Effects of preoperative administration of carprofen on renal function and hemostasis in dogs undergoing surgery for fracture repair

OBJECTIVE: To evaluate effects of preoperative administration of carprofen on renal function and hemostasis in dogs undergoing general anesthesia for fracture repair. ANIMALS: 26 client-owned dogs. PROCEDURE: Anesthesia was induced with levomethadone, diazepam, and propofol and maintained by administration of isoflurane in oxygen-nitrous oxide. Carprofen (4 mg/kg, SC) was administered 1 hour before induction to 13 dogs (group 1) and after extubation to the other 13 dogs (group 2). All dogs also received carprofen (4 mg/kg, SC, q 24 h) for the first 4 days after surgery. Renal function (glomerular filtration rate [GFR], urinary protein-to-urinary creatinine ratio [UP:UC], and results of urinalysis and biochemical analysis of plasma), hemostatic variables (bleeding time, platelet aggregation, prothrombin time [PT], activated partial thromboplastin time [APTT], and platelet count), and Hct were assessed before and at various time points after surgery. RESULTS: Analysis of results for renal function tests, most of the hemostatic and plasma biochemical variables, and Hct did not reveal significant differences between treatment groups. Values for GFR, UP:UC, PT, APTT, and platelet aggregation were outside reference ranges in many dogs before surgery and during the first 6 hours after surgery. In most dogs, these trauma-induced pathologic changes returned to within reference ranges during the 4-day period after surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Carprofen did not cause clinically relevant adverse effects in dogs anesthetized for fracture repair after 5 days of treatment, even when it was administered before surgery or given to patients with trauma-induced alterations in renal function or hemostasis.     

Evaluation of analgesia provided by the administration of epidural ketamine in dogs with a chemically induced synovitis

OBJECTIVE: To determine if epidural ketamine provides analgesia in dogs with a chemically induced synovitis. STUDY DESIGN: Prospective randomized experimental trial. ANIMALS: Thirty-two healthy, adult mongrel dogs (13-30 kg). METHODS: (Part I) Synovitis was induced in the right stifle of 16 dogs and allowed to develop for 12 hours. Epidural injection at the lumbosacral space of either ketamine (2 mg kg(-1); n = 8) or placebo (n = 8) was performed. Limb use and pain were measured using a force platform and numerical rating scale (NRS). Assessments were performed before and at 12, 14, 16, 18, 20, and 24 hours after the induction of synovitis. (Part II) Epidural injection of either ketamine (n = 8) or placebo (n = 8) was performed immediately before the induction of synovitis. Analgesia was assessed as in Part I. Assessments occurred before and at 2, 4, 6, 8, and 12 hours after the induction of synovitis. RESULTS: (Part I) Vertical ground reaction forces (VGRF) significantly decreased and NRS scores of total pain significantly increased after the induction of synovitis in all dogs (p < 0.05). No significant differences in VGRF or NRS scores were measured between treatment groups at any assessment period. (Part II) Dogs that received ketamine had significantly lower NRS scores 2 hours after treatment (p < 0.05). NRS scores did not differ between groups at any other evaluation. VGRF did not differ significantly between treatment groups at any assessment period. CONCLUSION: Epidural ketamine at a dose of 2 mg kg(-1) administered after the development of synovitis does not provide significant levels of analgesia. Administration of ketamine before the induction of synovitis significantly decreased the NRS score 2 hours post-induction. CLINICAL RELEVANCE: Administration of epidural ketamine before tissue injury may provide analgesia of short duration in dogs.     

L-Bupivacaine 0.5% vs. racemic 0.5% bupivacaine for caudal epidural analgesia in horses

Bupivacaine is available as a racemic mixture of its enantiomers, d -bupivacaine and l -bupivacaine (LB). The aim of this randomized, double-blind study was to investigate the clinical efficacy and safety of S(−)-bupivacaine compared with standard racemic bupivacaine (RB) in horses under caudal epidural analgesia. Two treatments were administered to each horse, with a 2-week interval between subsequent treatments. Treatment 1 consisted of 0.5% LB at a dose of 0.06 mg/kg of body weight, and treatment 2 consisted of 0.5% RB at a dose of 0.06 mg/kg of body weight. Epidural injections were given in all animals between the first and second coccygeal vertebra. Heart rate (HR), arterial pressures, respiratory rate (RR), rectal temperature (RT), analgesia, and motor blocking were determined before drug administration (basal) and 5, 10, 15 and 30 min after drug administration, and at 30 min intervals thereafter. There were no significant differences between the two treatments in the quality of sensory and motor block. The duration of analgesia was 320 ± 30 min (mean ± SD) for RB and 360 ± 42 min for LB. HRs and RRs, arterial pressures and RT did not change ( P  < 0.05) significantly from basal values after epidural administration of LB or RB. This study supports that 0.5% LB is an effective alternative to RB in caudal epidural analgesia in conscious, standing horses. The use of LB vs. RB warrants further investigation, particularly for long-lasting surgery in the perineal region.     

