Clinical and radiographic evaluation

Immediately upon admission, physical examinations were performed of each turtle, including curved carapace length, curved carapace width, and weight, as well as core body temperature that was measured via a temperature probe inserted ~ 10 cm into the cloaca.

Full-body radiographs in dorsal–ventral (DV vertical beam) (Eurocolumbus, AEX 125 kV/300 Ma) and cranial-caudal (Cr-Cd horizontal beam) and lateral-lateral (LL horizontal beam) (Diagnostic X-RAY unit, Orange 1060 HF Ultra Plus) projections were performed. All radiographs were assessed independently by three experienced sea turtle veterinarians (A. D. B., D. F. and C. V.) to evaluate signs of drowning, characterised by interstitial and peribronchial thickening, and gas embolism within the cardiovascular system. In all turtles with radiographic signs of GE, we evaluated and listed the cardiovascular sites (CAS) where the gas was well detectable.

After radiographic examination, in turtles with signs of GE, respiratory rate (assessed visually), heart rate (assessed by ECG), PCV, and neurological and sensory deficits were recorded. Mentation was assessed as alert (responsive to external stimuli), depressed (reduced, compared with normal, but appropriate responsiveness to external stimuli) and lethargic/comatose (not responsive, loss of consciousness)⁵⁷.

Heart rate was performed with the turtle placed in the transport tank, after a 10 min period from the previous manipulations, using ECG vector in lead II with electrodes distributed on the four limb positions⁵⁸. Time to perform ECG was ranged from 3 to 5 min.

Additional clinical findings that were recorded included peripheral oedema such as neck or palpebral oedema, cloacal prolapse and the eventual presence or absence of particular postures such as retraction of the hind limbs under the carapace.