Advanced Cardiovascular Monitoring

The Frank-Starling curve (the curvilinear relation between cardiac output (CO) and preload) can be used for optimalization of the blood circulation and tissue oxygenation, in order to decrease morbidity and mortality in high risk surgery and critically ill patients. Measurement of CO and preload with a pulmonary artery catheter (PAC) does not lead to diminished morbidity and mortality, partly because of the complications described from the PAC. CO can be measured with sufficient validity with intermittent transpulmonary thermodilution or lithium dilution and continuously with pulse contour cardiac output or arterial waveform analysis (Vigileo), as long as a sufficient arterial pulse wave is available. Bioimpedance CO can be used in children to track changes in CO, but is not sufficient in adults. The prediction of an improvement of the circulation by fluid infusion (fluid responsiveness) is the primary endpoint for preload optimalization. SPV, PPV and SVV as dynamic preload parameters are adequate predictors of fluid responsiveness, as long as patients are mechanically ventilated continuously with closed chest and without arrhythmias. Volumetric preload parameters, such as GEDV and ITBV are not useful, as well as CVP and PCWP measured with the PAC, because of a diminished cardiac and pulmonary vascular compliance in the presence of pathology. It is preferable to combine less invasive CO monitoring with a dynamic preload parameter for the optimalization of the ciculation and tissue oxygenation.