This book describes the pathophysiological significance of the hemodynamic monitoring parameters available to the clinician and their role in providing reliable and reproducible information on the cardiocirculatory status of a patient in shock. It is explained how measurements of these parameters enable the intensivist to understand the patient’s condition and to make more informed treatment decisions in order to optimize the hemodynamic status and improve the prognosis. Full guidance is provided on measurement of intravascular blood pressures, cardiac output, and derived variables. Methods of cardiac output determination based on the classical pulmonary thermodilution, transpulmonary thermodilution, echocardiography, and Doppler techniques are reviewed. Techniques based on calibrated and non-calibrated pulse contour analysis are discussed, with attention to their limitations. Furthermore, the dynamic indices of fluid responsiveness, their clinical applications, and issues related to their use are addressed. Care is also taken to explain the physiological concepts underlying various devices used by anesthesiologists and intensivists.