System for screening of the state of oxygenation of a subject

A processor for use in a system for screening of the state of oxygenation of a subject, said system comprising an imaging unit for obtaining a plurality of image frames of the subject over time, said processor being configured to process the image frames by

• recognizing the subject within an image frame,
• locating body parts of interest of the subject including at least the right upper extremity and at least one lower extremity of the subject,
• determining, per body part of interest, the perfusion index,
• selecting, per body part of interest, a plurality of pixels and/or pixel groups by use of said perfusion index,
• determining the blood oxygen saturation level for said plurality of pixels and/or pixel groups of the subject from pulse oximetry waveforms for at least two different wavelengths contained in the image frames,
• determining a difference blood oxygen saturation level between the determined blood oxygen saturation level for the right upper extremity and the determined blood oxygen saturation level for the at least one lower extremity, and
• comparing the determined difference blood oxygen saturation level, the determined blood oxygen saturation level for the right upper extremity and the determined blood oxygen saturation level for the at least one lower extremity to respective blood oxygen saturation level thresholds to obtain an screening indicator for the subject indicating the quality of the subject's oxygenation.