Non-Invasive Characterization of Oxygen Transport in Sickle Cell Disease: A Pilot Study

Abstract

Introduction: Vaso-occlusive (VOC) crisis is, in part, a result of microvascular ischemic insults to tissue causing pain in Sickle Cell Disease patients, which is a common presentation to the Emergency Department (ED). This study simultaneously measured and compared several global and regional indicators of oxygen transport in normal volunteers and subjects with Sickle Cell Disease (SCD).
Materials and Methods: Healthy African American volunteers were compared to SCD patients, assessed at states of clinical non-distress, referred to herein as “baseline”. All subjects under went 10 minutes of non-invasive monitoring to measure cardiac output, oxygen consumption, arterial oxygen saturation (SpO2), and Cutaneous tissue saturation of oxygenation (CtSO2).
Results: Twenty one patients (9=healthy & 12=SCD baseline) were chosen. The median super ficial CtSO2 (healthy vs. SCD baseline) was 72% (IQR=10.94) and 56% (IQR=26.86) with a p-value of 0.0011. Traditional measures of hemodynamic performance (heart rate, blood pressure, cardiac index) were not statistically significant between the two groups.
Conclusion: The study shows Sickle Cell Disease to share similarities with sub-clinical compensated state of shock on a microcirculatory level. The values obtained from the study can hopefully shed light into the intricacies of the baseline biophysiology of Sickle Cell Disease; with a foresight to further understand Vaso-occlusive crises pathological processes and sickled cells interactions with its surrounding environment.