Is circulatory phospholipase A₂ removed by continuous hemodiafiltration in septic acute renal failure?

Abstract

Type II phospholipase A₂ (PLA₂) is an enzyme of 14kD. The increased plasma activity of PLA₂ plays a significant role in the pathophysiology of sepsis. This study was carried out to determine if PLA₂ could be removed by continuous hemodiafiltration (CHDF). We assayed the plasma activity of PLA₂ and the clearance of PLA₂ by CHDF in patients with septic acute renal failure. CHDF was performed using a polyacrylonitrile (PAN) hemofilter. The blood flow rate through the extracorporeal system was 60-100ml·min^-1 with a dialysis fluid rate of 500ml·hr^-1. The ultrafiltration rate was 500ml·hr^-1 and the replacement solution was administered at a rate of 350-500ml·hr^-1. The extracorporeal circuit was protected against coagulation with nafamostat mesilate. Blood and ultrafiltrate samples were collected before starting CHDF (0hrs), and 12 hours (12hrs) and 24 hours (24hrs) after starting CHDF. Arterial PLA₂ activity was 839±684pmol·min^-1·ml^-1 at 0hrs, 642±414pmol·min^-1·ml^-1 at 12hrs and 573±355 pmol·min^-1·ml^-1 at 24hrs, respectively. The changes in arterial PLA₂ activity were not statistically significant. PLA₂ activitiy at the entry port of the filter was significantly higher than that at the exit port at 24hrs. The clearance of PLA₂ activity from the ultrafiltrate was 0.09±0.06ml·min^-1 at 12hrs and 0.15±0.15ml·min^-1 at 24hrs. The clearance of PLA₂ activity from the blood was 27±29ml·min^-1 at 12hrs and 23±12ml·min^-1 at 24hrs. The results suggest that plasma PLA₂ can be removed to some extent, but arterial PLA₂ activity is not significantly decreased. Further investigation is needed to develop an efficient technique to remove plasma PLA₂.