Since its introduction in 1970, patients who landed in a hospital's intensive care unit (ICU) were often given a PAC, or pulmonary artery catheter. The catheter, threaded into the right side of the heart via a blood vessel in the neck or groin, was a monitoring device that measured the pressure in the patient's heart and lung blood vessels [source: NCIB]. By 1986, 20 to 40 percent of all ICU patients got one -- surprising, since the device's safety, accuracy and benefits were never proven [source: Marik].
Although complications from the use of a PAC were uncommon, and PAC-associated deaths rare, patients sometimes suffered from bleeding in the lung and changes in heart rhythm [source: NCIB]. Eventually, studies from 1990s and early 2000s showed the routine use of a PAC with patients in shock was actually inferior to less-invasive strategies, as the PAC could be unreliable and inaccurate and did not improve patient outcomes. Further, newer devices were developed that produced better results and were less invasive. In 2014, the device is rarely used on patients in shock [source: Marik].