Optimizing Oximetry
By Sai Satvik Kolla
Arjun Putcha
Source: Srilakshmi Putcha
In the rapidly evolving landscape of medical technology, Arjun Putcha, a first-year doctoral student in the Applied Physical Sciences department’s Bai Lab, stands at the forefront of a groundbreaking initiative aimed at rectifying a critical flaw in pulse oximetry—ensuring accuracy across diverse skin tones with varying amounts of melanin. His journey began with a perceptive observation during his tenure as an Emergency Medical Technician (EMT), where he discerned a consistent overestimation in pulse oximeter readings for patients of color. These overestimations can be life-threatening when a patient requires oxygen, yet a pulse-oximetry reading indicates otherwise to a first responder.¹
Putcha illuminates the origins of his research, citing a pivotal 2020 FDA statement highlighting the unreliability of pulse oximeter readings, particularly for patients with varying skin tones. This revelation prompted Putcha to delve into the issue, emphasizing that it transcends a mere calibration challenge and constitutes a fundamental mathematical problem where the amount of melanin in the skin is not accounted for when calculating a pulse-ox reading. The FDA's subsequent requisite for approval, which specifies a minimum proportion of patients of color in calibration samples, further underscored the need to address the underlying mathematical issue.¹
Putcha’s overarching goal is clear: to provide a robust mathematical justification for the influence of skin pigmentation on pulse oximeter accuracy. His research aims to innovate existing calibration requirements, offering a hardware-based solution to a problem with far-reaching implications for equitable healthcare. Putcha seeks to pave the way for more accurate readings across diverse populations by challenging the prevailing assumptions and biases within pulse oximetry technology.¹
The mechanism underlying Putcha’s innovative device revolves around mitigating the impact of melanin on pulse oximeter accuracy. Typically, pulse oximeters calculate SpO2 levels, the percent saturation of hemoglobin in red-blood cells bound to oxygen, by measuring the amount of light which passes through the skin without getting absorbed by blood and tissue.²
A Schematic of the Device
Source: Arjun Putcha
Notably, experiments conducted on pigs with diverse skin tones have provided critical insights into the impact of skin pigmentation on oxygen level estimation. The team also obtained valuable data supporting the device's efficacy in real-world scenarios by testing the device on a model that mirrors human skin tones. Looking forward, Putcha envisions a continuum of trials, including Phase 1 clinical trials and further experiments, with the primary focus on solidifying the mathematical foundation of this groundbreaking device.¹
Arjun Tests the Quality of the Melanin Sensor
Source: Arjun Putcha
Putcha’s MABOS offers a promising solution to the persistent overestimation problem in pulse oximeters. The wearable and flexible patch is a practical "add-on" to existing pulse oximetry devices and corrects for the effects of melanin on pulse-ox measurements, enhancing accuracy. The broader implications of MABOS extend beyond technological innovation. Arjun and his team recognize MABOS’s societal impact, as the device illuminates how disparities in technology can inadvertently perpetuate inequities in clinical decisions, particularly for patients of color.² Putcha emphasizes that his priority is not merely to present a final solution but to catalyze industry attention towards this issue, advocating for developing more advanced devices that address challenges across the medical field.¹
Arjun Putcha's work epitomizes the intersection of technology and healthcare, showcasing how a focused pursuit of a solution can pave the way for more equitable and accurate medical practices.¹ As the healthcare industry embraces these innovations, the potential for precision medicine and inclusivity takes center stage, promising a brighter and more equitable future for patients worldwide. The transformative impact of MABOS extends far beyond the confines of a research lab, offering a glimpse into a future where medical technology is not only advanced but also genuinely inclusive, catering to the diverse needs of the global population.²
References:
Interview with Arjun Putcha, 1/10/24.
University of North Carolina at Chapel-Hill Department of Applied Physical Sciences. Redesigned pulse oximeter advances more equitable healthcare. Available at: https://aps.unc.edu/redesigned-pulse-oximeter-advances-more-equitable-healthcare/(Accessed 1/26/24).