title: Recovery from neuromuscular block in dogs: restoration of spontaneous ventilation does not exclude residual blockade.
abstract: OBJECTIVE
  To evaluate if return of spontaneous ventilation to pre-relaxation values indicates complete recovery from neuromuscular blockade.
  
  
  METHODS
  Prospective, with each individual acting as its own control.
  
  
  METHODS
  Ten healthy adult female Beagle dogs weighing 6.2-9.4 kg.
  
  
  METHODS
  Dogs were anesthetized with propofol, dexemedetomidine and isoflurane. Spontaneous ventilation was assessed by measuring end-tidal CO2 , expired tidal volume, peak inspiratory flow, respiratory rate and minute ventilation. Vecuronium 25 μg kg(-1) IV was administered and neuromuscular block was evaluated by measuring the train-of-four (TOF) ratio with acceleromyography in the hind limb. During spontaneous recovery from neuromuscular block, the TOF ratio when each ventilatory variable returned to baseline was recorded.
  
  
  RESULTS
  This dose of vecuronium produced moderate neuromuscular block in all dogs, with TOF ratio values of 0-18% at maximal block. Expired tidal volume, peak inspiratory flow and minute ventilation returned to pre-relaxation values when the median TOF ratio was ≤ 20%. The median TOF ratio was 42% when the end-tidal CO2 returned to pre-relaxation values.
  
  
  CONCLUSIONS
  Significant residual neuromuscular block could be measured at the hind limb with acceleromyography when ventilation had spontaneously returned to pre-vecuronium values. Monitoring spontaneous ventilation, including end-tidal CO2 , expired tidal volume, peak inspiratory flow or minute ventilation cannot be used as a surrogate for objective neuromuscular monitoring, and this practice may increase the risk of postoperative residual paralysis.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
authors.forename: Manuel
authors.initials: M
authors.lastname: Martin-Flores
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Sakai
authors.forename: Luis
authors.initials: L
authors.lastname: Campoy
authors.forename: R D
authors.initials: RD
authors.lastname: Gleed
mesh_terms: D000762:Anesthesia Recovery Period; D000768:Anesthesia, General / Q000662:veterinary; D000818:Animals; D004285:Dogs; D005260:Female; D019148:Neuromuscular Blockade / Q000009:adverse effects / Q000662:veterinary*; D003473:Neuromuscular Nondepolarizing Agents / Q000009:adverse effects / Q000494:pharmacology*; D012119:Respiration / Q000187:drug effects*; D014673:Vecuronium Bromide / Q000009:adverse effects / Q000494:pharmacology*
chemical_list: D003473:Neuromuscular Nondepolarizing Agents; D014673:Vecuronium Bromide
keywords: anaesthesia; neuromuscular blockade; residual blockade; vecuronium; ventilation