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in Journal of the American Veterinary Medical Association

Abstract

Objective

To develop a technique for objective assessment of modulation of nociperception in conscious perching birds.

Animals

31 adult African grey parrots.

Procedure

Birds were randomly assigned to receive saline (0.9% NaCl) solution (n = 10), butorphanol tartrate (11), or buprenorphine hydrochloride (10), IM. Birds were fitted with a surface electrode on the medial metatarsus of 1 leg. An electrical stimulus was delivered to the bird’s foot through an aluminum surface on half of the perch. The alternate side of the perch delivered a noxious thermal stimulus. A withdrawal response to either stimulus was recorded when the bird lifted its foot or vigorously flinched its wings.

Results

Responses to thermal stimuli were extremely variable during baseline testing and after administration of drugs. Thus, significant differences were not detected after drug injection. In contrast, responses to an electrical stimulus were predictable with much less variation.

Conclusions and Clinical Relevance

This method and device allowed for the reliable determination of withdrawal threshold in perching birds. Use of this technique for objective assessment of modulation of nociperception in conscious perching birds will enable assessment of analgesic drugs. (Am J Vet Res 1999;60:1213–1217)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To evaluate effects of butorphanol tartrate and buprenorphine hydrochloride on withdrawal threshold to a noxious stimulus in conscious African grey parrots.

Animals

29 African grey parrots (Psittacus erithacus erithacus and Psittacus erithacus timneh).

Procedure

Birds were fitted with an electrode on the medial metatarsal region of the right leg, placed into a test box, and allowed to acclimate. An electrical stimulus (range, 0.0 to 1.46 mA) was delivered to each bird’s foot through an aluminum perch. A withdrawal response was recorded when the bird lifted its foot from the perch or vigorously flinched its wings. Baseline threshold to a noxious electrical stimulus was determined. Birds then were randomly assigned to receive an IM injection of saline (0.9% NaCI) solution, butorphanol (1.0 mg/kg of body weight), or buprenorphine (0.1 mg/kg), and threshold values were determined again.

Results

Butorphanol significantly increased threshold value, but saline solution or buprenorphine did not significantly change threshold values.

Conclusions and Clinical Relevance

Butorphanol had an analgesic effect, significantly increasing the threshold to electrical stimuli in African grey parrots. Buprenorphine at the dosage used did not change the threshold to electrical stimulus. Butorphanol provided an analgesic response in half of the birds tested. Butorphanol would be expected to provide analgesia to African grey parrots in a clinical setting. (Am J Vet Res 1999;60:1218–1221)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To compare mask anesthesia induction and recovery characteristics between 2 inhalant anesthetic agents: isoflurane and sevoflurane.

Animals

16 clinically normal, young adult Beagles.

Procedure

Using a cross-over design, dogs were randomly selected to receive sevoflurane or isoflurane via a face mask and a circle anesthetic system. Vaporizer setting concentrations were increased in step-wise, equal minimum alveolar concentrations (MAC) for each anesthetic until the vaporizer setting of 2.6% for isoflurane or 4.8% for sevoflurane (2 MAC) was reached. Concentration was kept constant until the dog had a negative tail clamp response and was intubated. End-tidal concentration was maintained at 1.8 to 2.0% or 3.3 to 3.8% for isoflurane or sevoflurane, respectively (1.4 to 1.6 MAC) for 30 minutes. Dogs were allowed to recover with only tail clamp stimulation until a positive response was obtained. Extubation was performed when a spontaneous swallow reflex was observed. Dogs were allowed to achieve sternal recumbency and stand unassisted without further stimulation.

Results

Sevoflurane induction resulted in shorter time to loss of palpebral reflex, negative tail clamp response, and time to tracheal intubation, and was of better quality than isoflurane induction. Both anesthetics were associated with rapid and smooth recovery.

Conclusions

Sevoflurane mask induction is faster and of better quality, compared with isoflurane, in adult dogs. Recovery time and quality are comparable.

Clinical Relevance

On the basis of these results, sevoflurane is a suitable inhalant anesthetic for mask induction and recovery in adult dogs and appears to have some advantages over isoflurane, including faster and smoother mask induction. (Am J Vet Res 1998;59:478–481)

Free access
in American Journal of Veterinary Research

SUMMARY

Anesthesia of equids is associated with pulmonary dysfunction. Cardiovascular and respiratory effects of inhalation anesthetic agents and duration of anesthesia have been studied, using oxygen as the carrier gas. To our knowledge, the effects of inspired oxygen have not been determined. We studied the cardiovascular and respiratory effects of 2 inspired oxygen fractions (0.30 and > 0.85) in 5 laterally recumbent, halothane-anesthetized horses. Mean systemic arterial blood pressure, cardiac output, central venous pressure, pulmonary arterial pressure, arterial pH, and arterial base excess were similar in horses of the 2 groups during 4 hours of anesthesia at constant end-tidal halothane concentration. End-tidal partial pressure of CO2, arterial partial pressure of CO2 and O2, and alveolar-to-arterial O2 tension difference were greater in horses exposed to the higher oxygen concentration. On the basis of the data obtained, we suggest that greater hypoventilation and ventilation/perfusion mismatch occur when horses are breathing high-oxygen fraction. Arterial partial pressure of O2 was not different between the 2 groups of horses after they were disconnected from the anesthesia circuit and allowed to breathe room air. Horses recovered from anesthesia without complications.

Free access
in American Journal of Veterinary Research