Ultrasonographical Assessment of Caudal Vena Cava Size through Different Views in Healthy Calves: A Pilot Study

SIMPLE SUMMARY: Ultrasonographic measurements of caudal vena cava and aorta are known as reliable tool to assess intravascular volume status in human. The aim of this study was to evaluate the feasibility to assess caudal vena cava with ultrasound in different sites, and to study effect of sex, age, body weight and breed on measurements in healthy calves. A single investigator took measurements of caudal vena cava by ultrasonography in two anatomic sites (subxiphoid and paralumbar site) in 48 calves aged less than 60 days, and then repeated 2,5 months after the first assessment. The study also evaluates the variability between measurements of three observers on five randomly selected calves. The results show that measurement of caudal vena cava by point of care ultrasound was easily obtained on paralumbar site in calves under 4 months of age, and measurements were correlated with the age of the calves. Further studies could compare caudal vena cava measurements in healthy calves to those in calves suffering from diarrhea or surgical disease to see if caudal vena cava point of care ultrasound could complement other shock evaluation parameters such as blood parameters or arterial blood pressure measurements. ABSTRACT: Ultrasonographic measurements of the caudal vena cava (CVC) and aorta (Ao) are known as reliable tools to assess intravascular volume status in humans. The aim of this study was to evaluate the feasibility of obtaining ultrasonographical measurements of CVC and Ao in two different views, assess intra- and interobserver variability, and study the effect of sex, age, body weight, and breed on measurements in healthy calves. The diameter and area of CVC and Ao were measured by a single investigator in two anatomic sites (subxiphoid and paralumbar window) in 48 calves aged less than 60 days and then repeated 2.5 months after the first assessment. For intra- and interobserver variability assessment, CVC and Ao measurements were repeated by three observers on five randomly selected calves. CVC and Ao measurements were easily obtained in PV and more difficult to obtain in SV. CVC and Ao area in PV showed high repeatability and reproducibility. A positive correlation was highlighted between age and CVC and Ao measurements in both sites. In conclusion, CVC size assessment by point of care ultrasound can be easily performed at a paralumbar site in calves under 4 months of age and could be used to assess intravascular volume status.