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Purpose: Neuromuscular monitoring is frequently plagued by artefacts, which along with the frequent unawareness of the principles of this subtype of monitoring by many clinicians, tends to lead to a cynical attitute by clinicians towards these monitors. As such, the present study aims to derive a feature set and evaluate its discriminative performance for the purpose of Train-of-Four Ratio (TOF-R) outlier analysis during continuous intraoperative EMG-based neuromuscular monitoring. Methods: Patient data was sourced from two devices: (1) Datex-Ohmeda Electromyography (EMG) E-NMT: a dataset derived from a prospective observational trial including 136 patients (21,891 TOF-R observations), further subdivided in two based on the type of features included; and (2) TetraGraph: a clinical case repository dataset of 388 patients (97,838 TOF-R observations). The two datasets were combined to create a synthetic set, which included shared features across the two. This process led to the training of four distinct models. Results: The models showed an adequate bias/variance balance, suggesting no overfitting or underfitting. Models 1 and 2 consistently outperformed the others, with the former achieving an F1 score of 0.41 (0.31, 0.50) and an average precision score (95% CI) of 0.48 (0.35, 0.60). A random forest model analysis indicated that engineered TOF-R features were proportionally more influential in model performance than basic features. Conclusions: Engineered TOF-R trend features and the resulting Cost-Sensitive Logistic Regression (CSLR) models provide useful insights and serve as a potential first step towards the automated removal of outliers for neuromuscular monitoring devices. Trial registration: NCT04518761 (clinicaltrials.gov), registered on 19 August 2020. Key points: • Neuromuscular monitoring is still suboptimally employed by anesthesiologists despite recent recommendations. • Artefactual phenomena are frequently reported as a cause of distrust in neuromuscular monitoring. • Machine-learning models based on universal neuromuscular monitoring variables can be developed to minimise artefacts and so increase end-user compliance. [ABSTRACT FROM AUTHOR]

Neuromuscular blocking agents are a crucial pharmacological element of general anesthesia. Decades of observations and scientific studies have resulted in the identification of many risks associated with the uncontrolled use of neuromuscular blocking agents during general anesthesia or an incomplete reversal of neuromuscular blockade in the postoperative period. Residual relaxation and acute postoperative respiratory depression are the most serious consequences. Cyclic recommendations have been developed by anesthesiology societies from many European countries as well as from the United States and New Zealand. The newest recommendations from the American Society of Anesthesiologists and the European Society of Anesthesiology were published in 2023. These publications contain very detailed recommendations for monitoring the dosage of skeletal muscle relaxants in the different stages of anesthesia—induction, maintenance and recovery, and the postoperative period. Additionally, there are recommendations for various special situations (for example, rapid sequence induction) and patient populations (for example, those with organ failure, obesity, etc.). The guidelines also refer to pharmacological drugs for reversing the neuromuscular transmission blockade. Despite the development of several editions of recommendations for monitoring neuromuscular blockade, observational and survey data indicate that their practical implementation is very limited. The aim of this review was to present the professional, technical, and technological factors that limit the implementation of these recommendations in order to improve the implementation of the guidelines and increase the quality of anesthesiological procedures and perioperative safety. [ABSTRACT FROM AUTHOR]

The aim of this study was to describe the onset and duration of action of escalating doses of atracurium in healthy, anesthetized goats. Randomized, blinded, triple crossover study. Animals A total of eight (five males and three females) healthy goats weighing 42.7–123.5 kg and aged from 11 months to 8 years. Goats were anesthetized three times with propofol and anesthesia was maintained with isoflurane. One of three doses of atracurium was administered intravenously 30 minutes after induction: 0.25 mg kg–1 (AT25), 0.5 mg kg–1 (AT50) or 0.75 mg kg–1 (AT75). Acceleromyographic train-of-four ratio (TOFR) followed by train-of-four counts (TOFC) were recorded at 30 second intervals after atracurium administration to determine blockade onset (TOFC = 0). The TOFR followed by TOFC were recorded at 5 minute intervals until return to pre-atracurium baseline (TOFR = 1.0). Normally distributed data were analyzed with repeated measures anova and a Tukey multiple comparison test. Data not normally distributed were analyzed with a Friedman test and a Dunn's multiple comparison test. For AT50 and AT75, 100% of goats achieved TOFC = 0 after atracurium administration. For AT25, however, 87.5% of goats achieved TOFC = 0 after atracurium administration. The onset time was shorter for AT75 [1.5 (0.5–1.5) minutes; median (range)] than for AT25 [2 (1–4) minutes] (p = 0.048). The duration of action [from onset time to complete reversal (TOFR = 1.0)] was significantly shorter for AT25 (52 ± 12 minutes, mean ± SD) than for AT50 (77 ± 18 minutes) (p < 0.001) and AT75 (85 ± 16 minutes) (p < 0.001). There was no significant difference in duration between AT50 and AT75 (p = 0.238). Doses of 0.5 and 0.75 mg kg–1 atracurium may produce complete neuromuscular blockade in healthy, anesthetized goats. [ABSTRACT FROM AUTHOR]

