Antagonism of profound cisatracurium and rocuronium block: the role of objective assessment of neuromuscular function

A real-world pharmacovigilance study of cardiac adverse events induced by sugammadex in the FDA adverse event reporting system

BACKGROUND

Sugammadex is a novel agent that reverses neuromuscular blockade during general anesthesia. Recent case reports have raised concerns regarding potential cardiac adverse events (CAEs). However, no large-scale real-world studies have yet evaluated the potential link between sugammadex and CAEs.

RESEARCH DESIGN AND METHODS

Data from the FDA Adverse Event Reporting System were obtained. The association between sugammadex and CAE was evaluated using reporting odds ratio, proportional reporting ratio, Bayesian confidence propagation neural network, and multi-item gamma Poisson shrinker methods. Serious outcomes resulting from sugammadex-related CAEs were assessed, and complications associated with CAEs were evaluated.

RESULTS

Nineteen CAEs were identified and classified into two categories: cardiac arrhythmias and coronary artery disorders. The most frequent CAEs were bradycardia (n = 202), cardiac arrest (n = 119), tachycardia (n = 30), and Kounis syndrome (n = 22). Subgroup analysis based on age, sex, and weight revealed parallel findings. The CAEs most likely to result in serious consequences were pulseless electrical activity and cardiac arrest. The most common concurrent adverse effects with CAEs were hypotension (n = 51), anaphylactic reactions (n = 46), and anaphylactic shock (n = 23).

CONCLUSION

This study suggests a potential link between sugammadex and CAEs, highlighting the need for careful monitoring and personalized risk assessment, especially in patients with cardiovascular risk factors.

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.

A randomized-controlled trial of sugammadex versus neostigmine: impact on early postoperative strength

BACKGROUND

Residual neuromuscular blockade after surgery is associated with airway obstruction, hypoxia, and respiratory complications. Compared with neostigmine, sugammadex reverses neuromuscular blockade to a train-of-four ratio > 0.9 more rapidly. It is unknown, however, whether the superior reversal profile of sugammadex improves clinically relevant measures of strength in the early postoperative period.

METHODS

Patients undergoing general, gynecological, or urologic surgery were randomized to receive either neostigmine (70 µg·kg^-1, maximum 5 mg) or sugammadex (2 or 4 mg·kg^-1) to reverse neuromuscular blockade. The primary outcome was the ability to breathe deeply measured by incentive spirometry at 30, 60, and 120 min after reversal.

RESULTS

We randomized 62 patients to either a neostigmine (n = 31) or sugammadex (n = 31) group. The incentive spirometry volume recovery trajectory was not different between the two groups (P = 0.35). Median spirometry volumes at baseline, 30, 60, and 120 min postoperatively were 2650 vs 2500 mL, 1775 vs 1750 mL, 1375 vs 2000 mL, and 1800 vs 1950 mL for the sugammadex and neostigmine groups, respectively. Postoperative incentive spirometry decrease from baseline was not different between the two groups. Hand grip strength, the ability to sit unaided, train-of-four ratio on postanesthesia care unit (PACU) admission, time to extubation, time to PACU discharge readiness, and Quality of Recovery-15 scores were also not different between the groups.

CONCLUSIONS

Measures of postoperative strength, such as incentive spirometry, hand group strength, and the ability to sit up in the early postoperative period were not different in patients who received neostigmine or sugammadex for the reversal of neuromuscular blockade.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT02909439); registered: 21 September, 2016.

Neuromuscular Blockade Agents Reversal with Sugammadex Compared to Neostigmine in the Living Kidney Donors

BACKROUND

The reversation of NMBA (neuromuscular blocking agents) prevents numerous postoperative complications, increases quality of recovery and decreases the time, expenditure spending in hospital. The choice of medicine used to reverse NMBA depends considered as a key fators to gain the best outcome and to avoid the side effects.

AIM

To evaluate the postoperative effect on muscle relaxation reversal and side effects of sugammadex 2 mg/kg versus the combination of neostigmine and atropine sulfate in the living kidney donors.

