Good clinical research practice in pharmacodynamic studies of neuromuscular blocking agents II: the Stockholm revision

Comparison of the trapezius and the adductor pollicis muscle as predictor of good intubating conditions: a randomized controlled trial

Background

Adequate muscle relaxation is important for ensuring optimal conditions for intubation. Although acceleromyography of the adductor pollicis muscle is commonly used to assess conditions for intubation, we hypothesized that acceleromyography of the trapezius is more indicative of optimal intubating conditions. The primary outcome was the difference between both measurement sites with regard to prediction of good or acceptable intubating conditions.

Methods

Neuromuscular blockade after injection of rocuronium 0.3 mg/kg IV was measured simultaneously with acceleromyography of the adductor pollicis muscle and the trapezius muscle in sixty female patients, American Society of Anesthesiologists physical status I to III, undergoing general anesthesia for gynecologic surgery. Exclusion criteria were: expected difficult tracheal intubation (e.g. history of difficult intubation, reduced mouth opening (< 2 cm) and/or Mallampati Score 4), increased risk of pulmonary aspiration (e.g. gastroesophageal reflux or delayed gastric emptying) allergies to drugs used during the study, pregnancy, neuromuscular diseases, medication with potential to influence neuromuscular function (e.g. furosemide, magnesium, cephalosporins) and hepatic or renal insufficiency (serum bilirubin >26 μmol/L, serum creatinine >90 μmol/l). Patients were randomized to 2 groups: group A (n = 30): endotracheal intubation after onset of the neuromuscular block at the adductor pollicis muscle. Group B (n = 30): endotracheal intubation after onset at the trapezius muscle. Intubating conditions were compared between both groups by means of a standardised score (the Copenhagen score) with Fisher’s exact test.

Results

Onset of the block after rocuronium injection was observed at the adductor pollicis muscle compared to the trapezius with 2.8 (1.1) versus 2.5 (1.1) min (mean ± SD; P = 0.006). Intubating conditions were poor in 2 patients (7%) of group A, and in 1 patient (3%) of group T. They were acceptable (either excellent or good) in 28 patients (93%) in group A, and in 1 patient (97%) in group T (P = 0.82).

Conclusions

Performing acceleromyography at the trapezius muscle reduced the time between injection of neuromuscular blocking agents and intubation by 18 s (11%). Thus, trapezius muscle acceleromyography is an acceptable alternative to adductor pollicis muscle acceleromyography in predicting acceptable intubating conditions, which allows for earlier indication of adequate intubating conditions.

Trial registration

ClinicalTrial.gov Identifier: NCT01849198. Registered April 29, 2013.

Development of an algorithm using clinical tests to avoid post-operative residual neuromuscular block

BACKGROUND

Quantitative neuromuscular monitoring is the gold standard to detect postoperative residual curarization (PORC). Many anesthesiologists, however, use insensitive, qualitative neuromuscular monitoring or unreliable, clinical tests. Goal of this multicentre, prospective, double-blinded, assessor controlled study was to develop an algorithm of muscle function tests to identify PORC.

METHODS

After extubation a blinded anesthetist performed eight clinical tests in 165 patients. Test results were correlated to calibrated electromyography train-of-four (TOF) ratio and to a postoperatively applied uncalibrated acceleromyography. A classification and regression tree (CART) was calculated developing the algorithm to identify PORC. This was validated against uncalibrated acceleromyography and tactile judgement of TOF fading in separate 100 patients.

RESULTS

After eliminating three tests with poor correlation, a model with four tests (r = 0.844) and uncalibrated acceleromyography (r = 0.873) were correlated to electromyographical TOF-values without losing quality of prediction. CART analysis showed that three consecutively performed tests (arm lift, head lift and swallowing or eye opening) can predict electromyographical TOF. Prediction coefficients reveal an advantage of the uncalibrated acceleromyography in terms of specificity to identify the EMG measured train-of-four ratio < 0.7 (100% vs. 42.9%) and <0.9 (89.7% vs. 34.5%) compared to the algorithm. However, due to the high sensitivity of the algorithm (100% vs. 94.4%), the risk to overlook an awake patient with a train-of-four ratio < 0.7 was minimal. Tactile judgement of TOF fading showed poorest sensitivity and specifity at train of four ratio < 0.9 (33.7%, 0%) and <0.7 (18.8%, 16.7%).

CONCLUSIONS

Residual neuromuscular blockade can be detected by uncalibrated acceleromyography and if not available by a pathway of four clinical muscle function tests in awake patients. The algorithm has a discriminative power comparable to uncalibrated AMG within TOF-values >0.7 and <0.3.

TRIAL REGISTRATION

Clinical Trials.gov (principal investigator's name: CU, and identifier: NCT03219138) on July 8, 2017.

Dexamethasone Does Not Inhibit Sugammadex Reversal After Rocuronium-Induced Neuromuscular Block

BACKGROUND

Sugammadex is a relatively new molecule that reverses neuromuscular block induced by rocuronium. The particular structure of sugammadex traps the cyclopentanoperhydrophenanthrene ring of rocuronium in its hydrophobic cavity. Dexamethasone shares the same steroidal structure with rocuronium. Studies in vitro have demonstrated that dexamethasone interacts with sugammadex, reducing its efficacy. In this study, we investigated the clinical relevance of this interaction and its influence on neuromuscular reversal.

METHODS

In this retrospective case-control study, we analyzed data from 45 patients divided into 3 groups: dexamethasone after induction group (15 patients) treated with 8 mg dexamethasone as an antiemetic drug shortly after induction of anesthesia; dexamethasone before reversal group (15 patients) treated with dexamethasone just before sugammadex injection; and control group (15 patients) treated with 8 mg ondansetron. All groups received 0.6 mg/kg rocuronium at induction, 0.15 mg/kg rocuronium at train-of-four ratio (TOF) 2 for neuromuscular relaxation, and 2 mg/kg sugammadex for reversal at the end of the procedure at TOF2. Neuromuscular relaxation was monitored with a TOF-Watch® system.

RESULTS

The control group had a recovery time of 154 ± 54 seconds (mean ± SD), the dexamethasone after induction group 134 ± 55 seconds, and the dexamethasone before reversal group 131 ± 68 seconds. The differences among groups were not statistically significant (P = 0.5141).

CONCLUSIONS

Our results show that the use of dexamethasone as an antiemetic drug for the prevention of postoperative nausea and vomiting does not interfere with reversal of neuromuscular blockade with sugammadex in patients undergoing elective surgery with general anesthesia in contrast to in vitro studies that support this hypothesis.

The Impact of Residual Neuromuscular Blockade, Oversedation, and Hypothermia on Adverse Respiratory Events in a Postanesthetic Care Unit: A Prospective Study of Prevalence, Predictors, and Outcomes

BACKGROUND

Residual neuromuscular blockade (RNMB) has been linked to adverse respiratory events (AREs) in the postanesthetic care unit (PACU). However, these events are often not attributed to RNMB by anesthesiologists because they may also be precipitated by other factors including obstructive sleep apnea, opioids, or hypnotic agents. Many anesthesiologists believe RNMB occurs infrequently and is rarely associated with adverse outcomes. This study evaluated the prevalence and predictors of RNMB and AREs.

