1 Department of Cardiology and the Division of Hematology of the Department of Medicine of the Children's Hospital Medical Center and the Laboratory for Neonatal Research, Boston Hospital for Women and the Department of Pediatrics, Harvard Medical School, Boston
The role of red blood cell (RBC) 2,3- Diphosphoglycerate (DPG) as a prime regulator of oxygen release by hemoglobin in congenital heart disease (CHD) was evaluated in 73 catheterized children. Although a decrease in arterial oxygen tension (Pao2) was associated with an increase in RBC DPG and P 50 (oxygen tension at 50% hemoglobin saturation), there was a great variability in the DPG concentration at any given Pao2. This variability may in part be related to the apparent influence of congestive heart failure (Pao2 > 60 mm Hg) and systemic oxygen transport (systemic blood flow times arterial oxygen content) on RBC DPG. Cardiac surgery, palliative or corrective, as well as noncardiac surgery (one patient) resulted in an unexplained, paradoxical rise in RBC DPG in the immediate postoperative period (3 to 14 days) despite normal or improved Pao2. RBC DPG and P 50 values returned to normal levels within a month after surgery in patients with successful cardiac repair, but remained elevated in those with palliative surgery. These observations suggest that in addition to a low Pao2, an increase in RBC DPG and consequent rightward shift of the oxygen hemoglobin dissociation curve in CHD may occur as a response to congestive heart failure, reduced systemic oxygen transport, and a major surgical procedure. The reversibility of this adaptive mechanism was demonstrated following successful surgical correction of cyanotic CHD.
Submitted on August 4, 1970