Pulse Ox Basics
This is being estimated by a pulse oximeter
Blood Oxygen Levels (SpO2)
This medical condition occurs when blood oxygen levels are low - often below 92%.
Hypoxemia
This type of regression analysis was used to assess slope and intercept differences across trials.
Linear Regression
This skin pigment is largely responsible for red-light absorption in the epidermis.
Melanin
This metric of 'peakiness' helps assess whether a pulse oximeter signal was 'sharp' or 'flat'
Kurtosis
Pulse oximeters typically use these two wavelengths to measure oxygen levels
Red & NIR
This phenomenon, where hypoxemia is missed due to overestimated oxygen levels by pulse oximeters, is twice as likely in black patients.
Occult Hypoxemia
This statistical test was used to compare paired results across pigmented and nonpigmented datasets
Paired T-Test
This skin pigment is largely responsible for red-light scattering in the epidermis.
Melanosome
This plotting library was used for real-time data visualization. It's fast...
Fastplotlib
Modulation Ratio (R)
Pulse oximetry has largely supplanted the use of this gold-standard method for measuring blood oxygen levels.
Arterial Blood Gas Test (ABG)
The authors used this spectral domain method to extract frequency-based features of pulse oximeter data
Fourier Transform
A variant of this law, used in the study's model, relates absorbance to concentration, path length, wavelength, and depth.
Beer-Lambert's Law
Light-Tissue interactions can be divided into transmission, absorption, reflection, and this.
Scattering
There are two components extracted when measuring light absorbance: the baseline (DC) component, and this.
pulsatile (AC)
According to Medicare, blood oxygen levels below this threshold can qualify a patient for home oxygen.
88%
When comparing the modulation ratio (R) and true oxygen saturation using a linear regression, a reduction in this parameter indicates reduced sensitivity of the pulse oximeter to changes in oxygen levels.
Slope
The author's used this animal model, featuring dual-pigmented skin regions, for their experiment.
Hampshire Pig
The authors added this coefficient to account for light lost as it travels through tissue.
Attenuation Coefficient
The pulsatile (AC) component of absorption is directly affected by this category of blood vessels.
Arteries
The study shows that reduced sensitivity of light absorbance for this color accounts for the racial bias in pulse oximetry.
Red
The use of this metric allows us to determine how consistently pulse oximeters perform on similar pigmentations.
Inter-Location Regression
Melanin has a higher absorbance in this wavelength region, thereby affecting pulse oximeter accuracy.
Red (660 nm)
This mathematical operation was used to model how a real-world LED (with spectral spread) interacts with the absorbance spectra of melanin and hemoglobin.
Convolution