Microbubble image enhancement and pericardiocentesis.

When performing pericardiocentesis, if blood-stained fluid is aspirated, one must ensure that the aspirating needle is not within one of the cardiac chambers. To clarify the position of the needle some contrast material may be injected using X-ray screening and for this reason pericardiocentesis is often performed in the catheter laboratory, particularly if the effusion is small, loculated or the heart is in an unusual position. Ultrasound immaging is now commonly used to guide the aspirating needle and if blood-stained fluid is withdrawn we reinject a few millilitres and this outlines the space from which the fluid is withdrawn with microbubbles. This modification of ultrasound immaging adds to the safety of the procedure and allows difficult procedures to be carried out in the ward or intensive care unit, where X-rays screening is not easily available.