A Technique for Ultrasound-Guided Catheterization of a Peripheral Vein in the Bottlenose Dolphin (Tursiops truncatus)
Abstract
A method for placement of a superficial indwelling IV catheter in cetaceans has not been described. Several techniques for venipuncture of the peduncle exist;1-5 however, none are detailed in peer-reviewed literature, and vascular nomenclature is inconsistent.6 Further, the use of ultrasound guidance in this region has not been described; all current methods designate a blind approach.1-5 A reliable technique for ultrasound-guided superficial IV catheter placement in the lateral caudal subcutaneous vein (LCSV)7 in T. truncatus is described.
Ultrasonography of the ventrolateral peduncle is performed in sternal or lateral recumbency using a linear transducer (13–6 MHz/10–5 MHz, SonoSite Edge®/M-Turbo®, Bothell, WA). A ventral, transverse acoustic window demonstrates the levator ani (pubocaudalis) muscle.8 It is identified directly deep to the blubber layer, extending dorsolaterally from ventral midline. The muscle has a triangular contour in cross-section, tapering dorsally to a point. The ventral branch of the LCSV is consistently identified dorsal to this muscular point as an anechoic circular to ovoid structure. In a longitudinal window, the vein is seen as a singular craniocaudal anechoic vessel just deep to the blubber. A site for cannulation is chosen that maximizes the diameter of the vein (craniad) while minimizing its depth (caudad). Under mild sedation, local anesthesia is administered and a single- or double-lumen, 4- or 5-Fr, peripheral or central venous catheter is placed percutaneously using a Seldinger technique. The diameter of the vessel is notably dynamic; the application of external abdominal pressure cranial to the transducer has been shown to expand its size in some animals.
Acknowledgements
The authors would like to thank Dr. Cynthia Smith, Dr. Eric Jensen, Dr. Sam Ridgway, and the veterinary, biotechnical, training, and management staff of the U.S. Navy Marine Mammal Program, and the training staff of Dolphins Plus, Island Dolphin Care, Theater of the Sea, and Dolphin Research Center for their support in developing these techniques.
* Presenting author
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