Pediatric Intraoperative Electromyographic Responses at the Adductor Pollicis and Flexor Hallucis Brevis Muscles: A Prospective, Comparative Analysis.

BACKGROUND: Peripheral nerve stimulation with a train-of-four (TOF) pattern can be used intraoperatively to evaluate the depth of neuromuscular block and confirm recovery from neuromuscular blocking agents (NMBAs). Quantitative monitoring can be challenging in infants and children due to patient size, equipment technology, and limited access to monitoring sites. Although the adductor pollicis muscle is the preferred site of monitoring, the foot is an alternative when the hands are unavailable. However, there is little information on comparative evoked neuromuscular responses at those 2 sites. METHODS: Pediatric patients undergoing inpatient surgery requiring NMBA administration were studied after informed consent. Electromyographic (EMG) monitoring was performed simultaneously in each participant at the hand (ulnar nerve, adductor pollicis muscle) and the foot (posterior tibial nerve, flexor hallucis brevis muscle). RESULTS: Fifty patients with a mean age of 3.0 ± standard deviation (SD) 2.9 years were studied. The baseline first twitch amplitude (T1) of TOF at the foot (12.46 mV) was 4.47 mV higher than at the hand (P <.0001). The baseline TOF ratio (TOFR) before NMBA administration and the maximum TOFR after antagonism with sugammadex were not different at the 2 sites. The onset time until the T1 decreased to 10% or 5% of the baseline value (T1) was delayed by approximately 90 seconds (both P =.014) at the foot compared with the hand. The TOFR at the foot recovered (TOFR ≥0.9) 191 seconds later than when this threshold was achieved at the hand (P =.017). After antagonism, T1 did not return to its baseline value, a typical finding with EMG monitoring, but the fractional recovery (maximum T1 at recovery divided by the baseline T1) at the hand and foot was not different, 0.81 and 0.77, respectively (P =.68). The final TOFR achieved at recovery was approximately 100% and was not different between the 2 sites. CONCLUSIONS: Although this study in young children demonstrated the feasibility of TOF monitoring, interpretation of the depth of neuromuscular block needs to consider the delayed onset and the delayed recovery of TOFR at the foot compared to the hand. The delay in achieving these end points when monitoring the foot may impact the timing of tracheal intubation and assessment of adequate recovery of neuromuscular block to allow tracheal extubation (ie, TOFR ≥0.9).

Effect of tetanic stimulation prior to train-of-four monitoring on the time to muscle response stabilization with neuromuscular blockade with rocuronium in patients aged 60 to 80 years: A prospective randomized controlled trial.

PURPOSE: To determine the effect of tetanic stimulation on the time to achieve stabilization of the T1 height, by acceleromyography train-of-four (TOF) ratio monitoring, in patients aged 60 to 80 years. METHODS: Randomized, prospective, single-blind, controlled trial in patients aged 60 to 80 years undergoing elective surgery under general anesthesia in two university hospitals in Brazil between December 2019 and March 2022. This trial was performed in accordance with the principles of the Helsinki Declaration and the guidelines for good clinical research practice in pharmacodynamic studies of neuromuscular blocking agents II. Participants were randomly allocated by computer-generated numbers to receive tetanic stimulation (intervention group, n = 25) or not receive tetanic stimulation (control group, n = 25) to achieve T1 height stabilization on TOF ratio monitoring. The primary endpoint was to evaluate the effect of tetanic stimulation on the time to achieve stabilization of the T1 height. We also evaluated the effect on the onset time of rocuronium and time to recover from neuromuscular blockade with a single dose of rocuronium 0.6 mg.kg-1 with spontaneous recovery. RESULTS: There was no statistically significant difference between the groups in the time to T1 height stabilization (intervention: 4.3 [2.0-8.0] min; control: 5.8 [2.0-10.5] min; p = 0.202), onset time of the neuromuscular blocking agent (intervention: 1.9 [±0.7] min; control: 2.2 [±1.0] min; p = 0.219), or neuromuscular blockade recovery times to normalized TOF values of 0.7 (intervention: 106.1 [±37.2] min; control: 91.7 [±27.5] min; p = 0.295), 0.8 (intervention: 114.3 [±40.1] min; control: 97.8 [±28.9] min; p = 0.225), 0.9 (intervention: 126.5 [±44.0] min; control: 106.9 [±30.6] min; p = 0.153), and 1.0 (intervention: 138.3 [±43.4] min; control: 123.8 [±43.5] min; p = 0.425). CONCLUSION: The results of this study suggest that the recommendation to use tetanic stimulation to shorten the time to T1 height stabilization in neuromuscular monitoring did not alter the stabilization time of the T1 twitch or the pharmacodynamics of neuromuscular blockade with rocuronium in patients aged 60 to 80 years.