Caudal epidural analgesia induced by xylazine administration in cows

Xylazine (0.05 mg/kg of body weight diluted to a 5-ml volume, using 0.9% NaCl) or 5 ml of 0.9% NaCl was administered epidurally into the first caudal intervertebral space (Co1-Co2) in 8 cows (mean +/- SD body weight, 583 +/- 150 kg). Cows were observed for responses to deep needle pricking of the caudal dermatomes (S3 to Co), sedation, and ataxia. Heart rate, respiratory rate, body temperature, rate of ruminal contractions, coccygeal arterial blood pressure, pHa, blood gas tension (PaO2, PaCO2), base excess, total solids concentration, and PCV were determined before and after xylazine administration. Epidurally administered xylazine induced sedation and selective (S3 to Co) analgesia for at least 2 hours. Mild ataxia of hind limbs was observed in 6 cows, but all cows remained standing. Heart rate, respiratory rate, rate of ruminal contractions, arterial blood pressure, PaO2, PCV, and total solids concentration were significantly (P less than 0.05) decreased, and PaCO2, base excess, and bicarbonate concentration were significantly (P less than 0.05) increased after xylazine administration. Epidurally administered 0.9% NaCl did not alter sensory perception to needle pricking and did not affect any of the physiologic variables determined. Although epidural administration of xylazine induced analgesia and sedation in healthy cows, it should be avoided for epidural analgesia in cattle with heart disease, lung disease, and/or gastrointestinal disease because of its potent cardiopulmonary and ruminal depressant effects.     

Stereoselective pharmacokinetics of ketamine and norketamine after racemic ketamine or S-ketamine administration in Shetland ponies sedated with xylazine

The pharmacokinetics of ketamine and norketamine enantiomers after administration of intravenous (IV) racemic ketamine (R-/S-ketamine; 2.2 mg/kg) or S-ketamine (1.1 mg/kg) to five ponies sedated with IV xylazine (1.1mg/kg) were compared. The time intervals to assume sternal and standing positions were recorded. Arterial blood samples were collected before and 1, 2, 4, 6, 8 and 13 min after ketamine administration. Arterial blood gases were evaluated 5 min after ketamine injection. Plasma concentrations of ketamine and norketamine enantiomers were determined by capillary electrophoresis and were evaluated by non-linear least square regression analysis applying a monocompartmental model. The first-order elimination rate constant was significantly higher and elimination half-life and mean residence time were lower for S-ketamine after S-ketamine compared to R-/S-ketamine administration. The maximum concentration of S-norketamine was higher after S-ketamine administration. Time to standing position was significantly diminished after S-ketamine compared to R-/S-ketamine. Blood gases showed low-degree hypoxaemia and hypercarbia.     

A comparison of epidural buprenorphine with epidural morphine for postoperative analgesia following stifle surgery in dogs

Objective To compare the efficacy of epidural buprenorphine with epidural morphine for post‐operative pain relief in dogs undergoing cranial cruciate ligament rupture repair. Study design A randomized, double blind clinical trial. Animals Twenty client‐owned dogs with cranial cruciate ligament rupture. Methods Dogs were randomly assigned to receive either epidural buprenorphine (4 µg kg^?1) or epidural morphine (0.1 mg kg^?1) in a total volume of 0.2 mL kg^?1. Epidural injections were performed immediately after induction of anesthesia. End‐tidal halothane and CO₂ were recorded every 15 minutes from the time of epidural administration of drug to extubation. A numerical rating pain score system was used by a blinded observer to evaluate analgesia beginning at extubation and continuing at specific intervals for 24 hours after surgery. Heart rate, respiratory rate, and blood pressure were recorded noninvasively at the same times. If pain score indicated moderate discomfort, rescue morphine at 1.0 mg kg^?1 was administered intramuscularly. Results There were no significant differences between groups with respect to pain score, heart rate, respiratory rate, indirect blood pressure, end‐tidal halothane or end‐tidal CO₂ at any time point. Fifty percent of dogs in the buprenorphine group and 50% of dogs in the morphine group required rescue analgesic medication. Time of systemic rescue morphine administration did not differ significantly between the two groups. There were no clinically observable side‐effects from epidural administration of either drug in any of the dogs of this study. Conclusions Epidural buprenorphine is as effective as epidural morphine for the relief of postoperative hindlimb orthopedic pain in dogs. Clinical relevance Buprenorphine appears to be an effective opioid for epidural use in healthy dogs. Buprenorphine may offer certain advantages over morphine for epidural use, such as lower abuse potential and, in some clinics, reduced cost and less wastage of drug.     

