Evaluation of a Protocol for the Management of Maintenance and Reversal of Rocuronium Block Using Neostigmine or Sugammadex.

BACKGROUND: Postoperative residual neuromuscular blockade (PRNB) is defined as an adductor pollicis train-of-four ratio (TOFR) <0.9. It is a common postoperative complication when nondepolarizing muscle relaxants are either not reversed or reversed with neostigmine. PRNB has been reported in 25% to 58% of patients who receive intermediate-acting nondepolarizing muscle relaxants, and it is associated with increased morbidity and decreased patient satisfaction. We conducted a prospective descriptive cohort study during the implementation of a practice guideline that included the selective use of sugammadex or neostigmine. The primary study aim of this pragmatic study was to estimate the incidence of PRNB at arrival to the postanesthesia care unit (PACU) when the practice guideline is followed. METHODS: We enrolled patients undergoing orthopedic or abdominal surgery requiring neuromuscular blockade. Rocuronium administration was guided by surgical requirements and based on ideal body weight, with dose reductions for women and/or age >55 years. Only qualitative monitoring was available to the anesthesia providers, and selection of sugammadex or neostigmine was guided by tactile assessments of the response to train-of-four (TOF) stimulation by a peripheral nerve stimulator. Neostigmine was administered if no fade was detected in the TOF response at the thumb. Deeper blocks were reversed with sugammadex. The prespecified primary and secondary end points were the incidence of PRNB at arrival to the PACU, defined as a normalized TOFR (nTOFR) < 0.9, and severe PRNB, defined as nTOFR <0.7 on arrival to the PACU. Anesthesia providers were blinded to all quantitative measurements made by research staff. RESULTS: Analysis included 163 patients, and 145 underwent orthopedic and 18 abdominal surgeries. Of the 163 patients, 92 (56%) were reversed with neostigmine and 71 (44%) with sugammadex. The overall incidence of PRNB at PACU arrival was 5 of 163 or 3% (95% confidence interval [CI], 1-7). The incidence of severe PRNB in PACU was 1% (95% CI, 0-4). Three of the 5 subjects with PRNB had TOFR <0.4 at time of reversal but were given neostigmine since anesthesia providers detected no fade by qualitative assessment. CONCLUSIONS: The use of a protocol that specifies rocuronium dosing and selective use of sugammadex versus neostigmine based on qualitative assessment of TOF count and fade allowed us to achieve an incidence of PRNB of 3% (95% CI, 1-7) at PACU arrival. Quantitative monitoring may be needed to further reduce this incidence.

Routine administration of neostigmine after recovery of spontaneous breathing versus neuromuscular monitor-guided administration of neostigmine in pediatric patients: a parallel, randomized, controlled study.

BACKGROUND: Neostigmine used to reverse the muscle relaxants should be guided by neuromuscular monitoring, as the degree of spontaneous pre-reversal recovery is the key to success to reverse the neuromuscular block. But neuromuscular monitoring is not always available for some patients during anesthesia and, in consequence, we need to use other clinical judgment to guide the use of neostigmine to reverse the neuromuscular block. In this trial, we aimed to evaluate the incidence of residual neuromuscular blockade (rNMB) in pediatric patients with routine use of neostigmine after recovery of spontaneous breathing compared with the patients with the use of neostigmine guided by neuromuscular monitoring. METHODS: A parallel, randomized, controlled noninferiority study was conducted. We enrolled aged 3 months to 12 years old patients who underwent inguinal hernia repair under general anesthesia. The enrolled patients were randomly divided into experimental and control groups. After surgery, children in the experimental group were given 0.02 mg/kg neostigmine after recovery of spontaneous breathing. Children in the control group were given 0.02 mg/kg neostigmine when the train-of-four (TOF) ratio was between 0.4 and 0.9. However, no neostigmine was administered if the TOF ratio was higher than 0.9. The primary outcome was the incidence of rNMB after extubation (TOF ratio < 0.9). Secondary outcomes included the incidence of neostigmine-induced muscle paralysis, end of surgery - extubation interval, end of surgery - exit OR interval, the length of stay in the PACU, the incidence of hypoxia in the PACU, the number of children who required assisted ventilation during the PACU stay, and neostigmine-related adverse events. RESULTS: A total of 120 children were included in this study, with 60 in the experimental group and 60 in the control group. There was no significant difference in the incidence of rNMB after extubation between the groups (45/60 vs 44/60, RR 1.02 [95% CI, 0.83 to 1.26], p = 0.84). There was no neostigmine-induced muscle paralysis in either group. Adverse events were similar occurred in both groups. However, time from end of the surgery to leaving the operating room was earlier in the experimental group than in the control group (13.6 ± 5.2 vs 15.7 ± 5.6 min, MD -2.10 min [95% CI, -3.70 to -0.50], p = 0.04). The risk ratio of the incidence of TOF ratio < 0.3 for the experimental group was 31.12 (95%CI, 1.89 to 512.61) compared with the control group (12/60 vs 0/60, p = 0.00) in exploratory analysis. CONCLUSIONS: Recovery of spontaneous breathing could be used as a substitute of neuromuscular monitoring to guide neostigmine use in pediatric patients following minor surgeries. However, care should be taken for the residual neuromuscular block. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR-IOR-17012890. Registered on 5 October 2017.

