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COVID-19大流行期间，由于脉搏血氧仪测量的 低氧血症已成为住院患者的主要指征。临床研究表明 市售脉搏血氧仪测量（SpO 2）系统性地高估了真实动脉氧 在血液中低浓度O2时，对深色皮肤色素沉着的人进行饱和度测量（SaO 2）。 这种偏倚导致呼吸系统受损的深色皮肤患者不符合住院标准， 启动呼吸机支持，从而将特定人群（黑人，拉丁美洲人和美洲原住民）置于 高死亡率或发病率的风险不成比例地高于浅色皮肤的人。没有已发表的 对这一有据可查的观察结果的解释是存在的，事实上，现有的文献往往相反， 指出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，这种偏见是由于目前的设备使用红色发光二极管 光源，其宽光谱带宽与黑色素浓度的光谱吸收相互作用， 皮肤来系统地改变设备的校准。这种变化导致低血流量时SpO 2值人为升高 对于皮肤黝黑的患者，氧气浓度。这三个拟议目标将延续我们迄今为止的努力， 消除这种偏见的科学基础，并促进开发和推广简单，廉价， 和无偏差脉搏血氧仪。在目标1中，我们将：（a）确定是否存在其他光谱依赖成分 （B）确定光源带宽如何与黑色素相互作用， 包括在通过指状物的光谱透射中是否存在其它脉冲相关的变化，以及 SpO 2测量对光源带宽的敏感程度;（c）指定实际峰值波长，以及 无偏差脉搏血氧测定法所需的光谱带宽;以及（d）制造优化的光源，其提供 Aim 2中用于测试的无偏差脉搏血氧仪测量。在目标2中，我们将证明手指探头 Aim 1d中开发的无偏倚脉搏血氧仪测量（SpO 2）不会高估真实 动脉血氧饱和度测量（SaO 2）的人与深色皮肤色素沉着在低血 O2的浓度。目标3不像目标1和目标2那样使用人类受试者，我们将把我们的 发现（即，印刷品、面对面和社交媒体），通常提供给医生、医院和医疗机构， 为代表性不足的少数民族服务。作为目标3的一部分，与利益攸关方委员会合作 由健康公平研究所召集，我们将针对医疗和受影响的社区， 通过教育推广减轻当前设备的影响，并向其介绍无偏置脉冲 血氧饱和度仪一旦可用。最后，我们将向脉冲的主要制造商授权该技术 血氧计，优先考虑那些为弱势群体提供医院和诊所的供应商。

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.