| Popis: |
In this chapter, the role of cardiac output (CO) and its place among other hemodynamic parameters, its physiological determinants and their interactions, as well as general aspects of CO measurement and monitoring regardless of technology choice are discussed. Although the current reference—organ (tissue) perfusion—has remained unavailable at the bedside until now, CO as its “gross substitute” has become the most desirable criterion for circulation adequacy over the past few decades. Strict goal-directed protocols, based on CO monitoring data, have demonstrated outcome improvement both in critical care and in high-risk surgical patients. Numerous CO measurement techniques have been developed over the last 150 years. The physiological analysis and data comparison have revealed that although pulmonary artery thermodilution remains the clinical gold standard, all the methods have certain errors and artifacts and should be considered as measuring different physiological variables with their own normal ranges, which can be carefully approximated as a cardiac index of 2.5–3.5 L⋅min−1⋅m−2. Therefore, knowledge of exact points of flow measurement and technique details along with dynamic assessment and a little physician’s common sense are crucial for correct data interpretation. As for the clinical decision making, based on monitoring results, CO response prediction is often difficult owing to the multidimensional character of the interaction of its determinants. |