To compare recovery times of sugammadex with spontaneous recovery from rocuronium-induced neuromuscular block (NMB) in dogs. Retrospective, unmatchedcase-control study. A total of 10 dogs administered sugammadex and 10 dogs recovering spontaneously from rocuronium-induced NMB. Files of dogs administered rocuronium between March and August 2023 were inspected. The train-of-four (TOF) count at the time of sugammadex administration and the time between administration and TOF ratio >90% (recovery time) were recorded. The recovery time for those not administered reversal agents was considered from the first TOF value >0 until TOF ratio >90%. The dose of sugammadex and the cumulative dose of rocuronium were recorded. Rocuronium doses and recovery times were compared using Mann–Whitney tests. The coefficient of determination (R2) between the cumulative rocuronium dose and sugammadex dose and the recovery time were calculated. Dogs in the sugammadex and spontaneous recovery groups were administered intravenously (IV) 0.76 (0.4–2.6) and 0.61 (0.3–2.9) mg kg–1 of rocuronium, respectively (p = 0.325). Recovery time after 3.9 (2.9–5.5) mg kg–1 of sugammadex IV was 1 (1–3) minutes and was 20 (10–35) min for spontaneous recovery (p < 0.0001). The R2 for rocuronium and sugammadex doses and recovery times were 0.19 (p = 0.2) and 0.012 (p = 0.758). Sugammadex 2.9–5.5 mg kg–1 reversed moderate (TOF count 1–3) or deep (TOF count 0) rocuronium-induced NMB within 3 minutes, substantially faster than spontaneous recovery. [ABSTRACT FROM AUTHOR]

Background: International guidelines recommend quantitative neuromuscular monitoring when administering neuromuscular blocking agents. The train-of-four count is important for determining the depth of block and appropriate reversal agents and doses. However, identifying valid compound motor action potentials (cMAPs) during surgery can be challenging because of low-amplitude signals and an inability to observe motor responses. A convolutional neural network (CNN) to classify cMAPs as valid or not might improve the accuracy of such determinations. Methods: We modified a high-accuracy CNN originally developed to identify handwritten numbers. For training, we used digitised electromyograph waveforms (TetraGraph) from a previous study of 29 patients and tuned the model parameters using leave-one-out cross-validation. External validation used a dataset of 19 patients from another study with the same neuromuscular block monitor but with different patient, surgical, and protocol characteristics. All patients underwent ulnar nerve stimulation at the wrist and the surface electromyogram was recorded from the adductor pollicis muscle. Results: The tuned CNN performed highly on the validation dataset, with an accuracy of 0.9997 (99% confidence interval 0.9994–0.9999) and F1 score=0.9998. Performance was equally good for classifying the four individual responses in the train-of-four sequence. The calibration plot showed excellent agreement between the predicted probabilities and the actual prevalence of valid cMAPs. Ten-fold cross-validation using all data showed similar high performance. Conclusions: The CNN distinguished valid cMAPs from artifacts after ulnar nerve stimulation at the wrist with >99.5% accuracy. Incorporation of such a process within quantitative electromyographic neuromuscular block monitors is feasible.

Abstract Introduction NMB facilitates intubating conditions in general anesthesia. However, it is associated with significant residual postoperative paralysis and morbidity. Objective To investigate the rate of underdiagnosed residual NMB based on two TOFR criteria (

Introduction: NMB facilitates intubating conditions in general anesthesia. However, it is associated with significant residual postoperative paralysis and morbidity. Objective: To investigate the rate of underdiagnosed residual NMB based on two TOFR criteria (< 0.91 and < 1.00). Methods: We performed a retrospective study adhering to STROBE guidelines. We included patients undergoing ENT surgery using single-dose neuromuscular block for balanced general anesthesia from June to December 2018. We collected demographic and anthropometric data, ASA score, NMBA dose, TOFR recordings at 5, 30 and 60 min and end of the surgery, anesthesia and surgery time, and administration of reversal agent. Statistical analysis included descriptive and dispersion measures statistics, curve and cross tables for residual NMB on different TOFR criteria with sub-analysis for AR, RR, and OR in patients over 65 years old. Results: We included 57 patients, mean age 41; 43 females and 14 males. Mean anesthetic and surgical time were 139.4 and 116.1 min, respectively. All the patients received rocuronium under a mean ponderal single-dose of 0.48 mg/kg. Residual NMB rates were 29.9 and 49.1% for a TOFR < 0.91 and < 1.00, respectively. Older adults had an OR of 6.08 for residual NMB. Conclusions: The rate of residual NMB was 29.9 to 49.1%, depending on the criteria used (TOFR < 0.91 and < 1.00, respectively). Patients above 65 years old had an increased risk of residual NMB (6.08 OR) and clinical symptoms related to residual NMB (11.75 OR). We recommend future research aiming to provide a specific surveillance protocol for patients above 65 years old, including shorter-action NMB, early reversal, and prolonged surveillance using the TOFR criteria of < 1.00 to identify patients at risk of residual NMB readily. Highlights: • The rate of residual NMB in our practice was in the range of 29.9 to 49.1% depending on the criteria used (TOFR < 0.91 or TOFR < 1.00, respectively). • Patients above 65 years old are at an increased risk of residual NMB (6.08 OR) due to increased NMBA duration of action, as demonstrated by the curves of NMB during surgery. • Older patients also had an increased risk (OR 11.75) of clinical symptoms related to the residual neuromuscular block. • We recommend providing specific surveillance protocols for patients above 65 years-old, including the use of shorter-action NMB, early reversal, and prolonged surveillance in the postoperative period. • We recommend using the TOFR criteria of < 1.00 to readily identify more patients at risk of residual neuromuscular block, especially in older people. • We recommend the use of reversal agents in patients at high risk of residual neuromuscular block, such as patients above 65 years-old, especially in those cases where patients have difficultness for reaching a TOFR criterion of 1.00 because of an increased risk of residual neuromuscular block and its complications. [ABSTRACT FROM AUTHOR]