REsidual Neuromuscular Block Prediction Score Versus Train-of-Four Ratio and Respiratory Outcomes: A Retrospective Cohort Study.

BACKGROUND: Residual neuromuscular blockade is associated with an increased incidence of postoperative respiratory complications. The REsidual neuromuscular block Prediction Score (REPS) identifies patients at high risk for residual neuromuscular blockade after surgery. METHODS: A total of 101,510 adults undergoing noncardiac surgery under general anesthesia from October 2005 to December 2018 at a tertiary care center in Massachusetts were analyzed for the primary outcome of postoperative respiratory complications (invasive mechanical ventilation requirement within 7 postoperative days or immediate postextubation desaturation [oxygen saturation {Spo2} <90%] within 10 minutes). The primary objective was to assess the association between the REPS and respiratory complications. The secondary objective was to compare REPS and train-of-four (TOF) ratio <0.90 on the strength of their association with respiratory complications. RESULTS: A high REPS (≥4) was associated with an increase in odds of respiratory complications (adjusted odds ratio [OR], 1.13 [95% confidence interval {CI}, 1.06-1.21]; P < .001). In 6224 cases with available TOF ratio measurements, a low TOF ratio (<0.9) was associated with respiratory complications (adjusted OR, 1.43 [95% CI, 1.11-1.85]; P = .006), whereas a high REPS was not (adjusted OR, 0.96 [95% CI, 0.74-1.23]; P = .73) (P = .018 for comparison between ORs). CONCLUSIONS: The REPS may be implemented as a screening tool to encourage clinicians to use quantitative neuromuscular monitoring in patients at risk of residual neuromuscular blockade. A positive REPS should be followed by a quantitative assessment of the TOF ratio.

Ease of Application of Various Neuromuscular Devices for Routine Monitoring.

BACKGROUND: Subjective evaluations to confirm recovery from neuromuscular blockade with a peripheral nerve stimulator (PNS) is inadequate. Quantitative monitors are the only reliable method to confirm adequate recovery of neuromuscular function. Unfortunately, many clinicians are unfamiliar with such devices and there is concern that the introduction of objective monitoring would be exceedingly laborious and could cause workflow delays. This study investigates how long it takes experienced nurse anesthetists to apply various neuromuscular devices as well as their perception regarding the ease of application. METHODS: Twenty nurse anesthetists were consented and participated in an educational session that familiarized them with 3 devices: SunStim Plus PNS (SunMed, Grand Rapids, MI), the acceleromyography-based IntelliVue NMT device (Philips, Amsterdam, the Netherlands), and electromyography-based TetraGraph device (Senzime B.V., Uppsala, Sweden). Participants were timed while placing each monitor on patients in a real-world setting. For the quantitative devices (IntelliVue NMT and TetraGraph), participants were also timed when obtaining calibrated baseline train-of-four (TOF) ratios. Friedman test and pairwise Wilcoxon signed-rank tests were used to evaluate the difference in time to connect different devices. Participants were surveyed about how easy they found it to utilize these devices. RESULTS: After adjusting for multiple comparison, time to connect was significantly less for PNS (median, 29; range, 16-58 seconds) compared to either the TetraGraph device (median, 62.8; range, 32-101 seconds; P < .001) or the IntelliVue NMT device (median, 46; range: 28-90 seconds; P < .001). The difference in time to connect between the TetraGraph device and the IntelliVue NMT device was not statistically significant (P = .053), but it took significantly less time to calibrate the TetraGraph device than the IntelliVue NMT device (median difference, -16; range, -88 to 49 seconds; P = .002). The participants found applying either the IntelliVue NMT device (P = .042) or the TetraGraph device (P = .048) more difficult than applying a PNS while finding it easier to calibrate the TetraGraph device versus the IntelliVue NMT device (P < .001). CONCLUSIONS: It takes 19 seconds longer to apply a quantitative neuromuscular monitor (the IntelliVue NMT device) than a PNS. While this difference reached significance, this relatively minimal additional time represents an inappropriate barrier to the application of quantitative monitors. Regardless of which quantitative monitor was utilized, these nurse anesthetists found the application and utilization of such devices relatively straightforward.

Postoperative residual neuromuscular blockade after reversal based on a qualitative peripheral nerve stimulator response: A randomised controlled trial.