METHODS

This prospective cohort study included 599 adult patients undergoing general anesthesia who received neuromuscular blocking agents. Baseline demographic, surgical, and anesthetic variables were collected. RNMB was defined as a train-of-four ratio below 0.90 measured by electromyography on admission to the PACU. AREs were defined based on the modified Murphy's criteria.

RESULTS

RNMB was present in 186 patients (31% [95% confidence interval (CI), 27%-35%]) on admission to the PACU. One or more AREs were experienced by 97 patients (16% [95% CI 13-19]). AREs were more frequent in patients with RNMB (21% vs 14%, P = .033). RNMB was significantly associated with age (adjusted relative risk [RR], 1.17 [95% CI, 1.06-1.29] per 10-year increase), type of operation (adjusted RR, 0.59 [95% CI, 0.34-0.99] for laparoscopic surgery compared with open abdominal surgery), and duration of operation (adjusted RR, 0.59 [95% CI, 0.39-0.86] for ≥90 minutes compared with <90 minutes). Using multivariate logistic regression, AREs were found to be independently associated with decreased level of consciousness (adjusted RR, 4.76 [95% CI, 1.49-6.76] for unrousable/unconscious compared with alert/awake) and lower core temperature (adjusted RR, 1.43 [95% CI, 1.04-1.92] per 1°C decrease). Although univariate analysis found a significant association between AREs and RNMB, the significance became borderline after adjusting for other covariates (adjusted RR, 1.46 [95% CI, 0.99-2.08]).

CONCLUSIONS

The prevalence of RNMB in the PACU was >30%. Older age, open abdominal surgery, and duration of operation <90 minutes were associated with increased risk of RNMB in our patients. Our RR estimate for AREs was highest for depressed level of consciousness. When AREs occur in the PACU, potentially preventable causes including RNMB, hypothermia, and reduced level of consciousness should be readily identified and treated appropriately. Delaying extubation until the patient is awake and responsive may reduce AREs.

Minimum Effective Doses of Succinylcholine and Rocuronium During Electroconvulsive Therapy: A Prospective, Randomized, Crossover Trial

BACKGROUND

Neuromuscular blockade is required to control excessive muscle contractions during electroconvulsive therapy (ECT). In a crossover, assessor-blinded, prospective randomized study, we studied the minimum effective dose (MED) of succinylcholine and rocuronium for ECT. The MED was the lowest dose to provide a predefined qualitative measure of acceptable control of muscle strength during induced convulsions.

METHODS

Succinylcholine (0.8 mg kg) or rocuronium (0.4 mg kg) was randomly administered in 227 ECT sessions to 45 patients. The dose was incrementally increased or decreased by 10% based on 2 psychiatrists' (blinded to treatment) assessment of "acceptable" or "not acceptable" control of evoked muscle contractions (sufficient versus insufficient or excessive paralysis). The neuromuscular transmission was monitored quantitatively until full recovery.

RESULTS

In our study, the MEDs of succinylcholine and rocuronium to produce acceptable ECT conditions in 50% of patients (MED50ECT) were 0.85 mg kg (95% confidence interval [CI], 0.77-0.94) and 0.41 mg kg (95% CI, 0.36-0.46) and in 90% of patients (MED90ECT) were 1.06 mg kg (95% CI, 1.0-1.27) and 0.57 mg kg (95% CI, 0.5-0.6), respectively. Nadir twitch height for acceptable muscle activity was 0% (0-4) and 4% (0-30; P < 0.001), respectively, and the time to recovery of the neuromuscular transmission was 9.7 ± 3.5 and 19.5 ± 5.7 minutes, respectively.

CONCLUSIONS

A twitch suppression of >90% is needed for control of motor contractions during ECT. The initial ECT dose of succinylcholine should be selected based on each patient's preprocedural condition, ranging between 0.77 and 1.27 mg kg to produce acceptable muscle blockade in 50% to 90% of patients. Rocuronium-neostigmine combination is a safe alternative if appropriately dosed (0.36-0.6 mg kg) and monitored.

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

OBJECTIVE

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

DESIGN

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

METHODS

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

RESULTS

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

Avoidance versus use of neuromuscular blocking agents for improving conditions during tracheal intubation or direct laryngoscopy in adults and adolescents

BACKGROUND

Tracheal intubation during induction of general anaesthesia is a vital procedure performed to secure a patient's airway. Several studies have identified difficult tracheal intubation (DTI) or failed tracheal intubation as one of the major contributors to anaesthesia-related mortality and morbidity. Use of neuromuscular blocking agents (NMBA) to facilitate tracheal intubation is a widely accepted practice. However, because of adverse effects, NMBA may be undesirable. Cohort studies have indicated that avoiding NMBA is an independent risk factor for difficult and failed tracheal intubation. However, no systematic review of randomized trials has evaluated conditions for tracheal intubation, possible adverse effects, and postoperative discomfort.

OBJECTIVES

To evaluate the effects of avoiding neuromuscular blocking agents (NMBA) versus using NMBA on difficult tracheal intubation (DTI) for adults and adolescents allocated to tracheal intubation with direct laryngoscopy. To look at various outcomes, conduct subgroup and sensitivity analyses, examine the role of bias, and apply trial sequential analysis (TSA) to examine the level of available evidence for this intervention.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, BIOSIS, International Web of Science, LILACS, advanced Google, CINAHL, and the following trial registries: Current Controlled Trials; ClinicalTrials.gov; and www.centerwatch.com, up to January 2017. We checked the reference lists of included trials and reviews to look for unidentified trials.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) that compared the effects of avoiding versus using NMBA in participants 14 years of age or older.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data independently. We conducted random-effects and fixed-effect meta-analyses and calculated risk ratios (RRs) and their 95% confidence intervals (CIs). We used published data and data obtained by contacting trial authors. To minimize the risk of systematic error, we assessed the risk of bias of included trials. To reduce the risk of random errors caused by sparse data and repetitive updating of cumulative meta-analyses, we applied TSA.

