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

Abstract

A scale with robust statistical validation is essential to diagnose pain and improve decision making for analgesia. This blind, randomised, prospective and opportunist study aimed to develop an ethogram to evaluate behaviour and validate a scale to assess acute ovine postoperative pain. Elective laparoscopy was performed in 48 healthy sheep, filmed at one preoperative and three postoperative moments, before and after rescue analgesia and 24 hours after. The videos were randomised and assessed twice by four evaluators, with a one-month interval between evaluations. Statistical analysis was performed using R software and differences were considered significant when p <0.05. Based on the multiple association, a unidimensional scale was adopted. The intra-and inter-observer reliability ranged from moderate to very good (intraclass correlation coefficient � 0.53). The scale presented Spearman correlations > 0.80 with the numerical, simple descriptive, and visual analogue scales, and a correlation of 0.48 with the facial expression scale. According to the mixed linear model, the scale was responsive, due to the increase and decrease in pain scores of all items after surgery and analgesic intervention, respectively. All items on the scale demonstrated an acceptable Spearman item-total correlation (0.56-0.76), except for appetite (0.25). The internal consistency was excellent (Cronbach's α = 0.81) and all items presented specificity > 0.72 and sensitivity between 0.61-0.90, except for appetite. According to the Youden index, the cutoff point was � 4 out of 12, with a diagnostic uncertainty zone of 4 to 5. The area under the curve > 0.95 demonstrated the excellent discriminatory capacity of the instrument. In conclusion, the Unesp-Botucatu pain scale in sheep submitted to laparoscopy is valid, reliable, specific, sensitive, with excellent internal consistency, accuracy, discriminatory capacity, and a defined cutoff point.

Validation of the Donkey Pain Scale (DOPS) for Assessing Postoperative Pain in Donkeys

“…A scale is specific and sensitive when a given pain behavior is absent when the animal is pain-free and present when the animal is suffering pain, respectively (6). A new proposed pain assessment instrument should undergo an indepth statistical validation, as reported in cats (7), cattle (8), pigs (9), and sheep (10), to ensure its experimental and clinical applicability.…”

Development, Validation, and Reliability of a Sedation Scale in Horses (EquiSed)

“…The alternative approach used in the current study for the concurrent criterion validity test was to correlate the EquiSed against unidimensional scales (NRS, VAS, SDS) and HHAG%. This was a similar approach used in previous studies which developed and validated pain scales in other species ( 20 , 26 , 56 , 57 ). In addition, HHAG% was incorporated in the current study because this is a well-recognized method for assessing the degree of sedation in horses ( 2 , 5 , 7 , 11 , 12 ).…”

Measurement properties of pain scoring instruments in farm animals: A systematic review protocol using the COSMIN checklist

“…Pain scoring instruments have been developed for farm animals and may include assessment of activity, body posture, response to interaction, attention to wound/ painful area, and/or facial expressions [14,[22][23][24][25][26]. In ruminants, for example, the most frequently observed behaviors that are possibly associated with pain include changes in appearance, posture, gait, appetite, interaction with other animals and the environment, decreased or increased frequency of locomotion, weight bearing, vocalization, increased attention to the injured area, lip-licking, curved lips, teeth grinding, tremors and strong tail wagging [5,[26][27][28][29]. Similarly, behaviours that could be associated with pain and changes in facial expressions have been identified in swine [14,22].…”

“…Unidimensional scales such as the numerical rating scale (NRS), simple descriptive scale (SDS) and visual analog scales (VAS) have been used in the past to measure postoperative pain in sheep [31,32]. However, these tools are not considered adequate because they were developed and validated for humans who self-report their degree of pain; these scales are subjective, not species-specific and influenced by the level of familiarity/expertise of the observer [26,33,34]. Species-specific pain scales have been developed for use in farm animals, such as sheep, cattle and pigs, and different levels of validation have been reported for some of these instruments [14,22,23,26,[35][36][37].…”

“…In other words, measurement properties refer to the quality of the methodology. The following are the most commonly reported measurement properties of pain scoring instruments: a) development/content validity (expert assessment of the items included in the scale, the calculation of a content validation index, development of ethograms and/or evidence from the literature [ 38 , 39 ]); b) structural and/or cross-cultural validity [ 39 – 41 ]; c) internal consistency (degree of the interrelatedness among the items [ 39 , 41 ]); d) measurement error (systematic and random error in a patient’s score that is not associated to real changes in the construct to be assessed including sensitivity, specificity and accuracy [ 41 ]); e) reliability (whether the scores are consistent between different observers and over time, known as inter- and intra-observer reliability, respectively [ 22 , 39 ]); f) criterion validity (correlation of the proposed tool with other existent scales [ 39 , 41 ]); g) construct validity (whether the tool measures what it is supposed to measure, in this case, pain, by comparing different known groups and if the scores decrease after rescue analgesia [ 39 , 41 ]); h) responsiveness (ability to detect changes over time); and i) a definition of a cut off point for administration of rescue analgesia [ 22 , 38 , 42 ].…”