Abstract

While there have been historical challenges in pursuing general anesthesia and surgery in cetaceans, recent advances have suggested that early intervention and laparoscopic techniques may be critical to achieve success.^1,2 During a routine examination, a behaviorally normal 28-year-old male bottlenose dolphin (Tursiops truncatus) was diagnosed with severe leukocytosis (27,000/µl) characterized by neutrophilia (76%) and monocytosis (9%). An extensive diagnostic work-up was performed. Concurrently, empiric therapy was initiated with systemic antibiotics, antifungal, and gastrointestinal protectants. Ultrasound and CT identified a left-sided retroperitoneal mass, and cytology and culture results were consistent with a sterile abscess. Infectious disease testing for Brucella, Mycobacteria, and Nocardia spp. were all negative. After a period of aggressive supportive care for suspected acute post-contrast nephropathy, an exploratory laparoscopy was performed and was immediately followed by surgical mass removal.

The animal was administered ketamine (1 mg/kg) and midazolam (0.02 mg/kg) IM, followed by propofol (0.6 mg/kg) and midazolam (0.02 mg/kg) IV for anesthetic induction and sevoflurane for maintenance. A left flank approach was used for rigid laparoscopy. The abdominal viscera were within normal limits with a left retroperitoneal mass displacing the caudal peritoneum. A full-thickness skin and blubber incision was made directly over the mass and dissection through body wall musculature was performed. Anesthetic recovery was prolonged after midazolam reversal and discontinuation of gas anesthesia; however, the patient showed interest in fish within 24 hours after recovery. Histopathology of the mass confirmed probable B-cell origin follicular lymphoma of three lymph nodes with massive necrosis of the largest lymph node. Viral discovery through next-generation sequencing was negative. This case report highlights critical advancements in pursuing surgical intervention in cetaceans prior to emergency presentation, employment of a ketamine-midazolam anesthetic protocol, and post-surgical complications associated with this procedure.

Acknowledgements

The authors wish to thank Stacey Tomlijenovich of Arnold Palmer Hospital for assistance in coordinating a CT scan for this patient. We also thank Stryker and the AdventHealth Nicholson Center for the contribution of laparoscopy equipment and surgical supplies for this procedure; Nick Travieso for his guidance and expertise with laparoscopy equipment during the surgery; and the SeaWorld Orlando dolphin management and husbandry team for their compassionate care of this patient during the perioperative period.

*Presenting author

Literature Cited

1.  Higgins JL, Hendrickson DA. Surgical procedures in pinniped and cetacean species. J Zoo Wildl Med. 2013;44(4):817–836.

2.  Marquardt S, Walsh M, Ivančić M, Stacy N, Wellehan J. Intestinal torsion in a bottlenose dolphin (Tursiops truncatus). In: IAAAM 52nd Annual Conference Proceedings; 2022.