Relationship between muscle mass ratio and rocuronium dose required for maintaining deep neuromuscular blockade: A prospective observational study.

BACKGROUND: Deep neuromuscular blockade (NMB) has benefits in various surgical procedures, however, precise quantitative neuromuscular monitoring is crucial for its proper maintenance and recovery. Neuromuscular blocking agent dosage relies on actual body weight (ABW), but this varies among individuals. Therefore, this study hypothesizes that there is a correlation between the rocuronium requirement for deep NMB and muscle mass ratio measured by bioelectric impedance analysis. METHODS: Ninety adult female patients undergoing laparoscopic operation were enrolled in this study. Muscle and fat masses were assessed using a body composition analyser. Deep NMB, defined as a post-tetanic count of 1-2, was maintained through the continuous infusion of rocuronium. The primary outcome involves determining the correlation between the rocuronium dose required for deep NMB and the muscle mass ratio. Conversely, secondary outcomes included assessing the relationship between the rocuronium dose for deep NMB and fat mass ratio, and ABW. Additionally, we investigated their relationship with rocuronium onset time and profound blockade duration. RESULTS: No relationship was observed between the muscle mass ratio and rocuronium dose required for maintaining deep NMB (r = 0.059 [95% CI = 0.153-0.267], p = 0.586). Fat mass ratio and ABW showed no correlation with the rocuronium dose, whereas rocuronium onset time was positively correlated with muscle mass ratio (r = 0.327) and negatively correlated with fat mass ratio (r = -0.302), respectively. Profound blockade duration showed no correlation with any of the assessed variables. CONCLUSIONS: No correlation was detected between muscle mass ratio and the rocuronium dose required to achieve deep NMB.

A compressomyograph train of four monitoring device.

The monitoring of the neuromuscular blockade is critical for patient's safety during and after surgery. The monitoring of neuromuscular blockade often requires the use of Train of Four (TOF) technique. During a TOF test two electrodes are attached to the ulnar nerve, and a series of four electric pulses are applied. The electrical stimulation causes the thumb to twitch, and the amount of twitch varies depending on the amount of neuromuscular blockade in patient's system. Current medical devices used to assist anesthesiologists to perform TOF monitoring often require free hand movement and do not provide accurate or reliable results. The goal of this work is to design, prototype and test a new medical device that provides reliable TOF results when thumb movement is restricted. A medical device that uses a pressurized catheter balloon to detect the response thumb twitch of the TOF test is created. An analytical model, numerical study, and mechanical finger testing were employed to create an optimum design. The design is tested through a pilot human subjects study. No significant correlation is reported with subjects' properties, including hand size.

Neuromuscular end-point predictive capability of published rocuronium pharmacokinetic/pharmacodynamic models: An observational trial.