In children, a high degree of variability has been demonstrated in response to muscle relaxants as well as in the recovery time of full muscle tissue function following neuromuscular junction blockage. Neonates and infants are patients in whom postoperative residual curarization (PORC) is particularly dangerous. Unrecognized residual neuromuscular block or the inability to completely reverse the effects of neuromuscular block can result in an increased risk of postoperative respiratory muscle dysfunction, which can lead to hypoxia, the need for mechanical ventilation, and prolonged hospital stay. The use of neuromuscular conduction monitoring devices significantly improves the safety of anaesthesia delivery in paediatric anaesthesiology. The pharmacokinetics of muscle relaxants in children (compared to adults) indicate a shorter duration of action and accelerated resolution of neuromuscular blockade when doses are adjusted for body weight. The following paper characterizes neuromuscular blockade in childhood and describes the peculiarities of striated muscle relaxant use in patients in this age group. [ABSTRACT FROM AUTHOR]

Respiratory and airway-protective muscle weakness caused by the blockade of neuromuscular transmission is a major cause of early mortality from snakebite envenoming (SBE). Once weakness is manifest, antivenom appears to be of limited effectiveness in improving neuromuscular function. Herein, we review the topic of venom-induced neuromuscular blockade and consider the utility of adopting clinical management methods originally developed for the safe use of neuromuscular blocking agents by anesthesiologists in operating rooms and critical care units. Failure to quantify neuromuscular weakness in SBE is predicted to cause the same significant morbidity that is associated with failure to do so in the context of using a clinical neuromuscular block in surgery and critical care. The quantitative monitoring of a neuromuscular block, and an understanding of its neurophysiological characteristics, enables an objective measurement of weakness that may otherwise be overlooked by traditional clinical examination at the bedside. This is important for the initial assessment and the monitoring of recovery from neurotoxic envenoming. Adopting these methods will also be critical to the conduct of future clinical trials of toxin-inhibiting drugs and antivenoms being tested for the reversal of venom-induced neuromuscular block. [ABSTRACT FROM AUTHOR]

Background: Fixed-rate infusions of weight-based neuromuscular blocking agents (NMBAs) were adopted during the COVID pandemic to limit caregiver exposure during titrations. Although fixed-rate infusions are supported in studies of acute respiratory distress syndrome (ARDS), the optimal scalar for weight-based NMBAs in patients with obesity remains controversial., Objective: This study sought to compare change in oxygenation using two weight-based dosing strategies for atracurium in obese patients with ARDS. Secondary outcomes included total atracurium dose, mortality, and intensive care unit (ICU) and ventilator-free days., Methods: Following an institutional practice update to use ideal body weight (IBW) for patients with obesity, we retrospectively compared adults (≥18 years) with ARDS and a body mass index (BMI) ≥ 30 kg/m 2 who received atracurium (15 µg/kg/min) based on actual body weight (ABW) with those using IBW. The primary outcome was change in PaO 2 /FiO 2 ratio (P/F) 48 hours after atracurium initiation. Analysis-of-covariance compared change in P/F between groups after adjustment for confounders., Results: The IBW group ( n = 123), compared with the ABW group ( n = 133), had lower baseline P/F (85.0 [71.0, 118.3] vs 93.3 [76.0, 128.3], P = 0.025) and sequential organ failure assessment (SOFA) score (9.7 ± 2.6 vs 10.5 ± 2.6, P = 0.015), with greater use of steroids (96% vs 89%, P = 0.032) and prone positioning (72% vs 58%, P = 0.015). No difference was detected in change in P/F at 48 hours (adjusted least squares mean [95% confidence interval, CI]: 55.8 [37.0, 74.5] vs 56.9 [39.6, 74.1], P = 0.90). Atracurium doses were higher in the ABW group (97.4 mg/h [84.4, 110.3] vs 55.4 [47.2, 65.7], P < 0.001). There was no difference in hospital mortality, ICU mortality, and ICU-free days or ventilator-free days., Conclusion and Relevance: In patients with obesity with ARDS receiving fixed-rate atracurium infusions, the change in P/F at 48 hours did not differ based on weight. Atracurium dosed on IBW may use less total drug without compromising ability to improve oxygenation. This is the first study comparing the dosing weight used for continuous infusion atracurium in hospitalized, critically ill ARDS patients with obesity. Additional studies are warranted to optimize dosing in obese patients., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: We aimed to compare the success of non-normalized acceleromyographic neuromuscular monitoring and recovery profiles based on the depth of anesthesia at the time of sugammadex administration., Methods: Patients undergoing general anesthesia were prospectively and randomly allocated to two groups. In the BIS60 group, sugammadex was administered when there was a bispectral index (BIS) <60 and anesthesia was maintained until a train-of-four ratio ≥1.0 was obtained, whereas in the BIS70 group, anesthesia was stopped at the completion of surgery, sugammadex was administered when the BIS was >70, and the recovery of neuromuscular function was monitored. The recovery profile and the incidence of emergence agitation of the two groups were compared., Results: The success rate of neuromuscular monitoring was significantly higher for the BIS60 group than for the BIS70 group (100% vs . 37.5%, respectively). The time taken for recovery for the two groups was comparable. The incidence of emergence agitation was significantly lower in the BIS60 group than in the BIS70 group (23.3% vs . 56.3%, respectively)., Conclusion: After the administration of sugammadex, the maintenance of anesthesia until the full recovery of neuromuscular function increases the success rate of neuromuscular monitoring without delaying recovery and reduces the risk of emergence agitation. Clinical trial registration: CRIS registration number KCT0007899 (https://cris.nih.go.kr/)., Competing Interests: Declaration of conflicting interestThe authors declare that there is no conflict of interest.