MAIN RESULTS

We identified 34 RCTs with 3565 participants that met our inclusion criteria. All trials reported on conditions for tracheal intubation; seven trials with 846 participants described 'events of upper airway discomfort or injury', and 13 trials with 1308 participants reported on direct laryngoscopy. All trials used a parallel design. We identified 18 dose-finding studies that included more interventions or control groups or both. All trials except three included only American Society of Anesthesiologists (ASA) class I and II participants, 25 trials excluded participants with anticipated DTI, and obesity or overweight was an excluding factor in 13 studies. Eighteen trials used suxamethonium, and 18 trials used non-depolarizing NMBA.Trials with an overall low risk of bias reported significantly increased risk of DTI with no use of NMBA (random-effects model) (RR 13.27, 95% CI 8.19 to 21.49; P < 0.00001; 508 participants; four trials; number needed to treat for an additional harmful outcome (NNTH) = 1.9, I² = 0%, D² = 0%, GRADE = moderate). The TSA-adjusted CI for the RR was 1.85 to 95.04. Inclusion of all trials resulted in confirmation of results and of significantly increased risk of DTI when an NMBA was avoided (random-effects model) (RR 5.00, 95% CI 3.49 to 7.15; P < 0.00001; 3565 participants; 34 trials; NNTH = 6.3, I² = 70%, D² = 82%, GRADE = low). Again the cumulative z-curve crossed the TSA monitoring boundary, demonstrating harmful effects of avoiding NMBA on the proportion of DTI with minimal risk of random error. We categorized only one trial reporting on upper airway discomfort or injury as having overall low risk of bias. Inclusion of all trials revealed significant risk of upper airway discomfort or injury when an NMBA was avoided (random-effects model) (RR 1.37, 95% CI 1.09 to 1.74; P = 0.008; 846 participants; seven trials; NNTH = 9.1, I² = 13%, GRADE = moderate). The TSA-adjusted CI for the RR was 1.00 to 1.85. None of these trials reported mortality. In terms of our secondary outcome 'difficult laryngoscopy', we categorized only one trial as having overall low risk of bias. All trials avoiding NMBA were significantly associated with difficult laryngoscopy (random-effects model) (RR 2.54, 95% CI 1.53 to 4.21; P = 0.0003; 1308 participants; 13 trials; NNTH = 25.6, I² = 0%, D²= 0%, GRADE = low); however, TSA showed that only 6% of the information size required to detect or reject a 20% relative risk reduction (RRR) was accrued, and the trial sequential monitoring boundary was not crossed.

AUTHORS' CONCLUSIONS

This review supports that use of an NMBA may create the best conditions for tracheal intubation and may reduce the risk of upper airway discomfort or injury following tracheal intubation. Study results were characterized by indirectness, heterogeneity, and high or uncertain risk of bias concerning our primary outcome describing difficult tracheal intubation. Therefore, we categorized the GRADE classification of quality of evidence as moderate to low. In light of defined outcomes of individual included trials, our primary outcomes may not reflect a situation that many clinicians consider to be an actual difficult tracheal intubation by which the patient's life or health may be threatened.

Sevoflurane at 1.0 MAC together with remifentanil and propofol produces clinically acceptable intubation conditions at the vocal cords: A prospective randomized study

Objective

The overall intubation conditions after tracheal intubation with remifentanil, propofol, and sevoflurane at 1.0 minimum alveolar concentration (MAC) are worse than with rocuronium at 0.45 mg/kg. Therefore, we compared the intubation conditions and laryngeal morbidity (vocal cord injuries, hoarseness, and sore throat) with sevoflurane at 1.2 and 1.4 MAC versus 1.0 MAC.

Methods

In this prospective clinical trial, 90 patients were randomized to 3 groups: the sevoflurane 1.0, 1.2, and 1.4 MAC groups. At 3 min, tracheal intubation was performed and the patients’ intubation conditions were assessed. The vocal cords were examined for injury by videolaryngoscopy. Additionally, the incidence and severity of laryngeal morbidity were compared between women and men.

Results

Acceptable intubation conditions were seen in 72% of the patients without significant differences between the groups. Overall, vocal cord injuries (oedema) occurred in three (4%) patients. Women reported sore throat more often than men (51% vs. 21%, respectively).

Conclusions

Intubation conditions were not improved with higher sevoflurane concentrations. The incidence and severity of sore throat were greater in women than men.

Trial registration: ClinicalTrials.Gov: NCT 01896245

Use of cis-atracurium to maintain moderate neuromuscular blockade in experimental pigs

OBJECTIVE

To determine the dose of cis-atracurium needed to produce a moderate neuromuscular blockade (NMB) in pigs.

STUDY DESIGN

Prospective experimental study.

ANIMALS

Seven pigs [five females and two males; median (range) body weight: 47 (36-64) kg].

METHODS

Pigs were premedicated with intramuscular midazolam (0.3 mg kg^-1) and ketamine (7 mg kg^-1). Anaesthesia was induced with intravenous (IV) propofol 3 (1-4) mg kg^-1 and maintained with isoflurane in oxygen. Based on a preliminary study, the subjects were administered 0.3 mg kg^-1 cis-atracurium followed by 0.48 mg kg^-1 hour^-1 constant rate infusion (CRI) IV. A moderate NMB was defined as a train-of-four (TOF) count of ≤2 by acceleromyography. When the TOF count was >2, 0.1 mg kg^-1 cis-atracurium was administered and the CRI was increased. The cis-atracurium CRI was decreased when the TOF count was under 2 for more than 15 minutes. The total dose of cis-atracurium required to maintain a moderate NMB was calculated as the total amount of cis-atracurium used (both CRI and supplementary boluses) divided by the administration time.

RESULTS

The cis-atracurium CRI lasted for 87 (76-151) minutes. To induce and maintain a moderate neuromuscular blockade, the initial dose of cis-atracurium was 0.3 (0.3- 0.5) mg kg^-1 and the CRI was 0.71 (0.37-0.98) mg kg^-1 hour^-1.

CONCLUSIONS AND CLINICAL RELEVANCE

The doses described in our study may help researchers obtain a moderate NMB using cis-atracurium in pigs.

Effect of dexamethasone on the onset time and recovery profiles of cisatracurium

BACKGROUND

The effect of dexamethasone injection on cisatracurium-induced neuromuscular block was compared according to different injection time points.

METHODS

One hundred seventeen patients were randomly assigned to three groups: 8 mg of dexamethasone injected intravenously 2-3 h before anesthesia (group A), just before anesthesia induction (group B), and at the end of surgery (control group). Three minutes after anesthesia induction, intubation was performed without neuromuscular blockers, and acceleromyography was initiated. All patients received 0.05 mg/kg cisatracurium; the onset time and recovery profiles were recorded.

RESULTS

Eighty patients were finally enrolled. The onset time (median [interquartile range], seconds) was significantly hastened in group A (520.0 [500.0-560.0], n = 30) compared to that in group B (562.5 [514.0-589.0], n = 22) (P = 0.008) and control group (586.5 [575.0-642.5], n = 28) (P < 0.001). The onset time in group B was faster than the control group (P = 0.015). The recovery time [mean (95% CI) minutes] was significantly hastened in group A [28.5 (27.3-29.6)] compared to that in group B [32.3 (31.0-33.6)] (P < 0.001) and control group [30.9 (29.9-31.8)] (P = 0.015). The total recovery time was significantly hastened more in group A [47.1 (45.5-48.6)] than group B [52.8 (51.6-54.0) minutes] (P < 0.001) and control group [50.5 (48.7-52.3) minutes] (P = 0.008).