BACKGROUND: Objective neuromuscular monitoring remains the single most reliable method to ensure optimal perioperative neuromuscular management. Nevertheless, the prediction of clinical neuromuscular endpoints by means of Pharmacokinetic (PK) and Pharmacodynamic (PD) modelling has the potential to complement monitoring and improve perioperative neuromuscular management.s STUDY OBJECTIVE: The present study aims to assess the performance of published Rocuronium PK/PD models in predicting intraoperative Train-of-four (TOF) ratios when benchmarked against electromyographic TOF measurements. DESIGN: Observational trial. SETTING: Tertiary Belgian hospital, from August 2020 up to September 2021. PATIENTS AND INTERVENTIONS: Seventy-four patients undergoing general anaesthesia for elective surgery requiring the administration of rocuronium and subject to continuous EMG neuromuscular monitoring were included. PK/PD-simulated TOF ratios were plotted and synchronised with their measured electromyographic counterparts and their differences analysed by means of Predictive Error derivatives (Varvel criteria). MAIN RESULTS: Published rocuronium PK/PD models overestimated clinically registered TOF ratios. The models of Wierda, Szenohradszky, Cooper, Alvarez-Gomez and McCoy showed significant predictive consistency between themselves, displaying Median Absolute Performance Errors between 38% and 41%, and intra-individual differences (Wobble) between 14 and 15%. The Kleijn model outperformed the former with a lower Median Absolute Performance Error (16%, 95%CI [0.01; 57]) and Wobble (11%, 95%CI [0.01; 34]). All models displayed considerably wide 95% confidence intervals for all performance metrics, suggesting a significantly variable performance. CONCLUSIONS: Simulated TOF ratios based on published PK/PD models do not accurately predict real intraoperative TOF ratio dynamics. TRIAL REGISTRATION: NCT04518761 (clinicaltrials.gov), registered on 19 August 2020.

The impact of electrosurgical devices on electromyography-based neuromuscular monitoring during abdominal laparotomy: a case series.

The present study aimed to evaluate the effect of electrosurgical devices on neuromuscular monitoring using an electromyography (EMG)-based neuromuscular monitor during abdominal laparotomy. Seventeen women (aged 32-64 years) undergoing gynecological laparotomy under total intravenous general anesthesia were enrolled in the study. A TetraGraph™ was placed to stimulate the ulnar nerve and to monitor the abductor digiti minimi muscle. After device calibration, train-of-four (TOF) measurements were repeated at intervals of 20 s. Rocuronium 0.6 to 0.9 mg/kg was administered for induction, and additional doses of 0.1 to 0.2 mg/kg were administered to maintain TOF counts ≤ 2 during the surgery. The primary outcome of the study was the ratio of measurement failure. The secondary outcomes of the study were the total number of measurements, the number of measurement failures, and the most extended consecutive number of measurement failures. The data are expressed as median (range). Of the 3091 (1480-8134) measurements, the number of measurement failures was 94 (60-200), resulting in a failure ratio of 3.5% (1.4-6.5%). The most extended consecutive number of measurement failures was 8 (4-13). All attending anesthesiologists were able to maintain and reverse neuromuscular blocks under EMG guidance. This prospective observational study demonstrated that the use of EMG-based neuromuscular monitoring does not seem to be heavily affected by electrical interference during lower abdominal laparotomic surgery. Trial registration This trial was registered in the University Hospital Medical Information Network under registration number UMIN000048138 (registration date; June 23, 2022).

Peri-operative diaphragm ultrasound as a new method of recognizing post-operative residual curarization.

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.

Effects of depth of neuromuscular blockade on the BIS-guided propofol requirement: A randomized controlled trial.

