Exploring hemodynamics: a review of current and emerging noninvasive monitoring techniques.

The lack of randomized controlled trials suggesting improved outcomes with pulmonary artery catheter use and pressure-based hemodynamic monitoring has led to a decrease in pulmonary artery catheter use. However, an increasing amount of literature supporting stroke volume optimization (SVO) has caused a paradigm shift from pressure-based to flow-based techniques. This article discusses emerging flow-based techniques, supporting evidence, and considerations for use in critical care for methods such as Doppler, pulse contour, bioimpedance, bioreactance, and exhaled carbon dioxide. Regardless of the device chosen, the SVO algorithm approach should be considered, and volume challenges should be guided by dynamic assessments of fluid responsiveness.