Effects of the fraction of inspired oxygen on alfaxalone-sedated inland bearded dragons (Pogona vitticeps)

Use of alfaxalone in bearded dragons (Pogona vitticeps): optimizing pharmacodynamics and evaluating cardiogenic effects via echocardiography

OBJECTIVE

Bearded dragons (Pogona vitticeps), a popular zoological companion species, frequently require sedation for procedures. A novel formulation of alfaxalone with preservatives was FDA approved for 28-day use after the vial is breached. Research has been performed in squamate species using alfaxalone without preservatives at various doses and routes of administration, but it is unknown whether preservatives affect quality of sedation or cardiac function.

ANIMALS

10 bearded dragons.

PROCEDURES

This complete crossover study evaluated the pharmacodynamic effects of alfaxalone with preservatives administered to bearded dragons via intracoelomic (ICo; n = 10), SC (10), IM (9), and IV (9) injection at 15 mg/kg.

RESULTS

Deep sedation was achieved in 9 of 10 ICo, 8 of 10 SC, 8 of 9 IM, and 9 of 9 IV administrations. Heart rate significantly decreased from baseline for ICo (P = .008; median heart rate, 46), IM (P = .018; 54), and IV (P = .033; 54) routes, but maintained within clinically acceptable limits. Respiratory rate significantly decreased from baseline for ICo (P = .011; median respiratory rate, 30), SC (P = .024; 12), IM (P = .028; 12), and IV (P = .043; 12) routes. Spontaneous ventilation was retained during all events. Time to first effects was significantly sooner with IV (0 min) administration compared with ICo (P = .02; 5 min) and IM (P = .008; 5 min). Time to loss and recovery of withdrawal, righting reflex, deep pain, and purposeful movement were not significantly different between routes of administration. End-systolic volume was the only echocardiographic parameter significantly affected by IV sedation.

CLINICAL RELEVANCE

Sedation quality was most consistent via IV administration at 15 mg/kg, and minimal changes in cardiac function were observed.

Sedation and Anesthesia of Lizards

The field of lizard sedation, anesthesia, and locoregional anesthesia is advancing with new drug protocols being evaluated, and new locoregional techniques being developed and evaluated. Inducing and maintaining effective and safe chemical restraint in lizards can be challenging, particularly in systemically diseased individuals. Understanding the anatomic and physiologic adaptations of lizards, using reversible or partially reversible injectable protocols, and using locoregional anesthesia may increase the quality of chemical restraint, facilitate faster recoveries, and limit anesthesia-related morbidity and mortality.