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Objective: To compare the ratio of the train-of-four (TOF) and double burst stimulation (DBS) obtained with three-axial acceleromyography (AMG) and mechanomyography (MMG) in dogs during recovery from a rocuronium-induced neuromuscular block., Study Design: Prospective, randomized, experimental study., Animals: A total of six intact healthy adult male Beagle dogs, weighing 9.1 ± 1.9 kg and aged 3-5 years., Methods: Dogs were anesthetized with intravenous (IV) dexmedetomidine and propofol, and isoflurane in oxygen. Neuromuscular function was measured with AMG and MMG in the contralateral thoracic limbs. Rocuronium (0.5 mg kg -1 ) was administered IV, and the TOF and DBS ratios measured. During neuromuscular block offset, MMG values were recorded when AMG first reached ratios of 0.9 and 1.0. True recovery from neuromuscular block was determined as MMG ratio ≥ 0.9. The false-positive (AMG ≥ 0.9 or 1.0, and MMG ratio < 0.9) rate was determined. Paired values were compared, and bias and limits of agreement were calculated. Receiver operating characteristic (ROC) curves were created., Results: When AMG first reached 0.9 and 1.0 during recovery, MMG values were lower (p < 0.040). When AMG reached 0.9, the false-positive rate was 29% with TOF and 27% with DBS. It decreased to 12% (TOF) and 11% (DBS) when a ratio of 1.0 was used. AMG values were higher than paired MMG values (p < 0.001). The AMG overestimated MMG by 24% and 22% for TOF and DBS, respectively. Areas under the ROC curves (95% confidence interval) were 0.91 (0.89, 0.94) and 0.86 (0.81, 0.94) for TOF and DBS, respectively., Conclusions: and clinical relevance The three-axial AMG monitor overestimated neuromuscular function and, in some cases, indicated adequate recovery despite the MMG ratio being < 0.9. A TOF or DBS ratio of at least 1.0 should be considered when monitoring recovery of neuromuscular block with this AMG device., (Copyright © 2023 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To assess the ability to visually detect fade during train-of-four (TOF) or double burst stimulation (DBS) in anesthetized dogs recovering from nondepolarizing neuromuscular block., Study Design: Online anonymous survey., Population: Data from 112 participants., Methods: A web-based survey containing 12 videos of the response to ulnar nerve stimulation with TOF and 12 with DBS obtained at different levels of recovery from rocuronium-induced block was distributed to participants of the American College of Veterinary Anesthesia and Analgesia and the Academy of Veterinary Technicians in Anesthesia and Analgesia e-mail lists. Participants were asked to provide their highest training degree in anesthesiology, watch each video no more than twice, and determine whether fade was present. The probability to correctly recognize fade was calculated using binomial general linear models. General linear models and Tukey's tests were used to assess the effects of level of neuromuscular block, pattern of stimulation, and observers' training on the probability to detect fade., Results: The survey was completed by 53 diplomates, 29 licensed veterinary technicians, 24 residents and six doctors of veterinary medicine (DVMs). The probability to detect fade decreased as partial neuromuscular block became more shallow (p < 0.0001). A TOF or DBS ratio of 0.7 had a 50% chance of being detected. DBS was superior to TOF for detecting fade when the ratio was 0.3-0.69. TOF was superior to DBS when the ratio was 0.7-0.9 (p < 0.0001). There were no differences among groups of observers when assessing fade with TOF or DBS., Conclusions and Clinical Relevance: Detection of fade from observations of the response to TOF in dogs is unreliable. Advance training in anesthesiology or the use of DBS confers little to no advantage for this subjective test., (Copyright © 2019 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: Anticholinesterase drugs may produce paradoxical neuromuscular block when administered at shallow levels of neuromuscular block. The objective of this study was to evaluate the effects of neostigmine and edrophonium when administered at near-complete reversal from nondepolarizing block in anesthetized dogs., Study Design: Incomplete crossover, randomized, blinded experimental study., Animals: A total of 12 Beagle dogs., Methods: Each dog was anesthetized twice with propofol and maintained with isoflurane and dexmedetomidine. Intravenous (IV) vecuronium (0.1 mg kg -1 ) was administered. When the mechanographic train-of-four (TOF) ratio had spontaneously recovered to ≥0.9, either neostigmine (0.04 mg kg -1 ) or edrophonium (0.5 mg kg -1 ) was administered IV, preceeded by atropine. Changes in twitch