BACKGROUND: Deep neuromuscular blockade is considered beneficial for improving the surgical space condition during laparoscopic surgery. Adequacy of the surgical space condition may affect the anesthetists' decision regarding titration of depth of anesthesia. We investigated whether deep neuromuscular blockade reduces the propofol requirement under bispectral index monitoring compared to moderate neuromuscular blockade. METHODS: Adult patients undergoing elective laparoscopic colorectal surgery were randomly allocated to a moderate or deep group. A train-of-four count of 1-2 in the moderate group, and a post-tetanic count of 1-2 in the deep group, were maintained by continuous infusion of rocuronium. The induction and maintenance of anesthesia were achieved by target-controlled infusion of propofol and remifentanil. The dose of propofol was adjusted to maintain the bispectral index in the range of 40-50. The remifentanil dose was titrated to maintain the systolic blood pressure to within 20% of the ward values. RESULTS: A total of 82 patients were included in the analyses. The mean±SD dose of propofol was 7.54 ±â€Š1.66 and 7.42 ±â€Š1.01 mg·kg-1·h-1 in the moderate and deep groups, respectively (P = .104). The mean±SD dose of remifentanil was 4.84 ±â€Š1.74 and 4.79 ±â€Š1.77 µg kg-1 h-1 in the moderate and deep groups, respectively (P = .688). In comparison to the moderate group, the deep group showed significantly lower rates of intraoperative patient movement (42.9% vs 22.5%, respectively, P = .050) and additional neuromuscular blocking agent administration (76% vs 53%, respectively, P = .007). Postoperative complications, including pulmonary complications, wound problems and reoperation, were not different between the two groups. CONCLUSION: Deep neuromuscular blockade did not reduce the bispectral index-guided propofol requirement compared to moderate neuromuscular blockade during laparoscopic colon surgery, despite reducing movement of the patient and the requirement for a rescue neuromuscular blocking agent. TRIAL REGISTRATION: Clinicaltrials.gov (NCT03890406).

Effects of deep neuromuscular block with low-pressure pneumoperitoneum on respiratory mechanics and biotrauma in a steep Trendelenburg position.

We hypothesized that deep neuromuscular blockade (NMB) with low-pressure pneumoperitoneum (PP) would improve respiratory mechanics and reduce biotrauma compared to moderate NMB with high-pressure PP in a steep Trendelenburg position. Seventy-four women undergoing robotic gynecologic surgery were randomly assigned to two equal groups. Moderate NMB group was maintained with a train of four count of 1-2 and PP at 12 mmHg. Deep NMB group was maintained with a post-tetanic count of 1-2 and PP at 8 mmHg. Inflammatory cytokines were measured at baseline, at the end of PP, and 24 h after surgery. Interleukin-6 increased significantly from baseline at the end of PP and 24 h after the surgery in moderate NMB group but not in deep NMB group (Pgroup*time = 0.036). The peak inspiratory, driving, and mean airway pressures were significantly higher in moderate NMB group than in deep NMB group at 15 min and 60 min after PP (Pgroup*time = 0.002, 0.003, and 0.048, respectively). In conclusion, deep NMB with low-pressure PP significantly suppressed the increase in interleukin-6 developed after PP, by significantly improving the respiratory mechanics compared to moderate NMB with high-pressure PP during robotic surgery.

An Implantable System For Chronic In Vivo Electromyography.

Electromyography (EMG) measures the muscle response to electrical stimulation or spontaneous activity of motor units and plays an important role in assessing neuromuscular function. Chronic recording of EMG activity reflecting a muscle's reinnervation status after nerve injury has been limited, due to the invasive nature of traditional EMG recording techniques. In this regard, an implantable system is designed for long-term, in vivo EMG recording and nerve stimulation. It has been applied and tested in a study on reinnervation of laryngeal muscles. This system consists of 1) two bipolar electrode nerve cuffs and leads for stimulating each of two nerves: the recurrent laryngeal nerve (RLN) and internal branch of the superior laryngeal nerve (SLN); 2) two EMG recording electrodes and leads for each of the two laryngeal muscles: posterior cricoarytenoid (PCA) muscle and thyroarytenoid-lateral cricoarytenoid (TA-LCA) muscle complex; and 3) a skin receptacle interfacing all implanted lead terminals to an external recording preamplifier and stimulator using a connection cable. The wire leads are Teflon-coated, multi-filament, type 316 stainless steel. They are coiled and can stretch during body movement of the awake animal to prevent lead breakage and electrode migration. This system is implanted during an aseptic surgery. Afterwards, baseline EMG recordings are performed before the RLN is transected in the second surgery to study muscle reinnervation. Throughout the study, multiple physiological sessions are conducted in the anesthetized animal to obtain evoked and spontaneous EMG activity that reflects the reinnervation status of laryngeal muscles. The system is compact, free of infection over the course of the study, and highly durable. This implantable system can provide a reliable platform for research in which long-term recording or nerve stimulation is required in an anesthetized or freely moving animal.

