Optimized hyperventilation preserves 2,3-diphosphoglycerate in severe traumatic brain injury

Abstract

Introduction: The concentration of 2,3-diphosphoglycerate (2,3-DPG/Hct) increases as a physiological occurrence to pH increase and hyperventilation. This response was tested in patients with severe traumatic brain injury (TBI). Method: The concentration of 2,3-DPG/Hct was measured daily for six days in eleven patients with severe TBI in need of optimized hyperventilation because of intracranial hypertension. Results: There was correlation between pH and the concentration of DPG/Hct. The concentration of 2,3-DPG/Hct remained predominantly within normal levels with slight increase in the sixth day of the study. The concentration of 2,3-DPG/Hct correlated significantly with measured partial pressure of oxygen that saturates 50% the hemoglobin of the blood (P50st), confirming the consistency of our data. Conclusion: The expected physiological response of a progressive increase in concentration of 2,3-DPG/Hct to hyperventilation was not observed. This fact may be explained by the intermittent and not sustained hyperventilation as dictated by the protocol of optimized ventilation.