METHODS

A randomised controlled trial on 70 patients undergoing living kidney donation surgery were allocated to 2 groups. Patients in group I (SUGA) were reversed with sugammadex 2 mg/kg and in group II (NEO/ATR) with the combination of neostigmine and atropine sulfat.

RESULTS

With 35 patients in each group, the study results showed that after 3 mintutes of reversal patients reaching TOF value ≥ 0.9 in group SUGA is 91.4%, after 5 minutes 100% of patients in group SUGA reached TOF value ≥ 0.9 . In group NEO/ATR after 3 minutes 28.6% patients reached TOF ≥ 0.9 and 40% patients reached TOF≥ 0.9 after 5 minutes. The difference in percentage of patients reaching TOF ≥ 0.9 after 3 minutes, 5 minutes of reversal between two groups is significant (p<0.05). After 10 minutes, 100% patients in both group got TOF ≥ 0.9. Time to exutubation of group SUGA was 249.43 ± 81.75 seconds and it was 456.29 ± 146.45 seconds in group NEO/ATR. Nausea, bradycardia, and increased phlegm production in group NEO/ATR was 22.9%; 28.5%; 25.7% respectively; while those side effects were not met in group SUGA, the difference was significant (p<0.05).

CONCLUSION

The muscle relaxation reversal effect of sugammadex was faster than that of neostigmine, the duration TOF ≥ 0.9 and the time to extubation was significantly faster. Sugammadex did not cause hemodynamic changes before and after muscle relaxation reversal, neostigmine resulted in the bradycardia, increased phlegm secreting and other side effects. The renal function after 24 hours postoperatively of two groups was similar.

Safety of sugammadex for reversal of neuromuscular block

Introduction: Sugammadex is a modified cyclodextrin that is able to reverse neuromuscular block induced by aminosteroidal neuromuscular blocking drugs. Compared to reversal with neostigmine, it reverses neuromuscular block quicker and more predictable and without cholinergic side effects. However, there have been concerns about sugammadex ability to bind other drugs and its effects on QT interval and clotting times. In addition, sugammadex might induce hypersensitivity reactions more frequently than initially anticipated. This review summarizes current evidence with regard to these and other safety aspects of sugammadex. Areas covered: This review provides an overview of the efficacy of sugammadex in various patient populations, evaluates potential interactions with other drugs and discusses adverse effects and reactions that have been reported in the literature. Expert opinion: Sugammadex quickly reverses aminosteroid neuromuscular block with less side effects compared to neostigmine. As such, it has the potential to significantly reduce the incidence of residual neuromuscular block and to improve postoperative pulmonary outcome. Current safety concerns mainly focus on hypersensitivity reactions and cardiac arrhythmias. Although the absolute risk for these events is low, ongoing vigilance and research in this area are needed.

Optimal dose of combined rocuronium and cisatracurium during minor surgery: A randomized trial

BACKGROUND

Combined rocuronium and cisatracurium have synergistic effects. We investigated whether reduced doses are effective during coadministration, by monitoring neuromuscular relaxation during surgery.

METHODS

This randomized, controlled clinical trial was registered at http://clinicaltrials.gov (registration number NCT02495038). The participants were 81 patients scheduled for elective mastoidectomy and tympanoplasty. Participants were assigned to groups, including the intubating dose group (Group I, n = 27; combined ED95 rocuronium and ED95 cisatracurium), the small reduction group (Group S, n = 27; dose reduced by 10% of each ED95), or the large reduction group (Group L, n = 27; dose reduced by 20% of each ED95). Drugs were administered to patients and a timer was started using TOF-Watch monitoring. TOF (train-of-four) was monitored at the ulnar nerve, at a setting of 2 Hz/12 s. We recorded the time to TOF ratio = 0 (onset), time to first TOF ratio > 25% (duration 25%), and TOF 25-75% (recovery index) under total intravenous anesthesia. One-way analysis of variance was used for statistical analyses (α = 0.05, β = 0.2).