Multimodality Intraoperative Neurophysiological Monitoring (IONM) During Shoulder Surgeries.

Introduction: The purpose of this study is to identify the advancing role of Intraoperative Neurophysiological Monitoring (IONM) in detecting and preventing nerve injuries during shoulder surgery procedures. Methods: We performed a retrospective analysis of IONM data from ten shoulder procedures. The patients consisted of nine females and one male with ages ranging from 67 to 81 years (median: 74 years). IONM modalities utilized were bilateral Somatosensory Evoked Potentials (SSEP), Transcranial Motor Evoked Potentials (TCeMEP), ipsilateral Electromyogram (EMG) from upper extremity muscles and Train of four (TOF) recordings. Results: A decrease in signals was noted in three patients (30%). Only upper SSEP amplitude decreased in one patient; both upper extremity SSEP and TCeMEP decreased in two patients. Only one patient had poor baseline radial nerve SSEP that improved during the surgery. We performed spontaneous EMG (s-EMG) in all ten patients and successfully recorded triggered (t-EMG) in seven patients (71.4%). In one patient, SSEP and TCeMEP did not improve, and the patient woke up with deficits. Conclusions: In this small series, we were able to identify real-time impending nerve injury. The use of IONM alerted and may have prevented intraoperative nerve injury in 30% of the patients in this series. In one patient, SSEP and TCeMEP did not recover even after the intervention due to severe blood loss. The patient woke up with sensory and motor deficits. The utilization of multimodality IONM can be helpful due to signal changes, therefore minimizing the frequency of nerve injury and deficits.

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).

Efficacy of profound versus moderate neuromuscular blockade in enhancing postoperative recovery after laparoscopic donor nephrectomy: A randomised controlled trial.

BACKGROUND: Profound neuromuscular blockade (NMB) during anaesthesia has been shown to reduce postoperative pain scores, when compared with a moderate block. We hypothesised that profound NMB during laparoscopic donor nephrectomy (LDN) could also improve the early quality of recovery after surgery. OBJECTIVES: To compare the effectiveness of profound versus moderate NMB during LDN in enhancing postoperative recovery. DESIGN: A phase IV, double-blinded, randomised controlled trial. SETTING: Multicentre trial, from November 2016 to December 2017. PATIENTS: A total of 101 living kidney donors scheduled for LDN were enrolled, and 96 patients were included in the analyses. INTERVENTIONS: Patients were randomised to receive profound (posttetanic count 1 to 3) or moderate (train-of-four count 1 to 3) neuromuscular block. MAIN OUTCOME MEASURES: The primary outcome was the early quality of recovery at postoperative day 1, measured by the Quality of Recovery-40 Questionnaire. Secondary outcomes were adverse events, postoperative pain, analgesic consumption and length-of-stay. RESULTS: The intention-to-treat analysis did not show a difference with regard to the quality of recovery, pain scores, analgesic consumption and length-of-stay. Less intra-operative adverse events occurred in patients allocated to profound NMB (1/48 versus 6/48). Five patients allocated to a profound NMB received a moderate block and in two patients neuromuscular monitoring failed. The as-treated analysis revealed that pain scores were significantly lower at 6, 24 and 48 h after surgery. Moreover, the quality of recovery was significantly better at postoperative day 2 in patients receiving a profound versus moderate block (179.5 ±â€Š13.6 versus 172.3 ±â€Š19.2). CONCLUSION: Secondary analysis indicates that an adequately maintained profound neuromuscular block improves postoperative pain scores and quality of recovery. As the intention-to-treat analysis did not reveal a difference regarding the primary endpoint, future studies should pursue whether a thoroughly maintained profound NMB during laparoscopy improves relevant patient outcomes. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02838134.