BACKGROUND: Incomplete recovery of neuromuscular blockade is a common postoperative adverse event in the postanaesthesia care unit. OBJECTIVE: We examined and compared the incidence of residual neuromuscular blockade when the recommended dose of neostigmine or sugammadex was administered according to a qualitative nerve stimulator response. DESIGN: A randomised controlled trial. SETTING: A tertiary care hospital in South Korea from September 2017 to November 2017. PATIENTS: Eighty patients aged between 18 and 69 years were included in this study. All were patients scheduled to undergo elective laparoscopic cholecystectomy and who had an American Society of Anaesthesiologists physical status of one or two were eligible. INTERVENTIONS: Patients were allocated randomly to receive neostigmine or sugammadex at the end of surgery. The doses of the reversal agents were based on the response to peripheral nerve stimulation, which was discontinued after administration of the reversal agent. MAIN OUTCOME MEASURES: The primary outcome was the incidence of postoperative residual neuromuscular blockade. The secondary outcomes were the incidences of symptoms or signs of residual neuromuscular blockade such as hypoxaemia, inability to maintain head-lift for 5 s and diplopia. RESULTS: The incidence of residual neuromuscular blockade on arrival in the recovery room was 44.4% in the neostigmine group and 0% in the sugammadex group (P < 0.0001, relative risk = 1.80, 95% confidence interval 1.36 to 2.41). The incidences of adverse events in the recovery room were low and comparable between the groups. CONCLUSION: The incidence of residual neuromuscular blockade on arrival in the recovery room was significantly higher in the neostigmine group than that in the sugammadex group. However, the incidence of adverse events was similar in the neostigmine and sugammadex groups. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03292965.

Comparison of neostigmine vs. sugammadex for recovery of muscle function after neuromuscular block by means of diaphragm ultrasonography in microlaryngeal surgery: A randomised controlled trial.

BACKGROUND: Postoperative residual curarisation (PORC) is a risk directly related to the use of neuromuscular blocking agents during surgical procedures. Acceleromyography is distressing for conscious patients when assessing PORC. Diaphragm ultrasonography could be a valid alternative. OBJECTIVES: The primary objective was to achieve a 28% lower incidence of PORC in patients who, after rocuronium administration, received neostigmine or sugammadex at 30 min after surgery. To assess PORC, diaphragm ultrasonography was used, and thickening fractioning [the difference of thickness at the end of inspiration (TEI) and at the end of expiration (TEE), normalised for TEE (TEI - TEE/TEE)] was measured. PORC was defined as thickening fractioning of 0.36 or less. The secondary object was the comparison, in the two treatment groups, of the return to baseline thickening fractioning at 30 min after surgery (ΔTF30). DESIGN: Randomised, double-blind, single-centre study. SETTING: University Hospital Careggi, Florence, Italy. PATIENTS: Patients of American Society Anesthesiologists' physical status 1 or 2, 18 to 80 years, receiving rocuronium during microlaryngeal surgery. INTERVENTIONS: At the end of surgery participants were randomised to receive neostigmine (NEO group) or sugammadex (SUG group) as the reversal drug. Thickening fractioning and ΔTF30 were evaluated at baseline and at 0, 10 and 30 min after surgery. MAIN OUTCOME MEASURES: TEE and TEI at each time point. RESULTS: A total of 59 patients with similar demographic characteristics were enrolled. An association between lack of recovery (thickening fractioning ≤0.36) and drug treatment was only observed at 0 min (SUG vs. NEO, P < 0.05). Concerning ΔTF, at 30 min more patients in the SUG group returned to baseline than those in the NEO group (P < 0.001), after adjusting for side (P = 0.52), baseline thickening fractioning (P < 0.0001) and time of measurement (P < 0.01). CONCLUSION: We found an early (0 min) but not long-lasting (30 min) association between diaphragm failure and treatment allocation; a full recovery in baseline diaphragm function was observed only in patients receiving sugammadex. We cannot exclude that further differences have not been found due to interpatients variability in assessing diaphragm contractility by ultrasonography. TRIAL REGISTRATION: EudraCT Identifier: 2013-004787-62, Clinicaltrials.gov Identifier: NCT02698969.

A comparison between the flexor hallucis brevis and adductor pollicis muscles in atracurium-induced neuromuscular blockade using acceleromyography: A prospective observational study.