CONCLUSIONS

A single dose of 8 mg of dexamethasone hastened the onset and total recovery times of cisatracurium-induced block by approximately 15 and 9%, respectively if administered 2-3 h prior to surgery.

Changes in duration of action of rocuronium following decrease in hepatic blood flow during pneumoperitoneum for laparoscopic gynaecological surgery

Background

A moderate insufflation pressure and deep neuromuscular blockade (NMB) have been recommended in laparoscopic surgery in consideration of the possible reduction in splanchnic perfusion due to the CO₂-pneumoperitoneum. Since the liver is the major organ for rocuronium metabolism, the question of whether NMB of rocuronium would change with the variation of liver perfusion during pneumoperitoneum during laparoscopic surgery merits investigation.

Methods

In this prospective study, a total of sixty female patients scheduled for either selective laparoscopic gynaecological surgery (group laparoscopy) or laparotomy for gynaecological surgery (group control) were analyzed. Rocuronium was administered with closed-loop feedback infusion system, which was also applied to monitor NMB complied with good clinical research practice (GCRP). The onset time, clinical duration, and recovery index were measured. Hepatic blood flow was assessed by laparoscopic intraoperative ultrasonography before insufflation/after entering the abdominal cavity (T1), 5 min after insufflation in the Trendelenburg position/5 min after skin incision (T2), 15 min after insufflation in the Trendelenburg position/15 min after skin incision (T3), 30 min after insufflation in the Trendelenburg position/30 min after skin incision (T4), and 5 min after deflation/before closing the abdomen (T5) in group laparoscopy/group control respectively. The relationship between the clinical duration of rocuronium and portal venous blood flow was analyzed using linear or quadratic regression.

Result

The clinical duration and RI of rocuronium were both prolonged significantly in group laparoscopy (36.8 ± 8.3 min; 12.8 ± 5.5 min) compared to group control (29.0 ± 5.8 min; 9.8 ± 4.0 min) (P < 0.0001; P = 0.018). A significant decrease was found in portal venous blood flow during the entire pneumoperitoneum period in group laparoscopy compared with group control (P < 0.0001). There was a significant correlation between the clinical duration of rocuronium and portal venous blood flow (Y = 51.800-0.043X + (1.86E-005) X²; r² = 0.491; P < 0.0001).

Conclusion

Rocuronium-induced NMB during laparoscopic gynaecological surgery might be prolonged due to the decrease in portal venous blood flow induced by CO₂-pneumoperitoneum. Less rocuronium could be required to achieve a desirable NMB in laparoscopic gynaecological surgery.

Trial registration

ChiCTR. Registry number: ChiCTR-OPN-15007524. Date of registration: December 4, 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s12871-017-0335-1) contains supplementary material, which is available to authorized users.

Recovery from rocuronium-induced neuromuscular block was longer in the larynx than in the pelvic limb of anesthetized dogs

OBJECTIVE

To determine if neuromuscular monitoring at the pelvic limb accurately reflects neuromuscular function in the larynx after administration of rocuronium in anesthetized dogs.

STUDY DESIGN

Prospective experimental study.

ANIMALS

Six healthy Beagle dogs.

METHODS

Anesthesia was maintained in dogs with isoflurane and a continuous infusion of dexmedetomidine. Rocuronium (0.6 mg kg^-1) was administered intravenously to induce neuromuscular block. Train-of-four (TOF) impulses were applied to the left recurrent laryngeal nerve (RLn) and the peroneal nerve (Pn). The evoked TOF ratio (TOFR; T4:T1) was measured with electromyography (EMG) simultaneously at the larynx and at the pelvic limb. Spontaneous recoveries of T1 to 25% (T1_25%) and 75% (T1_75%) of twitch height, and to TOFR of 0.70 and 0.90 (TOFR_0.90) at each EMG site were compared.

RESULTS

Data from five dogs were analyzed. Times to T1_25% were similar at the pelvic limb and larynx when measured by EMG; time to T1_75% was slower at the larynx by 6±4 minutes (p=0.012). The larynx had a slower recovery to TOFR_0.70 (41±13 minutes) and TOFR_0.90 (45±13 minutes) than did the pelvic limb [29±8 minutes (p=0.011) and 33±9 minutes (p=0.003), respectively]. When the pelvic limb EMG returned to TOFR_0.70 and TOFR_0.90, the larynx EMG TOFR_0.70 and TOFR_0.90 values were 0.32±0.12 (p=0.001) and 0.38±0.13 (p=0.001), respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

After administration of rocuronium, neuromuscular function assessed by EMG recovered approximately 36% slower at the larynx than at the pelvic limb. The results in these dogs suggest that quantitative neuromuscular monitoring instrumented at a pelvic limb may be unable to exclude residual block at the larynx in anesthetized dogs.

[Deep versus moderate neuromuscular block during one-lung ventilation in lung resection surgery]

BACKGROUND AND OBJECTIVES

Neuromuscular relaxants are essential during general anesthesia for several procedures. Classical anesthesiology literature indicates that the use of neuromuscular blockade in thoracic surgery may be deleterious in patients in lateral decubitus position in one-lung ventilation. The primary objective of our study was to compare respiratory function according to the degree of patient neuromuscular relaxation. Secondary, we wanted to check that neuromuscular blockade during one-lung ventilation is not deleterious.

METHODS

A prospective, longitudinal observational study was made in which each patient served as both treated subject and control. 76 consecutive patients programmed for lung resection surgery in Gregorio Marañon Hospital along the year of 2013 who required one-lung ventilation in lateral decubitus were included. Ventilator data, hemodynamic parameters were registered in different moments according to train-of-four response (intense, deep and moderate blockade) during one-lung ventilation.

RESULTS

Peak, plateau and mean pressures were significantly lower during the intense and deep blockade. Besides, compliance and peripheral oxygen saturation were significantly higher in those moments. Heart rate was significantly higher during deep blockade. No mechanical ventilation parameters were modified during measurements.

CONCLUSIONS

Deep neuromuscular blockade attenuates the poor lung mechanics observed during one-lung ventilation.

Postoperative shoulder pain after laparoscopic hysterectomy with deep neuromuscular blockade and low-pressure pneumoperitoneum: A randomised controlled trial

BACKGROUND

Postoperative shoulder pain remains a significant problem after laparoscopy. Pneumoperitoneum with insufflation of carbon dioxide (CO2) is thought to be the most important cause. Reduction of pneumoperitoneum pressure may, however, compromise surgical visualisation. Recent studies indicate that the use of deep neuromuscular blockade (NMB) improves surgical conditions during a low-pressure pneumoperitoneum (8 mmHg).

OBJECTIVE

The aim of this study was to investigate whether low-pressure pneumoperitoneum (8 mmHg) and deep NMB (posttetanic count 0 to 1) compared with standard-pressure pneumoperitoneum (12 mmHg) and moderate NMB (single bolus of rocuronium 0.3 mg kg with spontaneous recovery) would reduce the incidence of shoulder pain and improve recovery after laparoscopic hysterectomy.