Neuromuscular Performance and Hormonal Profile During Military Training and Subsequent Recovery Period.

INTRODUCTION: Military training loads may induce different physiological responses in garrison and field training and only a little is known about how short-time recovery, lasting a few days, affects neuromuscular fitness and hormonal profile. This study aimed to investigate the effects of garrison and field military service on neuromuscular performance and hormonal profile and to evaluate the effects of a 3-day recovery on those factors. METHODS: Twenty healthy male soldiers (20 ± 1 years) participated in the study, which consisted of 4 days of garrison training [days (D) 1-4] and 7 days of military field training (Days 5-12) followed by a 3-day recovery period (Day 15). Serum hormone concentrations [testosterone (TES), cortisol (COR), sex-hormone binding globulin (SHBG), free thyroxine (T4)] were assessed at D1, D5, D8-12, and D15. Handgrip strength was measured in 10 participants at D1, D5, D8, D12, and D15. Maximal isometric force, electromyography, and rate of force development (RFD) of the knee extensors and arm flexors were also measured at D5, D12, and D15. RESULTS: The maximal force of both the arm flexors and knee extensors was not affected by the garrison or field training, whereas the RFD of the knee extensors was decreased during the field training (D5: 383 ± 130 vs. D12: 321 ± 120 N/s, p < 0.05). In addition, handgrip strength was mostly no affected, although a significant difference was observed between D8 and D12 (531 ± 53 vs. 507 ± 43 N, p < 0.05) during the field training. TES decreased already during the garrison training (D1: 18.2 ± 3.9 vs. D5: 16.2 ± 4.0 nmol/L, p < 0.05) and decreased further during the field training compared to baseline (D8: 10.2 ± 3.6 - D11: 11.4 ± 5.4 nmol/L, p < 0.05) exceeding the lowest concentration in the end of the field training (D12: 7.1 ± 4.1 nmol/L, p < 0.05). Similar changes were observed in free TES (D1: 72.2 ± 31.4 vs. D12: 35.1 ± 21.5 nmol/L, p < 0.001). The TES concentration recovered back to the baseline level and free TES increased after the recovery period compared with the baseline values (D15: 19.9 ± 5.3 nmol/L, D15: 99.7 ± 41.1 nmol/L, respectively). No changes were observed in the COR or SHBG concentrations during the garrison period. COR was decreased in the end of the field training (D12: 388 ± 109 nmol/L) compared with baseline (D1: 536 ± 113 nmol/L) (p < 0.05-0.001) but recovered back to the baseline levels after the recovery period (D15: 495 ± 58 nmol/L), whereas SHBG linearly increased towards the end of the field training (p < 0.05-0.001). CONCLUSIONS: The present findings demonstrate that neuromuscular performance can be relatively well maintained during short-term garrison and field training even when a clear decrease in hormonal profile is evident. In addition, hormonal responses during field training seem to be greater compared to garrison training, however, the recovery of 3-day in free-living conditions seems to be sufficient for hormonal recovery. Therefore, a short-term recovery period lasting few days after the military field training may be required to maintain operational readiness after the field training.

Comparison of deep or moderate neuromuscular blockade for thoracoscopic lobectomy: a randomized controlled trial.

