This came up in Question 28.1 from the first paper of 2011. The anatomy of the pulmonary artery catheter is discussed in greater detail elsewhere. This is a brief summary, of which the most important aspect is really this diagram:
When handling one of these things in a viva, one may be expected to mention some of the safety features.
Safety features of the PA catheter include the following:
This a full-text version of the seminal paper from 1970:
Swan HJ, Ganz W, Forrester J, Marcus H, Diamond G, Chonette D (August 1970). "Catheterization of the heart in man with use of a flow-directed balloon-tipped catheter". N. Engl. J. Med. 283 (9): 447–51.
A manufacturer (Edwards) offers some free information about the PA catheter on their product page.
The PA catheter section from The ICU Book by Paul L Marino (3rd edition, 2007) is a valuable read.
Armstrong, Ehrin J., James M. McCabe, and Melvin D. Cheitlin. "Pulmonary artery catheterization in the intensive care unit: just numbers floating by?."Archives of internal medicine 171.12 (2011): 1110-1111.
Additionally, UpToDate has an article on PA catheter complication