Efficacy of ultrasonographic caudal vena cava to aorta ratios for quantifying canine parvoviral enteritis rehydration.

Quantifying changes in intravascular fluid volume is important for treatment planning and follow-up assessment in dogs with dehydration. Recently, it has been reported that current standard methods used to estimate intravascular fluid volume in dogs are inadequate, invasive, or have complications such as thrombosis. The ultrasonographic ratio of dimensions for the caudal vena cava relative to the aorta (CVC/Ao) has been previously described as a promising, noninvasive method for quantifying changes in blood volume in dogs. This prospective observational study aimed to describe ultrasonographic CVC/Ao values before and after fluid replacement in a sample of dogs with varying degrees of dehydration due to naturally-occurring canine parvoviral enteritis (CPE), test correlations between this measure and clinical dehydration scores and determine the clinical efficacy of this measure for fluid therapy follow-up. The clinical dehydration score of 30 dogs naturally infected with canine parvovirus was determined at the first admission using standard clinical scoring methods, and then CVC/Ao was measured ultrasonographically. Following initial fluid therapy, the clinical dehydration scores and ultrasonographic CVC/Ao values were remeasured. On the basis of receiver operating characteristic analyses, ultrasonographic CVC/Ao was found to be a more sensitive and specific indicator than physical examination-based methods for estimating intravascular fluid alterations in dogs with dehydration due to parvovirus and rehydration following fluid therapy. Findings supported the use of this measure for treatment planning and follow-up in future dogs presenting with dehydration.