Blood back flow into angiographic catheters.
OBJECTIVE
Because of a potential impact on thrombus formation, this study determines the degree of blood back flow into catheters filled with different fluids.


METHODS
Catheters filled with saline or non-ionic or ionic contrast medium were placed in pulsatile circulating human blood in vitro. Catheter orientation was varied, and blood back flow was recorded.


RESULTS
When the leading end of the catheter was angled downward, blood back flow into a contrast material-filled catheter was far greater than that into a saline-filled catheter (7.0 vs 0.5 cm). Conversely, when the leading end of the catheter was horizontal, blood back flow was much greater when the catheter contained saline versus contrast media (3.6 vs 0.4 cm). Ionicity of contrast material did not affect back flow.


CONCLUSIONS
Back flow of blood into a catheter can be considerable and is dependent on the type of fluid within the catheter and orientation of the leading end of the catheter. Angiographic techniques adjusted to these findings are important to maintain patient safety.
Department of Radiology, University of Washington Medical Center, Seattle, USA.
M A
MA
Savin
W H
WH
Bush
F L
FL
Starr
U P
UP
Schmiedl
J A
JA
Nelson
D001790:Blood Physiological Phenomena; D002404:Catheterization / Q000379:methods*; D003287:Contrast Media / Q000009:adverse effects*; D006801:Humans; D008955:Models, Cardiovascular; D013927:Thrombosis / Q000209:etiology*
D003287:Contrast Media