In vitro reappraisal of the pulmonary artery catheter balloon volume-pressure relationship: comparison of four different catheters.

The most serious risk of the use of the flow-directed pulmonary artery (PA) catheter is PA rupture due to high balloon inflation pressure of the catheter. Previously reported measurements of PA catheter intra-balloon pressure and volume during balloon inflation were performed mostly in a static fashion, that is, measurements were performed after a certain volume of air had been injected into the balloon. In this study, simultaneous measurements of pressure and volume, in addition to a static study, were performed in vitro using four PA catheters (Abbott Opticath, Arrow Hands-Off, Baxter Edwards and Spectramed). The peak intra-balloon pressure was recorded immediately before loss of resistance was felt in the inflating syringe. Contrary to previously reported studies, the peak intra-balloon pressure was not the pressure exerted on the pulmonary artery wall unless the tip of the catheter was already in the peripheral pulmonary artery. The loss of resistance volume which was constant for each catheter could be used reliably as an indicator of instantaneous balloon inflation. The slower the rate of injection, the lower were the peak pressure and the injection volume at the peak pressure. The Abbott, Edwards and Spectramed catheters had similar characteristics of inflation volume and intra-balloon pressure. The Arrow catheter had higher balloon opening and plateau pressures, and a smaller balloon volume compared with the other three catheters.