The effects of preoperative oral administration of carprofen or tramadol on postoperative analgesia in dogs undergoing cutaneous tumor removal

This prospective, blinded, controlled clinical study compared the effects of pre-emptive oral administration of carprofen or tramadol on pain scores and analgesic requirement in dogs undergoing cutaneous tumor removal. Thirty-six client-owned dogs presenting for cutaneous tumor removal were randomly assigned to receive carprofen, tramadol, or no treatment prior to surgery. Pain was assessed using a visual analog scale (VAS), the Modified Glasgow Composite Measure Pain Score (MGCMPS), and algometry at enrollment, prior to premedication, at extubation, then hourly for the first 4 h, and every 4 h for 24 h. Dogs scoring ≥ 7 (MGCMPS), or having a VAS measurement ≥ 40 mm were given rescue analgesia. There were no significant differences in pain VAS, MGCMPS, or algometry. There were no differences in rescue analgesia requirement, or time to rescue analgesia among groups. Carprofen, tramadol, or no pre-emptive analgesia, combined with pre-operative hydromorphone and rescue analgesia, resulted in satisfactory analgesia in the 24-hour postoperative period.     

Efficacy of concurrent epidural administration of neostigmine and lidocaine for perineal analgesia in geldings

Objective-To evaluate perineal analgesic effects of 3 doses of neostigmine coadministered epidurally with lidocaine to geldings. Animals-6 healthy geldings. Procedures-A few days before each treatment, a catheter was inserted between the first and second coccygeal vertebrae via the caudal approach in each gelding; the catheter tip was threaded approximately 10 cm cranial into the midsacral region. Each horse received 4 epidural treatments: 2% lidocaine (0.2 mg/kg) alone and 3 doses of neostigmine (0.5, 1, or 2 μg/kg) coadministered with that same dose of lidocaine. Horses were restrained in stocks in a standing position. Heart rate, blood pressure, respiratory rate, rectal temperature, intestinal motility, analgesia, behavior, and ataxia were determined before treatment (time 0; baseline); at 5, 10, 15, 30, 45, 60, 75, and 90 minutes; and every 30 minutes thereafter until the cessation of analgesia. Results-All doses of neostigmine coadministered with lidocaine improved and extended the duration of analgesia in the perineal region of the geldings. Total duration of analgesia was not a dose-dependent effect (120, 150, and 150 minutes for 0.5, 1, and 2 μg/kg, respectively). All treatments induced mild or moderate ataxia. Cardiovascular changes were within acceptable limits. Conclusions and Clinical Relevance-Administration of neostigmine (1 μg/kg) combined with lidocaine (0.2 mg/kg) in the caudal epidural space induced analgesia for 2.5 hours with a low prevalence of adverse effects in standing conscious geldings. Epidural doses of neostigmine greater than these should be avoided because they may cause undesirable effects in geldings.     

