Editor—The study published by Monge Garcia and colleagues1 in the British Journal of Anaesthesia was conducted on 18 rabbits anaesthetized with xylazine and ketamine and paralysed with rocuronium. The authors reported that the study involved procedures that had been approved by the Ethical Committee for Animal Experimentation of the School of Medicine of the University of Cadiz (license 07–9604), 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, and adhered to relevant aspects of the ARRIVE guidelines. Consequently, we were disappointed to discover that these regulatory bodies, along with the editorial process of the BJA, appear to be satisfied that assessing the animals' physiological responses to a nociceptive stimulus (tail clamping) represents a suitable method for determining adequacy of anaesthesia in animals receiving neuromuscular blocking agents. Putting aside concerns with the reliability of physiological (i.e. cardiovascular), responses as indicators of anaesthetic depth, we question the wisdom of this approach in an animal study primarily aimed at examining the interrelationship of many of the same variables commonly affected by accidental awareness under general anaesthesia.
- Journal Article