Objective--To refine and test construct validity and reliability of a composite pain scale for use in assessing acute postoperative pain in cats undergoing ovariohysterectomy. Sample Population--40 cats that underwent ovariohysterectomy in a previous study. Procedures--In a previous randomized, double-blind, placebo-controlled study, a composite pain scale was developed to assess postoperative pain in cats that received a placebo or an analgesic (tramadol, vedaprofen, or tramadol-vedaprofen combination). In the present study, the scale was refined via item analysis (distribution frequency and occurrence), a nonparametric ANOVA, and item-to-total score correlation. Construct validity was assessed via factor analysis and known-groups discrimination, and reliability was measured by assessing internal consistency. Results--Respiratory rate and respiratory pattern were rejected after item analysis. Factor analysis resulted in 5 dimensions (F1 [psychomotor change], posture, comfort, activity, mental status, and miscellaneous behaviors; F2 [protection of wound area], reaction to palpation of the surgical wound and palpation of the abdomen and flank; F3 [physiologic variables], systolic arterial blood pressure and appetite; F4 [vocal expression of pain], vocalization; and F5 [heart rate]). Internal consistency was excellent for the overall scale and for F1, F2, and F3; very good for F4; and unacceptable for F5. Except for heart rate, the identified factors and scale total score could be used to detect differences between the analgesic and placebo groups and differences among the analgesic treatments. Conclusions and Clinical Relevance--Results provided initial evidence of construct validity and reliability of a multidimensional composite tool for use in assessing acute postoperative pain in cats undergoing ovariohysterectomy.

Objective—To determine the analgesic and systemic effects of thoracic epidural administration of ketamine, lidocaine, or both in conscious dogs. Animals—6 adult mixed-breed dogs. Procedures—Each dog received 2% lidocaine hydrochloride without epinephrine (3.8 mg/kg), 5% ketamine hydrochloride (3.0 mg/kg), or both in randomized order with = 1 week between treatments. Drugs were administered in a total volume of 0.25 mL/kg through a thoracic epidural catheter implanted via the lumbosacral approach. Heart rate, blood pressure, respiratory rate, rectal temperature, analgesia, sedation, and ataxia were determined before treatment (baseline [time 0]) and at 5, 10, 15, 20, 30, 40, 50, 60, 90, 120, 150, and 180 minutes after administration. Results—The main areas of analgesia for the 3 treatments were the thorax and forelimbs bilaterally. Median duration of analgesia was shorter after administration of ketamine (30 minutes) than after administration of lidocaine (40 minutes) and lidocaine plus ketamine (90 minutes). All treatments caused moderate motor blockade, and only the ketamine and lidocaine plus ketamine treatments caused mild sedation. Significant decreases in systolic and mean arterial blood pressure were observed only with the lidocaine plus ketamine treatment. Conclusions and Clinical Relevance—Thoracic epidural administration of lidocaine plus ketamine resulted in longer duration of analgesia of the thorax and forelimbs bilaterally in conscious dogs, compared with administration of ketamine or lidocaine alone. Additional studies are needed to determine whether this technique adequately relieves postoperative pain after thoracic surgical procedures and whether it causes respiratory depression in dogs.