Dexmedetomidine chemical restraint of two raptor species undergoing inhalation anaesthesia

Evaluation of dexmedetomidine-midazolam sedation in budgerigars (Melopsittacus undulatus)

OBJECTIVE

To evaluate the sedative effects of IM administration of a high or low dose of dexmedetomidine in combination with midazolam in budgerigars (Melopsittacus undulatus).

ANIMALS

20 healthy adult budgerigars.

PROCEDURES

In a prospective, randomized, blinded study, birds were sedated with a high dose (HD; 0.04 mg/kg, IM; n = 10) or low dose (LD; 0.01 mg/kg, IM; 10) of dexmedetomidine in combination with midazolam (3 mg/kg, IM). Twenty minutes later, atipamezole (0.4 mg/kg [HD group] or 0.1 mg/kg [LD group], IM) and flumazenil (0.1 mg/kg, IM) were administered for reversal of sedation.

RESULTS

Times to first effect and to sternal recumbency after administration of the sedatives and times to standing and eating after administration of the antagonists did not differ between groups. Most birds (9/10 in the HD group and 7/10 in the LD group) lost the righting response by 10 minutes after sedative administration, and the peak effect for radiographic positioning was by 15 minutes. Although it was not clinically relevant, most birds showed mild resedation by 60 minutes after administration of the reversal agents. There was no significant cardiorespiratory compromise detected with either protocol.

CLINICAL RELEVANCE

Dexmedetomidine-midazolam can safely and effectively provide a dose-dependent level of sedation in healthy budgerigars. The HD protocol is recommended for radiographic positioning, as it allows for a more reliable, deeper plane of sedation.

Pharmacokinetics and Pharmacodynamics of Butorphanol and Dexmedetomidine after Intranasal Administration in Broiler Chickens (Gallus gallus domesticus)

Butorphanol and dexmedetomidine (DXM) can produce analgesia in birds. Intranasal (IN) route of drug administration is easier, and free of risks such as pain and tissue damage compared with intravenous, intramuscular or subcutaneous routes in bird species, including wild birds. Although previous studies have demonstrated the use of IN route for producing sedation, no studies are available on the pharmacokinetics and pharmacodynamics of IN drugs in birds. This study analyzed the pharmacokinetics and sedative–analgesic efficacy of intranasal butorphanol (2 mg/kg), dexmedetomidine (80 µg/kg) and their combination (butorphanol, 2 mg/kg; DXM, 80 µg/kg) in healthy, male, Ross broiler chickens (n = 6/group) aged between 6 and 8 weeks. Maximum plasma concentration (Cmax, p = 0.01), area under the plasma concentration-time curve from time zero to 120 min (AUC0 to 120, p = 0.02) and apparent volume of distribution at steady state (Vss, p = 0.02) of DXM were significantly higher than that of DXM co-administered with butorphanol. The mechanical nociceptive thresholds and the sedation scores of DXM group were significantly higher than the baseline value. Dexmedetomidine (80 µg/kg, IN) was effective in chickens, and the drug absorption was more rapid than that of DXM with butorphanol. However, the duration of action of DXM was short. Lower value of Cmax and nociceptive thresholds showed the nonsignificant efficacy of butorphanol at a dose of 2 mg/kg after IN administration in broiler chickens.

Raptor Sedation and Anesthesia

Sedation and/or anesthesia is routinely and successfully used in raptors for a wide variety of procedures from the routine such as physical examination, radiographs, or venipuncture, to the more complex, such as orthopedic surgeries. Understanding the anatomy and physiology of raptor patients who present for care, and being fully prepared before the start of any procedure, can increase the success of anesthetic procedures. Recent advances in raptor sedation and anesthesia continue to improve the health and welfare of these avian patients.

Backyard Poultry and Waterfowl Sedation and Anesthesia

The popularity of backyard poultry (chickens, turkey, guinea fowl) and waterfowl (ducks and geese) is increasing in the United States, and these animals frequently present for veterinary care. Like other birds, these species have unique anatomy that should be clinically considered before anesthesia. A balanced approach to an injectable, inhalational, or combination anesthesia protocol must be taken to ensure a safe outcome for the patient and to achieve the procedural needs. A well-informed clinician may use both sedation and general anesthesia to care for backyard bird patients in practice.