Accuracy of CardioWatch 287-2 with profound hypoxia (CIV-21-12-038447)

The present study is looking for calibration and accuracy of SpO2, Pulse Rate and Respiration Rate derived by a newly developed based wrist device (CardioWatch 287-2 or Test Device). These parameters will be computed from raw PPG data delivered by Test Device based on values of a benchmark comparator:

A well-known benchmark SpO2 sensor of Nellcor (PM10N), including its calculated pulse rate: The Non-Invasive study (NI study) branch.
Oxygen saturation in arterial blood samples measured by co-oximetry and Nellcor SpO2 will be used to define the accuracy of the test device: The Invasive study (IN study).
Respiratory rate is provided by measuring end tidal CO2 peaks by a capnometry in both studies.
Individuals undergo progressive hypoxia (10 min / % oxygen decrease) to 10 % of ambient O2 in a normobaric hypoxia room resulting in a subject’s SpO2 or SaO2 range between 97 to 100% and 73%. Nellcor’s finger clip, the wrist CardioWatch 287-2 and a small plastic tube placed near the mouth are attached to the volunteers before and during hypoxia.

Number of Participants
In the first NI study, 12 to 20 healthy volunteers are included, because some minor refinement of the software in the Test Device to improve PPG signals is allowed in the first volunteers. This NI study stops after completing 12 volunteers with the final software version of the Test Device.

In the second IN study, released after completion of the NI study, an arterial catheter is placed to 12 volunteers to obtain arterial oxygen saturation measured by co-oximetry at several time points during progressive hypoxia (25 blood samples/person). Thereafter the accuracy (Arms) of the test device’s SpO2 will be computed.

Per FDA guidance, at least 2, or 15% of the subjects will have dark skin. Equal numbers of men and women will be enrolled.

Inclusion / Exclusion criteria

Inclusion Criteria:
The subject is male or female, aged ≥18 and <65.
The subject is in good general health with no evidence of any medical problems.
The subject has provided informed consent and is willing to comply with the study procedures.

Exclusion criteria:
Heavy smokers or individuals exposed to high levels of carbon monoxide that result in elevated carboxyhemoglobin levels.
Individuals subject to conditions that result in elevated levels of methemoglobin
Individuals with hypoxia (SpO2 < 95 % at 21 % of oxygen)
Severe claustrophobia
Subject is known with altitude disease
The subject is obese (BMI ≥ 31 kg/m2).
The subject has a known history of moderate to severe heart disease, lung disease, kidney or liver disease.
The subject is diagnosed with moderate to severe asthma.
The subject is known with a hemoglobinopathy or history of anemia, e.g. sickle cell anemia, thalassemia, ... who, in the opinion of the investigator, would make them unsuitable for study participation.
The subject has any other serious systemic illness.
Any injury, deformity, or abnormality at the sensor sites that in the opinion of the investigators would interfere with the sensors working correctly.
The subject has a history of fainting or vasovagal response.
The subject has a history of sensitivity or allergy to local anesthetics or disinfectants.
The subject has a diagnosis of Raynaud’s disease.
The subject has unacceptable collateral circulation based on exam by the investigator.
The subject is pregnant, lactating or trying to get pregnant.
The subject is unable or unwilling to provide informed consent or is unable or unwilling to comply with study procedures.
The subject has any other condition, which in the opinion of the investigators would make the subject unsuitable for the study.
The subject refuses to remove nail-vanish.

Study Design
CardioWatch 287-2 is attached to the wrist. Subjects are in a comfortable semi-recumbent position. Subjects then breathe air mixtures containing reduced amounts of oxygen to produce the desired level of hypoxemia. Stable, safe and controlled hypoxia is achieved breath-by breath by breath respiratory gas analysis and a computer program that permits the inspired gas mixture to be adjusted to achieve a level of lung alveolar gas that will achieve the desired degree of saturation. Typically, saturation levels involve one period with air breathing and then at one of 6 levels with reduced oxygen, e.g. 94%, 90%, 85%, 80%, 75% and 70% saturation. Each level of saturation is held for 30-60 seconds. The operator then changes the inspired oxygen concentration to attain the next desired stead-state level of hypoxia. A "run" consists of several stable steady-state hypoxia levels and together takes 10-15 minutes. Each run is terminated by a breath of 100% O2 followed by room air. 2 Reference oximeters are used, a Nellcor and a Masimo to determine the blood oxygen saturation levels of the subject. The precise target levels of saturation can be adjusted to suit the sponsor, but typical testing is done to satisfy ISO and FDA standards for testing, which is 70% to 100%.

Measurement procedures
The number of subjects and the number of comparisons (paired pulse oximeter readings and arterial saturation values) is determined by current CE-MDR and FDA guidance requirements. This is a minimum of 200 data points and 10 subjects. In the course of this type of study, some subjects may drop out, some readings can be lost due to motion or other interference and occasionally some do not consent.

The following demographic data will be collected on the subjects:

gender (male, female, other)
skin tone (Fitspatrick’s skin color scale)
height (cm)
weight (kg)
wrist circumference (cm)
dominant hand (left or right)

Study Centre
CMC bvba
Europalaan 42b1
3600 Genk
BE 0449.103.169

Principle Investigator
Raf De Jongh, MD, PhD

Start time, Duration
April 2022, Two months


Interested in our Trial Programme?

Corsano Cardiowatch Bracelets enable continuous monitoring with multiple algorithms. Corsano is working closely with cardiologists, scientists, hospitals, patients, and research organisations.  Scientific research demonstrates the legitimacy of Cardiowatch 287 algorithms. 

We are currently performing pilots with selected clients. Contact us if you want to know more!

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The bracelet monitor offers flexibility to set data collection intervals by minute, by second or 25Hz, 32 Hz or 128 Hz. We measure Heart Rate, RR intervals, Breathing Rate, A-Fib detection, Skin Temperature, Activity and Sleep. SpO2, Core Body Temperature, ECG and Blood Pressure are in development.  
Clinical accuracy is paramount for us. In addition to third parties' algorithms, i.e. from Philips, we run our proprietary algorithms to realize superior data accuracy. Corsano technology has been clinically validated in major academic hospitals. The bracelet is manufactured under ISO 13485 and CE-MDR compliance. The process for FDA Clearance has started. 
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