DESIGN

A randomised, controlled, double-blinded study.

SETTING

Private hospital in Denmark.

PARTICIPANTS

Ninety-nine patients.

INTERVENTIONS

Randomisation to either deep NMB and 8 mmHg pneumoperitoneum (Group 8-Deep) or moderate NMB and 12 mmHg pneumoperitoneum (Group 12-Mod). Pain was assessed on a visual analogue scale (VAS) for 14 postoperative days.

MAIN OUTCOME MEASURES

The primary endpoint was the incidence of shoulder pain during 14 postoperative days. Secondary endpoints included area under curve VAS scores for shoulder, abdominal, incisional and overall pain during 4 and 14 postoperative days; opioid consumption; incidence of nausea and vomiting; antiemetic consumption; time to recovery of activities of daily living; length of hospital stay; and duration of surgery.

RESULTS

Shoulder pain occurred in 14 of 49 patients (28.6%) in Group 8-Deep compared with 30 of 50 (60%) patients in Group 12-Mod. Absolute risk reduction was 0.31 (95% confidence interval 0.12 to 0.48; P = 0.002). There were no differences in any secondary endpoints including area under the curve for VAS scores.

CONCLUSION

Deep NMB and low-pressure pneumoperitoneum (8 mmHg) reduced the incidence of shoulder pain after laparoscopic hysterectomy in comparison to moderate NMB and standard-pressure pneumoperitoneum (12 mmHg).

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT01722097.

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.

Dose–response and Cardiopulmonary Side Effects of the Novel Neuromuscular-blocking Drug CW002 in Man

Background

CW002 is a benzylisoquinolinium nondepolarizing neuromuscular-blocking drug found to be inactivated by cysteine in preclinical studies. The current study represents a dose escalation clinical trial designed to describe CW002 potency, duration, cardiopulmonary side effects, and histamine release.

Methods

Healthy subjects anesthetized with sevoflurane/nitrous oxide were divided into five groups (n = 6), each receiving a fixed CW002 dose (0.02, 0.04, 0.06, 0.08, or 0.10 mg/kg), and one group (n = 4) receiving 0.14 mg/kg. Blood pressure and heart rate were continuously recorded along with airway dynamic compliance. Neuromuscular blockade was assessed with mechanomyography at the adductor pollicis. Arterial blood was obtained before and after CW002 injection for analysis of plasma histamine concentration. Potency was estimated from a baseline sigmoid Emax model.

Results

ED50 was found to be 0.036 mg/kg (95% CI, 0.020 to 0.053 mg/kg) and ED95 0.077 mg/kg (95% CI, 0.044 to 0.114 mg/kg). At 0.14 mg/kg (1.8 × ED95), 80% twitch depression occurred in 94 ± 18 s with complete block in 200 ± 87 s. Clinical recovery (25% of maximum twitch) occurred in 34 ± 3.4 min, with a 5 to 95% recovery interval of 35.0 ± 2.7 min. The time to a train-of-four ratio greater than 0.9 ranged from 59 to 86 min. CW002 did not elicit histamine release or significant (greater than 10%) changes in blood pressure, heart rate, or dynamic airway compliance.

Conclusions

In healthy subjects receiving sevoflurane/nitrous oxide, CW002 at 1.8 × estimated ED95 produces a clinical duration less than 40 min, elicits no histamine release, and has minimal cardiopulmonary side effects.

Magnesium sulfate accelerates the onset of low-dose rocuronium in patients undergoing laryngeal microsurgery

STUDY OBJECTIVE

We evaluated the effect of magnesium sulfate-an enhancer of neuromuscular blockade-on onset and duration of low dose of rocuronium, and on operating conditions during laryngeal microsurgery.

DESIGN

Randomized, prospective, double-blinded study.

PATIENTS

Eighty-four patients scheduled for elective laryngeal microsurgery.

INTERVENTIONS

Patients were randomly allocated to receive different doses of rocuronium: 0.6 mg/kg (group C, n=28), 0.45 mg/kg (group LR, n=28), or 0.45 mg/kg plus magnesium sulfate 30 mg/kg (group LM, n=28).

MEASUREMENTS

We measured the onset time and duration of action of rocuronium, and evaluated the surgeon's satisfaction with the operating conditions.

MAIN RESULTS

Group LR showed significantly delayed onset time (group C: 87±22 seconds, group LR: 127±47 seconds, and group LM: 89±32 seconds; P=.001) and maximal suppression than did other groups (group C: 102±30 seconds, group LR: 155±66 seconds, and group LM: 105±36 seconds; P=.002). Duration of action of rocuronium was significantly longer in group C than in other groups (group C: 39±7 minutes, group LR: 28±8 minutes, group LRM: 31±8 minutes; P<.001). Laryngoscope placement score (P=.002), surgeon's satisfaction (P=.005), and sore throat (P=.035) were significantly worse in group LR.

CONCLUSIONS

Magnesium sulfate 30 mg/kg accelerated the onset and improved operating conditions of low-dose rocuronium without prolongation of action.

The effect of prior tetanic stimulation on train-of-four monitoring in paediatric patients: A randomised open-label controlled trial

BACKGROUND

In clinical research, neuromuscular monitoring must present a stable response for a period of 2 to 5 min before administration of a neuromuscular blocking agent. The time required to reach this stable response may be shortened by applying a 5-s tetanic stimulus.

OBJECTIVES

The aim of this study was to test whether tetanic stimulation interferes with onset and recovery times after a single dose of rocuronium 0.6 mg kg followed by spontaneous recovery.

DESIGN

A randomised, open-label, controlled trial.

SETTING

A single-centre trial, study period from January 2014 to July 2015.

PATIENTS

Fifty children aged 2 to 11 years scheduled for elective paediatric surgery.

INTERVENTION

Patients were randomly allocated to receive either tetanic stimulation (group T) or not (group C) before calibration of the neuromuscular monitor.

MAIN OUTCOME MEASURES

Onset and recovery times. Initial and final T1 height, time to obtain initial T1 height stability and monitor settings were also analysed.

RESULTS

There was no significant difference in mean onset time [(C: 57.5 (± 16.9) vs. T: 58.3 (± 31.2) s; P = 0.917]. Mean times to normalised train-of-four (TOF) ratios of 0.7, 0.8 and 0.9 were significantly shorter in the tetanic stimulation group [C: 40.1 (±7.9) vs. T: 34.8 (±10) min; P = 0.047, C: 43.8 (±9.4) vs. T: 37.4 (±11) min; P = 0.045 and C: 49.9 (±12.2) vs. T: 41.7 (±13.1) min; P = 0.026, respectively]. The mean time required for T1 height stabilisation was similar in the two groups [C: 195.0 (± 203.0) vs. T: 116.0 (± 81.6) s; P = 0.093], but the initial and final T1 height values were significantly lower in the tetanic stimulation group (C: 98.0 vs. T: 82.7%; P < 0.001 and C: 95.3 vs. T: 69.3%; P < 0.001, respectively).

