CARDIOPULMONARY BYPASS WITH MODIFIED FLUID GELATIN AND HEPARIN-COATEDCIRCUITS

We have assessed the efficacy of cardiopulmonary bypass (CPB) using no rmal colloid oncotic pressure (COP) in a randomized, controlled study of 20 patients undergoing elective coronary artery surgery using hepar in-coated circuits. For CPB, we used either crystalloid priming 1650 m l (n = 10) or colloid priming 1650 ml (2.4% modified fluid gelatin, n = 10). While COP did not change during bypass in the colloid group, a decline was observed in the crystalloid group (P = 0.005). By the end of bypass, the decrease in COP compared with baseline (Delta COP) was 8.5 (S.D. 1.1)mm Hg in the crystalloid group compared with 1.5 (2.1) m m Hg in the colloid group (P = 0.0001). Delta COP correlated positivel y with fluid balance during bypass (r(2) = 0.41, P = 0.002). Similar i ncrements in complement factors C3b/c and C4b/c, tumour necrosis facto r-alpha and neutrophil elastase, but not endotoxins, were found in bot h groups as indicators of a systemic inflammatory response. A clinical performance score composed of fluid balance, postoperative duration o f intubation and the difference between rectal temperature and skin te mperature was more favourable in patients treated with colloid priming (P = 0.03). Median postoperative hospital stay was 7 (range 5-16) day s in the crystalloid group compared with 5 (4-8) days in the colloid g roup (P = 0.016). Regression analysis indicated that CPB time, fluid b alance during operation and postoperative P-O2/FIO2 ratio were indepen dent factors that predicted postoperative hospital stay. From these pr eliminary results we conclude that in the absence of endotoxaemia, use of a normal COP during CPB with modified fluid gelatin in heparin-coa ted circuits resulted in an improved postoperative course an a reducti on in hospital stay.