Abstract Background This study sought to evaluate the diagnostic accuracy of peri-operative diaphragm ultrasound in assessing post-operative residual curarization (PORC). Methods Patients undergoing non-thoracic and non-abdominal surgery under general anaesthesia were enrolled from July 2019 to October 2019 at Peking Union Medical College Hospital. A train-of-four ratio (TOFr) lower than 0.9 was considered as the gold standard for PORC. Diaphragm ultrasound parameters included diaphragmatic excursion (DE) and diaphragm thickening fraction (DTF) during quiet breathing (QB) and deep breathing (DB). The diaphragm excursion fraction (DEF) was calculated as the DE-QB divided by the DE-DB. The diaphragm excursion difference (DED) was defined as DE-DB minus DE-QB. Receiver operating characteristic curve analysis was used to determine the cut-off values of ultrasound parameters for the prediction of PORC. Results In total, 75 patients were included, with a PORC incidence of 54.6%. The DE-DB and DED were positively correlated with the TOFr, while the DEF was negatively correlated with the TOFr. The DE-DB cut-off value for predicting PORC was 3.88 cm, with a sensitivity of 85.4% (95% confidence interval [CI]: 70.1–93.9%), specificity of 64.7% (95% CI: 46.4–79.7%), positive likelihood ratio of 2.42 (95% CI 1.5–3.9), and negative likelihood ratio of 0.23 (95% CI: 0.1–0.5). The DED cut-off value was 1.5 cm, with a specificity of 94.2% (95% CI: 80.3–99.3%), sensitivity of 63.4% (95% CI: 46.9–77.9%), positive likelihood ratio of 10.78 (95% CI: 2.8–42.2), and negative likelihood ratio of 0.39 (95% CI: 0.3–0.6). Conclusions Peri-operative diaphragm ultrasound may be an additional method aiding the recognition of PORC, with DED having high specificity.

Abstract Background Sugammadex reverses neuromuscular blockade induced by steroidal relaxants. We compared the recovery for neuromuscular blockade reversal with sugammadex in children aged 1–12 years. Methods From August 2019 to August 2020, patients who received 2.0 mg·kg− 1 sugammadex for neuromuscular blockade reversal after surgery were recruited. The primary outcome was the time for the train-of-four ratio (TOFR) to recover to 0.9; secondary outcomes included the incidence of the TOFR

What is known and objective: Intraoperative neurophysiological monitoring (IONM) has been widely used in clinical practice. Therefore, the influence of neuromuscular blockers essential for spinal anaesthesia on IONM is worthy of our attention, but no randomized study has evaluated the dose‐response effect. This study investigated the effects of different doses of rocuronium bromide on the intraoperative monitoring of motor evoked potentials (MEPs). Methods: We conducted a randomized, double‐blind trial to assess the effects of three rocuronium bromide doses (6.0, 9.0, 12 μg·kg−1·min−1) combined with intravenous infusion of propofol 6–8 mg·kg−1·h−1 and remifentanil 10 μg·kg−1·h−1 on the amplitudes of somatosensory evoked potentials (SEPs) and MEPs at the time of the baseline recording (T1), before pedicle screw placement (T2) and before spinal canal decompression (T3). Secondary outcomes included measurement of neuromuscular function, the occurrence of unexpected intraoperative body movement and recovery of spontaneous breathing. Results and discussion: A total of 123 patients were enrolled, and 120 patients were ultimately analysed. No differences were observed in the amplitude of SEPs among the three groups (p > 0.05). The MEP amplitude differences at T1, T2 and T3 in all limbs did not differ in patients receiving rocuronium at 6.0 μg·kg−1·min−1 and 9.0 μg·kg−1·min−1 (p > 0.05). However, when rocuronium was administered at 12.0 μg·kg−1·min−1, MEP amplitudes at the time point T3 were significantly attenuated compared with the time points T1 and T2 in both right upper limb and left lower limb (p = 0.002, p = 0.025, respectively). In patients treated with rocuronium 6.0 μg·kg−1·min−1, the incidence of unexpected body movement was significantly higher (p = 0.026), and the train‐of‐four count (TOF count) showed a significant increase at T2 and T3 (p < 0.001) compared to other doses. What is new and conclusion: Rocuronium bromide at a rate of 9.0 μg·kg−1·min−1 provided suitable and adequate muscle relaxation without inhibiting IONM; thus, this dose is recommended for spinal surgery. [ABSTRACT FROM AUTHOR]

Background: This study sought to evaluate the diagnostic accuracy of peri-operative diaphragm ultrasound in assessing post-operative residual curarization (PORC). Methods: Patients undergoing non-thoracic and non-abdominal surgery under general anaesthesia were enrolled from July 2019 to October 2019 at Peking Union Medical College Hospital. A train-of-four ratio (TOFr) lower than 0.9 was considered as the gold standard for PORC. Diaphragm ultrasound parameters included diaphragmatic excursion (DE) and diaphragm thickening fraction (DTF) during quiet breathing (QB) and deep breathing (DB). The diaphragm excursion fraction (DEF) was calculated as the DE-QB divided by the DE-DB. The diaphragm excursion difference (DED) was defined as DE-DB minus DE-QB. Receiver operating characteristic curve analysis was used to determine the cut-off values of ultrasound parameters for the prediction of PORC. Results: In total, 75 patients were included, with a PORC incidence of 54.6%. The DE-DB and DED were positively correlated with the TOFr, while the DEF was negatively correlated with the TOFr. The DE-DB cut-off value for predicting PORC was 3.88 cm, with a sensitivity of 85.4% (95% confidence interval [CI]: 70.1–93.9%), specificity of 64.7% (95% CI: 46.4–79.7%), positive likelihood ratio of 2.42 (95% CI 1.5–3.9), and negative likelihood ratio of 0.23 (95% CI: 0.1–0.5). The DED cut-off value was 1.5 cm, with a specificity of 94.2% (95% CI: 80.3–99.3%), sensitivity of 63.4% (95% CI: 46.9–77.9%), positive likelihood ratio of 10.78 (95% CI: 2.8–42.2), and negative likelihood ratio of 0.39 (95% CI: 0.3–0.6). Conclusions: Peri-operative diaphragm ultrasound may be an additional method aiding the recognition of PORC, with DED having high specificity. [ABSTRACT FROM AUTHOR]

