ARE THE ADVANTAGES OF PERCUTANEOUS CANNUL ATION OFFSET BY INCREASED BLOOD TRAUMA

The development of thin-walled cannulas which can be introduced by per cutaneous technique into femoral artery and vein has revived interest in emergency cardiopulmonary support (CPS). To assess possible blood d amaging effect due to the small-bore cannulas, 8 in vitro perfusions w ere performed with two parallel pump circuits: one circuit with a 17 F arterial and a 21 F venous cannula, one circuit without cannulas (con trol). The circuits were filled with 61 of bovine blood and run for 6 hours at a temperature of 37-degrees-C and a flow of 4 1/min. Serial b lood samples were taken before and during the experiment. There was a significantly higher level of free plasma haemoglobin (pl Hb) and a de creased number of leukocytes (Lc) after 6 hours of perfusion in the gr oup with percutaneous cannulas as compared with control (pl Hb: 63.2 /- 0.3 vs. 26.3 +/- 4.1 mumol/l, p <0.05, Lc: 2.4 +/- 0.6 vs. 4.6 +/- 0.8 x 10(9)/l, p <0.05, mean +/- se). Conclusion: percutaneous cannula s are associated with an increased blood trauma. If extended cardiopul monary support is considered (more than several hours), percutaneous c annulas should be replaced by large-bore cannulas.