Introduction

The ultrasonographic (US) measurement of caudal vena cava on aorta (CVC:Ao) ratio was successfully used to assess volume status in models of hypovolemia in dogs. The aim of this study was to determine the clinical utility of the CVC:Ao ratio to detect hypervolemic status in dogs. We used congestive heart failure (CHF) as spontaneous model of hypervolemia.

Methods

Dogs with CHF presented in the ICU (SIAMU) between September 2019 and April 2020 were prospectively included. CHF was suspected based on at least 2 of the following clinical signs: respiratory distress, heart murmur, pulmonary crackles sounds, tachycardia and ≥3 B-lines per window on TFAST exam. Cardiac disease was then confirmed by echocardiography or thoracic radiographs and positive clinical response to furosemide. CVC:Ao ratio was measured on the spleno-renal view of the AFAST protocol as previously described. Physical exam, blood lactate and US measures were performed before and 30 minutes after a 2 mg/kg intravenous bolus of furosemide. Reference intervals (RI) for CVC:Ao ratio were previously defined at our institution as: 0.93–1.32. Quantitative data comparison at the two times of the study was performed by a t-test for normally distributed data and Wilcoxon rank test for non-normally distributed data. Relationships between CVC:Ao ratio and physical parameter and blood lactates were calculated using Pearson’s correlation coefficients.

Results

Eight dogs with CHF were included. CVC:Ao ratios were above RI at admission in 6/8 dogs. After furosemide bolus, median CVC:Ao ratios significantly decreased [before:1.31 (0.95–1.52); after: 1.22 (1.00–1.44; p=0.0287)] and returned within the RI in 4/6 dogs. Blood lactate and physical parameters did not significantly change, and no significant linear correlation was observed with CVC:Ao ratio before and after treatment.

Conclusions

The US measurement of the CVC:Ao ratio appears as a promising tool for diagnosis and follow-up of hypervolemic status in dogs. Further studies with a higher number of dogs and in other spontaneous models as anuric acute kidney injury are warranted to confirm this result.

Disclosures

No disclosures to report.