Reply to Clutton and colleagues: assessing anaesthesia in rabbits receiving rocuronium

Abstract

Editor—Thanks to Clutton and colleagues1Clutton RE Clarke KW Jones RS Assessing anaesthesia in rabbits receiving rocuronium. Response to: Effects of arterial load variations on dynamic arterial elastance: an experimental study.Br J Anaesth. 2017; 119: 1055Abstract Full Text Full Text PDF PubMed Scopus (1) Google Scholar for their comments about our paper2Monge García MI Guijo González P Gracia Romero M et al.Effects of arterial load variations on dynamic arterial elastance: an experimental study.Br J Anaesth. 2017; 118: 938-946Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar. On behalf of my co-authors, I would like to reply regarding two points raised: (i) the welfare of animals in our research; and (ii) the experimental protocol. First, our study was performed in the Experimental Laboratory of the Servicio Central de Experimentación y Producción Animal (SEPA) of the University of Cádiz, which is regulated by the following: the Junta de Andalucía by the Decree 142/2002 and 199/2005 (which creates and regulates the registry of breeding establishments, suppliers, and users of experimental animals) and 65/2012 (which regulates animal health and zootechnical conditions); the European Directive 2010/63/UE (revising Directive 86/609/EEC on the protection of animals used for scientific purposes); and Royal Decree 1201/2005 (about the approximation of the laws, regulations, and administrative provisions of the Member States concerning the protection of animals used for experimental and other scientific purposes). The experimental protocol was approved by the Ethical Committee for Animal Experimentation of the School of Medicine of the University of Cadiz (license 07–9604), and conformed to European Ethical Standards (2012/707/EU) and Spanish Law (RD 53/2013) for the care and use of laboratory animals for experimental research. The Director of the animal laboratory (Dr Carlos Costella Villodres) also supervised the protocol and all the experimental procedures. Authors directly involved in the experiments have previously completed courses for accreditation category B (for personnel carrying out the procedures), or B and C (for personnel directing or designing procedures, M.I.M.G.), according to Decree 80/2011, through which training in animal welfare is regulated. As mentioned in our paper, during neuromuscular block, anaesthetic depth was monitored by the absence of significant changes in blood pressure, heart rate, or both, either spontaneous or in response to a noxious stimulus (tail clamping). As pain activates the sympathetic nervous system, causing increased heart rate and blood pressure, when neuromuscular blockers are used, autonomic responses are the only method to judge anaesthetic depth.3Suckow MA Stevens KA Wilson RP The Laboratory Rabbit, Guinea Pig, Hamster, and Other Rodents.1st Edn. Academic Press/Elsevier, London; Waltham, MA2012Google Scholar, 4Romanov A Moon RS Wang M Joshi S Paradoxical increase in the bispectral index during deep anesthesia in New Zealand white rabbits.J Am Assoc Lab Anim Sci. 2014; 53: 74-80PubMed Google Scholar, 5Wagner AE Brodbelt DC Arterial blood pressure monitoring in anesthetized animals.J Am Vet Med Assoc. 1997; 210: 1279-1285PubMed Google Scholar, 6Uhlig C Krause H Koch T Gama de Abreu M Spieth PM Anesthesia and monitoring in small laboratory mammals used in anesthesiology, respiratory and critical care research: a systematic review on the current reporting in top-10 impact factor ranked journals.PLoS One. 2015; 10: e0134205Crossref Scopus (19) Google Scholar Both blood pressure and heart rate were continuously monitored by an arterial line and oesophageal Doppler system. Although tail clamping was used during the experiment as a noxious stimulus, the sympathetic autonomic response was continuously monitored to judge anaesthetic depth when no other obvious reason modified these variables. Moreover, adequate depth of anaesthesia was always checked by tail clamping before administration of the neuromuscular block. Second, as blood pressure changes were part of our haemodynamic assessment, animals were allowed to stabilize heart rate and blood pressure before any haemodynamic recording. Only in the event of doubt about the depth of anaesthesia was the tail clamp repeated before recording. The response, if present, was never included in the haemodynamic assessments of the study. None declared.