Anesthetic effects of ketamine or isoflurane induction prior to isoflurane anesthesia in medetomidine-premedicated dogs.

Dogs were given medetomidine (10 microg/kg body weight, intramuscularly) followed in 10 minutes by either ketamine (4 mg/kg body weight, intravenously) or isoflurane mask induction and maintained on isoflurane for 30 minutes. Medetomidine induced lateral recumbency in all dogs. Endotracheal intubation was faster and smoother when dogs were given ketamine than when induced with isoflurane. Analgesia was excellent in all groups. Respiratory depression was more profound when dogs were given ketamine. Recovery quality was smooth and similar among all groups. Medetomidine-premedicated dogs could be induced with either ketamine or isoflurane and maintained on 1.3% isoflurane to achieve good analgesia with smooth recovery from anesthesia.

Effects of preemptive atropine administration on incidence of medetomidine-induced bradycardia in dogs.

OBJECTIVE: To determine the cardiorespiratory effects of preemptive atropine administration in dogs sedated with medetomidine. DESIGN: Randomized crossover trial. ANIMALS: 12 healthy adult dogs. PROCEDURES: Dogs underwent 6 treatments. Each treatment consisted of administration of atropine (0.04 mg/kg [0.018 mg/lb] of body weight, IM) or saline solution (0.9% NaCl, 1 ml, IM) and administration of medetomidine (10, 20, or 40 microg/kg [4.5, 9.1, or 18.2 microg/lb], IM) 10 minutes later. Treatments were administered in random order, with a minimum of 1 week between treatments. Cardiorespiratory effects before and after atropine and medetomidine administration were assessed. Duration of lateral recumbency and quality of sedation and recovery were assessed. RESULTS: Bradycardia (heart rate < 60 beats/min) was seen in all dogs when saline solution was administered followed by medetomidine, and the dose of medetomidine was not associated with severity or frequency of bradycardia or second-degree heart block. However, a medetomidine dose-dependent increase in mean and diastolic blood pressures was observed, regardless of whether dogs received saline solution or atropine. Preemptive atropine administration effectively prevented bradycardia and second-degree heart block but induced pulsus alternans and hypertension. The protective effects of atropine against bradycardia lasted 50 minutes. Blood gas values were within reference limits during all treatments and were not significantly different from baseline values. Higher doses of medetomidine resulted in a longer duration of lateral recumbency. CONCLUSIONS AND CLINICAL RELEVANCE: Preemptive administration of atropine in dogs sedated with medetomidine effectively prevents bradycardia for 50 minutes but induces hypertension and pulsus alternans.

Cardiorespiratory responses and plasma cortisol concentrations in dogs treated with medetomidine before undergoing ovariohysterectomy.

OBJECTIVE: To evaluate effects of medetomidine on anesthetic dose requirements, cardiorespiratory variables, plasma cortisol concentrations, and behavioral pain scores in dogs undergoing ovariohysterectomy. DESIGN: Randomized, prospective study. ANIMALS: 12 healthy Walker-type hound dogs. PROCEDURE: Dogs received medetomidine (40 micrograms/kg [18.2 micrograms/lb] of body weight, i.m.; n = 6) or saline (0.9% NaCl) solution (1 ml, i.m.; 6) prior to anesthesia induction with thiopental; thiopental dose needed for endotracheal intubation was compared between groups. Ovariohysterectomy was performed during halothane anesthesia. Blood samples were obtained at various times before drug administration until 300 minutes after extubation. Various physiologic measurements and end-tidal halothane concentrations were recorded. RESULTS: In medetomidine-treated dogs, heart rate was significantly lower than in controls, and blood pressure did not change significantly from baseline. Plasma cortisol concentrations did not increase significantly until 60 minutes after extubation in medetomidine-treated dogs, whereas values in control dogs were increased from time of surgery until the end of the recording period. Control dogs had higher pain scores than treated dogs from extubation until the end of the recording period. CONCLUSION AND CLINICAL RELEVANCE: Administration of medetomidine reduced dose requirements for thiopental and halothane and provided postoperative analgesia up to 90 minutes after extubation. Dogs undergoing ovariohysterectomy by use of thiopental induction and halothane anesthesia benefit from analgesia induced by medetomidine administered prior to anesthesia induction. Additional analgesia is appropriate 60 minutes after extubation.

