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A retrospective comparison of two analgesic strategies after uncomplicated tibial plateau levelling osteotomy in dogs
- Bini, Gianluca, Vettorato, Enzo, De Gennaro, Chiara, Corletto, Federico
- Veterinary anaesthesia and analgesia 2018 v.45 no.4 pp. 557-565
- adverse effects, analgesia, anti-inflammatory agents, chi-square distribution, confidence interval, dogs, food intake, isoflurane, methadone, odds ratio, osteotomy, pain, t-test, vocalization, vomiting
- To compare the efficacy and side effects of postoperative methadone administered according to pain score (PS) or every 4 hours (Q4), after unilateral uncomplicated tibial plateau levelling osteotomy (TPLO) in dogs in which a peripheral nerve block (PNB) was administered.Retrospective, case-control study.Clinical records of dogs that underwent a TPLO in 2015 were retrieved; 136 out of 174 dogs were included: 52 assigned to group PS, 84 to group Q4.In group PS, methadone was administered according to the short form of the Glasgow Composite Measure Pain Scale (CMPS-SF), whereas in group Q4 methadone was administered at 4 hour intervals. Demographic data, anaesthetic technique, surgery time, American Society of Anesthesiologists classification, PNB performed, local anaesthetic used and dose, anti-inflammatory drugs administered, end-expiratory fraction of isoflurane, perioperative opioid consumption, time to first postoperative methadone administration, pain scores, time to first pain score, food intake, number of postoperative observations, presence/absence of specific keywords representing the general state and behaviour of the animal, use of the operated limb and reaction to wound palpation were retrieved. Fisher's exact test, chi-square test, Student t test or Mann–Whitney U test were used, considering p<0.05 significant. Odds ratios and 95% confidence intervals were calculated, when indicated.Four times more methadone was administered to dogs in group Q4, and whilst not having lower pain scores or better short-term outcome (e.g. toe-touching and weight bearing), were 23.42 times (1.37 to 400.40) more likely to vomit, 3.76 (1.50 to 9.49) more likely to vocalize, and their food intake was 38% less than dogs in group PS. No dogs in group PS vomited postoperatively.Administration of methadone Q4 caused more side effects than administration guided by CMPS-SF. This should be considered when planning postoperative analgesia in dogs undergoing uncomplicated TPLO and in which a PNB has been performed.