Background: Sugammadex reverses neuromuscular blockade induced by steroidal relaxants. We compared the recovery for neuromuscular blockade reversal with sugammadex in children aged 1–12 years. Methods: From August 2019 to August 2020, patients who received 2.0 mg·kg− 1 sugammadex for neuromuscular blockade reversal after surgery were recruited. The primary outcome was the time for the train-of-four ratio (TOFR) to recover to 0.9; secondary outcomes included the incidence of the TOFR < 0.9, extubation time, length of stay at the post-anesthesia care unit, and adverse events. Hemodynamic parameters before and 5 min after sugammadex administration and vital signs in the recovery room were also recorded. Results: Eighty-six children were recruited (1 to < 3 years, n = 23; 3 to < 5 years, n = 33; 5 to ≤12 years, n = 30). Intergroup differences in the recovery of the TOFR to 0.9 were not statistically significant (F = 0.691, p = 0.504). Recurrence of the TOFR < 0.9 was not observed in any group. Five minutes after sugammadex administration, the heart rates of patients aged 3 to < 5 and 5 to ≤12 years were significantly lower than those at baseline (p < 0.05). Extubation time was similar in patients aged 1 to ≤12 years. Length of stay and end-tidal capnography at the post-anesthesia care unit as well as adverse events did not differ significantly. Conclusion: A moderate (TOF count two) rocuronium-induced neuromuscular blockade can be effectively and similarly reversed with sugammadex 2 mg·kg− 1 in Chinese children aged 1–12 years. Trial registration: Chinese Clinical Trial Registry: ChiCTR1900023715 (June 8, 2019). [ABSTRACT FROM AUTHOR]

Background and Aims: Less residual paralysis in recovery room was demonstrated when train-of-four (TOF) monitoring was applied. The aim of this study was to know whether optimisation of neostigmine reversal without TOF monitoring was equivalent to reversal using TOF monitoring. Methods: Seventy two patients, aged 18–60 years, undergoing elective surgery under general anaesthesia (sevoflurane and rocuronium) with intubation were randomised into two interventions: an optimised neostigmine reversal strategy without TOF monitoring (group A, n = 36) and a neostigmine reversal strategy using quantitative TOF monitoring (group B, n = 36). Per-protocol analysis was performed to compare incidence of residual paralysis in the recovery room between the two groups. Results: Six residual paralyses occurred in group A in the recovery room, whereas one case occurred in group B. The equivalence test showed that the 95% confidence interval of this study was outside the range of equivalence margin (15%). The absolute difference was 13.9%: standard error (SE) =0.068 (P = 0.107; 95% confidence interval (CI): 1%, 27.2%). No subjects had TOF ratio

Abstract Background We compared cost-effectiveness of anesthesia maintained with sevoflurane or propofol with and without additional monitoring, in the clinical setting of ear-nose-throat surgery. Methods One hundred twenty adult patients were randomized to four groups. In groups SEVO and SEVO+ anesthesia was maintained with sevoflurane, in group SEVO+ with additional bispectral index (BIS) and train-of-four (TOF) monitoring. In groups PROP and PROP+ anesthesia was maintained with propofol, in group PROP+ with additional BIS and TOF monitoring. Results Total cost of anesthesia per hour was greater in group SEVO+ compared to SEVO [€ 19.95(8.53) vs. 12.15(5.32), p

Background The concept of the effect-site concentration of anesthetic agents is important. The effect compartment model can be explained using the concepts of effect-site concentration and effect-site equilibration rate constant (ke0). This study confirms that the time-to-peak effect (tpe) can be measured easily in clinical practice by applying a priming dose and train-of-four (TOF) during general anesthesia induction, and ke0 can be calculated from the tpe of the four muscle relaxants that are commonly used in general anesthesia. Methods Eighty patients who received general anesthesia were divided into the succinylcholine, rocuronium, atracurium, or vecuronium groups. Priming doses of muscle relaxants were administered. The effects of muscle relaxants were quantified by recording the twitch response of the adductor pollicis muscle after stimulating the ulnar nerve. The tpe was measured at the lowest TOF value. ke0 was calculated from the measured tpe. Results The ke0 values of the succinylcholine, rocuronium, atracurium, and vecuronium groups were 0.076 (0.030)/min, 0.228 (0.122)/min, 0.062 (0.011)/min, and 0.077 (0.019)/min, respectively. Conclusions It is possible to estimate ke0 from the tpe of muscle relaxants using a priming dose and TOF during general anesthesia induction.

Background: The reported incidence of postoperative residual curarisation (PORC) is still unacceptably high. The capacity of intraoperative neuromuscular monitoring (NMM) to reduce the incidence of PORC has yet to be established from pooled clinical studies. We conducted a meta-analysis of data from 1979 to 2019 to reanalyse this relationship.Methods: English language, peer-reviewed, and operation room adult anaesthesia setting articles published between 1979 and 2019 were searched for on PubMed, Cochrane Central Register of Controlled Trials, ISI-WoK, and Scopus. The primary outcome was PORC incidence as defined by an at- or post-extubation train-of-four ratio (TOFR) of lower than 0.7, 0.9, or 1.0. Additional collected variables included the duration of action of neuromuscular blocking agents (NMBAs) used, sugammadex or neostigmine use, and the technique of anaesthesia maintenance.Results: Fifty-three studies (109 study arms, 12 664 patients) were included. The pooled PORC incidence associated with the use of intermediate duration NMBAs and quantitative NMM was 0.115 (95% confidence interval [CI], 0.057-0.188). This was significantly lower than the PORC rate for both qualitative NMM (0.306; 95% CI, 0.09-0.411) and no NMM (0.331; 95% CI, 0.234-0.435). Anaesthesia type did not significantly affect PORC incidence. Sugammadex use was associated with lower PORC rates. The GRADE global level of evidence was very low and the refined assessment of the network meta-analysis by means of a confidence in network meta-analysis raised concerns on within- and across-study bias.Conclusions: Quantitative NMM outperforms both subjective and no NMM monitoring in reducing PORC as defined by a TOFR of <0.9. [ABSTRACT FROM AUTHOR]

