Original Article
Copyright ©2014 Baishideng Publishing Group Inc. All rights reserved.
World J Radiol. Oct 28, 2014; 6(10): 833-839
Published online Oct 28, 2014. doi: 10.4329/wjr.v6.i10.833
Influence of breathing movements and Valsalva maneuver on vena caval dynamics
Alicia Laborda, Sergio Sierre, Mauro Malvè, Ignacio De Blas, Ignatios Ioakeim, William T Kuo, Miguel Angel De Gregorio
Alicia Laborda, Sergio Sierre, Ignatios Ioakeim, Miguel Angel De Gregorio, Minimally Invasive Techniques Research Group, Universidad de Zaragoza, 50013 Zaragoza, Spain
Mauro Malvè, Department of Mechanical Engineering, Energetics and Materials, Universidad Pública de Navarra. Aragon Institute of Engineering Research, 31006 Pamplona, Spain
Ignacio De Blas, Department of Animal Pathology, Faculty of Veterinary, Universidad de Zaragoza, 50013 Zaragoza, Spain
William T Kuo, Division of Vascular and Interventional Radiology, Stanford University Medical Center, CA 94305, United States
Author contributions: Laborda A and De Gregorio MA designed the research; Laborda A performed the majority of the experiments; Laborda A, Malvè M and Ioakeim I acquired the data; Laborda A, Sierre S, De Blas I and Ioakeim I analyzed the data; Laborda A, Malve M, De Blas I and Ioakeim I drafted the article; Sierre S, Kuo WT, and De Gregorio MA performed the critical review of the paper; All authors gave the final approval.
Correspondence to: Alicia Laborda, DVM, PhD, Minimally Invasive Techniques Research Group (GITMI), Universidad de Zaragoza, Calle Miguel Servet 177, 50013 Zaragoza, Spain. alaborda@unizar.es
Telephone: +34-976-761549 Fax: +34-976-761549
Received: July 2, 2014
Revised: August 19, 2014
Accepted: September 16, 2014
Published online: October 28, 2014
Processing time: 113 Days and 14.2 Hours
Abstract

AIM: To study changes produced within the inferior vena cava (IVC) during respiratory movements and identify their possible clinical implications.

METHODS: This study included 100 patients (46 women; 54 men) over 18 years of age who required an abdominal computed tomography (CT) and central venous access. IVC cross-sectional areas were measured on CT scans at three levels, suprarenal (SR), juxtarenal (JR) and infrarenal (IR), during neutral breathing and again during the Valsalva maneuver. All patients were instructed on how to perform a correct Valsalva maneuver. In order to reduce the total radiation dose in our patients, low-dose CT protocols were used in all patients. The venous blood pressure (systolic, diastolic and mean) was invasively measured at the same three levels with neutral breathing and the Valsalva maneuver during venous port implantation. From CT scans, three-dimensional models of the IVC were constructed and a collapsibility index was calculated for each patient. These data were then correlated with venous pressures and cross-sectional areas.

RESULTS: The mean patient age was 51.64 ± 12.01 years. The areas of the ellipse in neutral breathing were 394.49 ± 85.83 (SR), 380.10 ± 74.55 (JR), and 342.72 ± 49.77 mm2 (IR), and 87.46 ± 18.35 (SR), 92.64 ± 15.36 (JR) and 70.05 ± 9.64 mm2 (IR) during the Valsalva (Ps < 0.001). There was a correlation between areas in neutral breathing and in the Valsalva maneuver (P < 0.05 in all areas). Large areas decreased more than smaller areas. The collapsibility indices were 0.49 ± 0.06 (SR), 0.50 ± 0.04 (JR) and 0.50 ± 0.04 (IR), with no significant differences in any region. Reconstructed three-dimensional models showed a flattening of the IVC during Valsalva, adopting an ellipsoid cross-sectional shape. The mean pressures with neutral breathing were 9.44 ± 1.78 (SR), 9.40 ± 1.44 (JR) and 8.84 ± 1.03 mmHg (IR), and 81.08 ± 21.82 (SR), 79.88 ± 19.01 (JR) and 74.04 ± 16.56 mmHg (IR) during Valsalva (Ps < 0.001). There was a negative correlation between cross-sectional caval area and venous blood pressure, but this was not statistically significant in any of the cases. There was a significant correlation between diastolic and mean pressures measured during neutral breathing and in Valsalva.

CONCLUSION: Respiratory movements have a major influence on IVC dynamics. The increase in intracaval pressure during Valsalva results in a significant decrease in the IVC cross-sectional area.

Keywords: Inferior vena cava; Morphology; Respiratory movements; Size; Valsalva; Venous hemodynamics

Core tip: This study is focused on the poorly investigated and controversial field of vena caval dynamics. It provides findings about possible correlations between respiratory movements and caval hemodynamic characteristics. This knowledge may have many clinical applications for therapeutic minimally invasive strategies, especially for the study of intravenous devices.