This document provides a historical overview of the use of pulmonary artery catheters in anesthesia and critical care from 1970 to 2007, with an emphasis on studies from the past 6 years. It describes how the catheter was introduced in 1970 and how early studies suggested benefits to outcomes. However, over the past 6 years, several large, well-designed prospective trials and statistically sound retrospective studies have been published that show no benefit to outcomes from using pulmonary artery catheters and some even find potential increased morbidity with their use. The document focuses on randomized controlled trials in vascular surgery that failed to find improved outcomes from catheter use despite attempts at directed therapy based on catheter measurements.