Validation of the UNESP-Botucatu pig composite acute pain scale (UPAPS)

Abstract

The creation of species-specific valid tools for pain assessment is essential to recognize pain and determine the requirement and efficacy of analgesic treatments. This study aimed to assess behaviour and investigate the validity and reliability of an acute pain scale in pigs undergoing orchiectomy. Forty-five pigs aged 38±3 days were castrated under local anaesthesia. Behaviour was video-recorded 30 minutes before and intermittently up to 24 hours after castration. Edited footage (before surgery, after surgery before and after rescue analgesia, and 24 hours postoperatively) was analysed twice (one month apart) by one observer who was present during video-recording (in-person researcher) and three blinded observers. Statistical analysis was performed using R software and differences were considered significant when p<0.05. Intra and inter-observer agreement, based on intra-class correlation coefficient, was good or very good between most observers (>0.60), except between observers 1 and 3 (moderate agreement 0.57). The scale was unidimensional according to principal component analysis. The scale showed acceptable item-total Spearman correlation, excellent predictive and concurrent criterion validity (Spearman correlation � 0.85 between the proposed scale versus visual analogue, numerical rating, and simple descriptive scales), internal consistency (Cronbach's α coefficient >0.80 for all items), responsiveness (the pain scores of all items of the scale increased after castration and decreased after intervention analgesia according to Friedman test), and specificity (> 95%). Sensitivity was good or excellent for most of the items. The optimal cut-off point for rescue analgesia was � 6 of 18. Discriminatory ability was excellent for all observers according to the area under the curve (>0.95). The proposed scale is a reliable and valid instrument and may be used

Validation of the Unesp-Botucatu composite scale to assess acute postoperative abdominal pain in sheep (USAPS)

“…Therefore, the facial expression scale was used as a previously validated gold standard model for testing concurrent criterion validity. A second method compared the proposed instrument with the unidimensional scales, following the same criteria applied in cats [29], cattle [19], horses [24] and pigs [32]. The USAPS showed a high correlation with the unidimensional scales, as previously reported for validated scales in other species [19,24,29,32] and a claudication scale in sheep [76].…”

“…The validation process of an instrument to assess pain is based on the investigation of behaviours and, when possible, of species-specific physiological data present during pain situations, followed by a comparison of these changes with the state of normality [19,29,32]. This methodology was followed in the current study; an ethogram was constructed during the preoperative period when animals were supposedly devoid of pain, followed by the postoperative period when animals probably had severe pain, followed by rescue analgesia for pain reduction and reassessment after 24 hours.…”

“…A second method compared the proposed instrument with the unidimensional scales, following the same criteria applied in cats [29], cattle [19], horses [24] and pigs [32]. The USAPS showed a high correlation with the unidimensional scales, as previously reported for validated scales in other species [19,24,29,32] and a claudication scale in sheep [76]. Otherwise, correlation with the facial scale was only moderate possibly because other breeds of sheep were used in this study and their facial morphology was different from the original study [41].…”

“…Construct validity reflects the responsiveness of the scale and examines whether the instrument detects predictable differences between groups or moments [33]. The method tests the hypothesis that time and surgical and analgesic intervention should alter pain scores [29] and has been used to validate scales in veterinary medicine [19,24,29,32]. In this study, the differences observed in the pain scores between the moments, and especially at the expected moment of greatest pain compared to the other moments, confirm that the proposed scale is responsive both to identify intense degrees of pain, as well as moderate degrees, which occurred after rescue analgesia.…”

“…Another facial scale (sheep grimace) was published after the beginning of our research [42]. To improve the reliability of pain measurement it is necessary to develop an instrument with in-depth statistical validation, as reported in cats [29], cattle [19], horses [24], and pigs [32], by using a blind and random methodology with evidence of validity, reliability, sensitivity, specificity, and a defined analgesic intervention point [43].…”