This clinical investigation will investigate how accurate the SurePulse VS and SurePulse VS Patch (VSP) are for measuring blood oxygen levels (oxygen saturation). If the results are accurate, the VSP will be ready to apply for regulatory approval, meaning it could then be available for use on newborn babies in the National Health Service (NHS).

Healthy volunteers who express an interest in the study and meet the eligibility criteria will be invited to participate in the study. This study will investigate the accuracy and safety of the SurePulse VS and SurePulse VS Patch (VSP) in measuring blood oxygen levels. This is done by measuring blood oxygen levels across a range of values in healthy adults. The measurements from the VS and VSP will be compared to the known correct value. The study follows the internationally agreed standard for pulse oximeter approval.

Agreeing participants will have their name, contact details, medical history, height, weight, date of birth, skin colour, emergency contact details and address recorded, as necessary to conduct the study. After completion of the eligibility and consent process, participants will be enrolled in the study. Healthy volunteers will have their blood oxygen levels temporarily reduced in a controlled and stepwise manner. Oxygen levels will not be low for the entire duration of the session. Oxygen levels will be reduced to a specific target for a few minutes at a time. Volunteers will have a small tube inserted into an artery (blood vessel) in their wrist; this will be used to take blood samples throughout the session. The blood samples will be taken, analysed and destroyed in the same room. The session should take approximately 1.5 - 2 hours in total.

The output from the study will be compared to the primary and secondary outcomes to evaluate the performance and safety of the device. This study is required for the SurePulse VSP to be regulatory approved, meaning it could then become available in the NHS.

Inclusion Criteria:

• Age 18 to 55
• Willing and able to provide written informed consent
• Healthy adult subjects (ASA 1)
• Non-smoker
• Willing and able to comply with study procedures and duration

Exclusion Criteria:

• Smokers or individuals exposed to high levels of carbon monoxide
• Compromised circulation, injury, or physical malfunction of the sensor sites which would limit the ability to test sites needed for the study
• Female subjects that are actively trying to get pregnant or are pregnant (confirmed by Health Assessment Form). N.B. All female participants will be offered a pregnancy test
• Unwillingness or inability to remove coloured nail polish from test digits (relevant for reference pulse oximeter) or to have medical monitoring attached
• Known health conditions disclosed on Health Assessment Form which mean that participant is not healthy
• Allergy to lidocaine
• Allergy to adhesives used in medical dressings or tapes

There should be a minimum of 40% male and minimum of 40% female participants with the balance made up of either.

No masking