RESULTS

There were no significant demographic differences between groups. Group L had a longer duration to onset (mean ± standard deviation, 399.3 ± 147.8 seconds) and shorter duration 25% (39.4 ± 6.8 minutes) compared to Group I (212.8 ± 56.0 s and 51.3 ± 8.47 minutes, respectively) and Group S (230.7 ± 60.6 s and 47.9 ± 10.7 minutes, respectively). There were no other significant differences between groups.

CONCLUSION

Our findings contribute to determining clinically effective combinations of rocuronium and cisatracurium, as well as to predicting the pharmacokinetic characteristics of the synergistic effects. We suggest that reducing doses of both drugs by approximately 10% of their respective ED95 values is sufficient to maintain neuromuscular relaxation during minor surgery.

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.

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.

The use of sugammadex for bariatric surgery: analysis of recovery time from neuromuscular blockade and possible economic impact

BACKGROUND

Neuromuscular block (NMB) monitoring and use of reversal agents accelerate the recovery time and improve the workflow in the operating room. We aimed to compare recovery times after sugammadex or neostigmine administration, and estimate the time spent in operating theater and the possible economic impact of a faster recovery, in morbidly obese patients undergoing bariatric surgery.

METHODS

We conducted a retrospective study that analyzed data from records of morbidly obese patients (body mass index >40 kg/m(2)) undergoing elective laparoscopic bariatric surgery in which sugammadex or neostigmine were used to reverse NMB. Patients were divided in two groups: group 1 (sugammadex group [SUG]) received rocuronium and sugammadex for reversal and group 2 (neostigmine group [NEO]) received either rocuronium or cisatracurium and neostigmine. Data are presented as mean (standard deviation).

RESULTS

Compared with NEO, SUG group showed shorter times to achieve train-of-four ratio of 0.9 (P<0.05) and an Aldrete score of 10 (P<0.05), a higher cost (€146.7 vs €3.6 [P<0.05]), plus a remarkable less duration of operating theater occupancy (P<0.05). Sugammadex cost accounted for 2.58% of the total cost per surgery, while neostigmine cost accounted for 0.06%. Total time saved in SUG group was 19.4 hours, which could be used to perform 12 extra laparoscopic sleeve gastrectomies.

CONCLUSION

Reversal from NMB was significantly faster with sugammadex than with neostigmine. Although sugammadex was substantially more expensive, duration of operating theater occupancy was reduced with potentially workflow increase or personnel reduced cost.

Residual Paralysis: Does it Influence Outcome After Ambulatory Surgery?

Neuromuscular blocking agents are used to facilitate tracheal intubation in patients undergoing ambulatory surgery. The use of high-dose neuromuscular blocking agents to achieve muscle paralysis throughout the case carries an increased risk of residual post-operative neuromuscular blockade, which is associated with increased respiratory morbidity. Visually monitoring the train-of-four (TOF) fade is not sensitive enough to detect a TOF fade between 0.4 and 0.9. A ratio <0.9 indicates inadequate recovery. Quantitative neuromuscular transmission monitoring (e.g., acceleromyography) should be used to exclude residual neuromuscular blockade at the end of the case. Residual neuromuscular blockade needs to be reversed with neostigmine, but it's use must be guided by TOF monitoring results since deep block cannot be reversed, and neostigmine administration after complete recovery of the TOF-ratio can induce muscle weakness. The development and use of new selectively binding reversal agents (sugammadex and calabadion) warrants reevaluation of this area of clinical practice.

Effects of Neostigmine Reversal of Nondepolarizing Neuromuscular Blocking Agents on Postoperative Respiratory Outcomes

Background:

We tested the hypothesis that neostigmine reversal of neuromuscular blockade reduced the incidence of signs and symptoms of postoperative respiratory failure.

Methods:

We enrolled 3,000 patients in this prospective, observer-blinded, observational study. We documented the intraoperative use of neuromuscular blocking agents and neostigmine. At postanesthesia care unit admission, we measured train-of-four ratio and documented the ratio of peripheral oxygen saturation to fraction of inspired oxygen (S/F). The primary outcome was oxygenation at postanesthesia care unit admission (S/F). Secondary outcomes included the incidence of postoperative atelectasis and postoperative hospital length of stay. Post hoc, we defined high-dose neostigmine as more than 60 μg/kg and unwarranted use of neostigmine as neostigmine administration in the absence of appropriate neuromuscular transmission monitoring.

