Alfaxalone

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

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.

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.

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.

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.

To evaluate the accuracy, agreement, and trending ability of the pulse contour cardiac output (PulseCO) system calibrated with echocardiography-derived cardiac output (CO) in sevoflurane-anesthetized healthy dogs during 8 hours of general anesthetic.

Prospective, randomized, blinded experimental study.

A total of five healthy Beagle dogs, three intact females and two intact males.

Dogs were anesthetized using intravenous alfaxalone for induction and sevoflurane in 100% oxygen for maintenance for 8 hours. CO was estimated using three methods: pulmonary artery catheter thermodilution (PAC-TD)-derived CO (CO_PAC-TD), Doppler-based echocardiography-derived CO (CO_Echo), and PulseCO-derived CO (CO_PulseCO). The PulseCO monitor was calibrated at baseline using CO_Echo and not recalibrated during the anesthetic. Measurements were taken at baseline and at intervals up to 8 hours. All CO values were converted to cardiac index (CI) by indexing to body surface area. Statistical analysis included Bland-Altman and linear regression analyses for agreement assessment and Critchley's four-quadrant and polar plots for trending analysis.

A total of 100 paired CI measurements were obtained. Bland-Altman analysis revealed a mean bias of -0.1 L minute^-1 m^-2 and percentage error of 28.3% for CI_PAC-TDversus CI_PulseCO, and a mean bias of 0.01 L minute^-1 m^-2 with a percentage error of 24.9% for CI_PAC-TDversus CI_Echo. Trending analysis between CI_PAC-TD and CI_PulseCO showed a concordance rate of 98.2% in the four-quadrant plot and a mean angular bias of 2.6 ° with radial limits of agreement ranging from -21.47 ° to 26.67 ° in the polar plot.

The results indicate that the PulseCO system has acceptable accuracy, agreement, and trending ability compared with the traditional reference method of PAC-TD. This highlights the potential of the PulseCO system as a minimally invasive and practical monitoring tool in sevoflurane-anesthetized dogs.