Project Lead(s): Omar Ramahi
Hypoxemia (an abnormally low level of oxygen in the blood) is a common symptom in many serious illnesses, especially lung disease.
Hypoxemia is associated with in-patient death and disability in developing countries. It is estimated that the incidence of hypoxemia in pneumonia, asthma and advanced Chronic Obstructive Pulmonary Disease (COPD) cases is over 13%, 24% and 80%, respectively.
Oxygen therapy is commonly provided in intensive care units (ICUs) by continuous monitoring, using desktop pulse oximetry and manual adjustment of the oxygen supply by healthcare providers. But ICUs are expensive in terms of equipment and healthcare delivery, and often not available in resource-limited settings.
The goal of the project was to develop an affordable, portable, automated system (pulse oximeter) for continuously monitoring and adjusting supplemental oxygen levels for hypoxic patients.
Sub-components needed to develop the prototype included:
· An Oxygen Reader Subsystem with fingertip SpO2 (serum pressure and oxygen) sensor capable of reading the photoplethysmographm (PPG) signal non-invasively in a continuous manner, with sampling rate equal to 500 samples per second; every second, the acquired PPG measurements would be sent wirelessly to the Automatic Adjustment Oxygen Supplement Subsystem using Bluetooth technology
· An Automatic Adjustment Oxygen Supplement Subsystem with a small LCD (liquid crystal display) mounted on the same board and capable of:
1. Receiving wirelessly the PPG measurements from the Oxygen Reader Subsystem
2. Manipulating and processing these measurements, using algorithms as well as digital signal processing algorithms for filtering and processing
3. Computing the oxygen saturation level, heart rate and perfusion index
4. Displaying the oxygen saturation level, heart rate and perfusion index on the mounted LCD display
5. Controlling the closed-loop solenoid valve that determines the amount of delivered oxygen from the oxygen supplement.
A prototype was developed with the two subsystems that communicates wirelessly using Bluetooth technology, with the potential to produce a continuous supply of oxygen and to act as a pulse oximeter.
The computed oxygen saturation level and heart rate displayed on the LCD were compared to the corresponding measurements from a commercial pulse oximeter (Edan H100B Hand-Held Oximeter).
The comparisons showed that the measurements from the developed prototype are very close to those from the commercial pulse oximeter.
The teams intend to apply for Grand Challenges Canada Transition To Scale Phase II funding to perform more tests, in order to validate the accuracy of the oxygen reader subsystem in comparison to the commercial pulse oximeter.
Results of the project have been disseminated through conferences and publications.