Microbubble production in an in vitro cardiopulmonary bypass circuit ventilated with xenon

Xenon, as an anaesthetic gas, has the potential to be used in an increasing range of applications. However, its use in cardiopulmonary bypass (CPB) has not yet progressed from the rat model due to concerns that its relative insolubility may cause microbubble formation and/or expansion in the micro-vasculature of the patient. An in vitro CPB circuit was designed to create and measure gaseous microbubbles over a range of temperature gradients, pressure drop and gas tensions. We were able to demonstrate that our test circuit did not produce any significant microbubbles and that, under normal physiological blood pressures, a fixed gas bubble in connection with the circuit did not grow in the presence of Xe.