Cardiac output obtained by pulse pressure analysis: to calibrate or not to calibrate may not be the only question when used properly

摘要

Cardiac output (CO) is the main determinant of oxygen delivery and physical examination, and vital signs alone often fail to reflect significant derangements in CO [1]. Because of the complexity of assessment of clinical variables in unstable patients, direct measurement of CO is advisable. Pulse pressure (PP) analysis, often referred to as pulse contour (PC) analysis, is the analysis used by technologies that estimate changes in stroke volume (SV) and CO from an arterial pressure waveform signal [2, 3]. The theory behind this approach dates back to the end of the nineteenth century when the German physiologist Otto Frank proposed the Windkessel (air chamber) model of cardiovascular physiology [4]. In a system with air and fluid, different air chambers were filled with air in order to simulate compliance, resistance and impedance of the cardiovascular system.