The effects of ovariohysterectomy plus different combinations of halothane anaesthesia and butorphanol analgesia on behaviour in the bitch.

One hundred and sixty-six behaviours were identified as possible indices of post-operative pain-induced distress in the bitch. These were assessed in bitches after treatment with different combinations of halothane and butorphanol in the absence of surgery and following ovariohysterectomy under halothane anaesthesia with or without butorphanol analgesia given at different stages during the operation. Behaviour was monitored while the bitches were alone (non-interactive) and when routinely examined and handled prior to blood sampling (interactive). Seventy-six of the 166 behaviours occurred so infrequently (less than two occurrences per hour) as to be of no value as indices. Non-interactive behaviours associated with surgery were a decrease in normal speed cage circling and an increase in drawing the rear limbs up in the pike position. The infrequent non-interactive behaviours of incision licking, vomiting and flank gazing were considered to be expressions of pain caused by ovariohysterectomy. During the post-surgical period, bitches given analgesic moved less frequently than those not receiving analgesic. Vocalisation was associated with dysphoria of analgesia rather than pain-induced distress. The behaviour of bitches after ovariohysterectomy suggests that this is a painful procedure which warrants analgesia.

Sedative and cardiorespiratory effects of medetomidine, medetomidine-butorphanol, and medetomidine-ketamine in dogs.

OBJECTIVE: To determine sedative and cardiorespiratory effects of i.m. administration of medetomidine alone and in combination with butorphanol or ketamine in dogs. DESIGN: Randomized, crossover study. ANIMALS: 6 healthy adult dogs. PROCEDURES: Dogs were given medetomidine alone (30 micrograms/kg [13.6 micrograms/lb] of body weight, i.m.), a combination of medetomidine (30 micrograms/kg, i.m.) and butorphanol (0.2 mg/kg [0.09 mg/lb], i.m.), or a combination of medetomidine (30 micrograms/kg, i.m.) and ketamine (3 mg/kg [1.36 mg/lb], i.m.). Treatments were administered in random order with a minimum of 1 week between treatments. Glycopyrrolate was given at the same time. Atipamezole (150 micrograms/kg [68 micrograms/lb], i.m.) was given 40 minutes after administration of medetomidine. RESULTS: All but 1 dog (given medetomidine alone) assumed lateral recumbency within 6 minutes after drug administration. Endotracheal intubation was significantly more difficult when dogs were given medetomidine alone than when given medetomidine and butorphanol. At all evaluation times, percentages of dogs with positive responses to tail clamping or to needle pricks in the cervical region, shoulder region, abdominal region, or hindquarters were not significantly different among drug treatments. The Paco2 was significantly higher and the arterial pH and Pao2 were significantly lower when dogs were given medetomidine and butorphanol or medetomidine and ketamine than when they were given medetomidine alone. Recovery quality following atipamezole administration was unsatisfactory in 1 dog when given medetomidine and ketamine. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that a combination of medetomidine with butorphanol or ketamine resulted in more reliable and uniform sedation in dogs than did medetomidine alone.

Changes in plasma cortisol concentrations in bitches in response to different combinations of halothane and butorphanol, with or without ovariohysterectomy.

Changes in plasma cortisol concentrations were assessed in bitches in response to nine treatments: control, anaesthesia, analgesia, analgesia followed by anaesthesia, anaesthesia followed by analgesia at intubation, anaesthesia followed by analgesia at extubation, anaesthesia plus surgery, analgesia followed by anaesthesia plus surgery, and anaesthesia plus surgery followed by analgesia. The anaesthetic was halothane, the analgesic was butorphanol (0.4 mg kg(-1)) and the surgery was ovariohysterectomy. Blood samples, for plasma cortisol assays, were taken regularly from before treatment for five hours and then again after 24 hours. A small transient rise in plasma cortisol concentration in the control group was attributed to mild distress associated with novel experiences. A more pronounced and protracted rise in cortisol concentration in the analgesia group was ascribed to a dysphoric state of bitches under the influence of the agonist-antagonist butorphanol. Halothane anaesthesia alone resulted in no change in plasma cortisol concentration. When butorphanol was given after anaesthesia was induced or while the animal was still under the influence of anaesthesia (immediately after tracheal extubation), there was no immediate rise in plasma cortisol concentration and low concentrations were maintained for up to 60 minutes after halothane withdrawal. A marked rise in plasma cortisol concentration, which was sustained above pretreatment values for at least five hours, occurred in all surgery groups. Giving intravenous butorphanol 30 minutes prior to surgery had no effect on the surgically-induced rise in plasma cortisol concentration and no effect on the postsurgical plasma cortisol concentration. In contrast, butorphanol given at extubation did reduce plasma cortisol concentrations during the postsurgical period. These observations did not support the hypothesis that preoperative use of butorphanol would reduce the cortisol response after surgery under halothane anaesthesia.