BACKGROUND: Neuromuscular blockade (NMB) monitoring is essential to avoid residual NMB. While the adductor pollicis is the recommended site for monitoring recovery, it is not always accessible. The flexor hallucis brevis could be an interesting alternative. OBJECTIVE: The aim of our study was to compare NMB onset and recovery at both sites. DESIGN: Prospective observational study. SETTING: Operating rooms at the University Hospital of Poitiers, France. PATIENTS: Sixty patients scheduled for surgery under general anaesthesia with neuromuscular blocking agents were enrolled from January 2016 to September 2017. Data from 56 patients were finally analysed. Among these, 11 patients received pharmacological reversal with neostigmine and atropine before emergence from anaesthesia. INTERVENTION: After atracurium injection, NMB onset and recovery at the adductor pollicis and flexor hallucis brevis were monitored simultaneously. MAIN OUTCOME MEASURES: The time to NMB onset, defined as a train-of-four (TOF) count equal to 0, and the times to NMB recovery: TOF = 1, TOF = 4, T4/T1 ratio = 0.75 and T4/T1 ratio more than 0.90. RESULTS: NMB onset was significantly slower at the flexor hallucis brevis with a mean onset time of 4.4 ±â€Š1.5 versus 3.7 ±â€Š1.2 min at adductor pollicis (P = 0.0001). Recovery to TOF = 1 was significantly slower at flexor hallucis brevis. No difference was found for TOF = 4. The full recovery of NMB (T4/T1 > 0.90) was significantly faster at flexor hallucis brevis with a mean time to recovery of 59.5 ±â€Š9.9 versus 64.5 ±â€Š10.7 min at adductor pollicis (P < 0.0001), a difference of 4.9 min between both sites. This difference was not present after pharmacological reversal with a mean time to recovery of 53.0 ±â€Š12.2 min at flexor hallucis brevis versus 54.0 ±â€Š12.4 min at adductor pollicis (P = 0.28). However, NMB onset and recovery did not follow the same pattern in individual patients. CONCLUSION: Flexor hallucis brevis could be an interesting alternative site for NMB monitoring when the adductor pollicis is not accessible. However, in the absence of pharmacological reversal, monitoring at the hallucis brevis muscle should be used with caution for the detection of residual paralysis. TRIAL REGISTRATION: ClinicalTrials.gov (NCT02825121).

Neostigmine Versus Sugammadex for Reversal of Neuromuscular Blockade and Effects on Reintubation for Respiratory Failure or Newly Initiated Noninvasive Ventilation: An Interrupted Time Series Design.

BACKGROUND: Pulmonary complications related to residual neuromuscular blockade lead to morbidity and mortality. Using an interrupted time series design, we tested whether proportions of reintubation for respiratory failure or new noninvasive ventilation were changed after a system-wide transition of the standard reversal agent from neostigmine to sugammadex. METHODS: Adult patients undergoing a procedure with general anesthesia that included pharmacologic reversal of neuromuscular blockade and admission ≥1 night were eligible. Groups were determined by date of surgery: August 15, 2015 to May 10, 2016 (presugammadex), and August 15, 2016 to May 11, 2017 (postsugammadex). The period from May 11, 2016 to August 14, 2016 marked the institutional transition (washout/wash-in) from neostigmine to sugammadex. The primary outcome was defined as a composite of reintubation for respiratory failure or new noninvasive ventilation. Event proportions were parsed into 10-day intervals in each cohort, and trend lines were fitted. Segmented logistic regression models appropriate for an interrupted time series design and adjusting for potential confounders were utilized to evaluate the immediate effect of the implementation of sugammadex and on the difference between preintervention and postintervention slopes of the outcomes. Models containing all parameters (full) and only significant parameters (parsimonious) were fitted and are reported. RESULTS: Of 13,031 screened patients, 7316 patients were included. The composite respiratory outcome occurred in 6.1% of the presugammadex group and 4.2% of the postsugammadex group. Adjusted odds ratio (OR) and 95% confidence intervals (CIs) for the composite respiratory outcome were 0.795 (95% CI, 0.523-1.208) for the immediate effect of intervention, 0.986 (95% CI, 0.959-1.013) for the difference between preintervention and postintervention slopes in the full model, and 0.667 (95% CI, 0.536-0.830) for the immediate effect of the intervention in the parsimonious model. CONCLUSIONS: The system-wide transition of the standard pharmacologic reversal agent from neostigmine to sugammadex was associated with a reduction in the odds of the composite respiratory outcome. This observation is supported by nonsignificant within-group time trends and a significant reduction in intercept/level from presugammadex to postsugammadex in a parsimonious logistic regression model adjusting for covariates.

Risk factors of inadequate emergence following general anesthesia with an emphasis on patients with substance dependence history.

