Review
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Crit Care Med. Jul 31, 2019; 8(4): 36-48
Published online Jul 31, 2019. doi: 10.5492/wjccm.v8.i4.36
One approach to circulation and blood flow in the critical care unit
Camilo Pena-Hernandez, Kenneth Nugent
Camilo Pena-Hernandez, Department of Internal Medicine, Division of Nephrology and Hypertension, Texas Tech University Health Sciences Center, Lubbock, TX 79430, United States
Kenneth Nugent, Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, United States
Author contributions: Pena-Hernandez C and Nugent K contributed equally to this work.
Conflict-of-interest statement: Authors declare no conflict of interest for this article.
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/
Corresponding author: Camilo Pena-Hernandez, MD, Assistant Professor, Department of Internal Medicine, Division of Nephrology and Hypertension, Texas Tech University Health Sciences Center, 3601 4th Street STOP 9410, Lubbock, TX 79430, United States. camilo.pena@ttushc.edu
Telephone: +1-210-5511524 Fax: +1-806-7433143
Received: March 7, 2019
Peer-review started: March 11, 2019
First decision: April 16, 2019
Revised: May 14, 2019
Accepted: June 12, 2019
Article in press: June 12, 2019
Published online: July 31, 2019
Abstract

Evaluating and managing circulatory failure is one of the most challenging tasks for medical practitioners involved in critical care medicine. Understanding the applicability of some of the basic but, at the same time, complex physiological processes occurring during a state of illness is sometimes neglected and/or presented to the practitioners as point-of-care protocols to follow. Furthermore, managing hemodynamic shock has shown us that the human body is designed to fight to sustain life and that the compensatory mechanisms within organ systems are extraordinary. In this review article, we have created a minimalistic guide to the clinical information relevant when assessing critically ill patients with failing circulation. Measures such as organ blood flow, circulating volume, and hemodynamic biomarkers of shock are described. In addition, we will describe historical scientific events that led to some of our current medical practices and its validation for clinical decision making, and we present clinical advice for patient care and medical training.

Keywords: Shock, Volume status, Fluid, Vasopressors, Mean systemic pressure, Pulse pressure, Plethysmography variability index

Core tip: In this review, we depict the historical understanding of circulation and blood flow physiology. Also, by characterizing the different approaches to circulatory failure, we attempt to provide a simplified tool for education and one summarized clinical guideline for management in the critical care unit.