Cardiovascular monitoring tools: use and misuse.

Abstract

To review important areas of current and novel hemodynamic monitoring practice in the intensive care unit and to highlight potential areas of physiologic and clinical use or misuse, as well as areas of uncertainty and ongoing controversy. To truly determine when hemodynamic monitoring tools are misused would require randomized controlled evidence of a measurable improvement in relevant clinical (as opposed to physiologic) outcomes. Unfortunately, little evidence of this kind exists, and that which does exist is highly controversial in nature. Because of the limited evidence of an effect of hemodynamic monitoring on clinical outcomes, the use and misuse of hemodynamic monitoring tools is typically judged on physiologic grounds (Does it improve physiology? Does it predict physiology? Is it physiologically rational?). The relation between physiologic gain and final clinical outcome, however, is tenuous. Recent investigations confirm this lack of a clear link. They also suggest that new technology that is now emerging to less invasively measure cardiac output and intrathoracic fluid compartments is ready for formal evaluations of efficacy and effectiveness. The effectiveness of hemodynamic monitoring in the intensive care unit remains inadequately tested and unproven. New tools are now rapidly emerging to challenge established technologies. Formal assessment of their efficacy and effectiveness is needed to avoid a repeat of the pulmonary artery catheter experience.