BACKGROUND: This study aims to define the incidence and risk factors of both emergence agitation and hypoactive emergence in adult patients and substance-dependent patients following general anesthesia to elaborate on the risk factors and precise management of them. METHODS: The study recruited 1,136 adult patients who received elective surgeries under general anesthesia for this prospective observational study. Inadequate emergence was determined according to the Richmond Agitation-Sedation Scale (RASS). Emergence agitation was defined as a RASS ≥ +1 point, and hypoactive emergence was defined as a RASS ≤ -2 points. Subgroup analyses were then conducted on patients with substance dependence. RESULTS: Inadequate emergence in the post-anesthesia care unit (PACU) occurred in 20.3% of patients, including 13.9% with emergence agitation and 6.4% with hypoactive emergence. Ninety-five patients had a history of substance dependence. Compared to divorced patients, never-married and presently married patients, who underwent gynecological and thoracic surgeries, had a lower risk of agitation. Neurologic disorders, intraoperative blood loss, intraoperative morphine, and PACU analgesic drug administration were associated with increased agitation risk. Hypertension and psychological disorders, intraoperative opioids, and PACU Foley catheter fixation were associated with increased hypoactive emergence risk. Substance-dependent patients had higher risk for agitation (21.1%, P = 0.019) and hypoactive emergence (10.5%, P = 0.044). CONCLUSIONS: Inadequate emergence in PACU following general anesthesia is a significant problem correlated with several perioperative factors. Patients with a history of substance dependence appear to be more at risk of inadequate emergence than the general population.

Individualized Quality Data Feedback Improves Anesthesiology Residents' Documentation of Depth of Neuromuscular Blockade Before Extubation.

Reversal of neuromuscular blockade is an important anesthesia quality measure, and anesthesiologists should strive to improve both documentation and practice of this measure. We hypothesized that the use of an electronic quality database to give individualized resident anesthesiologist feedback would increase the percentage of cases that residents successfully documented quantitative depth of neuromuscular blockade before extubation. The mean baseline success rate among anesthesiology residents was 80% (95% confidence interval [CI], 78-81) and increased by 14% (95% CI, 11-17; P < .001) after the residents were given their individualized quality data. Practice patterns improved quickly but were not sustained over 6 months.

Unrecognised postoperative residual curarisation in developing countries remains a common problem.

BACKGROUND: Postoperative residual curarisation (PORC) is a potentially life-threatening complication of non-depolarising muscle relaxant use in anaesthesia. Quantitative neuromuscular monitoring has the potential to reduce the risk of PORC, but many anaesthetists rely on clinical assessment of neuromuscular function alone. OBJECTIVES: To investigate the occurrence of PORC in the recovery room at an academic hospital in Gauteng, South Africa. Additionally, this prospective, cross-sectional study aimed to determine the extent of intraoperative neuromuscular monitoring and to assess clinical factors that may influence the risk of PORC. METHODS: Patient characteristics and clinical information, including whether neuromuscular monitoring had been conducted, were recorded. Patients were evaluated by clinical assessment and determination of a quantitative train-of-four ratio (TOFR). PORC assessment methods were compared and clinical characteristics were analysed for association with TOFR status. RESULTS: The incidence of PORC (TOFR <0.9) in the study group was 45.5%; however, 78% passed the clinical assessment. The specificity of clinical assessment to detect residual paralysis was 24%. Notably, only 3 patients (6%) were monitored intraoperatively for neuromuscular function. Advanced age (p=0.011, r=-0.34) and female gender (p=0.001) were shown to be associated with a TOFR <0.7. CONCLUSIONS: PORC is more common in practice than currently recognised. This deduction is supported by the low rate of intraoperative neuromuscular monitoring conducted and the high pass rate on clinical assessment. Routine use of quantitative monitoring of neuromuscular function should be encouraged to minimise the risk of this serious yet preventable condition.

Incidence, risk factors, and consequences of residual neuromuscular block in the United States: The prospective, observational, multicenter RECITE-US study.

STUDY OBJECTIVE: To determine the incidence burden and associated risk factors of residual neuromuscular block (rNMB) during routine U.S. hospital care. DESIGN: Blinded multicenter cohort study. SETTING: Operating and recovery rooms of ten community and academic U.S. hospitals. PATIENTS: Two-hundred fifty-five adults, ASA PS 1-3, underwent elective abdominal surgery with general anesthesia and ≥1 dose of non-depolarizing neuromuscular blocking agent (NMBA) for endotracheal intubation and/or maintenance of NMB between August 2012 and April 2013. INTERVENTIONS: TOF measurements using acceleromyography were performed on patients already receiving routine anesthetic care for elective open or laparoscopic abdominal surgery. Measurements allowed assessment of the presence of residual neuromuscular block (rNMB), defined as a train-of-four (TOF) ratio <0.9 at tracheal extubation. We recorded patient and procedural characteristics and assessed TOF ratios (T4/T1) at various times throughout the procedure and at tracheal extubation. Differences in patient and clinical characteristics were compared using Fisher's exact test for categorical variables and t-test for continuous variables. Multivariate logistic regression assessed risk factors associated with rNMB at extubation. MAIN RESULTS: Most of the study population, 64.7% (n = 165) had rNMB (TOF ratio < 0.9), among them, 31.0% with TOF ratio <0.6. Among those receiving neostigmine and/or qualitative peripheral nerve stimulation per clinical decision, 65.0% had rNMB. After controlling for confounders, we observed male gender (odds ratio: 2.60, P = 0.008), higher BMI (odds ratio: 1.04/unit, P = 0.043), and surgery at a community hospital (odds ratio: 3.15, P = 0.006) to be independently associated with increased odds of rNMB. CONCLUSIONS: Assessing TOF ratios blinded to the care team, we found that the majority of patients (64.7%) in this study had rNMB at tracheal extubation, despite neostigmine administration and qualitative peripheral nerve stimulation used for routine clinical care. Qualitative neuromuscular monitoring and clinical judgement often fails to detect rNMB after neostigmine reversal with potential severe consequences to the patient. Our data suggests that clinical care could be improved by considering quantitative neuromuscular monitoring for routine care.