CONCLUSION

Tetanic stimulation shortened the mean times to normalised TOF ratios of 0.7, 0.8 and 0.9, but there was no difference in the mean onset time or the mean time required for T1 height stabilisation after a single dose of rocuronium 0.6 mg kg followed by spontaneous recovery in children aged 2 to 11 years.

TRIAL REGISTRATION

Clinicaltrials.gov. identifier: NCT02498678.

Repeated sugammadex reversal of muscle relaxation during lumbar spine surgery with intraoperative neurophysiological multimodal monitoring

Intraoperative neurophysiological monitoring during spine surgery is usually acomplished avoiding muscle relaxants. A case of intraoperative sugammadex partial reversal of the neuromuscular blockade allowing adequate monitoring during spine surgery is presented. A 38 year-old man was scheduled for discectomy and vertebral arthrodesis throughout anterior and posterior approaches. Anesthesia consisted of total intravenous anesthesia plus rocuronium. Intraoperatively monitoring was needed, and the muscle relaxant reverted twice with low dose sugammadex in order to obtain adequate responses. The doses of sugammadex used were conservatively selected (0.1mg/kg boluses increases, total dose needed 0.4mg/kg). Both motor evoqued potentials, and electromyographic responses were deemed adequate by the neurophysiologist. If muscle relaxation was needed in the context described, this approach could be useful to prevent neurological sequelae. This is the first study using very low dose sugammadex to reverse rocuronium intraoperatively and to re-establish the neuromuscular blockade.

Dexamethasone does not diminish sugammadex reversal of neuromuscular block - clinical study in surgical patients undergoing general anesthesia

Background

Sugammadex reverses neuromuscular block (NMB) through binding aminosteroid neuromuscular blocking agents. Although sugammadex appears to be highly selective, it can interact with other drugs, like corticosteroids. A prospective single-blinded randomized clinical trial was designed to explore the significance of interactions between dexamethasone and sugammadex.

Methods

Sixty-five patients who were anesthetized for elective abdominal or urological surgery were included. NMB was assessed using train-of-four stimulation (TOF), with rocuronium used to maintain the desired NMB depth. NMB reversal at the end of anaesthesia was achieved using sugammadex. According to their received antiemetics, the patients were randomized to either the granisetron or dexamethasone group. Blood samples were taken before and after NMB reversal, for plasma dexamethasone and rocuronium determination. Primary endpoint was time from sugammadex administration to NMB reversal. Secondary endpoints included the ratios of the dexamethasone and rocuronium concentrations after NMB reversal versus before sugammadex administration.

Results

There were no differences for time to NMB reversal between the control (mean 121 ± 61 s) and the dexamethasone group (mean 125 ± 57 s; P = 0.760). Time to NMB reversal to a TOF ratio ≥0.9 was significantly longer in patients with lower TOF prior to sugammadex administration (Beta = −0.268; P = 0.038). The ratio between the rocuronium concentrations after NMB reversal versus before sugammadex administration was significantly affected by sugammadex dose (Beta = −0.375; P = 0.004), as was rocuronium dose per hour of operation (Beta = −0.366; p = 0.007), while it was not affected by NMB depth before administration of sugammadex (Beta = −0.089; p = 0.483) and dexamethasone (Beta = −0.186; p = 0.131). There was significant drop in plasma dexamethasone after sugammadex administration and NMB reversal (p < 0.001).

Conclusions

Administration of dexamethasone to anesthetized patients did not delay NMB reversal by sugammadex.

Trial registration

The trial was retrospectively registered with The Australian New Zealand Clinical Trials Registry (ANZCTR) on February 28th 2012 (enrollment of the first patient on February 2nd 2012) and was given a trial ID number ACTRN12612000245897 and universal trial number U1111-1128-5104.

The neuromuscular effects of rocuronium under sevoflurane-remifentanil or propofol-remifentanil anesthesia: a randomized clinical comparative study in an Asian population

Background

We conducted a prospective, randomized, multicenter study to evaluate the differences in the blocking effect of different doses of rocuronium between sevoflurane- or propofol-remifentanil anesthesia in an Asian population.

Methods

A total of 368 ASA I–II patients was enrolled. Anesthesia was induced with 2.0 mg/kg propofol and 0.1 μg/kg/min remifentanil (TIVA) or 5.0 vol.% sevoflurane with 0.1 μg/kg/min remifentanil (SEVO). Tracheal intubation was facilitated at 180 s after the administration of rocuronium at 0.3, 0.6, or 0.9 mg/kg and then intubation condition was evaluated. The time to maximum block and recovery profile were monitored by TOF stimulation of the ulnar nerve and by recording the adductor pollicis response using acceleromyography.

Results

The numbers of patients with clinically acceptable intubation conditions were 41, 82, and 97 % (TIVA) and 34, 85, and 90 % (SEVO) at each dose of rocuronium, respectively. There were no significant differences in the time to maximum block between groups at each rocuronium dose. There were significant differences in the recovery to a train-of-four ratio of 90 % between the groups: 42.7 (19.5), 74.8 (29.9), and 118.4 (35.1) min (TIVA) and 66.5 (39.3), 110.2 (43.5), and 144.4 (57.5) min (SEVO) at 0.3, 0.6, and 0.9 mg/kg, respectively (P < 0.001).

Conclusions

There are no significant differences in intubation conditions between propofol-remifentanil and sevoflurane-remifentanil anesthesia at the same dose of rocuronium. The type of anesthetic does not significantly influence the time to maximum block by rocuronium. Rocuronium at a dose of 0.9 mg/kg should be used for better intubation conditions with both anesthesia regimens in an Asian population.

Trial registration

UMIN-CTR Clinical Trial (http://www.umin.ac.jp/ctr/index.htm; UMIN#000007289; date of registration 14^th February 2012).

Pharmacokinetics and pharmacodynamics of rocuronium in young adult and elderly patients undergoing elective surgery

Objective

To evaluate the impact of advanced age on rocuronium kinetic disposition in ASA I–III patients undergoing elective surgeries.

Methods

Young adult (20–50 years, n = 15) and elderly patients (65–85 years, n = 14) submitted to surgery under general anaesthesia were investigated. All patients were induced with individual intravenous doses of midazolam, rocuronium, fentanyl and propofol. Rocuronium-induced neuromuscular block was monitored by train of four stimulations of the adductor muscle of the thumb on the ulnar nerve. The pharmacokinetic parameters were calculated by non-compartmental analysis. The relationship between rocuronium plasma concentration and the neuromuscular blockade was described by a sigmoidal Emax model.

Key-findings

Elderly patients presented decreased Cl (2.1 ml/kg per min vs 2.8 ml/kg per min; P = 0.0123); increased AUC/dose (507.8 μg min/ml (mg/kg) vs 392.2 μg min/ml/(mg/kg); P = 0.0168) and reduced volume of distribution (285.4 ml/kg vs 435.6 ml/kg, P = 0.0434) compared to young adults. The concentrations required to achieve 50% of maximum neuromuscular block (EC50) were similar for young adult (338.8 ng/ml) and elderly (462.7 ng/ml) patients (P &gt; 0.05).

