Clinical review: Does it matter which hemodynamic monitoring system is used?

Abstract

Hemodynamic monitoring and management has greatly improved during the past decade. Technologies have evolved from very invasive to non-invasive, and the philosophy has shifted from a static approach to a functional approach. However, despite these major changes, the critical care community still has potential to improve its ability to adopt the most modern standards of research methodology in order to more effectively evaluate new monitoring systems and their impact on patient outcome. Today, despite the huge enthusiasm raised by new hemodynamic monitoring systems, there is still a big gap between clinical research studies evaluating these monitors and clinical practice. A few studies, especially in the perioperative period, have shown that hemodynamic monitoring systems coupled with treatment protocols can improve patient outcome. These trials are small and, overall, the corpus of science related to this topic does not yet fit the standard of clinical research methodology encountered in other specialties such as cardiology and oncology. Larger randomized trials or quality improvement processes will probably answer questions related to the real impact of these systems.

Figure 1

Fluid optimization concept based on stroke volume monitoring. The concept of cardiac output maximization based on fluid administration and stroke volume monitoring. Small boluses of fluid are administered intravenously (200 to 250 ml at a time) until the stroke volume increases by <10%.

Figure 2

Fluid optimization concept based on minimization of dynamic parameters of fluid responsiveness. The concept of cardiac output maximization based on the minimization of dynamic parameters of fluid responsiveness. This minimization can be achieved by monitoring pulse pressure variation (PPV), stroke volume variation or respiratory variations in the plethysmographic waveform.

Figure 3

Integrative hemodynamic monitoring approach. ED, emergency department; HD, hemodynamic; OR, operating room; PAC, pulmonary artery catheter. Reproduced with permission from Alhashemi and colleagues [3].