Supporting health equity with bias-free pulse oximetry

项目摘要 脉搏血氧仪对于医生诊断和监测患者的呼吸异常是必不可少的。 在新冠肺炎大流行期间，它们的重要性增加了，因为脉搏血氧饱和度测量 低氧血症已成为住院患者的主要指征。临床研究表明， 商用脉搏血氧饱和度测量仪(SpO2)系统性高估了真实动脉血氧分压 饱和度测量(SaO2)适用于血液中氧气浓度较低的深色皮肤色素沉着者。 这种偏见会导致黑皮肤的人呼吸功能受损，不符合住院或 启动呼吸机支持，从而使特定人群(黑人、拉丁裔和美洲原住民) 与白皮肤的人相比，高死亡率或发病率的风险高得不成比例。未发布 对这一有充分记录的观察结果存在解释，事实上，现有的文献往往是相反的 声明脉搏血氧仪测量不受皮肤色素沉着的影响。我们的理论分析和 然而，初步研究表明，这种偏差是由于当今设备使用红色发光二极管造成的 光源，其宽光谱带宽与黑色素浓度的光谱吸收相互作用 皮肤，以系统地转移设备的校准。这种变化导致人为低血时血氧饱和度偏高 深色皮肤患者的氧气浓度。拟议的3个目标将扩大我们迄今的努力，提供一个 为消除这种偏见并促进开发和推广简单、廉价、 和无偏压脉搏血氧仪。在目标1中，我们将：(A)确定是否有其他依赖光谱的成分 (B)确定光源带宽如何与黑色素相互作用， 包括在通过手指的光谱传输中是否存在其他依赖于脉冲的变化，以及 SpO2测量对光源带宽的敏感度；(C)具体说明实际峰值波长和 无偏压脉搏血氧仪所需的光谱带宽；和(D)制造优化的光源，以提供 目标2中用于测试的无偏压脉搏血氧仪测量。在目标2中，我们将演示手指探头 在Aim 1D中开发，提供不会高估真值的无偏压脉搏血氧计测量(SpO2 低血黑皮肤色素沉着者的动脉血氧饱和度测定 氧气浓度。在目标3中，不会像目标1和目标2那样使用人类主体，我们将把我们的 结果(即，打印、面对面和社交媒体)通常提供给医生、医院和医疗保健机构 为未被充分代表的少数群体服务。作为目标3的一部分，与利益攸关方董事会合作 由健康公平研究所召集，我们将以医疗和受影响社区为目标 通过教育推广减轻当前设备的影响，并向它们介绍无偏压脉冲 一旦血氧计可用。最后，我们将把这项技术授权给PULSE的主要制造商 血氧计，优先考虑那些为弱势人群提供医院和诊所的人。

Project Summary Pulse oximeters are essential for physicians’ diagnosis and monitoring of respiratory anomalies in patients. During the COVID-19 pandemic, their importance has grown because pulse-oximeter measurements of hypoxemia have become the major indication for hospitalizing patients. Clinical studies have shown that commercially available pulse oximeter measurements (SpO2) systematically overestimate true arterial oxygen saturation measurements (SaO2) for persons with dark skin pigmentation at low concentrations of O2 in the blood. This bias results in respiratory compromised persons with dark skin not meeting criteria for hospitalization or initiation of ventilator support, thereby putting specific populations (Black, Latinx, and Native American) at disproportionately greater risk for higher mortality or morbidity than those with light skin. No published explanations exist for this well-documented observation and, indeed, the available literature often contrarily states that pulse oximeter measurements are not affected by skin pigmentation. Our theoretical analysis and pilot research, however, demonstrate that the bias is due to present-day devices’ use of red light-emitting diode light sources, whose broad spectral bandwidth interacts with the spectral absorption of melanin concentration in skin to systematically shift the devices’ calibration. This shift causes artificially high values of SpO2 at low blood concentrations of O2 for patients with dark skin. The 3 proposed aims will extend our efforts to date, providing a scientific foundation for eliminating this bias and to foster development and promotion of simple, inexpensive, and bias-free pulse oximeters. In Aim 1, we will: (a) determine if there are other spectrally-dependent constituents in the finger that change with each pulse; (b) determine how light-source bandwidth interacts with melanin, including whether there are other pulse-dependent changes in spectral transmission through the fingers, and how sensitive SpO2 measurements are to light source bandwidth; (c) specify the practical peak wavelength and spectral bandwidth needed for bias-free pulse oximetry; and (d) fabricate an optimized light source that provides bias-free pulse oximeter measurements for testing in Aim 2. In Aim 2, we will demonstrate that the finger probe developed in Aim 1d provides bias-free pulse oximeter measurements (SpO2) that do not overestimate true arterial oxygen saturation measurements (SaO2) for persons with dark skin pigmentation at low blood concentrations of O2. In Aim 3, which will not employ human subjects as in Aims 1 and 2, we will translate our findings (i.e., print, in-person, and social media) to physicians, hospitals, and health care facilities commonly serving underrepresented minority populations. As part of Aim 3, in collaboration with a Stakeholder Board convened by the Institute for Health Equity Research, we will target the medical and affected communities to mitigate the impact of current devices through educational outreach and introduce them to bias-free pulse oximeters once they are available. Finally, we will license the technology to major manufacturers of pulse oximeters, giving preference to those who supply hospitals and clinics serving disadvantaged populations.