Venoarterial modified ultrafiltration versus conventional arteriovenous modified ultrafiltration during cardiopulmonary bypass surgery

BACKGROUND AND OBJECTIVES: Different types of modified ultrafiltration (MUF) systems evaluated showed that none of the MUF techniques adhered to the normal venous to arterial blood flow dynamics. This study compared a conventional arteriovenous modified ultrafiltration (AVMUF) system to a custom-designed venoarterial modified ultrafiltration (VAMUF) system. DESIGN AND SETTINGS: Randomized, controlled clinical study conducted at the Northwest Armed Forces Military hospital in Tabuk, Saudi Arabia. PATIENTS AND METHODS: Sixty patients who underwent MUF during the years 2007 and 2009 were divided into 2 groups: the AVMUF (n=30) and the VAMUF (n=30) groups. MUF was performed for a mean time of 12 minutes in both groups. In AVMUF, blood was removed from the aorta, hemoconcentrated, and infused into the right atrium (RA). In VAMUF, blood flow was from the RA through a hemoconcentrator and re-infused into the aorta. RESULTS: Results of the study showed that the VAMUF group required a shorter ventilation time (P<.001), intensive care unit (ICU) (P=.003), and hospital stay (P=.007) than the AVMUF group. Results also demonstrated a lower percentage of fluid balance (P=.008) in the VAMUF group. The systolic (P<.001) and mean blood pressures (P<.001) were significantly higher after VAMUF, with a decrease in heart rate (P<.001) and central venous pressure (P=.002). The VAMUF group showed a significantly greater decrease of creatinine (P<.001), serum lactacte (P<.001), and uric acid (P<.027) over time with no significant differences in oximetry. CONCLUSION: Results prove that VAMUF is a more physiological technique than AVMUF.