Evaluation of epidural administration of morphine or morphine and bupivacaine for postoperative analgesia after premedication with an opioid analgesic and orthopedic surgery in dogs

OBJECTIVE: To evaluate the analgesic efficacy of epidural administration of morphine or a morphine-bupivacaine combination administered before orthopedic surgery in dogs that received opioid premedication. DESIGN: Prospective, randomized, blinded, clinical study. ANIMALS: 36 healthy adult dogs that underwent elective orthopedic surgery on a pelvic limb. PROCEDURES: Each dog received 1 of 3 epidural treatments before surgery. Anesthetic and supportive care protocols were standardized. Dogs under going different surgical procedures were randomly allocated among the 3 treatment groups. Respiratory and cardiovascular variables, end-tidal isoflurane concentration, and requirements for rescue analgesia were monitored. Postsurgical analgesia was evaluated with a multiparametric pain scoring system and by determination of rescue analgesia requirements and cortisolemia. RESULTS: The morphine-bupivacaine combination was associated with lower values than morphine or a saline solution for intraoperative arterial blood pressure; minimum and maximum isoflurane requirements; and postoperative pain scores, rescue analgesia requirements, and plasma cortisol concentrations. Values obtained after administration of morphine alone were not significantly different from those obtained after administration of saline solution for most variables. CONCLUSIONS AND CLINICAL RELEVANCE: The preoperative epidurally administered morphine-bupivacaine combination induced better analgesia than morphine alone and should be considered for use in clinical patients. The degree of hemodynamic depression associated with the combination was considered acceptable for healthy patients undergoing elective surgery.     

Cardiopulmonary effects of diazepam/ketamine/isoflurane or xylazine/ketamine/isoflurane in foals undergoing abdominal surgery

The purpose of this study was to evaluate the cardiopulmonary effects of anesthetic induction with diazepam/ketamine or xylazine/ketamine with subsequent maintenance of anesthesia using isoflurane in foals undergoing abdominal surgery. Seventeen foals underwent laparotomy at 7–10 days of age and a laparoscopy 7–10 days later. Foals were randomly assigned to receive xylazine (0.8 mg kg^?1)/ketamine (2 mg kg^?1) (X/K)(n = 9) or diazepam (0.2 mg kg^?1)/ketamine (2 mg kg^?1) (D/K)(n = 8) for induction of anesthesia for both procedures. In all foals, anesthesia was maintained with isoflurane in oxygen with the inspired concentration adjusted to achieve adequate depth of anesthesia as assessed by an individual blinded to the treatments. IPPV was employed throughout using a tidal volume of 10 mL kg^?1 adjusting the frequency to maintain eucapnia (PaCO₂ 35–45 mm Hg, 4.7–6.0 kPa). Cardiopulmonary variables were measured after induction of anesthesia prior to, during, and following surgery. To compare the measured cardiopulmonary variables between the two anesthetic regimes for both surgical procedures, results were analyzed using a three‐way factorial anova for repeated measures (p < 0.05). During anesthesia for laparotomy, mean CI and MAP ranged from 110 to 180 mL kg^?1 minute^?1 and 57–81 mm Hg, respectively, in the D/K foals and 98–171 mL kg^?1 minute^?1 and 50–66 mm Hg in the X/K foals. Overall, CI, HR, SAP, DAP, and MAP were significantly higher in foals in the D/K group versus the X/K group during this anesthetic period. During anesthesia for laparoscopy, mean CI and MBP ranged from 85 to 165 mL kg^?1 minute^?1 and 67–83 mm Hg, respectively, in the D/K group, and 98–171 mL kg^?1 minute^?1 and 48–67 mm Hg in the X/K group. Only HR, SAP, DAP, and MAP were significantly higher in the D/K group versus X/K group during this latter anesthetic period. There were no significant differences between groups during either surgical procedure for end‐tidal isoflurane, PaO₂, PaCO₂, or pH. In conclusion, anesthesia of foals for laparotomy and laparoscopy with diazepam/ketamine/isoflurane is associated with less hemodynamic depression than with xylazine/ketamine/isoflurane.     

Epidural injection of ketamine for caudal analgesia in the cow

The objective of the study was to determine the analgesic and sedative effects of epidural ketamine in the cow. Eight healthy cows weighing 350–450 kg were used. One of 3 doses of ketamine (0.5, 1 and 2.0 mg/kg) or a saline control were injected into the epidural space at the first intercoccygeal interspace in random sequence at one-week intervals. Ketamine was diluted in saline (0.9%) before the experiment, and the volume adjusted according to animal size. Analgesia was tested by applying a standard stimulus (needle insertion into the skin and deep muscle) and scored using a 3-point scale. A second voltage-based stimulus was also applied and the responses scored. Another scale was used for scoring the degree of sedation. The response and the degree of sedation were assessed before drug administration and at 2, 5, 10, 15 min, and every 15 min until 120 min after ketamine or saline administration. Ketamine produced dose-related analgesia of the tail, anus, perineum and vulva but not of the hindlimb area. The effect was dose-dependent in terms of intensity and duration. None of the doses produced analgesia when 70 or 80 volts were applied. Minimal side effects were observed. Epidural ketamine produces caudal analgesia in the cow. Further studies are required to determine whether this is sufficient for surgery.     

