Cardiac output monitoring: basic science and clinical application

Abstract

Summary Derangements in the circulation are a common feature of sepsis, trauma, major surgery and other critical illnesses. Detailed evaluation of the circulation is therefore an essential aspect of the clinical management of such patients. The use of cardiac output monitoring technology is an increasingly important aspect of evaluating patients in the operating theatre, critical care unit and elsewhere. There are now a number of different technologies available for this purpose, which use a diverse range of physiological principles. A detailed understanding of the physiological principles applied by such technology is essential for safe and effective use in clinical practice. The aim of this article is to describe the physiological principles used to measure cardiac output and their application in various monitors in common clinical use.

Validation of cardiac output measurement with the LiDCOTM pulse contour system in patients with impaired left ventricular function after cardiac surgery*

“…3. Since the LiDCO system employs pulse power analysis, it should in general be more robust as compared with other pulse contour techniques regarding alterations of the pulse pressure curve that are either caused by changes in afterload or by reflections of the pressure wave [25].…”

The precision of PiCCO®measurements in hypothermic post‐cardiac arrest patients

“…A 15-ml bolus of iced (< 8°C) saline 0.9% was injected through the central venous catheter, and the thermodilution curve was used to estimate cardiac output, global end-diastolic volume, extravascular lung water and the pulmonary vascular permeability index. The detailed principles and the validation of these single-indicator transpulmonary thermodilution-derived variables have been discussed elsewhere [17,[30][31][32]. The extravascular lung water was indexed using predicted body weight [17,33,34].…”

Acute kidney injury in surgical patients

“…At present only a minority of such patients are admitted to critical care in the perioperative period. 119,121 Optimal perioperative fluid management is of great importance in improving outcomes for the high-risk surgical patient. There is also a growing body of evidence to suggest that the use of low dose inotropic therapy may also be of benefit in selected cases.…”