Influence of the Respiratory Cycle on Caudal Vena Cava Diameter Measured by Sonography in Healthy Foals: A Pilot Study

Abstract

BackgroundIntravascular volume assessment in foals is challenging. In humans, intravascular volume status is estimated by the caudal vena cava (CVC) collapsibility index (CVC‐CI) defined as (CVC diameter at maximum expiration [CVC max] – CVC diameter at minimal inspiration [CVC min])/CVC max × 100%.Hypothesis/ObjectivesTo determine whether the CVC could be sonographically measured in healthy foals, determine differences in CVC max and CVC min, and calculate inter‐ and intrarater variability between 2 examiners. We hypothesized that the CVC could be measured sonographically at the subxiphoid view and that there would be a difference between CVC max and CVC min values.AnimalsSixty privately owned foals <1‐month‐old.MethodsProspective study. A longitudinal subxiphoid sonographic window in standing foals was used. The CVC max and CVC min were analyzed by a linear mixed effect model. Inter‐rater agreement and intrarater variability were expressed by Bland‐Altman and intraclass correlation coefficients, respectively.ResultsMeasurements were attained from 58 of 60 foals with mean age of 15 ± 7.9 days and mean weight of 75.7 ± 17.7 kg. The CVC max was significantly different from CVC min (D = 0.515, SE = 0.031, P < 0.001). Inter‐rater agreement of the CVC‐CI differed by an average of −0.9% (95% limits of agreement, −12.5 to +10.7%). Intrarater variability of CVC max was 0.540 and 0.545, of CVC min was 0.550 and 0.594, and of CVC‐CI was 0.894 and 0.853 for observers 1 and 2, respectively.Conclusions and Clinical ImportanceThese results indicate it is possible to reliably measure the CVC sonographically in healthy foals, and the CVC‐CI may prove useful in assessing the intravascular volume status in hypovolemic foals.

Continuous fluid infusion per rectum compared with intravenous and nasogastric fluid administration in horses

“…Bodyweight was measured at baseline and 6 h. Packed cell volume (PCV), total solids (TS), albumin, electrolytes, lactate, urine specific gravity, vital parameters, gastrointestinal borborygmi and central venous pressure were measured every 2 h. Results: Rectal fluid administration with plain water was well tolerated and caused clinical chemistry changes consistent with haemodilution, indicating absorption. Mean (95% confidence interval) PCV decreased from 40% [40][41][42] at 0 h to 35% [34][35][36] at 6 h during rectal fluid treatment (P<0.001), similar to decreases in PCV occurring also with i.v. and nasogastric (NGT) treatment (P<0.001).…”

“…In humans, CVP shows a poor correlation to blood volume as evidenced by a systematic review and meta-analysis and is now not recommended to be used to guide fluid therapy [38,39]. Noninvasive techniques, such as inferior vena cava collapsibility index (IVC-CI), are emerging in humans and the utility of a similar technique has been demonstrated in foals (caudal vena cava collapsibility index [CVC-CI]) [40][41][42]. These techniques, although promising, require further assessment in horses and may be useful for future studies [40][41][42].…”

Caudal vena cava collapsibility index in healthy cats by ultrasonography

“…According to Tuplin et al (2017), in healthy standing foals CVC was easily and consistently obtained during sonographic measurement and the significant variation between CVC diameters in inspiration and in expiration allowed the calculation of the CI. Bucci et al (2017) investigated the ability of distensibility index of the caudal vena cava (CVCDI) to predict fluid response in healthy, anesthetized and mechanically ventilated dogs.…”

Establishment of reference values of the caudal vena cava by fast‐ultrasonography through different views in healthy dogs

“…In veterinary medicine, 2 studies reported a positive correlation between CVP and caudal vena cava diameter (CVC D ) in anesthetized dogs receiving IV fluids and positive pressure ventilation . Three recent studies evaluating CVC diameter, CVC collapsibility (CVC CI ), and the CVC to Ao ratio (CVC/Ao) showed promise in evaluation of intravascular volume status in dogs . Another study on healthy dogs undergoing general anesthesia and mechanical ventilation reported that the CVC CI is a reliable predictor of fluid responsiveness.…”

“…16,17 Three recent studies evaluating CVC diameter, CVC collapsibility (CVC CI ), and the CVC to Ao ratio (CVC/Ao) showed promise in evaluation of intravascular volume status in dogs. [18][19][20] Another study on healthy dogs undergoing general anesthesia and mechanical ventilation 21 reported that the CVC CI is a reliable predictor of fluid responsiveness.…”