be higher in patients with PRNB.

CONCLUSION

PRNB remains a clinically significant problem, but routine PNS monitoring is rare in our institution. This is compounded by inadequate knowledge and poor adherence to best clinical guidelines related to neuromuscular blockade.

Anesthesiologists' Overconfidence in Their Perceived Knowledge of Neuromuscular Monitoring and Its Relevance to All Aspects of Medical Practice: An International Survey

BACKGROUND

In patients who receive a nondepolarizing neuromuscular blocking drug (NMBD) during anesthesia, undetected postoperative residual neuromuscular block is a common occurrence that carries a risk of potentially serious adverse events, particularly postoperative pulmonary complications. There is abundant evidence that residual block can be prevented when real-time (quantitative) neuromuscular monitoring with measurement of the train-of-four ratio is used to guide NMBD administration and reversal. Nevertheless, a significant percentage of anesthesiologists fail to use quantitative devices or even conventional peripheral nerve stimulators routinely. Our hypothesis was that a contributing factor to the nonutilization of neuromuscular monitoring was anesthesiologists' overconfidence in their knowledge and ability to manage the use of NMBDs without such guidance.

METHODS

We conducted an Internet-based multilingual survey among anesthesiologists worldwide. We asked respondents to answer 9 true/false questions related to the use of neuromuscular blocking drugs. Participants were also asked to rate their confidence in the accuracy of each of their answers on a scale of 50% (pure guess) to 100% (certain of answer).

RESULTS

Two thousand five hundred sixty persons accessed the website; of these, 1629 anesthesiologists from 80 countries completed the 9-question survey. The respondents correctly answered only 57% of the questions. In contrast, the mean confidence exhibited by the respondents was 84%, which was significantly greater than their accuracy. Of the 1629 respondents, 1496 (92%) were overconfident.

CONCLUSIONS

The anesthesiologists surveyed expressed overconfidence in their knowledge and ability to manage the use of NMBDs. This overconfidence may be partially responsible for the failure to adopt routine perioperative neuromuscular monitoring. When clinicians are highly confident in their knowledge about a procedure, they are less likely to modify their clinical practice or seek further guidance on its use.

Muscle Weakness after Muscle Relaxants: An Audit of Clinical Practice

Residual muscle weakness after general anaesthesia, assessed using handgrip strength, was audited in a teaching hospital. The relationships between residual weakness, the use of muscle relaxants and patient characteristics were examined.

Handgrip strength was measured preoperatively, one hour postoperatively and one day postoperatively using a hand dynamometer in 151 patients having general anaesthesia. Forty-nine patients received no muscle relaxant, 34 patients received vecuronium and 68 received rocuronium. Patients were managed by their anaesthetist according to that anaesthetist's clinical choice. All patients who received muscle relaxants received neostigmine.

One hour postoperatively, there was a decline in handgrip strength of 16% for the no relaxant group, 24% for vecuronium and 29% for rocuronium. The degree of weakness for the relaxant groups was unrelated to age (P=0.89) but was strongly influenced by the patient's sex. Almost all of the increased weakness with relaxants was found in the female patients. The mean decline in handgrip strength in the male patients who received either vecuronium or rocuronium was similar to that seen when relaxants had not been used (P=0.40). One hour postoperatively, female patients showed a marked decrease in handgrip strength after both vecuronium and rocuronium (32% and 34% respectively, combined P=0.01).

These results suggest that in usual clinical practice at our institution, female patients are more likely to have residual weakness after muscle relaxants.

Reversal of residual neuromuscular block: complications associated with perioperative management of muscle relaxation

The use of anticholinesterases to reverse residual neuromuscular block at the end of surgery became routine practice in the 1950s. These drugs could only be used when recovery from block was established [two twitches of the train-of-four (TOF) count detectable] and concern was expressed about their cholinergic side-effects. By the 1990s, it was recognized that failure to reverse residual block adequately to a TOF ratio (TOFR) >0.7 was associated with increased risk of postoperative pulmonary complications (POPCs) following the long-acting non-depolarizing neuromuscular blocking drug (NDNMBD) pancuronium. By 2003, and the introduction of acceleromyography, a TOFR ≥0.9 was considered necessary to protect the airway from aspiration before tracheal extubation. It was also considered that four, not two, twitches of the TOF should be detectable before neostigmine was given. Use of any NDNMBD was subsequently shown to be associated with increased risk of POPCs, but it was thought that neostigmine reduced that risk. Recently, there has been conflicting evidence that use of neostigmine might increase the incidence of POPCs. Although sugammadex has been shown to rapidly reverse profound neuromuscular block from aminosteroidal agents, there is currently no evidence that sugammadex is superior to neostigmine in its effect on POPCs. Other new antagonists, including cysteine to degrade CW002 and calabadion 1 and 2 to antagonize aminosteroidal and benzylisoquinolium NDNMBDs, are being studied in preclinical and clinical trials. Quantitative neuromuscular monitoring is essential whenever a NDNMBD is used to ensure full recovery from neuromuscular block.

