Anesthesia for Shell Fracture Reduction in a Turtle D'Orbigny's slider (Trachemys dorbigni)

Abstract

Background: In reptile veterinary practice, trauma incidents are increasingly prevalent due to various etiologies. However, compared to other domestic mammals, the literature is notably sparse and contains few documented cases. Anesthetic management in chelonians for surgical procedures presents unique challenges and considerations due to species-specific physiological differences. This report aims to detail the anesthesia protocol employed for the correction of an automotive-induced shell fracture in a turtle D'Orbigny's slider (Trachemys dorbigni).

Case: One turtle mature D'Orbigny's slider (Trachemys dorbigni) weighing 1,3 kg presented with a caudal right shell fracture, approximately 8 cm in wedge shape, extending from the peripheral edge to the midline. The patient exhibited signs of pain and discomfort upon initial examination but remained stable for surgical intervention. Pre-anesthetic medication included dexmedetomidine (10 mcg/kg), esketamine (10 mg/kg) and methadone (1 mg/kg) administered intramuscularly to achieve sedation. Anesthesia induction was facilitated via jugular cannulation, with propofol administered intravenously at 4 mg/kg. Endotracheal intubation was performed, and anesthesia was maintained with isoflurane in oxygen via a circle breathing system, titrated to effect. Concurrently, a lateral approach intercoccygeal epidural block was administered using 2% lidocaine without vasoconstrictor (0.1 mL / 5 cm of carapace) to provide regional anesthesia and perioperative analgesia. Fracture reduction involved careful manipulation and alignment of the shell fragments followed by hemicerclage application using stainless steel wires and subsequent application of bone cement (polymethylmethacrylate) to stabilize and promote healing of the fracture site. 

Discussion: D'Orbigny's slider (Trachemys dorbigni), commonly known as the South American river turtle, belongs to the Emydidae family and inhabits freshwater environments. Anesthesia management in reptiles requires meticulous pre-anesthetic assessment to maintain body temperature near the upper limits of the ideal range, crucial for preventing metabolic compromise. Pre-anesthetic medication plays a pivotal role in facilitating procedures such as endotracheal intubation and jugular catheterization, often combining ketamine and alpha-2 adrenergic agonists for induction. Drug administration must consider the unique reptilian portal-renal system, where only a fraction of blood from the hind 3rd of chelonians directly reaches the kidneys, emphasizing the importance of thoracic limb administration to minimize complications. Jugular access was employed for drug delivery in this case, with thoracic limb access facilitating fluid administration and ongoing anesthetic support. Propofol induction and maintenance with isoflurane are recommended due to their rapid metabolism and excretion in reptilian species, ensuring precise titration and expedited postoperative recovery. Anesthetic recovery in reptiles can be prolonged, necessitating controlled environmental conditions and vigilant monitoring of oropharyngeal reflexes for safe extubation. Surgical interventions, such as shell fracture reduction, commonly involve advanced techniques like stainless steel wire cerclage and bone cement application to expedite healing and ensure optimal shell integrity and function restoration, essential for the successful rehabilitation of reptilian patients undergoing complex surgical procedures. 

Keywords: anesthesia, Chelonian, D'Orbigny's slider, fracture redution, Trachemys dorbigni.

Título: Anestesia para redução de fratura de casco em uma tartaruga-tigre-d’água (Trachemys dorbigni)

Descritores: anestesia, quelônios, tigre-d’água, redução de fratura, Trachemys dorbigni.