Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2017 Sep;31(5):1556-1562.
doi: 10.1111/jvim.14793. Epub 2017 Aug 1.

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

M C Tuplin  1 , A E Romero  1 , S R Boysen  1
Affiliations

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

M C Tuplin et al. J Vet Intern Med. 2017 Sep.

Abstract

Background: Intravascular 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 [CVCmax ] - CVC diameter at minimal inspiration [CVCmin ])/CVCmax × 100%.

Hypothesis/objectives: To determine whether the CVC could be sonographically measured in healthy foals, determine differences in CVCmax and CVCmin , 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 CVCmax and CVCmin values.

Animals: Sixty privately owned foals <1-month-old.

Methods: Prospective study. A longitudinal subxiphoid sonographic window in standing foals was used. The CVCmax and CVCmin were analyzed by a linear mixed effect model. Inter-rater agreement and intrarater variability were expressed by Bland-Altman and intraclass correlation coefficients, respectively.

Results: Measurements 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 CVCmax was significantly different from CVCmin (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 CVCmax was 0.540 and 0.545, of CVCmin 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 importance: These 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.

Keywords: Collapsibility index; Fluid estimation; Intravascular volume status; Ultrasound.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Schematic of the right side of a foal, with approximate location of ribs and sonographic probe shown for the subxiphoid window.
Figure 2
Figure 2
Sonographic image: B‐Mode (upper), demonstrating the liver, diaphragm, and caudal vena cava (CVC) with the M‐Mode line crossing the CVC perpendicularly at the level of the diaphragm. M‐Mode (lower) showing CVC diameter on expiration (trough) and inspiration (peak). Five respiratory cycles are shown in M‐Mode. Large white arrows indicate site of measurement for minimum inspiratory CVC diameter (CVC min), and white arrow heads indicate site of measurement for maximum expiratory CVC diameter (CVC max).
Figure 3
Figure 3
(A,B,C) Bland‐Altman plots for the caudal vena cava (CVC) maximum, CVC minimum diameter, and the caudal vena cave collapsibility index (CVC‐CI) inter‐rater variability (n = 25). The lines connecting the dots indicate the first and second examination performed by each observer for an individual foal. The bold horizontal line is the mean difference between observers 1 and 2. The finer horizontal lines represent the 95% limit of agreements for mean difference.
See this image and copyright information in PMC

References

    1. Hollis AR, Boston RC, Corley KT. Plasma aldosterone, vasopressin and atrial natriuretic peptide in hypovolaemia: A preliminary comparative study of neonatal and mature horses. Equine Vet J 2008;40:64–69. - PubMed
    1. Palmer JE. Fluid therapy in the neonate: Not your mother's fluid space. Vet Clin North Am Equine Pract 2004;20:63–75. - PubMed
    1. Palmer J. Update on the management of neonatal sepsis in horses. Vet Clin North Am Equine Pract 2014;30:317–336, vii. - PubMed
    1. Stawicki SP, Braslow BM, Panebianco NL, et al. Intensivist use of hand‐carried ultrasonography to measure IVC collapsibility in estimating intravascular volume status: Correlations with CVP. J Am Coll Surg 2009;209:55–61. - PubMed
    1. Stawicki SP, Adkins EJ, Eiferman DS, et al. Prospective evaluation of intravascular volume status in critically ill patients: Does inferior vena cava collapsibility correlate with central venous pressure? J Trauma Acute Care Surg 2014;76:956–963; discussion 63‐4. - PubMed

LinkOut - more resources