Perioperative monitoring of both neuromuscular blockade and depth of anaesthesia has undergone considerable advancement and technological development in the past few decades. This article describes the role of the peripheral nerve stimulator and commonly used patterns of stimulation. It also discusses key technologies used to provide quantitative assessment of motor response. Techniques used to assess depth of anaesthesia are predominantly based on electroencephalogram analysis and stimulated evoked potentials. This article outlines the physical principles of these methodologies and discusses their role and limitations within the clinical context. Knowledge of advanced monitoring technologies available is essential to ensure correct use and avoid complications. Current clinical guidance and recommendations for neuromuscular blockade and depth of anaesthesia assessment are also discussed. [ABSTRACT FROM AUTHOR]

Introduction: The advantages of the use of muscle relaxants in the current practice of balanced anesthesia are well documented. Most often, nondepolarizing muscle relaxants (NDMR) with minimal side effects are used to serve the purpose. Atracurium is a commonly used NDMR in day-to-day anesthetic practice, although it is not desirable for rapid sequence induction and intubation due to its late onset of action. To overcome this problem priming principle was introduced. Aim: This study aims to determine optimal priming dose of atracurium to speed up the onset of action. Patients and Methods: In this prospective randomized controlled study, 90 patients were allocated into one of the three groups by a computer-generated table of random numbers, i.e., Group A, B, and C. Total dose of atracurium used in all patients was 0.5 mg/kg body weight, including the priming dose. Each group received different priming doses of atracurium as follows: Group A received 0.05 mg/kg body weight, Group B received 0.025 mg/kg body weight, whereas Group C (control) received saline as priming dose. Results: Patients were comparable with respect to demographic data. The mean duration in seconds for train-of-four (TOF) count to reach zero were 147 s, 193, and 218 s in Group A, B, and C, respectively, with statistically significant P values. Of 60 patients who were administered atracurium as priming drug, two patient had ptosis at the end of 3 min after priming with 0.05 mg/kg body weight, with no other side effects. Conclusions: Priming principle employing atracurium reduces the time required for TOF count to reach zero by approximately 71 s while using 0.05 mg/kg body weight and by around 25 s while employing 0.025 mg/kg body weight, with clinically insignificant incidence of adverse effects.

Abstract Background Neuromuscular blocking agents (NMBAs) have been shown to improve the outcome of the most severely hypoxemic, acute respiratory distress syndrome (ARDS) patients. However, the recommended dosage as well as the necessity of monitoring the neuromuscular block is unknown. We aimed to evaluate the efficiency of a nurse-directed protocol of NMBA administration based on a train-of-four (TOF) assessment to ensure a profound neuromuscular block and decrease cisatracurium consumption compared to an elevated and constant dose regimen. A prospective open labeled study was conducted in two medical intensive care units of two French university hospitals. Consecutive ARDS patients with a PaO2/FiO2 ratio less than 120 with a PEEP ≥5 cm H2O were included. Cisatracurium administration was driven by the nurses according to an algorithm based on TOF monitoring. The primary endpoint was cisatracurium consumption. The secondary endpoints included the quality of the neuromuscular block, the occurrence of adverse events, and the evolution of ventilatory and blood gas parameters. Results Thirty patients were included. NMBAs were used for 54 ± 30 h. According to this new algorithm, the initial dosage of cisatracurium was 11.8 ± 2 mg/h, and the final dosage was 14 ± 4 mg/h, which was significantly lower than in the ACURASYS study protocol (37.5 mg/h with a constant infusion rate (p

To evaluate whether use of partial nondepolarizing neuromuscular blocking agents, at a train-of-four level 1, compromise facial nerve monitoring during vestibular schwannoma (VS) resection. Sixty consecutive patients undergoing VS resection were enrolled into a partial peripheral neuromuscular blockade group or free of neuromuscular blockade group. Stimulation threshold to elicit an electromyographic response amplitude of at least 100 μV was recorded at the proximal and distal facial nerve after VS removal. The proximal-to-distal ratio of amplitude of the orbicularis oculi and oris muscles was calculated. All patients successfully passed the electromyography monitoring test. Mean electrical stimulation thresholds were higher in the peripheral neuromuscular blockade group than in the free of neuromuscular blockade group (0.12 mA vs. 0.06 mA at proximal site, P = 0.001; 0.08 mA vs. 0.03 mA at distal site, P = 0.0002). The differences in median proximal-to-distal amplitude ratios were not statistically significant in both groups. There was a trend toward more patients needing phenylephrine. Recovery profiles were comparable in the 2 groups. Although mean stimulation threshold to elicit a response amplitude was higher in the peripheral neuromuscular blockade group than in the free of neuromuscular blockade group at the proximal site, the stimulation thresholds in both groups were sufficient for facial nerve monitoring in VS surgery, indicating no clinical difference in both groups. [ABSTRACT FROM AUTHOR]

