Sunday, March 09, 2014

The rise and fall of the PA catheter

From an article in Annals of Intensive Care:

The birth of the intermittent injectate-based conventional pulmonary artery catheter (fondly nicknamed PAC) was proudly announced in the New England Journal of Medicine in 1970 by his parents HJ Swan and William Ganz. PAC grew rapidly, reaching manhood in 1986 where, in the US, he was shown to influence the management of over 40% of all ICU patients. His reputation, however, was tarnished in 1996 when Connors and colleagues suggested that he harmed patients. This was followed by randomized controlled trials demonstrating he was of little use…
While a handful of die-hard followers continued to promote his mission, the last few years of his existence were spent as a castaway until his death in 2013. His cousin (the continuous cardiac output PAC) continues to eke a living mostly in cardiac surgery patients who need central access anyway…
In the 1980s 20% to 40% of seriously ill patients who were hospitalized were reported to undergo pulmonary artery catheterization [4]. This phenomenon occurred despite that fact that the safety, accuracy, and benefit of the device had never been established.

This has a familiar ring. It’s where we are today with techniques such as point of care ultrasound and pulse contour analysis. I think the problem with the PA cath was a lack of skill applied to interopretation of the data derived from the catheter. There is no reason to think PCWP and all the other measurements weren’t valid surrogates. Applying the measurements to clinical decision making is another matter. The use of POC echo and application of results to patient care is even more demanding. The new techniques are rapidly gaining in popularity but have not been validated in high level studies.

In the review some problems inherent in the technology itself, particularly in the measurement of cardiac output, are cited.

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