Reevaluation and update on efficacy and safety of neostigmine for reversal of neuromuscular blockade

Postoperative residual neuromuscular block is a serious threat which endangers the patient safety. Neostigmine has been the most commonly used anticholinesterase for the pharmacological reversal of neuromuscular blockade. Although newer agents have been introduced recently, neostigmine has some irreplaceable advantages, including broad-spectrum reversal of all nondepolarizing neuromuscular blocking drugs, low cost, and availability of more related data for clinical practice to refer to. Neostigmine is also noticed to have some drawbacks, such as the inability to reverse profound and deep blockade, potential induction of muscle weakness, cardiovascular adverse effects, and so on. Data on the usage of neostigmine in the geriatric and the pediatric population are still insufficient. Some discrepancies are observed in the results from previous studies which need further investigation. However, recent studies offer some renewed information. Regarding both efficacy and safety, the key for successful reversal of neuromuscular blockade is to use neostigmine “appropriately,” optimizing the dosage and timing of administration under close monitoring.

A randomized control trial comparing train of four ratio > 0.9 to clinical assessment of return of neuromuscular function before endotracheal extubation on critical respiratory events in adult patients undergoing elective surgery at a tertiary hospital in Nairobi

BACKGROUND

There is increasing evidence that the incidence of postoperative residual paresis after using neuromuscular blockers ranges from 24 to 50% in post anaesthesia care unit (PACU) and is associated with postoperative complications such as critical respiratory events as evidenced by hypoxia, hypoventilation and upper airway obstruction. Quantitative neuromuscular monitoring (such as the assessment of Train of four (TOF) ratio) and reversal of neuromuscular blockers has been shown to reduce postoperative residual paresis. There are very few outcome studies on effect of residual paresis in PACU. There is a paucity of published randomized controlled trials investigating whether using a TOF ratio ≥0.9 before endotracheal extubation compared to clinical assessment of return of neuromuscular function reduces the incidence of critical respiratory events in PACU.

OBJECTIVE

To determine whether using TOF ratio ≥ 0.9 compared to clinical assessment of return of neuromuscular function before endotracheal extubation reduces the incidence of critical respiratory events in PACU.

METHODS

Onehundred sixty eight adult patients in ASA physical status I and II requiring general anaesthesia for elective surgery with cisatracurium as the muscle relaxant were randomized into 2 groups of 84 each. Group 1 were patients who required a TOF ratio of ≥0.9 before extubation. Group 2 patients were extubated based on clinical assessment of return of adequate neuromuscular function by the anaesthetist as is the standard of practice at the Aga Khan University hospital Nairobi. General anaesthesia was standardized in both groups. Both the investigators and patients were blinded during the study.Once the patient was transferred to PACU, oxygen saturation (SP02), respiratory rate and any signs of upper airway obstruction as demonstrated by stridor, laryngospasms or requirement of any airway manipulation was recorded for the first 30 minutes. Duration of anaesthesia and surgery was also recorded. Patient demographics were recorded and analyzed.

