Editorial
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Crit Care Med. Feb 4, 2016; 5(1): 7-11
Published online Feb 4, 2016. doi: 10.5492/wjccm.v5.i1.7
Optimizing the value of measuring inferior vena cava diameter in shocked patients
Fikri M Abu-Zidan
Fikri M Abu-Zidan, Department of Surgery, College of Medicine and Health Sciences, UAE University, PO Box 17666, Al-Ain, United Arab Emirates
Author contributions: Abu-Zidan FM had the idea, critically read the literature, supplied the images, wrote the paper, and approved its final version.
Conflict-of-interest statement: None declared by the author.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Fikri M Abu-Zidan, MD, FACS, FRCS, PhD, Dip Applied Statistics Professor, Acute Care Surgeon, Point-of-care Sonographer, Statistical Consultant, Department of Surgery, College of Medicine and Health Sciences, UAE University, Tawam Roundabout, Tawam Street, PO Box 17666, Al-Ain, United Arab Emirates. fabuzidan@uaeu.ac.ae
Telephone: +971-50-8335390 Fax: +971-3-7672067
Received: July 15, 2015
Peer-review started: July 16, 2015
First decision: September 28, 2015
Revised: October 22, 2015
Accepted: December 8, 2015
Article in press: December 11, 2015
Published online: February 4, 2016
Abstract

Point-of-care ultrasound has been increasingly used in evaluating shocked patients including the measurement of inferior vena cava (IVC) diameter. Operators should standardize their technique in scanning IVC. Relative changes are more important than absolute numbers. We advise using the longitudinal view (B mode) to evaluate the gross collapsibility, and the M mode to measure the IVC diameter. Combining the collapsibility and diameter size will increase the value of IVC measurement. This approach has been very useful in the resuscitation of shocked patients, monitoring their fluid demands, and predicting recurrence of shock. Pitfalls in measuring IVC diameter include increased intra-thoracic pressure by mechanical ventilation or increased right atrial pressure by pulmonary embolism or heart failure. The IVC diameter is not useful in cases of increased intra-abdominal pressure (abdominal compartment syndrome) or direct pressure on the IVC. The IVC diameter should be combined with focused echocardiography and correlated with the clinical picture as a whole to be useful.

Keywords: Inferior vena cava diameter, Point-of-care ultrasound, Measurement

Core tip: Bedside measurement of inferior vena cava is useful in evaluating and resuscitating shocked patients. To achieve that, the operator should be well-trained, use standardized techniques, understand ultrasound limitations, and finally correlate the findings with the clinical picture as a whole.