Results:

Neostigmine reversal did not improve S/F at postanesthesia care unit admission (164 [95% CI, 162 to 164] vs. 164 [161 to 164]) and was associated with an increased incidence of atelectasis (8.8% vs. 4.5%; odds ratio, 1.67 [1.07 to 2.59]). High-dose neostigmine was associated with longer time to postanesthesia care unit discharge readiness (176 min [165 to 188] vs. 157 min [153 to 160]) and longer postoperative hospital length of stay (2.9 days [2.7 to 3.2] vs. 2.8 days [2.8 to 2.9]). Unwarranted use of neostigmine (n = 492) was an independent predictor of pulmonary edema (odds ratio, 1.91 [1.21 to 3.00]) and reintubation (odds ratio, 3.68 [1.10 to 12.4]).

Conclusions:

Neostigmine reversal did not affect oxygenation but was associated with increased atelectasis. High-dose neostigmine or unwarranted use of neostigmine may translate to increased postoperative respiratory morbidity.

Assessment of neuromuscular blockade in children at the time of block reversal and the removal of the endotracheal tube

BACKGROUND AND OBJECTIVES

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.

METHOD

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.

RESULTS

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.

CONCLUSIONS

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.

Neostigmine injected 5 minutes after low-dose rocuronium accelerates the recovery of neuromuscular function

STUDY OBJECTIVE

To determine whether neostigmine 5 minutes after 0.4 mg/kg rocuronium accelerates reversal.

DESIGN

Prospective, randomized, comparative open-label study.

SETTING

Operating room.

PATIENTS

60 ASA physical status I and II patients, aged 18 to 65 years.

INTERVENTIONS

Patients received 0.4 mg/kg rocuronium during nitrous oxide (N(2)O)-propofol-opioid anesthesia. Reversal of neuromuscular blockade was achieved with neostigmine, either at 0.03 mg/kg or 0.05 mg/kg intravenously (IV), together with glycopyrrolate administered 5 minutes after relaxant and compared with spontaneous recovery. Onset, depth, and duration of neuromuscular block, as well as recovery of train-of-four (TOF) to 0.8 and 0.9 were evaluated.

MAIN RESULTS

Times to achieve TOF ratios of 0.8 and 0.9 were significantly shorter when 0.03 mg/kg or 0.05 mg/kg neostigmine was administered 5 minutes after administration of rocuronium (20.2 ± 5 min and 22.6 ± 5.9 min or 17.8 ± 4.8 min and 19.4 ± 5.1 min, respectively) compared with controls (36.2 ± 8.5 min and 39.0 ± 8.7 min; P < 0.01). Duration to spontaneous T1 25% recovery after rocuronium was 15.5 ± 6.5 min versus 9.3 ± 2.3 min and 7.7 ± 1.6 min in the treatment groups (P < 0.01). Recovery index (T1 from 25% to 75%) was significantly shorter after neostigmine (7.1 ± 2.4 min and 5.7 ± 4.0 min) versus controls (13.3 ± 8.3 min; P < 0.01). Speed of reversal did not differ significantly between IV neostigmine doses of 0.03 mg/kg or 0.05 mg/kg.

CONCLUSION

Neostigmine accelerates recovery when administered 5 minutes after injection of IV rocuronium 0.4 mg/kg.

Reversal of rocuronium-induced neuromuscular blockade with sugammadex compared with neostigmine during sevoflurane anaesthesia: results of a randomised, controlled trial

BACKGROUND AND OBJECTIVE

Sugammadex, a modified gamma-cyclodextrin, is a selective relaxant-binding agent designed to reverse the effects of the steroidal neuromuscular blocking agents rocuronium or vecuronium. This study compared the efficacy of sugammadex and neostigmine for reversal of neuromuscular blockade induced by rocuronium for facilitating elective surgery.