height or TOF ratio were measured for the next 10 minutes. Recurarization was considered to be present if values decreased by ≥10%., Results: Data from four dogs in each treatment were excluded from analysis, resulting in data from five dogs administered both treatments, three dogs administered neostigmine and three dogs administered edrophonium. There was no difference between groups for age, weight, T1 and T4 twitch heights or TOF ratio values, before or after anticholinesterase administration. The TOF ratio decreased by 17% and 18% in two of the eight dogs administered neostigmine, resulting from a larger increase in T1 relative to T4. No reductions in individual twitch amplitudes were recorded in those dogs. When edrophonium was used, no cases of recurarization were observed., Conclusions and Clinical Relevance: The results support use of edrophonium for reversal of shallow neuromuscular block. The decreases in TOF ratio recorded after neostigmine does not necessarily indicate muscular weakness. Although the clinical implications are uncertain, the results suggest that, at these doses, edrophonium may be preferable to neostigmine for reversal of shallow neuromuscular block in dogs., (Copyright © 2017 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To evaluate the effect of two levels of partial neuromuscular block (NMB) on arytenoid abduction, tidal volume (V T ) and peak inspiratory flow (PIF) in response to a hypercarbic challenge in anesthetized dogs., Study Design: Prospective laboratory study., Animals: Eleven healthy male Beagle dogs aged 3-5 years., Methods: Dogs were anesthetized with propofol and dexmedetomidine infusions. The rima glottidis was observed via an endoscope placed through a laryngeal mask airway. Atracurium infusion was titrated to obtain two levels of partial NMB. The normalized glottal gap area (NGGA; glottal gap area normalized to height squared of rima glottidis) at peak inspiration during a hypercarbic challenge (10% CO 2 inspired for 1 minute) was measured at baseline, during mild [train-of-four (TOF) ratio 0.4-0.6] and shallow (TOF ratio 0.7-0.9) NMB, and 30 minutes after spontaneous recovery from NMB. The V T and PIF were measured at the same time points and compared using anova for repeated measures and Tukey's post hoc tests., Results: The NGGA and V T were significantly lower than baseline during both levels of partial NMB with no difference between mild and shallow NMB (p < 0.05). They returned to baseline values after spontaneous recovery from NMB. PIF was not altered significantly during partial NMB., Conclusions and Clinical Relevance: The NGGA and V T at peak inspiration in response to a hypercarbic challenge were reduced during partial NMB block, with decreased abduction of the arytenoid cartilages. This dysfunction was present even at shallow levels of NMB., (Copyright © 2017 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To determine if neuromuscular monitoring at the pelvic limb accurately reflects neuromuscular function in the larynx after administration of rocuronium in anesthetized dogs., Study Design: Prospective experimental study., Animals: Six healthy Beagle dogs., Methods: Anesthesia was maintained in dogs with isoflurane and a continuous infusion of dexmedetomidine. Rocuronium (0.6 mg kg -1 ) was administered intravenously to induce neuromuscular block. Train-of-four (TOF) impulses were applied to the left recurrent laryngeal nerve (RLn) and the peroneal nerve (Pn). The evoked TOF ratio (TOFR; T4:T1) was measured with electromyography (EMG) simultaneously at the larynx and at the pelvic limb. Spontaneous recoveries of T1 to 25% (T1 25% ) and 75% (T1 75% ) of twitch height, and to TOFR of 0.70 and 0.90 (TOFR 0.90 ) at each EMG site were compared., Results: Data from five dogs were analyzed. Times to T1 25% were similar at the pelvic limb and larynx when measured by EMG; time to T1 75% was slower at the larynx by 6±4 minutes (p=0.012). The larynx had a slower recovery to TOFR 0.70 (41±13 minutes) and TOFR 0.90 (45±13 minutes) than did the pelvic limb [29±8 minutes (p=0.011) and 33±9 minutes (p=0.003), respectively]. When the pelvic limb EMG returned to TOFR 0.70 and TOFR 0.90 , the larynx EMG TOFR 0.70 and TOFR 0.90 values were 0.32±0.12 (p=0.001) and 0.38±0.13 (p=0.001), respectively., Conclusions and Clinical Relevance: After administration of rocuronium, neuromuscular function assessed by EMG recovered approximately 36% slower at the larynx than at the pelvic limb. The results in these dogs suggest that quantitative neuromuscular monitoring instrumented at a pelvic limb may be unable to exclude residual block at the larynx in anesthetized dogs., (Copyright © 2017 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)