Systemic oxygen transport during zero-balanced continuous hemofiltration in porcine endotoxemia

Introduction: Whether hemofiltration improves oxygen metabolism during sepsis is controversial. The aim of this study was to evaluate the effect of continuous hemofiltration on oxygen transport using an awake porcine model of endotoxemia. Methods: Nineteen pigs were divided into a control group (CTRL, n=7), a hemofiltration group (HF, n=7), and an extracorporeal circuit only group (ECC, n=5). All animals, spontaneously breathing room air, received intravenous E-coli endotoxin (10 μg/kg/hr) and lactated Ringer's resuscitation in a common regimen for 24 hours. Hemofiltration was started 30 minutes after initiation of endotoxin and continued until the end of the experiment (filter sieving property < 21,000 Dallons, circuit flow 100 ml/min, filtration rate 1,000 ml/hr, equivalent D5 lactated Ringer's solution replaced). Results: Data are represented by mean ± SD,*;p<.05 vs. CTRL. (Figure Presented) A subacute increase of oxygen consumption (VO2) in HF and ECC was noted beginning at 4 hours. Oxygen delivery (DO2) subsequently tended to increase in HF and ECC. At 24 hours, those changes became insignificant and acidosis was not seen. Conclusions: Changes in DO2 and VO2 were associated with extracorporeal blood flow. We have previously reported that hemofiltration increases cardiac output, but has no striking effects in respiratory dysfunction. It is uncertain whether elevated cardiac output is beneficial, since the expected hyperdynamic change was amplified by hemofiltration. The change in oxygen metabolism could not explain why cardiac output increased, since it occurred before the increase in cardiac output.