Development and validation of an android-based application for anaesthesia neuromuscular monitoring.

Quantitative neuromuscular block (NMB) assessment is an internationally recognised necessity in anesthesia care whenever neuromuscular blocking agents are administered. Despite this, the incidence of residual neuromuscular block and its associated major respiratory morbidity and mortality remain unacceptably high considering its preventable nature. Recent surveys show that quantitative NMB assessment is not consistently employed by anesthesiologists. Availability, price and practical concerns are some of the factors determining this phenomenon. Clinically assess and validate an Android cell phone application conceived specifically for NMB Monitoring in the anesthesia setting. Twenty-two adult ASA I to III patients scheduled to undergo elective surgical procedures under general anaesthesia requiring administration of a neuromuscular blocking agent were included. After anaesthesia induction, the grade of neuromuscular block was assessed at multiple independent time-points by paired comparison of the train of four (TOF) Ratios obtained by a Stimpod™ accelerometer and the currently developed application. Accelerometric measurements were made at the patient's hand after retrograde supramaximal stimulation of the ipsilateral ulnar nerve. TOF-ratios were subjected to bias analysis with 0.001 as the a priori established clinical significance cut-off. The difference between the two methods averaged 0.0004 (95% limits of agreement: ± 0.12), with 83.3% of the differences being under 0.05. This average inter-method difference was not significantly different than the a priori hypothesized difference cut-off of 0.001 (p = 0.78). Lin's concordance correlation coefficient and Pearson's correlation were both of 0.98. The custom developed Android application proved accurate for diagnosis of residual neuromuscular block.

Dexamethasone concentration affecting rocuronium-induced neuromuscular blockade and sugammadex reversal in a rat phrenic nerve-hemidiaphragm model: An ex vivo study.

BACKGROUND: The concentration range of dexamethasone that inhibits neuromuscular blockade (NMB) and sugammadex reversal remains unclear. OBJECTIVE: To evaluate the effects of dexamethasone on rocuronium-induced NMB and sugammadex reversal. DESIGN: Ex vivo study. SETTING: Asan Institute for Life Sciences, Asan Medical Center, Korea, from July 2015 to November 2015. ANIMALS: One hundred sixty male Sprague-Dawley rats. INTERVENTIONS: We assessed the effect of four concentrations of dexamethasone [0, 0.5, 5 (clinical concentrations) and 50 µg ml (experimental concentration)] on partial NMB on 40 phrenic nerve-hemidiaphragm preparations (n=10 per concentration). Once the first twitch of train-of-four (TOF) had been depressed by 50% with rocuronium, dexamethasone was administered. To assess the effect of dexamethasone on sugammadex reversal, 120 phrenic nerve-hemidiaphragm preparations were used in three subexperiments (n=40 per experiment), using three administration regimens of rocuronium-equimolar sugammadex: a single dose, a split-dose (split and ) and a reduced split-dose (split and ). After complete NMB was achieved, dexamethasone and sugammadex were administered. MAIN OUTCOME MEASURES: The change in the first twitch height, the recovery time to a TOF ratio at least 0.9, and the TOF ratio at 30 min were evaluated. RESULTS: There were no significant differences in the first twitch height among groups (P = 0.532). With a single dose of sugammadex, dexamethasone did not affect the recovery time to a TOF ratio at least 0.9 (P = 0.070). After using a split-dose of sugammadex, the recovery time to a TOF ratio at least 0.9 was delayed only at a concentration of 50 µg ml of dexamethasone. With a reduced split-dose of sugammadex, the TOF ratio at 30 min was lowered only by a concentration of 50 µg ml of dexamethasone (P < 0.010). CONCLUSION: Acute bolus administration of dexamethasone at clinical concentrations had no effect on NMB or on sugammadex reversal.

Comparison of a novel clinical score to estimate the risk of REsidual neuromuscular block Prediction Score and the last train-of-four count documented in the electronic anaesthesia record: A retrospective cohort study of electronic data on file.