BACKGROUND: Laparoscopic surgery typically requires deep neuromuscular blockade (NMB), but whether deep or moderate NMB is superior for thoracoscopic surgery remains controversial. METHODS: Patients scheduled for thoracoscopic lobectomy under intravenous anesthesia were randomly assigned to receive moderate [train of four (TOF) 1-2] or deep NMB [TOF 0, post-tetanic count (PTC) 1-5]. Depth of anesthesia was controlled at a Narcotrend rating of 30 ± 5 in both groups. The primary outcome was the need to use an additional muscle relaxant (cisatracurium) during surgery. Secondary outcomes included surgeon satisfaction, recovery time of each stage after drug withdrawal [time from withdrawal until TOF recovery to 20% (antagonists administration), 25, 75, 90, 100%], blood gas data, VAS pain grade after extubation, the time it takes for patients to begin walking after surgery, postoperative complications and hospitalization time. Results were analyzed on an intention-to-treat basis. RESULTS: Thirty patients were enrolled per arm, and all but one patient in each arm was included in the final analysis. Among patients undergoing moderate NMB, surgeons applied additional cisatracurium in 8 patients because of body movement and 5 because of coughing (13/29, 44.8%). Additional cisatracurium was not applied to any of the patients undergoing deep NMB (p < 0.001). Surgeons reported significantly higher satisfaction for patients undergoing deep NMB (p < 0.001, Wilcoxon rank sum test). The mean difference between the two groups in the time from withdrawal until TOF recovery of 25% or 90% was 10 min (p < 0.001). The two groups were similar in other recovery data, blood gas analysis, VAS pain grade, days for beginning to walk and mean hospitalization time. CONCLUSIONS: Deep NMB can reduce the use of additional muscle relaxant and increase surgeon satisfaction during thoracoscopic lobectomy. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR-IOR-15007117 , 22 September 2015.

Rocuronium pharmacodynamic models for published five pharmacokinetic models: age and sex are covariates in pharmacodynamic models.

PURPOSE: Equilibration rate constant is necessary to calculate effect-site concentration, which is useful to control drug effect. We developed pharmacodynamic models for published five compartmental pharmacokinetic models published by Wierda, Szenohradszky, Cooper, Alvarez-Gomez, and McCoy. METHODS: We used 3848 train-of-four ratios from 15 male and nine female patients (21-76 years; 44-93 kg body weight; 148-181 cm height; and 17.3-29.8 kg/m2 body mass index) as pharmacodynamic measures, which were collected at the start of 0.6 mg/kg rocuronium administration until the end of the surgery. Effect compartment was assumed to be connected to central compartment of the pharmacokinetic model with equilibration rate constant (ke0). Sigmoid Emax model was fitted to describe the relationship between train-of-four ratio and effect-site concentration. Age, sex, and body mass index were assessed as possible covariates of the following model parameters: ke0, effect-site concentration for half of maximum effect, and the steepness of the effect-site concentration versus effect relationship. RESULTS: The duration of neuromuscular monitoring was 69 (37-129) [median (range)] min. All pharmacodynamic models included age and three included sex as significant covariates. Ke0 values ranged between 0.0820 and 0.247 depending on the pharmacokinetic model. The time-courses of the effect-site concentration were similar among the pharmacodynamic models for Wierda, Cooper, and Alvarez-Gomez pharmacokinetic models, which were lower than that for the Szenohradszky pharmacokinetic model. CONCLUSION: Each pharmacodynamic model with the corresponding pharmacokinetic model can be described the time course of rocuronium effect appropriately. The required effect-site concentration of rocuronium for a pharmacodynamic effect was depending on the applied models.

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.