Safety and efficacy of preoperative administration of meloxicam, compared with that of ketoprofen and butorphanol in dogs undergoing abdominal surgery

OBJECTIVE: To compare the safety and efficacy of preoperative administration of meloxicam with that of ketoprofen and butorphanol in dogs undergoing abdominal surgery. ANIMALS: 36 dogs undergoing laparotomy, splenectomy, or cystotomy. PROCEDURE: Dogs were randomly assigned to 1 of 3 groups. In the first part of the study, dogs were given a single dose of meloxicam, ketoprofen, or a placebo, and buccal mucosal bleeding times were measured. In the second part of the study, dogs were given meloxicam, ketoprofen, or butorphanol prior to surgery. Dogs in the butorphanol group received a second dose immediately after surgery. Pain scores (1 to 10) were assigned hourly for 20 hours after surgery and used to determine an overall efficacy score for each dog. Dogs with a pain score > or =3 were given oxymorphone for pain. Dogs were euthanatized 8 days after surgery, and gross and histologic examinations of the liver, kidneys, and gastrointestinal tract were conducted. RESULTS: Overall efficacy was rated as good or excellent in 9 of the 12 dogs that received meloxicam, compared with 9 of the 12 dogs that received ketoprofen and only 1 of the 12 dogs that received butorphanol. No clinically important hematologic, biochemical, or pathologic abnormalities were detected. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that preoperative administration of meloxicam is a safe and effective method of controlling postoperative pain for 20 hours in dogs undergoing abdominal surgery; the analgesic effects of meloxicam were comparable to those of ketoprofen and superior to those of butorphanol.     

Efficacy and safety of preoperative etodolac and butorphanol administration in dogs undergoing ovariohysterectomy

Eighteen dogs undergoing ovariohysterectomy were premedicated with etodolac, butorphanol, or their combination. Various parameters, such as blood pressure, isoflurane requirements, behavioral pain scores, plasma cortisol concentration, plasma glucose concentration, and mucosal bleeding time, were assessed. The integrated plasma cortisol values were significantly lower in the etodolac and etodolac with butorphanol groups. Dogs receiving etodolac and butorphanol had the lowest behavioral pain scores from extubation until the end of monitoring. Isoflurane concentration over time (area under the curve), buccal mucosal bleeding time, and indices of renal function were not significantly different among the treatment groups.     

Effects of preoperative administration of ketoprofen on anesthetic requirements and signs of postoperative pain in dogs undergoing elective ovariohysterectomy

OBJECTIVE: To determine the effects of preoperative administration of ketoprofen on anesthetic requirements and signs of postoperative pain in dogs undergoing elective ovariohysterectomy. DESIGN: Randomized, controlled clinical trial. ANIMALS: 22 clinically normal client-owned dogs. PROCEDURE: 60 minutes before induction of anesthesia, 11 dogs were given ketoprofen (2 mg/kg [0.9 mg/lb], i.m.), and the other 11 were given saline (0.9% NaCl) solution. Dogs were premedicated with glycopyrrolate, acepromazine, and butorphanol and anesthetized with thiopental; anesthesia was maintained with isoflurane. Ovariohysterectomy was performed by an experienced surgeon, and butorphanol was given 15 minutes before completion of the procedure. Objective behavioral scores and numerical pain scores at rest and with movement were recorded every 2 hours for 12 hours after surgery and then every 4 hours for an additional 12 hours. RESULTS: Preoperative administration of ketoprofen did not reduce the dose of thiopental required to induce anesthesia or the end-tidal concentration of isoflurane required to maintain anesthesia. Activity levels and median objective behavioral scores were significantly higher 4 and 6 hours after surgery in dogs given ketoprofen than in dogs given saline solution. However, mean numerical pain scores in dogs given ketoprofen were not significantly different from scores for dogs given saline solution at any time. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that preoperative administration of ketoprofen does not reduce anesthetic requirements in dogs undergoing elective ovariohysterectomy but may reduce signs of pain after surgery. Results also suggest that the objective behavioral score may be a more sensitive measure of acute postoperative pain than traditional numerical pain scores.