Potential Misuse of the Pulmonary Artery Catheter

Abstract

The pulmonary artery catheter is a basic tool of critical care medicine. It was the development of bedside hemodynamic monitoring and effective mechanical ventilators that drove the widespread increase in the number of intensive care units (ICUs) in the 1970s and 1980s. ICUs are largely intended to provide care for patients who need (or may need) mechanical ventilation or for those who need (or may need) invasive hemodynamic monitoring. Teams of professionals were trained in hemodynamic monitoring and in the management of mechanical ventilators to provide care in these units. Pulmonary artery catheterization is not just something we do in the ICU; it is at the core of critical care medicine. Recently, the effectiveness of this tool has been questioned. In a prospective cohort study of 5735 critically ill patients, my colleagues and I demonstrated that management with right heart catheterization in the first 24 hours in the ICU was not associated with an improvement in outcome. In fact, management guided by the right heart catheter was associated with an increased risk of death in the 30 days following catheterization. This finding was met with great concern by the critical care community. The Society for Critical Care Medicine convened an expert panel to review the evidence for and against the effectiveness of right heart catheterization and to make recommendations to guide the use of the catheter by intensivists. The panel concluded that there were very few indications for right heart catheterization for which there was any published evidence of effectiveness. The report from this meeting was criticized, not for being too harsh in their criticism of the right heart catheterization but for giving too much weight to expert opinion in defending the use of right heart catheterization. The panel recommended that prospective, randomized, experimental studies be performed to determine the safety, effectiveness, and optimal use of the right heart catheter in the care of critically ill patients. Our study supports the hypothesis that right heart catheterization may not be effective as it is used today. But how could right heart catheterization fail to benefit patients? The right heart catheter measures intracardiac pressures and flows with acceptable accuracy. It provides valuable information that allows the diagnosis of cardiac and hemodynamic disorders. When this information is presented to clinicians, it frequently results in changes in therapy. It is logical to conclude, as many have, that the right heart catheter should provide benefit for critically ill patients. The purpose of this article is to explore the various ways that right heart catheterization may fail to provide benefit to critically ill patients. Table 1 indicates the logical chain of events (column 1) thought to occur when a patient with hemodynamic abnormalities is identified, catheterized, and treated using information from the right heart catheter. This chain of events is thought to lead to improved outcomes for patients. There are many potential problems that occur commonly and may result in outcomes that are less beneficial or even harmful for the patient (column 2).

Key Words:

ICU - pulmonary artery catheterization