Can we see fade? A survey of anesthesia providers and our ability to detect partial neuromuscular block in dogs

Published:January 21, 2019DOI:



      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.


      Data from 112 participants.


      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.


      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.


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        • Ali H.H.
        • Utting J.E.
        • Gray C.
        Stimulus frequency in the detection of neuromuscular block in humans.
        Br J Anaesth. 1970; 42: 967-978
        • Auer U.
        Clinical observations on the use of the muscle relaxant rocuronium bromide in the dog.
        Vet J. 2007; 173: 422-427
        • Capron F.
        • Fortier L.P.
        • Racine S.
        • Donati F.
        Tactile fade detection with hand or wrist stimulation using train-of-four, double-burst stimulation, 50-hertz tetanus, 100-hertz tetanus, and acceleromyography.
        Anesth Analg. 2006; 102: 1578-1584
        • Capron F.
        • Alla F.
        • Hottier C.
        • et al.
        Can acceleromyography detect low levels of residual paralysis? A probability approach to detect a mechanomyographic train-of-four ratio of 0.9.
        Anesthesiology. 2004; 100: 1119-1124
        • Della Rocca G.
        • Iannuccelli F.
        • Pompei L.
        • et al.
        Neuromuscular block in Italy: a survey of current management.
        Minerva Anestesiol. 2012; 78: 767-773
        • Engbaek J.
        • Ostergaard D.
        • Viby-Mogensen J.
        Double burst stimulation (DBS): a new pattern of nerve stimulation to identify residual neuromuscular block.
        Br J Anaesth. 1989; 62: 274-278
        • Eriksson L.I.
        • Sato M.
        • Severinghaus J.W.
        Effect of a vecuronium-induced partial neuromuscular block on hypoxic ventilatory response.
        Anesthesiology. 1993; 78: 693-699
        • Eriksson L.I.
        • Lennmarken C.
        • Wyon N.
        • Johnson A.
        Attenuated ventilatory response to hypoxaemia at vecuronium-induced partial neuromuscular block.
        Acta Anaesthesiol Scand. 1992; 36: 710-715
        • Eriksson L.I.
        • Sundman E.
        • Olsson R.
        • et al.
        Functional assessment of the pharynx at rest and during swallowing in partially paralyzed humans: simultaneous videomanometry and mechanomyography of awake human volunteers.
        Anesthesiology. 1997; 87: 1035-1043
        • Kopman A.F.
        • Mallhi M.U.
        • Justo M.D.
        • et al.
        Antagonism of mivacurium-induced neuromuscular blockade in humans. Edrophonium dose requirements at threshold train-of-four count of 4.
        Anesthesiology. 1994; 81: 1394-1400
        • Martin-Flores M.
        • Sakai D.M.
        • Campoy L.
        • Gleed R.D.
        Survey of how different groups of veterinarians manage the use of neuromuscular blocking agents in anesthetized dogs.
        Vet Anaesth Analg. 2018; 45: 443-451
        • Martin-Flores M.
        • Campoy L.
        • Ludders J.W.
        • et al.
        Comparison between acceleromyography and visual assessment of train-of-four for monitoring neuromuscular blockade in horses undergoing surgery.
        Vet Anaesth Analg. 2008; 35: 220-227
        • Murphy G.S.
        • Szokol J.W.
        • Marymont J.H.
        • et al.
        Residual neuromuscular blockade and critical respiratory events in the postanesthesia care unit.
        Anesth Analg. 2008; 107: 130-137
        • Naguib M.
        • Kopman A.F.
        • Lien C.A.
        • et al.
        A survey of current management of neuromuscular block in the United States and Europe.
        Anesth Analg. 2010; 111: 110-119
        • Norton M.
        • Xara D.
        • Parente D.
        • et al.
        Residual neuromuscular block as a risk factor for critical respiratory events in the post anesthesia care unit.
        Rev Esp Anestesiol Reanim. 2013; 60: 190-196
        • Sakai D.M.
        • Martin-Flores M.
        • Romano M.
        • et al.
        Recovery from rocuronium-induced neuromuscular block was longer in the larynx than in the pelvic limb of anesthetized dogs.
        Vet Anaesth Analg. 2017; 44: 246-253
        • Samet A.
        • Capron F.
        • Alla F.
        • et al.
        Single acceleromyographic train-of-four, 100-Hertz tetanus or double-burst stimulation: which test performs better to detect residual paralysis?.
        Anesthesiology. 2005; 102: 51-56
        • Sauer M.
        • Stahn A.
        • Soltesz S.
        • et al.
        The influence of residual neuromuscular block on the incidence of critical respiratory events. A randomised, prospective, placebo-controlled trial.
        Eur J Anaesthesiol. 2011; 28: 842-848
        • Sundman E.
        • Witt H.
        • Olsson R.
        • et al.
        The incidence and mechanisms of pharyngeal and upper esophageal dysfunction in partially paralyzed humans: pharyngeal videoradiography and simultaneous manometry after atracurium.
        Anesthesiology. 2000; 92: 977-984
        • Teoh W.H.
        • Ledowski T.
        • Tseng P.S.
        Current trends in neuromuscular blockade, management, and monitoring amongst Singaporean anaesthetists.
        Anesthesiol Res Pract. 2016; 2016: 7284146
        • Viby-Mogensen J.
        • Jensen N.H.
        • Engbaek J.
        • et al.
        Tactile and visual evaluation of the response to train-of-four nerve stimulation.
        Anesthesiology. 1985; 63: 440-443
        • Yip P.C.
        • Hannam J.A.
        • Cameron A.J.
        • Campbell D.
        Incidence of residual neuromuscular blockade in a post-anaesthetic care unit.
        Anaesth Intensive Care. 2010; 38: 91-95