Background and Aims: Less residual paralysis in recovery room was demonstrated when train-of-four (TOF) monitoring was applied. The aim of this study was to know whether optimisation of neostigmine reversal without TOF monitoring was equivalent to reversal using TOF monitoring. Methods: Seventy two patients, aged 18–60 years, undergoing elective surgery under general anaesthesia (sevoflurane and rocuronium) with intubation were randomised into two interventions: an optimised neostigmine reversal strategy without TOF monitoring (group A, n = 36) and a neostigmine reversal strategy using quantitative TOF monitoring (group B, n = 36). Per-protocol analysis was performed to compare incidence of residual paralysis in the recovery room between the two groups. Results: Six residual paralyses occurred in group A in the recovery room, whereas one case occurred in group B. The equivalence test showed that the 95% confidence interval of this study was outside the range of equivalence margin (15%). The absolute difference was 13.9%: standard error (SE) =0.068 (P = 0.107; 95% confidence interval (CI): 1%, 27.2%). No subjects had TOF ratio <0.70 in the recovery room. The TOF ratio in the recovery room did not differ between the two groups (mean difference: −2.58; P = 0.05; 95% CI: −5.20, 0.29). One respiratory adverse event occurred in this study. Conclusion: An optimised reversal strategy without TOF monitoring is not equivalent to a reversal strategy based on quantitative TOF monitoring. TOF monitoring should be used whenever applicable, although neostigmine is optimised. [ABSTRACT FROM AUTHOR]

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

Background: The concept of the effect-site concentration of anesthetic agents is important. The effect compartment model can be explained using the concepts of effect-site concentration and effect-site equilibration rate constant (ke0). This study confirms that the time-to-peak effect (tpe) can be measured easily in clinical practice by applying a priming dose and train-of-four (TOF) during general anesthesia induction, and ke0 can be calculated from the tpe of the four muscle relaxants that are commonly used in general anesthesia. Methods: Eighty patients who received general anesthesia were divided into the succinylcholine, rocuronium, atracurium, or vecuronium groups. Priming doses of muscle relaxants were administered. The effects of muscle relaxants were quantified by recording the twitch response of the adductor pollicis muscle after stimulating the ulnar nerve. The tpe was measured at the lowest TOF value. ke0 was calculated from the measured tpe. Results: The ke0 values of the succinylcholine, rocuronium, atracurium, and vecuronium groups were 0.076 (0.030)/min, 0.228 (0.122)/min, 0.062 (0.011)/min, and 0.077 (0.019)/min, respectively. Conclusions: It is possible to estimate ke0 from the tpe of muscle relaxants using a priming dose and TOF during general anesthesia induction. [ABSTRACT FROM AUTHOR]

The article focuses on the efficacy of Sugammadex, cyclodextrin used for the reversal of neuromuscular blockade caused by the aminosteroid rocuronium and, to a lesser extent vecuronium. It mentions quantitative assessment of a train-of-four (TOF) response to ulnar nerve stimulation of the adductor pollicis muscle. It also mentions Laryngeal microsurgery is an example of a short procedure that requires deep levels of anaesthesia and neuromuscular blockade.

This case report describes delayed muscular recovery in a patient with amyotrophic lateral sclerosis (ALS) after general anesthesia using rocuronium and sugammadex. A 62-year-old woman with ALS with bulbar involvement underwent ureteroscopic ureterolithotomy. We performed standard general anesthesia using propofol, rocuronium and sevoflurane with standard and neuromuscular monitoring. Rocuronium was administered at a dose of 20 mg (0.38 mg/kg) to facilitate endotracheal intubation, and anesthesia was maintained with sevoflurane in the range of 1-3 vol%. After the procedure, 100 mg of sugammadex (1.92 mg/kg) was administered and a train-of-four (TOF) ratio > 0.9 was observed in 80 s. However, the muscle strength was not the same as the preoperative level and tidal volume was judged to be inadequate for extubation. No further improvement in muscle strength was observed after administration of an additional 100 mg of sugammadex. The patient was transferred to the intensive care unit and pressure support ventilation was applied. Muscle strength was checked periodically and tracheal extubation was performed based on complete neuromuscular recovery to preanesthetic level after 4 h. [ABSTRACT FROM AUTHOR]

Background: Neuromuscular blocking agents (NMBAs) have been shown to improve the outcome of the most severely hypoxemic, acute respiratory distress syndrome (ARDS) patients. However, the recommended dosage as well as the necessity of monitoring the neuromuscular block is unknown. We aimed to evaluate the efficiency of a nurse-directed protocol of NMBA administration based on a train-of-four (TOF) assessment to ensure a profound neuromuscular block and decrease cisatracurium consumption compared to an elevated and constant dose regimen. A prospective open labeled study was conducted in two medical intensive care units of two French university hospitals. Consecutive ARDS patients with a PaO/FiO ratio less than 120 with a PEEP ≥5 cm HO were included. Cisatracurium administration was driven by the nurses according to an algorithm based on TOF monitoring. The primary endpoint was cisatracurium consumption. The secondary endpoints included the quality of the neuromuscular block, the occurrence of adverse events, and the evolution of ventilatory and blood gas parameters. Results: Thirty patients were included. NMBAs were used for 54 ± 30 h. According to this new algorithm, the initial dosage of cisatracurium was 11.8 ± 2 mg/h, and the final dosage was 14 ± 4 mg/h, which was significantly lower than in the ACURASYS study protocol (37.5 mg/h with a constant infusion rate ( p < 0.001). The overall cisatracurium dose used was 700 ± 470 mg in comparison with 2040 ± 1119 mg for patients had received the ACURASYS dosage for the same period ( p < 0.001). A profound neuromuscular block (TOF = 0, twitches at the ulnar site) was obtained from the first hour in 70% of patients. Modification of the cisatracurium dosage was not performed from the beginning to the end of the study in 60% of patients. Patient-ventilator asynchronies occurred in 4 patients. Conclusion: A nurse-driven protocol based on TOF monitoring for NMBA administration in ARDS patients was able to decrease cisatracurium consumption without significantly affecting the quality of the neuromuscular block. [ABSTRACT FROM AUTHOR]