METHODS

This randomised, multicentre, parallel-group trial included 98 adult patients. Patients received intravenous propofol for induction followed by sevoflurane maintenance anaesthesia. Neuromuscular blockade was monitored using acceleromyography and a train-of-four (TOF) mode of stimulation. Patients were randomly allocated to receive sugammadex 2.0 mg kg(-1) or neostigmine 50 microg kg (-1) (with glycopyrrolate 10 microg kg(-1)) at reappearance of the second response of the TOF (mean 16% twitch height of first response) after the last dose of rocuronium. Safety was evaluated by assessing adverse events, laboratory variables and vital signs.

RESULTS

Time to recovery of the TOF ratio of 0.9 after sugammadex compared with neostigmine was significantly shorter (P < 0.0001), being 1.5 versus 18.6 min (geometric means). Predictability of response was greater with sugammadex than neostigmine: with 98% of sugammadex patients versus 11% of neostigmine patients recovering to a TOF ratio of 0.9 within 5 min. There were no clinical events related to residual neuromuscular blockade or reoccurrence of blockade. Serious adverse events were observed in two sugammadex-treated patients and in three neostigmine-treated patients, respectively, but none were considered related to study drugs.

CONCLUSION

Sugammadex achieved significantly faster recovery of neuromuscular function after rocuronium to a TOF ratio of 0.9 compared with neostigmine (Clinicaltrials.gov identifier: NCT00451217).

The duration of residual neuromuscular block after administration of neostigmine or sugammadex at two visible twitches during train-of-four monitoring

BACKGROUND

Adequate recovery from neuromuscular block (NMB) is imperative for the patient to have full control of pharyngeal and respiratory muscles. The train-of-4 (TOF) ratio should return to at least 0.90 to exclude potentially clinically significant postoperative residual block. Fade cannot be detected reliably with a peripheral nerve stimulator (PNS) at a TOF ratio >0.4. The time gap between loss of visual fade by using a PNS until objective TOF ratio has returned to >0.90 can be considered "the potentially unsafe period of recovery." According to our hypothesis the duration of this period would be significantly shorter with sugammadex than with neostigmine.

METHODS

Fifty patients received volatile anesthetics, opioids, and a rocuronium-induced NMB. TOF-Watch without a preload was used, but the anesthesiologist relied on visual evaluation of the TOF responses only. At end of operation, patients were randomized to receive either neostigmine 50 μg/kg or sugammadex 2 mg/kg, when 2 twitch responses were detected after the last dose of rocuronium. Timing of tracheal extubation was based on PNS and clinical data. Duration of the potentially unsafe period of recovery after reversal by either neostigmine or sugammadex was analyzed. Mann-Whitney U test and Pearson χ(2) test were used for statistical analysis.

RESULTS

The times [mean ± sd (range)] from loss of visual fade to TOF ratio >0.90 were 10.3 ± 5.5 (1.3 to 26.0) minutes and 0.3 ± 0.3 (0.0 to 1.0) minutes in the neostigmine and sugammadex groups, respectively (P < 0.001). The times from reversal by neostigmine or sugammadex to TOF ratio >0.90 were 13.3 ± 5.7 (3.5 to 28.9) and 1.7 ± 0.7 (0.7 to 3.5) minutes, respectively (P < 0.001). The values of TOF ratios at the time of loss of visual fade were 0.34 ± 0.14 (0.00 to 0.56) in patients given neostigmine and 0.86 ± 0.11 (0.64 to 1.04) in patients given sugammadex (P < 0.001).

CONCLUSIONS

There is a significant time gap between visual loss of fade and return of TOF ratio >0.90 after reversal of a rocuronium block by neostigmine. Sugammadex in comparison with neostigmine allows a safer reversal of a moderate NMB when relying on visual evaluation of the TOF response.

