Development of the Bristol Rabbit Pain Scale (BRPS): A multidimensional composite pain scale specific to rabbits (Oryctolagus cuniculus)

Abstract

A species-specific composite pain scale is a prerequisite for adequate pain assessment. The aim of this study was to develop a multidimensional pain scale specific to rabbits (Oryctolagus cuniculus) called the Bristol Rabbit Pain Scale (BRPS). The scale was developed over five phases using a unique combination of methods: focus groups and behavioural observation. The first two phases aimed at identifying descriptors to describe a rabbit in pain, and then reducing their number, both using focus groups. A total of 72 pain descriptors were grouped under six categories (Demeanour, Posture, Facial expression, Attention to the painful area, Audible and Other) and ‘No pain’ descriptors were added. The third phase aimed to confirm, through video observation of rabbits, the categories and descriptors previously described, to reject those terms that were ambiguous, and identify any new descriptors that had not been included in the previous list of descriptors. This led to the rejection of the categories Audible and Attention to the painful area and of 34 descriptors. Seven new descriptors were identified. The last two phases constructed the final format of the BRPS by refining the categories, ranking the descriptors on an ordinal scale and testing the internal reliability of the scale using Cronbach’s alpha test. This led to a composite pain scale of six categories (Demeanour, Posture, Locomotion, Ears, Eyes and Grooming) with four intensities of pain (0, 1, 2, and 3), a total score of 0–18, and a high Cronbach’s alpha coefficient (alpha = 0.843). This BRPS fills an important gap in the field of rabbit medicine and has the potential to improve the assessment and management of pain in rabbits providing veterinary professionals with a novel multidimensional pain assessment tool. Further studies will investigate the clinical utility, validity and reliability of the BRPS.

Validation of the rabbit pain behaviour scale (RPBS) to assess acute postoperative pain in rabbits (Oryctolagus cuniculus)

“…Internal consistency showed that the scale items behave in the same way, with a concomitant increase or decrease in their scores according to the intensity of pain [ 50 ]. Our values were similar but a little lower than the BRPS [ 20 ].…”

“…This reflects the need to submit new instruments to strict statistical refinement criteria to increase its discriminatory capacity and avoid the insertion of unnecessary items. The RPBS items are similar to those approved in five phases during the creation of the BRPS [ 20 ], a scale developed in parallel and published after completion of the current study. The RPBS is based on strict and complete behaviour selection criteria, which confirms its importance in identifying pain in the species.…”

“…This is an important attribute to determine the repeatability of measurements, as this represents the consistency of scores over time [ 21 , 58 , 63 ]. The recently published BRPS [ 20 ] also did not assess repeatability and reproducibility.…”

“…The scales previously developed to assess pain in rabbits [ 18 – 20 ] did not determine a cut-off point for rescue analgesia. In the present study, the RPBS cut-off point was set at ≥ 3, with a high area under the curve representing the scale’s excellent discriminatory ability to identify pain [ 72 ].…”

“…Recent research associated this tool with physiological and behavioural parameters to assess clinical pain in pet rabbits, developing the composite pain scale for assessing and quantifying pain in rabbits (CANCRs) [ 19 ]. Recently, a study developed in parallel with the present study established the Bristol Rabbit Pain Scale (BRPS), based on the selection of behavioural descriptors approved in five phases by experts in the field and on evaluation of videos [ 20 ]. However, none of the tools described above to assess pain in rabbits has determined a cut-off point for rescue analgesic.…”