Modified ultrafiltration versus conventional ultrafiltration: a randomized prospective study in neonatal piglets.

UNLABELLED: Cardiopulmonary bypass in neonates generates large increases in inflammatory mediators, causing edema formation that may lead to multiple organ dysfunction. Clinical strategies aimed at removing inflammatory mediators, reducing edema formation, and improving organ function include conventional and modified ultrafiltration. OBJECTIVE: This study examines the effectiveness of conventional and modified ultrafiltration in preventing weight gain, myocardial edema formation, and left ventricular dysfunction in neonatal piglets undergoing cardiopulmonary bypass. METHODS: In this randomized prospective study, 18 1-week-old piglets were supported with cardiopulmonary bypass at 100 ml kg(-1) x min(-1), cooled to 25 degrees C, exposed to 75 minutes of cardioplegic arrest, rewarmed to 37 degrees C, and weaned from bypass. Left ventricular myocardial contractility was assessed by the preload-recruitable stroke work method, with the use of a sonomicrometric two-dimensional cylindrical model, before bypass and at 10, 60, and 120 minutes after separation from bypass. RESULTS: Total body weight gain was significantly less in the modified ultrafiltration group than in either the conventional ultrafiltration group or the control group (no filtration). Myocardial wet/dry ratios were also improved with modified ultrafiltration, but not with conventional ultrafiltration, when compared with no filtration (control group). Hemodynamically, modified ultrafiltration was superior to conventional ultrafiltration and no filtration (control) in raising the mean arterial pressure and increasing the left ventricular preload-recruitable stroke work after bypass. CONCLUSION: Modified ultrafiltration is superior to conventional ultrafiltration and no filtration in reducing the total body weight gain, lessening myocardial edema, raising mean arterial pressure, and improving left ventricular contractility in neonatal piglets undergoing cardiopulmonary bypass and cardioplegic arrest.