Nora S. Matthews

Repetitive Propofol Administration in Dogs and Cats

A bolus of propofol was administered to 10 dogs (6 mg/kg intravenously [IV]) and 10 cats (10 mg/kg IV) on three consecutive days. The occurrence of apnea, heart and respiratory rates, blood pressure, time to movement, and changes in a complete blood count and biochemical profile were recorded. Apnea was not seen in the dogs but was seen in three cats. Slight increases in the number of Heinz bodies were seen in six cats, but the increases were not considered clinically significant. No apparent cumulative adverse effects were seen from a bolus of bisulfite-containing propofol, administered on three consecutive days.

Effect of ketamine hydrochloride on the analgesic effects of tramadol hydrochloride in horses with signs of chronic laminitis- associated pain

OBJECTIVE To investigate the effects of ketamine hydrochloride on the analgesic effects of tramadol hydrochloride in horses with signs of pain associated with naturally occurring chronic laminitis. ANIMALS 15 client-owned adult horses with chronic laminitis. PROCEDURES Each horse received tramadol alone or tramadol and ketamine in a randomized, crossover study (≥ 2 months between treatments). Tramadol (5 mg/kg) was administered orally every 12 hours for 1 week. When appropriate, ketamine (0.6 mg/kg/h) was administered IV for 6 hours on each of the first 3 days of tramadol administration. Noninvasive systemic blood pressure values, heart and respiratory rates, intestinal sounds, forelimb load and off-loading frequency (determined via force plate system), and plasma tumor necrosis factor-α and thromboxane B(2) concentrations were assessed before (baseline) during (7 days) and after (3 days) each treatment. RESULTS Compared with baseline data, arterial blood pressure decreased significantly both during and after tramadol-ketamine treatment but not with tramadol alone. Forelimb off-loading frequency significantly decreased during the first 3 days of treatment with tramadol only, returning to baseline frequency thereafter. The addition of ketamine to tramadol treatment reduced off-loading frequency both during and after treatment. Forelimb load did not change with tramadol alone but increased with tramadol-ketamine treatment. Plasma concentrations of tumor necrosis factor-α and thromboxane B(2) were significantly reduced with tramadol-ketamine treatment but not with tramadol alone. CONCLUSIONS AND CLINICAL RELEVANCE In horses with chronic laminitis, tramadol administration induced limited analgesia, but this effect was significantly enhanced by administration of subanesthetic doses of ketamine.

A comparison of three combinations of injectable anesthetics in miniature donkeys

OBJECTIVE To compare three combinations of injectable anesthetics in miniature donkeys for quality of induction, recovery, muscle relaxation, cardiopulmonary changes during anesthesia and duration of recumbency. Design  Prospective, randomized experimental study. ANIMALS Six miniature donkeys (< 90 cm in height at the withers) weighing 92-127 kg were used. MATERIALS AND METHODS The drug combinations were: xylazine-butorphanol-ketamine (XBK), xylazine-butorphanol-tiletamine-zolazepam (XBT) and xylazine-propofol (XP). Each miniature donkey was anesthetized with each combination at 1-week intervals in random order. Heart and respiratory rates, indirect blood pressure and temperature were measured before and at 5-minute intervals during recumbency. Arterial blood samples were drawn for blood-gas analysis before and at 5, 15 and 30 minutes of anesthesia when samples could be collected. Recumbency time to sternal and time to standing were recorded and a subjective evaluation of induction, muscle relaxation and recovery were made. RESULTS Mean recumbency time ± SD was 14.7 ± 9.4, 33.8 ± 6.3 and 14.6 ± 1.9 minutes with XBK, XBT and XP, respectively. Mean time to standing ± SD was 28.4 ± 11.3, 43.7 ± 7.2 and 26.3 ± 2.9 minutes with XBK, XBT and XP, respectively. Heart and respiratory rates and blood pressures varied from baseline but were always within normal ranges. Hemoglobin saturation, pH and PaO2 tended to be lower with these doses of XBT and XP. CONCLUSIONS AND CLINICAL RELEVANCE Overall quality of anesthesia was poor with XBK. At the doses used this combination did not provide sufficient anesthesia compared with the combinations of XBT and XP, which appeared to provide acceptable anesthesia of short duration in miniature donkeys.

A multisite case report on the clinical use of sevoflurane in dogs

The purpose of this report was to evaluate the clinical safety and efficacy of sevoflurane as an inhalant anesthetic in dogs. Subjective and objective data from 196 clinical cases utilizing sevoflurane as the maintenance anesthetic was collected at three sites. After preanesthetic evaluation, the attending anesthesiologist assigned the dogs to one of the following six anesthetic protocols: protocol 1, oxymorphone premedication and thiopental induction; protocol 2, oxymorphone/acetylpromazine premedication and thiopental induction; protocol 3, xylazine/butorphanol premedication and thiopental induction; protocol 4, opioid premedication and propofol induction; protocol 5, optional premedication and mask induction with sevoflurane in oxygen; and protocol 6, optional premedication and optional induction. The average quality of induction, maintenance, and recovery was good to excellent in all protocols. The three most common side effects during maintenance and recovery were hypotension, tachypnea, and apnea. Sevoflurane produces anesthesia in dogs comparable to the other inhalation anesthetics currently used (i.e., halothane and isoflurane) for diagnostic or therapeutic procedures.

