Abstract

Live-stranded pinnipeds often present to rehabilitation centers systemically debilitated with poor perfusion.¹ In many terrestrial species, blood lactate elevation has been correlated with global tissue hypoxia.^2,3,4 Serial lactate measurements in companion animals and humans have been used to guide fluid resuscitation therapy and evaluate prognosis.^5-8 The primary objective of this study was to evaluate the relationship between serial blood lactate values and survival in live-stranded pinnipeds. Fifty-five live-stranded pinnipeds (30 Northern elephant seals [Mirounga angustirostris]; 21 Pacific harbor seals [Phoca vitulina richardsi]; and four California sea lions [Zalophus californianus]) that presented to a rehabilitation center were manually restrained for blood collection and lactate measurement using the portable Lactate Plus™ analyzer prior to fluid or other medical therapy. Lactate measurements were repeated 72 hours after initiation of fluid therapy, and prior to euthanasia or release. Serum samples from potassium oxalate/sodium fluoride tubes were frozen for 30–100 days, then thawed and evaluated using both the Lactate Plus™ and bench-top (ABL 815) analyzers. Results from this study validated the Lactate Plus™ meter for pinniped lactate measurement, and potassium oxalate/sodium fluoride tubes for preserving lactate levels in serum. Released animals had significantly greater lactate improvement (clearance) at 72 hours (p=0.039) than animals that died or were euthanized. Therefore, serial lactate measurements and lactate clearance may be useful for evaluating prognosis in live-stranded pinnipeds. Initial lactate and lactate values prior to euthanasia or release were not significantly associated with outcome. Given these findings, clinicians should interpret isolated lactate values (both normal and abnormal) in pinnipeds with caution.

Acknowledgements

This project was funded by the Phil and Karen Drayer Wildlife Health Center Fellowship Award. The authors thank The Karen C. Drayer Wildlife Health Center and Dr. Kate Hopper from the Veterinary Medical Teaching Center (VMTH) at the University of California, Davis. Finally, the authors thank the staff and volunteers of The Marine Mammal Center for their support and assistance with this study.

* Presenting author
+ Student presenter

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