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

BACKGROUND: There is increasing evidence that the incidence of postoperative residual paresis after using neuromuscular blockers ranges from 24 to 50% in post anaesthesia care unit (PACU) and is associated with postoperative complications such as critical respiratory events as evidenced by hypoxia, hypoventilation and upper airway obstruction. Quantitative neuromuscular monitoring (such as the assessment of Train of four (TOF) ratio) and reversal of neuromuscular blockers has been shown to reduce postoperative residual paresis. There are very few outcome studies on effect of residual paresis in PACU. There is a paucity of published randomized controlled trials investigating whether using a TOF ratio ≥0.9 before endotracheal extubation compared to clinical assessment of return of neuromuscular function reduces the incidence of critical respiratory events in PACU. OBJECTIVE: To determine whether using TOF ratio ≥ 0.9 compared to clinical assessment of return of neuromuscular function before endotracheal extubation reduces the incidence of critical respiratory events in PACU. METHODS: Onehundred sixty eight adult patients in ASA physical status I and II requiring general anaesthesia for elective surgery with cisatracurium as the muscle relaxant were randomized into 2 groups of 84 each. Group 1 were patients who required a TOF ratio of ≥0.9 before extubation. Group 2 patients were extubated based on clinical assessment of return of adequate neuromuscular function by the anaesthetist as is the standard of practice at the Aga Khan University hospital Nairobi. General anaesthesia was standardized in both groups. Both the investigators and patients were blinded during the study.Once the patient was transferred to PACU, oxygen saturation (SP02), respiratory rate and any signs of upper airway obstruction as demonstrated by stridor, laryngospasms or requirement of any airway manipulation was recorded for the first 30 minutes. Duration of anaesthesia and surgery was also recorded. Patient demographics were recorded and analyzed. RESULTS: There was no statistical difference between the 2 groups in terms of patient demographics, duration of surgery and anaesthesia and duration since last muscle relaxant was given. In terms of hypoxia on arrival in PACU, the incidence of mild hypoxia (SPO2 90-93%) was 11% in clinical assessment groupversus 5% in TOF group P-value 0.149 while severe hypoxia (SPO2 <90%) was 19% versus 10% P-value 0.078. During the first 30 minutes in PACU, the incidence of mild hypoxia (SPO2 90-93%) was statistically significant between the 2 groups (12% in clinical assessment group versus 1% in TOF group, P-value 0.005) while severe hypoxia (SPO2 <90%) was 7% versus 5%, P-value 0.373. The incidence of upper airway obstruction was statistically significant between the two groups (45% in clinical assessment group versus 14% in TOF group P-value<0.0001 for patients requiring airway maneuver, 21% versus 2% P-value <0.0001 for those who required tactile stimulation and 31% versus 12% were snoring, P-value 0.003. Logistic regression analysis revealed TOF group was less likely associated with mild hypoxia (OR 0.09 95% CI 0.01-0.71 P-value 0.023), tactile stimulation (OR 0.09 95% CI 0.02-0.40 P-value 0.002), airway maneuver (OR 0.20 95% CI 0.10-0.43 P-value <0.001) and snoring (OR 0.30 95% CI 0.13-0.68 P-value 0.04). CONCLUSION: Among this population, there is a lower incidence of critical respiratory events in PACU with the use of neuromuscular monitoring using TOF ratio ≥0.9 to assess neuromuscular function before endotracheal extubation compared with the use of clinical assessment methods.

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

BACKGROUND: When a muscle relaxant is administered to facilitate intubation, the benefits of anticholinesterase reversal must be balanced with potential risks. The aim of this double-blinded, randomized noninferiority trial was to evaluate the effect of neostigmine administration on neuromuscular function when given to patients after spontaneous recovery to a train-of-four ratio of 0.9 or greater. METHODS: A total of 120 patients presenting for surgery requiring intubation were given a small dose of rocuronium. At the conclusion of surgery, 90 patients achieving a train-of-four ratio of 0.9 or greater were randomized to receive either neostigmine 40 µg/kg or saline (control). Train-of-four ratios were measured from the time of reversal until postanesthesia care unit admission. Patients were monitored for postextubation adverse respiratory events and assessed for muscle strength. RESULTS: Ninety patients achieved a train-of-four ratio of 0.9 or greater at the time of reversal. Mean train-of-four ratios in the control and neostigmine groups before reversal (1.02 vs. 1.03), 5 min postreversal (1.05 vs. 1.07), and at postanesthesia care unit admission (1.06 vs. 1.08) did not differ. The mean difference and corresponding 95% CI of the latter were -0.018 and -0.046 to 0.010. The incidences of postoperative hypoxemic events and episodes of airway obstruction were similar for the groups. The number of patients with postoperative signs and symptoms of muscle weakness did not differ between groups (except for double vision: 13 in the control group and 2 in the neostigmine group; P = 0.001). CONCLUSIONS: Administration of neostigmine at neuromuscular recovery was not associated with clinical evidence of anticholinesterase-induced muscle weakness. VISUAL ABSTRACT: An online visual overview is available for this article.(Figure is included in full-text article.).