Abstract
Dear Editors,
We would like to voice our concern about an investigation published OnlineFirst in November 2017 and in this issue of the Journal of Feline Medicine and Surgery, ‘Effect of non-steroidal anti-inflammatory drugs on postoperative respiratory and heart rate in cats subjected to ovariohysterectomy’. 1
The manuscript has two inextricably linked problems: the ethical justification and the limitations of the study design. The investigation depended on the hypothesis that cats undergoing ovariohysterectomy without non-steroidal anti-inflammatory drug (NSAID) treatment would experience more postoperative pain than those so treated, and the untreated cats would develop higher heart rates (HRs) and respiratory rates (RRs).
This is unacceptable on two counts: first, it is unethical and inhumane to conduct a study in which half the animals are expected to experience pain without either evaluating its degree or providing contingency for administration of rescue analgesia; secondly, if RR and HR are to be used as surrogate measures of pain they need to be correlated with measured pain. No pain assessments were made, validated or otherwise, so the study protocol is flawed, and no reliable conclusion can be drawn. While no scale is perfect, pain assessment tools are now available that are capable of discriminating pain intensity. The UNESP-Botucatu multidimensional composite pain scale 2 and the revised composite measure pain scale (rCMPS-F) for the assessment of acute pain in cats3,4 are both validated and practicable for a clinical situation. Thus, there remains no valid reason to exclude the assessment of pain.