Reconstruction of the medial collateral ligament for tarsocrural luxation in the dog: a preliminary study.

Seven cases of tarsocrural subluxation/luxation resulting from ruptures of the medial collateral ligament were treated by double prosthetic replacement. The technique was a revision of an earlier described method without the use of metallic implants. Six (100%) of six cases not involving additional joint fractures had excellent clinical results with minimal compromise to range of joint motion. In three (50%) of six cases where braided polyester sutures were implanted as the prosthesis, fistulating tracts developed. Drainage resolved with removal of the suture in each of these three cases, and two of the three proceeded to excellent results after replacing the braided suture with monofilament suture.

Mechanisms of action of anti-inflammatory medications used for the treatment of osteoarthritis.

Nonsteroidal anti-inflammatory (NSAID) drugs have been used to treat osteoarthritis ever since 1899, when the effects of aspirin were first recognized. Widespread use of these compounds continues despite their recognized potential toxicity, mostly because they are generally effective for palliation of the pain associated with osteoarthritis. The discovery of cyclooxygenase (COX)-1 and COX-2 has sparked interest in development of NSAID that specifically target COX-2, with the hope that such compounds would be associated with a lower incidence of adverse gastrointestinal effects. Other potential methods of avoiding adverse gastrointestinal effects associated with NSAID use include concurrent administration of prostaglandins and use of pure analgesics, such as acetaminophen. The role of nitric oxide in inflammation is an exciting area of research, and addition of nitric oxide-producing moieties to NSAID may prove to be another mechanism of avoiding gastrointestinal toxicity. There is likely to be considerable reward for the development of an NSAID that relieves pain associated with a wide variety of conditions, does not cause gastrointestinal toxicoses, and spares normal cartilage. Whether such a drug exists remains speculative.

Use of carprofen for the treatment of pain and inflammation in dogs.

Most studies of nonsteroidal anti-inflammatory drugs (NSAID) do not demonstrate appreciable differences in efficacy. As awareness of the adverse effects associated with NSAID use increases, safety is becoming the primary concern among physicians when selecting NSAID for use by their human patients. However, veterinarians may be less aware of the safety concerns associated with NSAID use. A wide range of NSAID is used to treat human beings with osteoarthrits; however, it is imperative to remember that dogs are especially sensitive to these drugs, and reports of serious, and occasionally fatal, complications are numerous. Carprofen is a propionic acid-derived NSAID that has anti-inflammatory, analgesic, and antipyretic activity. In animals, carprofen is as potent as indomethacina and more potent than aspirin or phenlbutazone, but carprofen appears to be safer than most other NSAID.

Ununited anconeal process: lag-screw fixation.

A technique of lag-screw fixation for ununited anconeal process is described, and the results of surgery in eight dogs (on 10 elbows) treated by this technique are presented. Approximation of the process was confirmed postoperatively, and union was confirmed by radiographic followup in six of the 10 forelimbs from two-to-six months after surgery. Four other cases were lost to radiographic follow-up. This report of a limited number of cases suggests encouraging results obtained by lag-screw fixation.

Broncho-oesophageal fistula in two dogs.

Two clinical cases of broncho-oesophageal fistula in the dog are presented. While both cases illustrate the value of oesophagoscopy as a diagnostic tool, one case depicts the complications which may be associated with positive contrast oesophagography. These two cases support previous observations that broncho-oesophageal fistulae are frequently of foreign body aetiology and usually extend from the caudal oesophagus, via the pleural space, to the caudal or middle right lung lobes.

