A double volume exchange transfusion exchanges approximately what percent of the infant's blood volume?

• A. 60%
• B. 85%
• C. 100%
• D. 120%

Answer: (B)

A double-volume exchange transfusion works by continuously removing patient blood and replacing it with donor blood in volumes that equal roughly the patient’s total circulating blood volume, repeated twice. Because each volume exchange dilutes the native blood rather than instantly removing all of it, you don’t perfectly swap out every original cell with each pass. The process is often modeled as a dilution process: after one volume exchanged, about 63% of the infant’s original red cells have been replaced; after a second volume, about 86% have been replaced. That’s why a double-volume exchange transfusion typically exchanges roughly 85% of the infant’s blood volume.