Blood temperature and cardiovascular stability in hemofiltration.

Temperature (T) changes in the blood flowing through the extracorporeal circuit markedly affect cardiovascular tolerance to fluid removal during either hemodialysis (HD) and isolated ultrafiltration. In this study we investigated the effect of blood T changes during postdilutional hemofiltration (HF). To this purpose we compared the changes in mean arterial pressure (MAP) and heart rate (HR) during HF and HD carried out at equivalent T of blood in the venous segment of the extracorporeal circuit. Results show that HF entails some heat loss from blood flowing in the extracorporeal circuit; if heat loss is made similar, HD affords nearly as much blood pressure protection as HF does. On the other hand at equivalent heat gain, HF causes nearly as much hypotension as HD does. We conclude that blood T changes in the extracorporeal circuit affect vascular stability (VS) even in HF. The marginal benefit of HF over HD, still observed at equalized T changes, remains to be elucidated.