Conclusions

Elderly patients showed increased AUC/D and reduced total Cl compared to young adult patients due to the age-related reduced renal function. Differences in the PK-PD properties of rocuronium in elderly population are due to changes in drug disposition rather than to alterations in the sensitivity to the drug.

Operating room discharge after deep neuromuscular block reversed with sugammadex compared with shallow block reversed with neostigmine: a randomized controlled trial

OBJECTIVE

To determine if reversing a deep or moderate block with sugammadex, compared with a shallow block reversed with neostigmine, reduces the time to operating room discharge after surgery and the time spent in the postanesthesia care unit.

DESIGN

A randomized controlled trial.

SETTING

Monocentric study performed from February 2011 until May 2012.

PATIENTS

One hundred consenting women with American Society of Anesthesiologists grade I or II were randomized into 2 groups.

INTERVENTION

Laparoscopic hysterectomy was performed under desflurane general anesthesia. For the neostigmine (N) group, 0.45 mg · kg^-1 rocuronium was followed by spontaneous recovery. A 5-mg rescue bolus was administered only if surgical evaluation was unacceptable. At the end of surgery, 50 μg · kg^-1 neostigmine with glycopyrrolate was administered. For the sugammadex (S) group, a higher intubating rocuronium dose (0.6 mg · kg^-1) was followed by 5-mg boluses each time the train-of-four count exceeded 2. Sugammadex (2-4 mg · kg^-1) was administered to reverse the block. All patients were extubated after obtaining a train-of-four ratio of 0.9.

MEASUREMENTS

The duration between the end of surgery and operating room discharge and the time spent in the postanesthesia care unit.

MAIN RESULTS

The time till operating room discharge was shorter and more predictable in group S (9.15±4.28 minutes vs 13.87±11.43 minutes in group N; P=.005). The maximal duration in group S was 22 minutes, compared with 72 minutes in group N. The time spent in the postanesthesia care unit was not significantly different (group S: 47.75±31.77 minutes and group N: 53.43±40.57 minutes; P=.543).

CONCLUSION

Maintaining a deep neuromuscular block during laparoscopic hysterectomy reversed at the end of the procedure with sugammadex enabled a faster and more predictable time till operating room discharge than did the classical combination of a shallower block reversed with neostigmine.

Rocuronium pharmacokinetics and pharmacodynamics in the adductor pollicis and masseter muscles

BACKGROUND

The aim of this study was to characterize the dose-effect relationship of rocuronium at the adductor pollicis and masseter muscles.

METHODS

Ten, ASA I, adult patients, received a bolus dose of rocuronium 0.3 mg/kg during propofol based anesthesia. Train-of-four (TOF) was simultaneously monitored at the masseter and the adductor pollicis muscles until recovery. Rocuronium arterial serum concentrations were measured during 120 min. The first twitch of the TOF response was used to characterize the time-effect profile of both muscles using pharmacokinetic-pharmacodynamic analysis in NONMEM. A decrease in NONMEM objective function (∆OFV) of 3.84 points for an added parameter was considered significant at the 0.05 level.

RESULTS

Onset time at the masseter (mean ± SD, 1.5 ± 0.9 min) was faster than at the adductor pollicis (2.7 ± 1.4 min, P < 0.05). Recovery, measured as the time to TOF ratio = 0.9 was similar between muscles 29.9 ± 6.7 (adductor pollicis) vs. 29.3 ± 8.1 (masseter). (P = 0.77). The estimated pharmacodynamic parameters [mean (95% CI)] of the adductor pollicis muscle and the masseter muscle were; plasma effect-site equilibration half-time (teq) 3.25 (2.34, 3.69) min vs. 2.86 (1.83, 3.29) min, (∆OFV 383.665); Ce50 of 1.24 (1.13, 1.56) mg/l vs. 1.19 (1.00, 1.21) mg/l, (∆OFV 184.284); Hill coefficient of 3.97 (3.82, 5.62) vs. 4.68 (3.83, 5.71), (∆OFV 78.906).

CONCLUSIONS

We found that the masseter muscle has faster onset of blockade and similar recovery profile than adductor pollicis muscle. These findings were best, explained by a faster plasma effect-site equilibration of the masseter muscle to rocuronium.

Is deep neuromuscular blockade beneficial in laparoscopic surgery? Yes, probably

BACKGROUND

Deep neuromuscular blockade during laparoscopic surgery may provide some clinical benefit. We present the 'Pro-' argument in this paired position paper.

METHODS

We reviewed recent evidence from a basic database of references which we agreed on with the 'Con-' side, and present this in narrative form. We have shared our analysis and text with the authors of the 'Con-' side of these paired position papers during the preparation of the manuscripts.

RESULTS

There are a few low risk of bias studies indicating that use of deep neuromuscular blockade improve surgical conditions and improve patient outcomes such as post-operative pain in laparoscopic surgery.

CONCLUSION

Our interpretation of recent findings is that there is reason to believe that there may be some patient benefit of deep neuromuscular blockade in this context, and more detailed study is needed.

Relationship between first-twitch depression and train-of-four ratio during sugammadex reversal of rocuronium-induced neuromuscular blockade

Background

The primary outcome of sugammadex reversal for rocuronium-induced neuromuscular block (NMB) is a train-of-four ratio (TOFR) of 0.9, not first twitch (T₁) height. We investigated whether the recovery of TOFR or T₁ differs based on the reversal of NMB with neostigmine or sugammadex.

Methods

The acceleromyographic responses from 0.6 mg/kg of rocuronium were monitored supramaximally in 80 patients after induction of anesthesia. The TOFR and T₁ height were recorded, and saved in a personal computer using TOF-Watch SX Monitor software in all patients. Patients were randomly assigned to 2 groups to receive either neostigmine 50 µg/kg with glycopyrrolate 10 µg/kg (neostigmine group, n = 40) or sugammadex 2.0 mg/kg (sugammadex group, n = 40). The primary objective was to determine the difference of recovery time between TOFR to 0.9 and T₁ to 0.9 after sugammadex or neostigmine administration during moderate rocuronium-induced NMB.

Results

The recovery pattern of the TOFR 2 min after sugammadex administration was 1.0 or more, but that of T₁ was less than 90% (T₁ / control value) up to 6 min after drug was injected. The recovery pattern of TOFR and T₁ was similar during the 20 min after reversal with neostigmine.

Conclusions

If you have not performed the T₁ monitoring, both TOFR and T₁ should be considered to confirm suitable recovery during the 6 min after reversal with sugammadex during rocuronium-induced moderate NMB.