BACKGROUND: Residual neuromuscular block (rNMB) after surgery is not difficult to identify if proper neuromuscular monitoring is used, but many clinicians do not use quantitative neuromuscular monitoring. OBJECTIVE: The aim of this study was to develop a REsidual neuromuscular block Prediction Score (REPS) to predict postoperative rNMB and compare the predictive accuracy of the prediction score with train-of-four count (TOFC) measurement at the end of a surgical case. DESIGN: Retrospective cohort study of data on file. DATA SOURCE: Electronic patient data and peri-operative data on vital signs, administered medications, and train-of-four ratio (TOFR) obtained in the postoperative recovery rooms [postanaesthesia care unit (PACU)] at Massachusetts General Hospital in Boston, Massachusetts, USA. PATIENTS: Quantitative TOFR measurements obtained on admission to the PACU were available from 2144 adult noncardiac surgical patients. MAIN OUTCOME MEASURE: Presence of rNMB at PACU admission, defined as a TOFR of less than 0.9. RESULTS: In the score development cohort (n=2144), rNMB occurred in 432 cases (20.2%). Ten independent predictors for residual paralysis were identified and used for the score development. The final model included: hepatic failure, neurological disease, high-neostigmine dose, metastatic tumour, female sex, short time between neuromuscular blocking agent administration and extubation, aminosteroidal neuromuscular blocking agent, BMI more than 35, absence of nurse anaesthetist and having an experienced surgeon. The model discrimination by C statistics was 0.63, 95% confidence interval (0.60 to 0.66), and risk categories derived from the REPS had a higher accuracy than the last documented intra-operative TOFC for predicting rNMB (net reclassification improvement score 0.26, standard error 0.03, P < 0.001). CONCLUSION: The REPS can be used to identify patients at greater risk of rNMB. This tool may inform anaesthetists better than an intra-operative TOFC and thus enable peri-operative anaesthetic practices to be tailored to the patient and minimise the undesirable effects of rNMB. TRIAL REGISTRY NUMBER: Approved by Partners Human Research Committee (protocol number 2016P000940) at MGH in Boston, Massachusetts, USA on 25 April 2016.

Emergence times and airway reactions during general anaesthesia with remifentanil and a laryngeal mask airway: A multicentre randomised controlled trial.

BACKGROUND: Avoidance of airway complications and rapid emergence from anaesthesia are indispensable for the use of a laryngeal mask airway (LMA). Evidence from adequately powered randomised studies with a low risk of bias for the optimal anaesthetic in this context is limited. OBJECTIVE: We tested the hypothesis that when using remifentanil-based intra-operative analgesia, desflurane would be the most suitable anaesthetic: with noninferiority in the occurrence of upper airway complications and superiority in emergence times compared with sevoflurane or propofol. DESIGN: A randomised, multicentre, partially double-blinded, three-arm, parallel-group study. SETTING: Two university and two regional German hospitals, from February to October 2015. PATIENTS: A total of 352 patients (age 18 to 75 years, ASA physical status I to III, BMI less than 35 kg m and fluent in German) were enrolled in this study. All surgery was elective with a duration of 0.5 to 2 h, and general anaesthesia with a LMA was feasible. INTERVENTION: The patients were randomised to receive desflurane, sevoflurane or propofol anaesthesia. MAIN OUTCOME MEASURES: This study was powered for the primary outcome 'time to state date of birth' and the secondary outcome 'intra-operative cough'. Time to emergence from anaesthesia and the incidence of upper airway complications were assessed on the day of surgery. RESULTS: The primary outcome was analysed for 343 patients: desflurane (n=114), sevoflurane (n=111) and propofol (n=118). The desflurane group had the fastest emergence. The mean (± SD) times to state the date of birth following desflurane, sevoflurane and propofol were 8.1 ±â€Š3.6, 10.1 ±â€Š4.0 and 9.8 ±â€Š5.1 min, respectively (P < 0.01). There was no difference in upper airway complications (cough and laryngospasm) across the groups, but these complications were less frequent than in previous studies. CONCLUSION: When using a remifentanil infusion for intra-operative analgesia in association with a LMA, desflurane was associated with a significantly faster emergence and noninferiority in the incidence of intra-operative cough than either sevoflurane or Propofol. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02322502; EudraCT identifier: 2014-003810-96.

Accidental Ketamine Overdose on Induction of General Anesthesia.

BACKGROUND Ketamine is used as an induction and sedation agent in emergency departments and operating rooms throughout the country. Despite its widespread clinical use, there are few cases of significant morbidity and mortality attributed to ketamine overdose in the clinical setting. CASE REPORT The anesthesia provider in the room was an oral maxillofacial surgeon who inadvertently took out a more highly concentrated bottle of ketamine that is typically used for pediatric patients. The patient received 950 mg (100 mg/ml concentration) of intravenous ketamine instead of the intended 95 mg (10 mg/ml concentration). After the ketamine was given, there were no signs to any involved provider that a mistake had occurred until the wake-up appeared to be unusually prolonged. CONCLUSIONS Despite this, the patient did not demonstrate any systemic effects such as hemodynamic or CNS perturbations other than prolonged awakening. This case highlights one (drug overdose) of many causes of delayed emergence from anesthesia and reminds the provider caring for the patient to be mindful of drug concentrations used when preparing to sedate a patient, as relying on effects of the parent drug is not always adequate.