Anesthesia and Analgesia for Geriatric Veterinary Patients

The number of geriatric veterinary patients presented for anesthesia appears to be increasing. This article summarizes physiologic changes that occur in geriatric patients that are relevant to anesthesia. Proper patient preparation and vigilant monitoring are the best defense against anesthetic problems in the geriatric animal. The authors also discuss particular anesthetic problems as they relate to geriatric patients and seek to present solutions to these problems.

Mammoth asses—selected behavioural considerations for the veterinarian

Abstract Observations of the behaviour of domestic mammoth and standard asses (donkeys) receiving routine herd health and therapeutic procedures are described. These procedures include capture, physical examination, restraint, medicating, adapting to hospitalization and training for interspecies breeding.

Drug Interactions During Anesthesia: General Principles

Anesthesia for most procedures in small animal practice involves administration of more than one drug. In addition, many patients concurrently receive a number of other drugs related to their surgical condition or disease. The probability of a drug interaction increases exponentially with the number of drugs a patient receives; therefore, the potential for drug interactions may be greater in anesthesia than for any other area of medicine. This article describes potentially harmful drug interactions that may occur in the anesthetic setting.

Physiologic responses during an exhaustive driving test in donkeys: effect of conditioning

Abstract Improvement in performance following a 1-month conditioning period was tested in five donkeys. The two females and three geldings weighed 235 kg (SD, 54) and were 4 to 8 years old. The donkeys had previously been trained to pull a cart and were accustomed to wearing heart rate monitors. Following resting readings of heart rate (HR), respiratory rate (RR), rectal temperature ( T ), and venous lactate samples, the donkeys were driven to the cart with a draft load equal to 21% body weight, at a trot, until exhausted (defined as when they would not continue trotting). Time to exhaustion, distance and speed were measured. HR was recorded at 5-min intervals during the test and at 1, 5, 10, 20, 30 and 60 min after the test ended. T , RR and lactate were measured at 30-min intervals during the test and at 1, 5, 10, 20, 30 and 60 min post-test. The donkeys were then conditioned for 1 month by being driven 3×/week for 90 min, with a draft load equal to 15% body weight, and weekly increases in trotting time. Donkeys were then re-tested as before conditioning. Resting HR decreased significantly post-conditioning. Working HR values were lower and post-exercise HR decreased to resting rate post-conditioning. Lactate increased 3-fold pre-conditioning, but only by 50% post-conditioning. Average distance covered post-conditioning was increased by 67% (from 12.7 to 21.2 km), while time to exhaustion increased by 86% (from 84 to 155 min). Donkeys worked under conditions of high ambient temperate and humidity: temperatures ranged from 29 to 34°C while humidity ranged from 43 to 65%. Conditioning significantly increased the donkeys apparent productivity (as measured by distance covered).

Repeated injectable anesthesia in six horses for cobalt therapy

Little information exists about repeated injectable anesthesia in horses, therefore our purpose is to report the anesthetic method we used to facilitate clinical treatment. Between 1992 and 1999, we anesthetized 6 horses 12 times each at 2^3 day intervals, to allow cobalt therapy (CO) of their tumors. One horse received an additional 10 treatments (T). The ¢ve mares and one gelding (3 QH, 1 Paint, 1TB, 1grade) had a mean age of 927 years (mean 2 SD) and mean weight of 505254 kg. Horses were anesthetized with xylazine (X, 1.020.08mg kgÿ1) and tiletamine-zolazepam (TZ, 1.020.08mg kgÿ1) given IV. Butorphanol (B, 0.02620.01) was given with X, 12 times in one horse and11 times in two horses. A portable multifunction monitor was used to provide ECG, hemoglobin saturation and NIBP. Additional drugs (X, B or ketamine) were required to maintain immobility during transport from the CO room or when horses were repositioned for bilateralT (¢ve horses). No horse required additional drugs after the fourth T. Heart rates were always within normal range (30^45 beats minÿ1) and mean arterial blood pressures were elevated (85^140mmHg). Mean maintenance time (T plus transport time) was 3026minutes, while recovery time (when placed in recovery stall to standing) was 46216 minutes. Oxygen was nasally insu¥ated at 15 Lminÿ1 during T and in recovery. Recoveries were generally good and improved over the course of T. All horses lost weight duringT; meanweight loss was 27222 kg. Horses appeared to acclimatize to transport and treatment, as judged by the fact that lower X doses (10% decrease) or no additional drugs were required during treatment or transport after the ¢rst 3^4 treatments. In conclusion, all horses tolerated repeated anesthesia with injectable agents without apparent adverse side e¡ects.

The Role of the Horse in Studies Relative to Malignant Hyperthermia

Malignant hyperthermia (MH) is now a well recognized syndrome in man and there are extensive efforts to understand the syndrome in both human and animal health.1 The pig has served for a number of years as an experimental model, since a number of characteristics of MH are observed in both man and the pig, including fulminant hyperthermia, muscle rigidity, and a rapid triggering effect by either halothane anesthesia or succinyl-choline.1–4 Similar responses to circulation and ventilation have been observed in both man and swine. Malignant hyperthermia has been reported also in dogs,5,6 horses,7,8 and rabbits.9