Dangerously wrong oxygen readings in dark-skinned patients spur FDA scrutiny
Dangerously wrong oxygen readings in dark-skinned patients spur FDA scrutiny

          
          
Dubious devices
Pulse oximeters were developed in the 1970s and have since become a mainstay in routine patient care, with current devices typically clipping onto a finger. They estimate blood oxygen saturation (SpO2) by assessing the relative absorbance of two wavelengths of light (red and infrared, generally) beamed into the finger, plus the pulse-based flow of blood through the arteries.
But, the devices were mainly tested and calibrated on light-skinned patients. Researchers suspect that the high levels of skin pigment, melanin, in dark-skinned patients can interfere with the absorbance measurements. Numerous studies have found that pulse oximeters tend to overestimate oxygen saturation in dark-skinned patients.
The dangers of those faulty readings were realized during the pandemic. A study published in May found that pulse oximeters' overestimation of SpO2 in Black and Hispanic patients with COVID-19 caused significant delays in care, including access to lifesaving treatments, such as dexamethasone. For some patients, the faulty readings meant their eligibility for treatment was never recognized by the devices. That study, led by researchers at Johns Hopkins University, appeared in JAMA Internal Medicine.
In July, another study in JAMA Internal Medicine by researchers in Boston found that darker-skinned patients in intensive care who had inaccurate pulse oximeter readings ended up receiving less supplemental oxygen. Meanwhile, a study published in the same month in BMJ by researchers in Michigan looked at records of more than 30,000 patients at the Veterans Health Administration between 2013 and 2019. It found that Black patients were more likely to have hypoxemia undetected by pulse oximetry. The study notes that hidden hypoxemia is linked to an increased risk of morbidity and mortality.


          
                  