Delineating the Trajectory of Cognitive Recovery From General Anesthesia in Older Adults: Design and Rationale of the TORIE (Trajectory of Recovery in the Elderly) Project.

BACKGROUND: Mechanistic aspects of cognitive recovery after anesthesia and surgery are not yet well characterized, but may be vital to distinguishing the contributions of anesthesia and surgery in cognitive complications common in the elderly such as delirium and postoperative cognitive dysfunction. This article describes the aims and methodological approach to the ongoing study, Trajectory of Recovery in the Elderly (TORIE), which focuses on the trajectory of cognitive recovery from general anesthesia. METHODS: The study design employs cognitive testing coupled with neuroimaging techniques such as functional magnetic resonance imaging, diffusion tensor imaging, and arterial spin labeling to characterize cognitive recovery from anesthesia and its biological correlates. Applying these techniques to a cohort of age-specified healthy volunteers 40-80 years of age, who are exposed to general anesthesia alone, in the absence of surgery, will assess cognitive and functional neural network recovery after anesthesia. Imaging data are acquired before, during, and immediately after anesthesia, as well as 1 and 7 days after. Detailed cognitive data are captured at the same time points as well as 30 days after anesthesia, and brief cognitive assessments are repeated at 6 and 12 months after anesthesia. RESULTS: The study is underway. Our primary hypothesis is that older adults may require significantly longer to achieve cognitive recovery, measured by Postoperative Quality of Recovery Scale cognitive domain, than younger adults in the immediate postanesthesia period, but all will fully recover to baseline levels within 30 days of anesthesia exposure. Imaging data will address systems neuroscience correlates of cognitive recovery from general anesthesia. CONCLUSIONS: The data acquired in this project will have both clinical and theoretical relevance regardless of the outcome by delineating the mechanism behind short-term recovery across the adult age lifespan, which will have major implications for our understanding of the effects of anesthetic drugs.

Neostigmine-based reversal of intermediate acting neuromuscular blocking agents to prevent postoperative residual paralysis: A systematic review.

BACKGROUND: Neostigmine is widely used to antagonise residual paralysis. Over the last decades, the benchmark of acceptable neuromuscular recovery has increased progressively to a train-of-four (TOF) ratio of at least 0.9. Raising this benchmark may impact on the efficacy of neostigmine. OBJECTIVE(S): The systematic review evaluates the efficacy of neostigmine to antagonise neuromuscular block to attain a TOF ratio of at least 0.9. DESIGN: We performed a systematic search of the literature from January 1992 to December 2015. DATA SOURCES OR SETTING: PubMed, EMBASE and the Cochrane Controlled Clinical Trials database were searched for randomised controlled human studies. Search was performed without language restrictions, using the following free text terms: 'neostigmine', 'sugammadex', 'edrophonium' or 'pyridostigmine' AND 'neuromuscular block', 'reversal' or 'reverse'. ELIGIBILITY CRITERIA: Studies were accepted for inclusion if they used quantitative neuromuscular monitoring and neostigmine as the reversal agent. Selected trials were checked by two of the authors for data integrity. Trials relevant for inclusion had to report the number of patients included, the type of anaesthetic maintenance, the type of neuromuscular blocking agent used, the reversal agent and dose used, the depth of neuromuscular block when neostigmine was administered and the reversal time (time from injection of neostigmine until a TOF ratio ≥0.9 was attained). RESULTS: 19 trials were eligible for quantitative analysis. In patients with deep residual block [T1 (first twitch height) <10%] 70 µg kg neostigmine was used (five trials, 118 patients), and the mean reversal time was 17.1 min (95% confidence interval (CI) [12.4 to 21.8]). In patients with moderate residual block (T1 10% to <25%) the mean neostigmine dose was 56 µg kg (seven trials, 342 patients), and the mean reversal time was 11.3 min (95% CI [9.2 to 13.4]). In patients with a shallow residual block (T1 ≥ 25%) the mean neostigmine dose was 40 µg kg (13 trials, 535 patients), and the mean reversal time was 8.0 min (95% CI [6.8 to 9.2]). CONCLUSION: Based on the findings of this systematic review, we recommend that the administration of neostigmine be delayed until an advanced degree of prereversal recovery has occurred (i.e. a T1 >25% of baseline), or that a recovery time longer than 15 min be accepted.