Thrombogenicity of tips of umbilical catheters.

In an experiment in which several types of umbilical artery catheters were inserted into the aortas of newborn lambs, several catheters had discrete thrombi located at the tip. There appeared to be a difference between types of catheters in the proportion with thrombi at the tip. Scanning electron micrographs of catheter tips showed that several types had rough tips. It is suggested that a rough tip would promote the formation of thrombus at a location where it could be dislodged by flushing of the catheter. The problems that have been reported with umbilical artery catheters may have been caused by thrombus at the tip rather than on the shaft of these catheters.