RESULTS

There was no statistical difference between the 2 groups in terms of patient demographics, duration of surgery and anaesthesia and duration since last muscle relaxant was given. In terms of hypoxia on arrival in PACU, the incidence of mild hypoxia (SPO2 90-93%) was 11% in clinical assessment groupversus 5% in TOF group P-value 0.149 while severe hypoxia (SPO2 <90%) was 19% versus 10% P-value 0.078. During the first 30 minutes in PACU, the incidence of mild hypoxia (SPO2 90-93%) was statistically significant between the 2 groups (12% in clinical assessment group versus 1% in TOF group, P-value 0.005) while severe hypoxia (SPO2 <90%) was 7% versus 5%, P-value 0.373. The incidence of upper airway obstruction was statistically significant between the two groups (45% in clinical assessment group versus 14% in TOF group P-value<0.0001 for patients requiring airway maneuver, 21% versus 2% P-value <0.0001 for those who required tactile stimulation and 31% versus 12% were snoring, P-value 0.003. Logistic regression analysis revealed TOF group was less likely associated with mild hypoxia (OR 0.09 95% CI 0.01-0.71 P-value 0.023), tactile stimulation (OR 0.09 95% CI 0.02-0.40 P-value 0.002), airway maneuver (OR 0.20 95% CI 0.10-0.43 P-value <0.001) and snoring (OR 0.30 95% CI 0.13-0.68 P-value 0.04).

CONCLUSION

Among this population, there is a lower incidence of critical respiratory events in PACU with the use of neuromuscular monitoring using TOF ratio ≥0.9 to assess neuromuscular function before endotracheal extubation compared with the use of clinical assessment methods.

Neuromuscular blockers and reversal agents and their impact on anesthesia practice

Neuromuscular blockers have long been an intricate part of the anesthesia regimen. The scientific progress in pharmacology and physiology has strengthened their clinical relevance, has helped to delineate with precision their medical role, and has enhanced the safety and effectiveness of their use. New frontiers in research will define further the role of these agents in modern anesthesia practice and guide their expanding and discrete clinical applications.

Reversal agents: do we need to administer with neuromuscular monitoring - an observational study

Background and Aims

In clinical practice, in the majority of patients, recovery from the effect of muscle relaxants is assessed using subjective methods such as head lift, eye-opening, or by sustained hand grip after giving anticholinesterases (neostigmine) at the end of surgery. We planned a prospective observational cohort study to test the hypothesis that objective neuromuscular monitoring can help us in avoiding the use of anticholinesterases for reversal.

Methods

The patients posted for surgery of <2 h duration were included in the study. The cohort of patients was formed on the basis of those who were exposed to objective neuromuscular monitoring of recovery (train-of-four [TOF] ratio of 0.9 or more; exposed group) and the patients who were not exposed to objective neuromuscular monitoring (non-exposed group) acting as a control. Using objective neuromuscular monitoring, the time required for recovery from muscle relaxation when neostigmine was not given for reversal was noted and it was then compared with that of the control group.

Results

A total of 190 patients were enrolled over a period of 3 years. With the use of TOF ratio of 0.9 for extubation, patients safely recovered from neuromuscular blockade, without using neostigmine, with no difference in the mean recovery time (14.48 ± 1.138 min) as compared to the control group (12.14 ± 1.067 min, P = 0.139). There was no incidence of reintubation in post-operative period.

Conclusion

With objective neuromuscular monitoring, we can ensure complete recovery from the neuromuscular blockade while avoiding the use of anticholinesterases.

Neostigmine Administration after Spontaneous Recovery to a Train-of-Four Ratio of 0.9 to 1.0: A Randomized Controlled Trial of the Effect on Neuromuscular and Clinical Recovery

BACKGROUND

When a muscle relaxant is administered to facilitate intubation, the benefits of anticholinesterase reversal must be balanced with potential risks. The aim of this double-blinded, randomized noninferiority trial was to evaluate the effect of neostigmine administration on neuromuscular function when given to patients after spontaneous recovery to a train-of-four ratio of 0.9 or greater.

METHODS

A total of 120 patients presenting for surgery requiring intubation were given a small dose of rocuronium. At the conclusion of surgery, 90 patients achieving a train-of-four ratio of 0.9 or greater were randomized to receive either neostigmine 40 μg/kg or saline (control). Train-of-four ratios were measured from the time of reversal until postanesthesia care unit admission. Patients were monitored for postextubation adverse respiratory events and assessed for muscle strength.

RESULTS

Ninety patients achieved a train-of-four ratio of 0.9 or greater at the time of reversal. Mean train-of-four ratios in the control and neostigmine groups before reversal (1.02 vs. 1.03), 5 min postreversal (1.05 vs. 1.07), and at postanesthesia care unit admission (1.06 vs. 1.08) did not differ. The mean difference and corresponding 95% CI of the latter were -0.018 and -0.046 to 0.010. The incidences of postoperative hypoxemic events and episodes of airway obstruction were similar for the groups. The number of patients with postoperative signs and symptoms of muscle weakness did not differ between groups (except for double vision: 13 in the control group and 2 in the neostigmine group; P = 0.001).