This article outlines the physical principles underlying peripheral nerve stimulation and depth of anaesthesia monitoring in relation to anaesthesia. The patterns of nerve stimulation most commonly used in clinical practice are described including train-of-four, double burst stimulation and tetanic stimulation, as well as methods used to measure motor response. The key technologies currently used to monitor level of consciousness during anaesthesia are also described, namely methods based on electroencephalography and stimulus evoked potentials, including limitations of their use. Published clinical guidelines on the use of both nerve stimulators and level of consciousness monitors are also discussed. [ABSTRACT FROM AUTHOR]

The effects of atropine (non selective muscarinic antagonist) and ZM241385 (A2A receptors antagonist) in the cisatracurium-induced drastic (100%) level of fade at 50 Hz (10 s) (100% Fade) were compared in the phrenic nerve-diaphragm muscle preparations of rats indirectly stimulated at a physiological tetanic frequency (50 Hz). The lowest dose and the instant cisatracurium caused 100% Fade were investigated. Cisatracurium induced 100% Fade 15 min after being administered. Atropine reduced the cisatracurium-induced 100% Fade, but the administration of ZM241385 separately, or combined with atropine, did not cause any effect in the cisatracurium-induced 100% Fade. Data indicate that the simultaneous blockage of M1 and M2 muscarinic receptors on motor nerve terminal by atropine is more efficient than the blockage of presynaptic A2A receptors for a safer recovery of patients from neuromuscular blockade caused by cisatracurium.

The increase in mortality and morbidity associated with the use of muscle relaxants, is associated with a lack of clinical pharmacological knowledge of the drugs, and a lack of understanding the risk of postoperative residual curarization. This is due to the absence of standards for neuromuscular monitoring. Clinicians experienced in neuromuscular monitoring and using muscle relaxants in the clinic may have some queries regarding the monitoring: Why should neuromuscular monitoring be done? Are clinical tests really not effective? Why is it not good when I actually perform neuromuscular monitoring? Would using sugammadex not require neuromuscular monitoring? This review answers most of the questions that many clinicians have, and also forwards the knowledge required of clinicians. [ABSTRACT FROM AUTHOR]

Objectives Neostigmine is routinely used to reverse non-depolarizing neuromuscular block. Given its indirect mechanism, a plateau may exist whereby increasing doses of neostigmine do not result in clinical benefit. This study was designed to measure the speed of reversal of vecuroniuminduced neuromuscular block in isofluraneanesthetized dogs after the administration of three doses of neostigmine as used in clinical practice. Study design Prospective, crossover, randomized study. Animals Seven adult, mixed-breed dogs with a mean ± standard deviation (SD) age of 2.0 ± 0.8 years and weight of 19.1 ± 9.1 kg. Methods Dogs were anesthetized on three occasions with isoflurane and administered vecuronium (0.1 mg kg-1) intravenously (IV). The trainof- four (TOF) ratio was measured on the pelvic limb with acceleromyography. When the second twitch of the TOF had returned spontaneously, atropine (0.03 mg kg-1) and neostigmine (0.02, 0.04 or 0.07 mg kg-1) were administered IV. Time to reach a TOF ratio of ≥ 0.9 after neostigmine administration was recorded. Results Increasing the dose of neostigmine from 0.02 mg kg-1 to 0.04 mg kg-1 and 0.07 mg kg-1 resulted in significant reductions in mean ± SD reversal times (10.5 ± 2.3, 7.4 ± 1.1 and 5.4 ± 0.5 minutes, respectively) (p < 0.0001) and smaller coefficients of variation (22%, 15% and 10%, respectively). Conclusions and clinical relevance Increasing the dose of neostigmine from 0.02 mg kg-1 to 0.04 mg kg-1 and 0.07 mg kg-1 produced faster and less variable reversal of vecuronium-induced neuromuscular block in isoflurane-anesthetized dogs. No ceiling effect was observed at this dose range. [ABSTRACT FROM AUTHOR]

Objectives We aimed to conduct a pharmacodynamic comparison of rocuronium bromide between patients from the plateau area and from the plain area. Methods A total of 104 patients who received laparoscopic cholecystectomy in Sichuan Provincial People's Hospital and Aba Autonomous Prefecture People's Hospital from October 2015 to December 2015 were included in this study. Among them, 46 patients were from the plateau area and 58 were from the plain area. Both groups received total intravenous anesthesia (TIVA) with a dose of 0.6 mg/kg rocuronium bromide during induction. In the meantime, neuromuscular block was monitored using a train-of-four (TOF) stimulation mode. The onset time (time to achieve the lowest TOF value after the injection of rocuronium bromide), duration of maximal neuromuscular block (duration of lowest T1 value), time to 25% recovery, time to 75% recovery, recovery index (time from 25% recovery to 75% recovery), time to extubation, length of stay in Post Anesthesia Care Unit (PACU) and muscle strength upon PACU discharge were all recorded. Results The onset time, time to 25% recovery, time to 75% recovery and time to extubation were all significantly prolonged in patients from the plateau area after receiving one single dose of rocuronium bromide (P < 0.05). However, both groups didn't show any significant difference in maximal neuromuscular block, recovery index (time from 25% recovery to 75% recovery), length of stay in PACU, or muscle strength upon PACU discharge (P > 0.05). Conclusions Compared to patients from the plain area, patients from the plateau area showed prolonged onset time of rocuronium bromide, reduced metabolic capabilities, and longer duration of muscular relaxation. [ABSTRACT FROM AUTHOR]

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