ELEVATED EXHALED CARBON MONOXIDE CONCENTRATION IN HEMOGLOBINOPATHIES AND ITS RELATION TO RED BLOOD CELL TRANSFUSION THERAPY

Abstract

In this study, the authors examined a possible role of measurements of end-tidal carbon monoxide (CO), corrected for inhaled CO (ETCOc), as a noninvasive screening tool for hemoglobinopathies and as an indicator for when transfusions would be required in patients receiving chronic transfusions. ETCOc measurements were obtained in subjects with sickle cell disease (n = 18), thalassemia (n = 21), and healthy controls (n = 62). ETCOc values less than 3 parts per million (ppm) yielded a positive predictive value of 93% and negative predictive value of 94% in identifying hemoglobinopathies. Subsequently, 7 subjects with thalassemia had laboratory parameters and ETCOc measured over 2 transfusion cycles. ETCOc values were 4.90 ± 0.32 ppm (mean ± SD), with 89% of values being above normal (≥3 ppm). Pretransfusion ETCOc levels significantly correlated with pretransfusion reticulocyte count (r = .96, P <.001), but not with pretransfusion hemoglobin (r = .44, P = .16) or pretransfusion soluble transferrin receptors (sTfR, r = .52, P = .10). In conclusion, we found that patients with hemoglobinopathies have ETCOc values above the range for healthy controls and ETCOc measurements can be used as an adjunct to hemoglobin measurements to determine the proper timing of transfusions.

Keywords :

• adults
• children
• end-tidal carbon monoxide
• hemolysis
• thalassemia
• transfusion
• sickle cell disease

ACKNOWLEDGMENTS

The study was supported by Natus Medical, Inc., San Carlos, CA, and by the National Institutes of Health, contract grant numbers M01-RR00070 (Stanford University), M01-RR01271-16, HL-20985, and MCJ-061016-06 (Children's Hospital & Research Center Oakland).

Declaration of Interest: The authors report no conflicts of interest. Judith Hall was employed by Natus Medical, Inc. and Hendrik J. Vreman, Ronald J. Wong, David K. Stevenson were consultants to Natus Medical, Inc. at the time the study was performed. The authors alone are responsible for the content and writing of the paper.