Volumetric Monitoring in Critically Ill Patients

In patients with shock that are hemodynamically unstable, it is important to keep track of changes in preload, afterload, and contractility. Although much attention has been shifted toward assessment of fluid responsiveness and avoiding fluid overload, correct preload assessment is still the mainstay of advanced hemodynamic monitoring. Different tools exist to assess preload, and volumetric monitoring is one of these. Echocardiography, pulmonary thermodilution, and transpulmonary thermo- or dye/indicator dilution techniques able to assess end-diastolic volume (right, left, or global) received most attention, among other techniques estimating surrogate parameters of intravascular fluid volume. In this chapter we will discuss the different available volumetric monitoring techniques. After finishing this chapter, the reader will understand the differences between these different techniques.