To the Editor.
—The recent article on autologous blood donation1 was welcome and informative. Further aspects of optimal blood conservation deserve mention. Normovolemic hemodilution is an extremely useful anesthetic technique,2 which can be used in conjunction with autologous donations to further avoid homologous transfusion. It is more underutilized than autologous donation and may be erroneously deferred because autologous blood is available. Seventeen of 44 patients in the autologous group undergoing orthopedic surgery required homologous blood.1 The nadir hematocrit of 0.304 (30.4%) suggests that hemodilution was not attempted in these patients.In healthy adult patients without cerebrovascular, myocardial, or severe pulmonary disease, intraoperative hemodynamic stability and adequate oxygen transport can be maintained with stress-free anesthesia and a 100% inspired oxygen concentration with hematocrits as low as 0.20 (20%). In children, successful hemodilution with hematocrits between 0.10 (10%) and 0.20 (20%) is possible.3 Hemodilution is safely done with