CONCLUSIONS

Administration of neostigmine at neuromuscular recovery was not associated with clinical evidence of anticholinesterase-induced muscle weakness.

VISUAL ABSTRACT

An online visual overview is available for this article.(Figure is included in full-text article.).

The efficacy and safety of sugammadex for reversing postoperative residual neuromuscular blockade in pediatric patients: A systematic review

The aim of this study is to evaluate the efficacy and safety of sugammadex for reversing neuromuscular blockade in pediatric patients. MEDLINE and other three Databases were searched. Randomized clinical trials were included if they compared sugammadex with neostigmine or placebo in pediatric patients undergoing surgery involving the use of rocuronium or vecuronium. The primary outcome was the time interval from administration of reversal agents to train-of-four ratio (TOFr, T4/T1) > 0.9. Incidences of any drug-related adverse events were secondary outcomes. Trial inclusion, data extraction, and risk of bias assessment were performed independently. Mean difference and relative risk were used as summary statistics with random effects models. Statistical heterogeneity was assessed by the I2 statistic. Funnel plot was used to detect publication bias. Ten studies with 580 participants were included. Although considerable heterogeneity (I2 = 98.5%) was detected in primary outcome, the results suggested that, compared with placebo or neostigmine, sugammadex can reverse rocuronium-induced neuromuscular blockade more rapidly with lower incidence of bradycardia. No significant differences were found in the incidences of other adverse events. Compared with neostigmine or placebo, sugammadex may reverse rocuronium-induced neuromuscular blockade in pediatric patients rapidly and safely.

Current Status of Neuromuscular Reversal and Monitoring

Postoperative residual neuromuscular block has been recognized as a potential problem for decades, and it remains so today. Traditional pharmacologic antagonists (anticholinesterases) are ineffective in reversing profound and deep levels of neuromuscular block; at the opposite end of the recovery curve close to full recovery, anticholinesterases may induce paradoxical muscle weakness. The new selective relaxant-binding agent sugammadex can reverse any depth of block from aminosteroid (but not benzylisoquinolinium) relaxants; however, the effective dose to be administered should be chosen based on objective monitoring of the depth of neuromuscular block.

To guide appropriate perioperative management, neuromuscular function assessment with a peripheral nerve stimulator is mandatory. Although in many settings, subjective (visual and tactile) evaluation of muscle responses is used, such evaluation has had limited success in preventing the occurrence of residual paralysis. Clinical evaluations of return of muscle strength (head lift and grip strength) or respiratory parameters (tidal volume and vital capacity) are equally insensitive at detecting neuromuscular weakness. Objective measurement (a train-of-four ratio greater than 0.90) is the only method to determine appropriate timing of tracheal extubation and ensure normal muscle function and patient safety.

Nondepolarizing Neuromuscular Blocking Agents, Reversal, and Risk of Postoperative Pneumonia

Background

Residual postoperative paralysis from nondepolarizing neuromuscular blocking agents (NMBAs) is a known problem. This paralysis has been associated with impaired respiratory function, but the clinical significance remains unclear. The aims of this analysis were two-fold: (1) to investigate if intermediate-acting NMBA use during surgery is associated with postoperative pneumonia and (2) to investigate if nonreversal of NMBAs is associated with postoperative pneumonia.

Methods

Surgical cases (n = 13,100) from the Vanderbilt University Medical Center National Surgical Quality Improvement Program database who received general anesthesia were included. The authors compared 1,455 surgical cases who received an intermediate-acting nondepolarizing NMBA to 1,455 propensity score–matched cases who did not and 1,320 surgical cases who received an NMBA and reversal with neostigmine to 1,320 propensity score–matched cases who did not receive reversal. Postoperative pneumonia incidence rate ratios (IRRs) and bootstrapped 95% CIs were calculated.

Results

Patients receiving an NMBA had a higher absolute incidence rate of postoperative pneumonia (9.00 vs. 5.22 per 10,000 person-days at risk), and the IRR was statistically significant (1.79; 95% bootstrapped CI, 1.08 to 3.07). Among surgical cases who received an NMBA, cases who were not reversed were 2.26 times as likely to develop pneumonia after surgery compared to cases who received reversal with neostigmine (IRR, 2.26; 95% bootstrapped CI, 1.65 to 3.03).