Residual neuromuscular block: lessons unlearned. Part II: methods to reduce the risk of residual weakness

The aim of the second part of this review is to examine optimal neuromuscular management strategies that can be used by clinicians to reduce the risk of residual paralysis in the early postoperative period. Current evidence has demonstrated that frequently used clinical tests of neuromuscular function (such as head lift or hand grip) cannot reliably exclude the presence of residual paralysis. When qualitative (visual or tactile) neuromuscular monitoring is used (train-of-four [TOF], double-burst, or tetanic stimulation patterns), clinicians often are unable to detect fade when TOF ratios are between 0.6 and 1.0. Furthermore, the effect of qualitative monitoring on postoperative residual paralysis remains controversial. In contrast, there is strong evidence that acceleromyography (quantitative) monitoring improves detection of small degrees (TOF ratios >0.6) of residual blockade. The use of intermediate-acting neuromuscular blocking drugs (NMBDs) can reduce, but do not eliminate, the risk of residual paralysis when compared with long-acting NMBDs. In addition, complete recovery of neuromuscular function is more likely when anticholinesterases are administered early (>15-20 minutes before tracheal extubation) and at a shallower depth of block (TOF count of 4). Finally, the recent development of rapid-onset, short-acting NMBDs and selective neuromuscular reversal drugs that can effectively antagonize deep levels of blockade may provide clinicians with novel pharmacologic approaches for the prevention of postoperative residual weakness and its associated complications.

Neostigmine but not sugammadex impairs upper airway dilator muscle activity and breathing

BACKGROUND

Cholinesterase inhibitor-based reversal agents, given in the absence of neuromuscular block, evoke a partial upper airway obstruction by decreasing skeletal upper airway muscle function. Sugammadex reverses neuromuscular block by encapsulating rocuronium. However, its effects on upper airway integrity and breathing are unknown.

METHODS

Fifty-one adult male rats were anaesthetized with isoflurane, tracheostomized, and a femoral artery and vein were cannulated. First, we compared the efficacy of sugammadex 15 mg kg(-1) and neostigmine 0.06 mg kg(-1) to reverse respiratory effects of rocuronium-induced partial paralysis [train-of-four ratio (T4/T1)=0.5]. Subsequently, we compared the safety of sugammadex and neostigmine given after recovery of the T4/T1 to 1, by measuring phasic genioglossus activity and breathing.

RESULTS

During partial paralysis (T4/T1=0.5), time to recovery of minute volume to baseline values was 10.9 (2), 75.8 (18), and 153 (54) s with sugammadex, neostigmine, and placebo, respectively (sugammadex was significantly faster than neostigmine and placebo, P<0.05). Recovery of T4/T1 was also faster for sugammadex than neostigmine and placebo. Neostigmine administration after complete recovery of T4/T1 decreased upper airway dilator muscle activity to 64 (30)% of baseline and decreased tidal volume (P<0.05 for both variables), whereas sugammadex had no effect on either variable.

CONCLUSIONS

In contrast to neostigmine, which significantly impairs upper airway dilator muscle activity when given after recovery from neuromuscular block, a reversal dose of sugammadex given under the same conditions does not affect genioglossus muscle activity and normal breathing. Human studies will be required to evaluate the clinical relevance of our findings.

Neuromuscular monitoring and postoperative residual curarisation: a meta-analysis

We conducted a meta-analysis to examine the effect of intraoperative monitoring of neuromuscular function on the incidence of postoperative residual curarisation (PORC). PORC has been considered present when a patient has a train-of-four (TOF) ratio of < 0.7 or < 0.9. We analysed data from 24 trials (3375 patients) that were published between 1979 and 2005. We excluded data on mivacurium from this meta-analysis because only three studies had examined the incidence of PORC associated with its use. Long- and intermediate-acting neuromuscular blocking drugs had been given to 662 and 2713 patients, respectively. Neuromuscular function was monitored in 823 patients (24.4%). A simple peripheral nerve stimulator was used in 543 patients, and an objective monitor was used in 280. The incidence of PORC was found to be significantly lower after the use of intermediate neuromuscular blocking drugs. We could not demonstrate that the use of an intraoperative neuromuscular function monitor decreased the incidence of PORC.