A behaviour-based pain scale for horses with acute colic: scale construction.

The research work sought to develop a verifiable tool for assessing the severity of sudden abdominal pain, known as colic in horses. To construct the proposed behavior-based pain scale, the researchers combined mathematical and judgemental approaches and validated the scales using a series of expert-driven procedures and assessments.

Theory and Approach

• Two behavior-based scales for evaluating colic pain in horses were created, utilizing both mathematical and judgmental methodologies; both approaches use recognized pain behaviors as key elements.
• The mathematical approach focused on identifying clear indicators of pain that could be quantitatively measured, while the judgmental approach involved the subjective evaluation and weighting of these indicators by experts.

Scale Construction and Validation

• The pain levels in 23 video clips of horses demonstrating symptoms of acute abdominal pain were examined by 30 equine practitioners. Their evaluations were done using a 10cm visual analog scale (VAS).
• These experts also made note of all notable behaviors exhibited by the horses in these clips by referencing a checklist of 23 behaviors previously identified in literature.
• Out of the 23 behaviors identified, nine were found to have insignificant bias and moderate-to-excellent inter-observer agreement with multirater kappas between 0.5 and 0.95. This process ensured those selected behaviors were reliable for scale construction.
• An iterative Delphi questionnaire process was then used to determine which items best reflected pain severity. Six experienced veterinarians independently evaluated and selected the top 15 behaviors out of 42. As a result, two key behaviors were identified through this process.

Results and Conclusion

• Using the results from both mathematical and judgemental approaches, an advisory panel of three equine practitioners constructed two clinimetric-type scales. These scales were then incorporated into the practical equine acute abdominal pain scales (EAAPS).
• The EAAPS-1 assigned equal weight to each behavior, while the EAAPS-2 used a gradation of weights based on the frequency each behavior was demonstrated in their sample cases.
• The EAAPS scales, which consist of 12 behavioral indicators, are the first pain severity scales specifically designed for assessing acute colic in horses using the clinimetric approach to measure the severity of pain in horses.
• The team acknowledges that further studies are needed to validate the scales, but the current studies mark a significant step towards a systematic approach to pain assessment in horses.