Conclusions

Intraoperative use of intermediate nondepolarizing NMBAs is associated with developing pneumonia after surgery. Among patients who receive these agents, nonreversal is associated with an increased risk of postoperative pneumonia.

Neuromuscular blockade in the elderly patient

Neuromuscular blockade is a desirable or even essential component of general anesthesia for major surgical operations. As the population continues to age, and more operations are conducted in the elderly, due consideration must be given to neuromuscular blockade in these patients to avoid possible complications. This review considers the pharmacokinetics and pharmacodynamics of neuromuscular blockade that may be altered in the elderly. Compartment distribution, metabolism, and excretion of drugs may vary due to age-related changes in physiology, altering the duration of action with a need for reduced dosage (eg, aminosteroids). Other drugs (atracurium, cisatracurium) have more reliable duration of action and should perhaps be considered for use in the elderly. The range of interpatient variability that neuromuscular blocking drugs may exhibit is then considered and drugs with a narrower range, such as cisatracurium, may produce more predictable, and inherently safer, outcomes. Ultimately, appropriate neuromuscular monitoring should be used to guide the administration of muscle relaxants so that the risk of residual neuromuscular blockade postoperatively can be minimized. The reliability of various monitoring is considered. This paper concludes with a review of the various reversal agents, namely, anticholinesterase drugs and sugammadex, and the alterations in dosing of these that should be considered for the elderly patient.

Current recommendations for monitoring depth of neuromuscular blockade

PURPOSE OF REVIEW

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. Although adequate recovery of neuromuscular function has been defined as a train-of-four ratio of at least 0.9, monitoring with a qualitative peripheral nerve stimulator makes it impossible to determine the actual train-of-four ratio.

RECENT FINDINGS

Peripheral nerve stimulators are not routinely used in clinical practice. Without their use, dosing of neuromuscular blocking agents and anticholinesterases is often inappropriate and adequacy of recovery of neuromuscular function upon tracheal extubation cannot be guaranteed.

SUMMARY

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.

Technological advances in perioperative monitoring: Current concepts and clinical perspectives

Minimal mandatory monitoring in the perioperative period recommended by Association of Anesthetists of Great Britain and Ireland and American Society of Anesthesiologists are universally acknowledged and has become an integral part of the anesthesia practice. The technologies in perioperative monitoring have advanced, and the availability and clinical applications have multiplied exponentially. Newer monitoring techniques include depth of anesthesia monitoring, goal-directed fluid therapy, transesophageal echocardiography, advanced neurological monitoring, improved alarm system and technological advancement in objective pain assessment. Various factors that need to be considered with the use of improved monitoring techniques are their validation data, patient outcome, safety profile, cost-effectiveness, awareness of the possible adverse events, knowledge of technical principle and ability of the convenient routine handling. In this review, we will discuss the new monitoring techniques in anesthesia, their advantages, deficiencies, limitations, their comparison to the conventional methods and their effect on patient outcome, if any.

Adverse respiratory events in a post-anesthesia care unit

INTRODUCTION

Adverse respiratory events (ARE) are a leading causes of postoperative morbidity and mortality. This study investigated the incidence and determinants of postoperative ARE.

METHODS

This observational prospective study was conducted in a post anesthesia care unit (PACU). A total of 340 adult subjects were admitted consecutively, and AREs were measured after elective surgery. Population demographics, perioperative parameters, ARE occurrence, and length of stay in the postoperative PACU and in hospital were recorded. Data were analyzed descriptively using the Mann-Whitney U-test and the Chi-square or Fisher's exact test. Multivariate analyses were carried outusing logistic binary regression, and the odds ratio (OR) and 95% confidence interval (CI) were calculated.

RESULTS

Postoperative AREs occurred in 67 subjects (19.7%). AREs were more frequent after high-risk procedures (42% vs 24%; P=.003), in patients undergoing major surgery (37% vs 25%; P=.041), those receiving general anesthesia (85% vs 67%; P=.004), and in patients administered intraoperative muscle relaxants (79% vs 55%; P<.001) and neostigmine (69% vs 49%; P=.002). Hypoactive emergence (13% vs 5%; P=.015) and residual neuromuscular blockade (46% versus 11%; P<.001) were more frequent in subjects with postoperative ARE. On multivariate analyses, residual neuromuscular blockade was an independent risk factor for ARE in the PACU (OR 6.4; CI 3.0-13.4; P<.001).