Severity of Myasthenia Gravis Influences the Relationship between Train-of-four Ratio and Twitch Tension and Run-down of Rat Endplate Potentials

BACKGROUND

Train-of-four ratio (TOFR) is often used to evaluate muscle relaxation caused by neuromuscular-blocking agents (NMBAs). However, it is unknown whether TOFR reliably correlates with the first twitch tension (T1) in patients with myasthenia gravis (MG). By using rat models of experimental autoimmune MG (EAMG), the authors verified the hypothesis that the severity of MG influences the relationship between TOFR and T1.

METHODS

EAMG rats were divided into sham, moderate MG, and severe MG groups. Isometric twitch tension of the hemidiaphragm was elicited by phrenic nerve stimulation with and without use of the NMBA rocuronium to measure TOFR and T1, and run-down of endplate potentials was estimated in the three groups. Changes around the neuromuscular junction in EAMG rats were investigated by observation of electron micrographs.

RESULTS

With similar attenuation of T1, TOFR was significantly (n = 6) different among the three groups in the presence of 50% inhibitory concentrations of rocuronium (IC50). Run-down in the sham group was significantly (n = 8) greater with exposure to IC50, whereas that in the severe MG group was statistically insignificant. Width of the primary synaptic cleft in the severe MG group was significantly (n = 80) greater than that in the other groups.

CONCLUSIONS

Severity of MG influences the relationship between TOFR and T1, together with changes in run-down of endplate potentials and those around the neuromuscular junction in rats. TOFR may, therefore, not be an accurate indicator of recovery from NMBAs in MG patients.

Effects of nicardipine on the onset time and intubation conditions of rocuronium-induced neuromuscular blockade

STUDY OBJECTIVE

The objective of this study was to identify the effects of nicardipine on neuromuscular blockade of rocuronium, such as the onset time and intubation conditions, using a nicardipine dose that attenuates cardiovascular responses during endotracheal intubation.

DESIGN

Randomized, double-blinded, placebo-controlled clinical comparison was used as the design of this study

SETTING

The study was conducted at the operating room of a university hospital.

PATIENTS

Participants of this study comprise 78 American Society of Anesthesiologists physical status 1 and 2 patients, aged 18 to 60 years who were undergoing elective surgery under general anesthesia.

INTERVENTIONS

The nicardipine group was given an intravenous bolus of 20 μg/kg nicardipine before tracheal intubation: the control group was given an intravenous bolus of a comparable volume of normal saline before tracheal intubation.

MEASUREMENTS

Using a TOF-Watch SX monitor, the time from the end of the injection of rocuronium to maximum depression of T1 (onset time) was measured. Intubation was performed 1 minute after rocuronium administration, and the status of the intubation conditions was assessed. The mean blood pressure and heart rate were each measured after endotracheal intubation. Rate pressure product values were also calculated.

MAIN RESULTS

Intubation conditions were clinically acceptable in 37 (94.9%) of 39 patients in group N compared with 29 (74.4%) of 39 in group C (P < .05). The onset time of rocuronium was significantly faster in group N than in group C (P < .05). The mean blood pressure was significantly lower in group N than in group C (P < .05). The heart rate was significantly higher in group N than in group C (P < .05). Rate pressure product values showed no significant difference between the two groups (P > .05).

CONCLUSIONS

Pretreatment with 20 μg/kg nicardipine improves intubation conditions, shortens the onset time of rocuronium, and attenuates cardiovascular responses to tracheal intubation.

Recovery of laryngeal nerve function with sugammadex after rocuronium-induced profound neuromuscular block

STUDY OBJECTIVE

The aim of this study was to evaluate the efficacy of sugammadex in reversing profound rocuronium-induced neuromuscular block at the laryngeal adductor muscles using motor-evoked potentials (mMEPs).

DESIGN

A prospective observational study.

SETTING

University surgical center.

PATIENTS

Twenty patients with American Society of Anesthesiologists physical class I-II status who underwent propofol-remifentanil anesthesia for the surgery of the thyroid gland.

INTERVENTIONS

Patients were enrolled for reversal of profound neuromuscular block (sugammadex 16 mg/kg, 3 minutes after rocuronium 1.2 mg/kg). To prevent laryngeal nerve injury during the surgical procedures, all patients underwent neurophysiologic monitoring using mMEPs from vocal muscles. At the same time, the registration of TOF-Watch acceleromyograph at the adductor pollicis muscle response to ulnar nerve stimulation was performed; recovery was defined as a train-of-four (TOF) ratio ≥0.9.

MEASUREMENT AND MAIN RESULTS

After injection of 16 mg/kg of sugammadex, the mean time to recovery of the basal mMEPs response at the laryngeal adductor muscles was 70 ± 18.2 seconds. The mean time to recovery of the TOF ratio to 0.9 was 118 ± 80 seconds. In the postoperative period, 12 patients received follow-up evaluation of the vocal cords and no lesions caused by the surface laryngeal electrode during electrophysiological monitoring were noted.

CONCLUSIONS

Recovery from profound rocuronium-induced block on the larynx is fast and complete with sugammadex. In urgent scenarios, "early" extubation can be performed, even with a TOF ratio ≤0.9. However, all procedures to prevent postoperative residual curarization should still be immediately undertaken.

Comparative Effectiveness of Calabadion and Sugammadex to Reverse Non-depolarizing Neuromuscular-blocking Agents

BACKGROUND

The authors evaluated the comparative effectiveness of calabadion 2 to reverse non-depolarizing neuromuscular-blocking agents (NMBAs) by binding and inactivation.

METHODS

The dose-response relationship of drugs to reverse vecuronium-, rocuronium-, and cisatracurium-induced neuromuscular block (NMB) was evaluated in vitro (competition binding assays and urine analysis), ex vivo (n = 34; phrenic nerve hemidiaphragm preparation), and in vivo (n = 108; quadriceps femoris muscle of the rat). Cumulative dose-response curves of calabadions, neostigmine, or sugammadex were created ex vivo at a steady-state deep NMB. In living rats, the authors studied the dose-response relationship of the test drugs to reverse deep block under physiologic conditions, and they measured the amount of calabadion 2 excreted in the urine.

RESULTS

In vitro experiments showed that calabadion 2 binds rocuronium with 89 times the affinity of sugammadex (Ka = 3.4 × 10 M and Ka = 3.8 × 10 M-). The results of urine analysis (proton nuclear magnetic resonance), competition binding assays, and ex vivo study obtained in the absence of metabolic deactivation are in accordance with an 1:1 binding ratio of sugammadex and calabadion 2 toward rocuronium. In living rats, calabadion 2 dose-dependently and rapidly reversed all NMBAs tested. The molar potency of calabadion 2 to reverse vecuronium and rocuronium was higher compared with that of sugammadex. Calabadion 2 was eliminated renally and did not affect blood pressure or heart rate.

CONCLUSIONS

Calabadion 2 reverses NMB induced by benzylisoquinolines and steroidal NMBAs in rats more effectively, i.e., faster than sugammadex. Calabadion 2 is eliminated in the urine and well tolerated in rats.