Can Remote Photoplethysmography Be Used for Contactless Vital Sign Acquisition in a Healthcare Setting? A Prospective Comparative Study.

Can Remote Photoplethysmography Be Used for Contactless Vital Sign Acquisition in a Healthcare Setting? A Prospective Comparative Study.

Contactless and widely available health monitoring technologies are of growing interest in the context of the worldwide COVID-19 pandemic. Remote photoplethysmography (rPPG) is a well-studied technology that interprets variations in skin colour related to blood flow which, when analysed with complex mathematical algorithm, generates vital sign readings. This technology has been refined and embedded in a smartphone app designed to acquire heart rate, respiratory rate and oxygen saturation using a front-facing smartphone camera.

Preliminary data comparing the accuracy of smartphone rPPG readings with conventional vital sign monitor readings are promising; however, less than 5% of the population studied in the app development phase had oxygen saturation levels below 95% making it impossible to ensure reliability in these populations.

The goal of this study is to compare readings acquired using this rPPG app with the readings from hospital grade, Health Canada approved vital signs monitors used in healthcare settings with a focus on subject with low oxygen saturations. We will also study other sociodemographic and clinical features that may influence the accuracy of the readings. This will be achieved by recruiting consenting adults presenting to care in acute care settings and a designated COVID outpatient clinic. Vital signs will be acquired using the rPPG app and conventional hospital vital sign monitors simultaneously. Readings will be repeated within 2-5 minutes when time permits. Statistical analysis will be performed to analyze the findings and determine the accuracy and precision of the rPPG app readings.

It is expected that the vital sign readings acquired with the rPPG app will be almost identical to those acquired using hospital-grade monitors for all subjects regardless of age, gender, skin colour, COVID status and relevant comorbidities.

Inclusion Criteria:

• Persons willing to participate and capable of providing informed consent, age of 18 years of more.
• Person able to sit still for the duration of the reading (maximum 2 minutes per reading).
• Persons with freckles, discreet skin pigmentation changes

Exclusion Criteria:

• Unable to provide informed consent
• Persons who are unable to follow basic instructions due to altered mental status, delirium, dementia or other conditions.
• Age < 18
• Intubated patients and patients requiring masks for supplemental oxygen
• Persons refusing to remove masks, eyewear, or clothing obstructing the face for the duration of readings.
• Persons with facial tattoos, large birthmarks or other skin alterations (scars, hemangiomas) on their nose or upper cheeks (cheekbones).