A New Pulse Contour Analysis for Cardiac Output Estimation: The Systolic Volume Balance Method

Cardiac output (CO) monitoring is essential for the optimal management of critically ill patients. Several methods have been proposed for CO estimation based on arterial pressure waveform analysis, known as “pulse contour cardiac output” (PCCO) monitoring. Most of them are based on invasive recording of blood pressure and require repeated calibrations, while they are still subject to inaccuracy under specific conditions. The Systolic Volume Balance (SVB) method was developed as a new non-invasive method based on physical principles and was further validated by a one-dimensional model of the systemic arterial tree. CO estimates were compared against the “real” CO values of the one dimensional model. 507 different hemodynamic cases were simulated by altering heart rate (HR), total arterial compliance (C) and total arterial resistance (R). It was found that CO can be accurately estimated by the new SVB formula. The bias between the brachial PCCO and the model’s CO was 0.042 L/min with 0.341 L/min SD of difference. The limits of agreement were −0.7–0.6 L/min indicating high precision. The intraclass correlation coefficient and the root mean square error between estimated and “real” CO values were 0.861 and 0.041 L/min respectively, indicating good accuracy and agreement.