Doxapram increases respiratory rate, heart rate, and blood lactate concentration in juvenile green sea turtles (Chelonia mydas).

OBJECTIVE

To evaluate the physiologic effects of IM doxapram compared to a control on respiratory rate, heart rate, venous blood gas, electrolytes, glucose, and lactate parameters in clinically healthy, rehabilitated juvenile green sea turtles (Chelonia mydas).

METHODS

In a randomized, complete crossover design completed from 2023 through 2025 with a 24-hour washout period, juvenile green sea turtles (2.9 to 7.6 kg) under care at a sea turtle rehabilitation center received either IM doxapram (5 mg/kg) or 0.9% sodium chloride (equivalent volume) in the pectoral muscle. Turtles were left unstimulated out of water, and venous blood was collected for blood gas, electrolyte, glucose, and lactate evaluation at 0, 30, and 60 minutes. Serial heart and respiratory rates (0 to 60 minutes) were collected by a blinded observer. Data were analyzed with linear mixed-effects models (P < .05).

RESULTS

8 turtles were included. Doxapram administration resulted in significantly higher respiratory rate (5 to 30 minutes; 2.3 to 3.9 times higher), heart rate (15 to 60 minutes; 9.1 to 10.2 beats/min higher), and blood lactate concentration (30 to 60 minutes; 1.6 to 2.5 times higher) compared to control.

CONCLUSIONS

IM doxapram, 5 mg/kg, increased respiratory rate and heart rate for up to 30 and at least 60 minutes, respectively, and increased blood lactate concentration for at least 60 minutes in juvenile green sea turtles.

CLINICAL RELEVANCE: While net effects of oxygenation are unknown, potential outcomes should be evaluated, and clinical discretion should be used when considering doxapram administration as a short-lived respiratory and/or cardiac stimulant in juvenile green sea turtles.