Intravenous lidocaine administered in the dorsal occipital sinus was ineffective for euthanasia of Asian box turtles (Cuora spp).

OBJECTIVE

Determine the ability of IV lidocaine and pentobarbital to induce rapid euthanasia.

METHODS

In this blinded, randomized study, Asian box turtles (Cuora spp) designated for euthanasia were sedated with alfaxalone before euthanasia with lidocaine (20 mg/kg) or pentobarbital (200 mg/kg) IV in the dorsal occipital sinus over a 3-day period. The sinus was located by ventral flexion of the head with needle insertion ventral to the supraoccipital crest. Time to loss of cardiorespiratory and neurologic function was documented. Supplemental doses were administered at 30-, 60-, and 90-minute time points if the heartbeat persisted. Pentobarbital was administered regardless of treatment group at the 90-minute time point.

RESULTS

15 Asian box turtles were assigned to lidocaine (8) and pentobarbital (7) treatment groups. Intravenous injections were successfully administered in the dorsal occipital sinus. Turtles given lidocaine had cessation of heartbeat at varying time points but had spontaneous return of heartbeat; all required pentobarbital 90 minutes after initial injection to induce permanent cardiac arrest. The majority of the pentobarbital group (5 of 7) had a permanent loss of heartbeat.

CONCLUSIONS

The dorsal occipital sinus was reliable and easily accessible for high-volume injections. Lidocaine IV, even at high doses, was ineffective for euthanasia. In contrast, pentobarbital IV produced repeated rapid loss of detectable heartbeat.

CLINICAL RELEVANCE: This study highlights the successful administration of IV medications through a more easily accessed venipuncture site, the dorsal occipital sinus. Pentobarbital is reliable and efficient for euthanasia; however, higher doses than the current published guidelines are recommended for rapid cardiac arrest in reptiles.