CONCLUSIONS

ARE is an important and common postoperative complication. Residual neuromuscular blockade was an independent risk factor for ARE in the PACU.

Survey of postoperative residual curarization, acute respiratory events and approach of anesthesiologists

BACKGROUND AND OBJECTIVES

residual paralysis following the use of neuromuscular blocking drugs (NMBDs) without neuromuscular monitoring remains a clinical problem, even when NMBDs are used. This study surveys postoperative residual curarization and critical respiratory events in the recovery room, as well as the clinical approach to PORC of anesthesiologists in our institution.

METHODS

This observational study included 415 patients who received general anesthesia with intermediate-acting NMBDs. Anesthesia was maintained by non-participating anesthesiologists who were blinded to the study. Neuromuscular monitoring was performed upon arrival in the recovery room. A CRE was defined as requiring airway support, peripheral oxygen saturation <90% and 90-93% despite receiving 3 L/min nasal O2, respiratory rate > 20 breaths/min, accessory muscle usage, difficulty with swallowing or speaking, and requiring reintubation. The clinical approach of our anesthesiologists toward reversal agents was examined using an 8-question mini-survey shortly after the study.

RESULTS

The incidence of PORC was 43% (n = 179) for TOFR < 0.9, and 15% (n = 61) for TOFR < 0.7. The incidence of TOFR < 0.9 was significantly higher in women, in those with ASA physical status 3, and with anesthesia of short duration (p < 0.05). In addition, 66% (n = 272) of the 415 patients arriving at the recovery room had received neostigmine. A TOFR < 0.9 was found in 46% (n = 126) of the patients receiving neostigmine.

CONCLUSIONS

When routine objective neuromuscular monitoring is not available, PORC remains a clinical problem despite the use of NMBDs. The timing and optimal antagonism of the neuromuscular blockade, and routine objective neuromuscular monitoring is recommended to enhance patient safety.

Pharyngeal function and breathing pattern during partial neuromuscular block in the elderly: effects on airway protection

BACKGROUND

Intact pharyngeal function and coordination of breathing and swallowing are essential for airway protection and to avoid respiratory complications. Postoperative pulmonary complications caused by residual effects of neuromuscular-blocking agents occur more frequently in the elderly. Moreover, elderly have altered pharyngeal function which is associated with increased risk of aspiration. The purpose of this study was to evaluate effects of partial neuromuscular block on pharyngeal function, coordination of breathing and swallowing, and airway protection in individuals older than 65 yr.

METHODS

Pharyngeal function and coordination of breathing and swallowing were assessed by manometry and videoradiography in 17 volunteers, mean age 73.5 yr. After control recordings, rocuronium was administered to obtain steady-state train-of-four ratios of 0.70 and 0.80 followed by spontaneous recovery to greater than 0.90.

RESULTS

Pharyngeal dysfunction increased significantly at train-of-four ratios 0.70 and 0.80 to 67 and 71%, respectively, compared with 37% at control recordings, and swallowing showed a more severe degree of dysfunction during partial neuromuscular block. After recovery to train-of-four ratio of greater than 0.90, pharyngeal dysfunction was not significantly different from the control state. Resting pressure in the upper esophageal sphincter was lower at all levels of partial neuromuscular block compared with control recordings. The authors were unable to demonstrate impaired coordination of breathing and swallowing.

CONCLUSION

Partial neuromuscular block in healthy elderly individuals causes an increased incidence of pharyngeal dysfunction from 37 to 71%, with impaired ability to protect the airway; however, the authors were unable to detect an effect of partial neuromuscular block on coordination of breathing and swallowing.

Respiratory complications in the pediatric postanesthesia care unit

This article focuses on common respiratory complications in the postanesthesia care unit (PACU). Approximately 1 in 10 children present with respiratory complications in the PACU. The article highlights risk factors and at-risk populations. The physiologic and pathophysiologic background and causes for respiratory complications in the PACU are explained and suggestions given for an optimization of the anesthesia management in the perioperative period. Furthermore, the recognition, prevention, and treatment of these complications in the PACU are discussed.