Impulse Oscillometry Pulmonary Function Abnormalities in Sickle Cell Disease
Context: Sickle Cell Disease (SCD) is characterized by an inherited point mutation in the hemoglobin (Hgb) HBB gene, which results in hemoglobin polymerization and red blood cell sickling when not fully oxygenated. Inflammatory responses to intravascular hemolysis may be the cause of abnormal pulmonary function found in sickle cell disease. Objective: Our goal was to determine if Impulse Oscillometry (IOS), a measure of pulmonary function, is a sensitive tool to detect a subpopulation of sickle cell patients at increased risk of sickle cell related complications. Design: We conducted a case control study of subjects with SCD, hemolytic anemia controls with other Hemoglobinopathies and Hereditary Spherocytosis (HS), and Hgb AA/AS controls. Setting: Our study took place at Children’s Hospital of Los Angeles in the outpatient setting. Methods: We collected each subject’s self-reported medical history, and blood samples to measure markers of hemolysis and inflammation. IOS was performed to measure airway reactance (AX) and total airway resistance at an oscillation frequency of 5Hz (R5). Results: 22 SCD, 20 Control, and 19 Hemoglobinopathy and HS subjects were studied. The percentage of abnormal R5 readings were high in all populations with no significant difference between the populations (SCD: 37% Controls: 40% Hemoglobinopathies and HS:32%; p>.05). There was, however, a significant difference in AX between SCD, Controls, and Hemoglobinopathies and HS (p<.05). Conclusion: Our study demonstrates a high rate of pulmonary function abnormalities in sickle cell disease subjects and the control populations. Analysis will be done to determine the relationship between the level of hemolysis amongst the SCD subjects with normal R5 and AX readings compared to SCD with abnormal readings. IOS may be a more sensitive measure of airway obstruction but would need to be correlated with complete spirometry and plethysmography with pre and post bronchodilator pulmonary function testing.
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"Impulse Oscillometry Pulmonary Function Abnormalities in Sickle Cell Disease" (2018). MU-COM Research Day. 90.