Hemodynamics following normovolemic hemodilution in elderly patients

The hemodynamic effects of acute hemodilution with dextran 70 as dilutional agent were evaluated in a group of elderly patients (mean age 68, range 60-79 years) anesthetized with neurolept analgesia. The isovolemic exchange of 1.1 liter of blood (mean) with a 6% solution of dextran 70 decreased the hematocrit value from 41 to 28%. As cardiac index did not exchange, the oxygen transport capacity was significantly reduced. The main compensating mechanism for this was an increased extraction of oxygen in the tissues and, to a minor extent, a raised arterial oxygen tension. The results of this study suggest that intentional hemodilution should be used with caution in aged patients.