Primary intraosseous fibrosarcoma in a cat.

A case of primary intraosseous fibrosarcoma of the left femur in a cat was diagnosed at necropsy following 9 months of managing a fracture of the same bone. Case features were those of probable pathological fracture, fracture repair and ultimate lysis of all but a fragment of the distal femoral epiphysis. Histology revealed closely packed whorls of fibroblasts typical of fibrosarcoma. This neoplasm is rare in the cat.

Antebrachial deformities in the dog: treatment with external fixation.

The results of 12 dogs with antebrachial deformity treated by ulnar ostectomy, radial osteotomy and external skeletal fixation are presented. Postoperative complications were seen in only one dog; a delayed union requiring placement of autogenous cancellous bone graft at a second surgery to achieve healing. Postoperatively, owners reported limb function was good in almost all cases, although they were less pleased with the cosmetic appearance.

Changes in plasma cortisol concentrations before, during and after analgesia, anaesthesia and anaesthesia plus ovariohysterectomy in bitches.

Plasma cortisol concentrations were determined before, during and after analgesia, anaesthesia and anaesthesia plus ovariohysterectomy in six New Zealand border collie cross bitches. The treatments were: control, analgesia with butorphanol, anaesthesia with thiopentone sodium, halothane and oxygen and anaesthesia plus surgery. In addition, each bitch was given an ACTH challenge. All the bitches showed transient increases in plasma cortisol concentrations and the integrated cortisol responses (calculated as the area under the cortisol curve above the pre-treatment concentration) for 6.25 hours after treatment increased in the order: control, anaesthesia, analgesia, surgery. The control group had increased cortisol concentrations attributable to the excitement from handling. The plasma cortisol concentrations of the group subjected to surgery were greater than the other groups for at least 6.25 hours, with an approximately four-fold increase above pre-treatment values, but they had returned to pre-treatment levels after 24 hours.

Ondansetron versus ondansetron, dexamethasone, and chlorpromazine in the prevention of nausea and vomiting associated with multiple-day cisplatin chemotherapy.

PURPOSE: This study is designed to evaluate the effectiveness of ondansetron alone (OND) or in combination with 2 days of dexamethasone and 5 days of chlorpromazine (ODC) in the prevention of emetic episodes in patients receiving multiple-day cisplatin. PATIENTS AND METHODS: Forty-four patients receiving 20 or 40 mg/m2 of cisplatin daily for 4 to 5 days plus etoposide (VP-16) alone or in combination with bleomycin or ifosfamide were randomized to receive three doses of OND (0.15 mg/kg 30 minutes before and 4 and 8 hours after cisplatin) versus the identical OND regimen plus dexamethasone 8 mg before cisplatin and 4 mg 4 and 8 hours later on days 1 and 2, plus chlorpromazine 50 mg every 4 hours for four doses per day. Patients were chemotherapy-naive, had a Karnofsky performance status > or = 60, and were not receiving nonstudy antiemetics. RESULTS: Nineteen of 22 patients (86%) on ODC had fewer than three emetic episodes throughout the study period, compared with 10 of 22 (46%) on OND (P = .009), and 55% of patients on ODC had no emetic episodes, compared with 32% on OND (P = .22). The ODC arm had fewer treatment failures (5%) than the OND arm (32%). The mean nausea ratings per visual analog scale were 15.0 for OND and 5.5 for ODC (P = .046). Headache was less frequent with ODC versus OND (14% and 41%, respectively, P = .09). CONCLUSION: ODC was superior to OND with respect to therapeutic efficacy and decreased headaches. Both OND and ODC were more effective on days 1 and 2, rather than days 4 and 5, suggesting tachyphylaxis, anticipatory nausea, or delayed nausea from the first few days of cisplatin combination chemotherapy.

Corrective osteotomy for bilateral forelimb varus deformities in a working dog.

Bilateral varus antebrachial deformity in a 7-month-old working dog was surgically corrected. The deformity was a sequela to premature closure of the distal radial physes after trauma to the forelimbs. Treatment was by ulnectomy and oblique radial osteotomy. Stabilisation of the fractures was maintained by an external fixation device. The treatment was successful and the dog returned to work as a sheep dog.