in ICU 2/30 Vital signs screening in COPD Heart rate Oxygen - PowerPoint PPT Presentation

PhO 2 Smartphone based Blood Oxygen Level Measurement using Near-IR and RED Wave-guided Light Nam Bui, Anh Nguyen, Phuc Nguyen, Hoang Truong, Ashwin Ashok, Thang Dinh, Robin Deterding, Tam Vu 1/30

Chronic Obstructive Pulmonary Disease ( COPD ) 24 Million Americans have COPD Leading cause of death in the US, 2016 Early detection of COPD is key to successful treatment OFTEN $34,000 treatment FOUND IN LATE STAGE in ICU 2/30

Vital signs screening in COPD Heart rate Oxygen Saturation needs to be measured frequently Blood pressure Oxygen saturation (SpO2) Breathing rate Wheezing sound 3/30

Oxygen Saturation (SpO 2 ) Oxygenated hemoglobin Deoxygenated hemoglobin O O 2 2 O O 2 2 𝑻𝒒𝟏𝟑 = 𝑶𝒑. 𝒑𝒚𝒛𝒉𝒇𝒐𝒃𝒖𝒇𝒆 𝒊𝒇𝒏𝒑𝒉𝒎𝒑𝒄𝒋𝒐 𝟐𝟏𝟏% 𝑼𝒑𝒖𝒃𝒎 𝑶𝒑. 𝒊𝒇𝒏𝒑𝒉𝒎𝒑𝒄𝒋𝒐 4/30

Non-invasive Measurement of Oxygen Saturation Intensity Red emitter IR emitter AC IR t Intensity AC R t AC 𝑩𝑫 𝑺 𝑻𝒒𝟏𝟑 = 𝒈 𝑩𝑫 𝑱𝑺 Photon Detector R IR 5/30

Red and IR Wavelength Selection Harmful Low penetration Absorbed by red pigmentation At Red= 660 nm and IR = 960 nm, the difference of light absorption by oxygenated hemoglobin and deoxygenated hemoglobin is largest. 6/30

Dedicated Hardware Solutions Smartphone-based blood oxygen measurement Pros Cons  Inconvenient  High accuracy  Costly

A solution to capture the oxygen level and is High accuracy. Low-cost. Easy to make by patients 8/30

PhO 2 Smartphone based Blood Oxygen Level Measurement 9/30

Hardware Challenges PULSE OXIMETER PHONE BASED PULSE OXIMETER Red emitter IR emitter Light Source 10/30

Challenge. Phone’s camera IR filter IR filter Sensor 11/30

Existing Software-based Solutions DISADVANTAGES  Inaccurate: Green channel is mostly absorbed by red pigmentation. Red Light  Coarse-grained: one record per 10 seconds. IR Light R B G Color Image DigiDoc iHealthCare

Solution. Red and NIR for Oxygen Saturation Measurement NIR NIR has similar characteristics of hemoglobin absorption with the IR lights. NIR is available in most of phone’s flashlight and is not filtered by the phone’s camera. 14/30

PhO 2 NIR Extraction Technique Absorbed by red pigmentation Absorbe d Green filter Red and Green filter cuttoff NIR 15/30

And 5 More Challenges … RGB Intensity Smartphone’s camera picks up most of the lights Conversion between RGB and light intensity Pressure Micro movements Flashlight heat can cause skin burn Finger movement and Contact pressure 16/30

3D printed Optical Hardware Add-on 17/30

3D printed Optical Hardware Add-on Intensity RGB Smartphone’s camera picks up most of the lights Conversion between RGB and light intensity Pressure Micro movements Finger movement and contact pressure Flashlight can cause skin burn 18/30

Wavelength selection 𝜷 = 𝒃𝒔𝒅𝒖𝒃𝒐(𝒃/𝒄) 𝜻 𝑰𝒄 𝒔 − 𝜻 𝑰𝒄 𝒔 𝑺 𝑻𝒒𝟏𝟑 = 𝜻 𝑰𝒄 𝒋𝒔 − 𝜻 𝑰𝒄𝑷 𝟑 𝒔 + 𝜻 𝑰𝒄𝑷 𝟑 𝒋𝒔 − 𝜻 𝑰𝒄 𝒋𝒔 𝑺 𝜷 b a X:678 Y: 724 Z:1.002 𝝁 𝑺 = 678 nm 𝝁 𝑶𝑱𝑺 = 724 nm 20/30

Pressure Detection and Recommendation PPG signal in a 7 seconds window Normalized Intensity Sample PPG signal in a 7 seconds window Normalized Intensity Sample PPG signal in a 7 seconds window Normalized Intensity Sample 21/30

Heat Reduction with Distributed Lighting Source 𝑰 Bandpass filter 𝐹 𝑞 = ℎ𝑔 Modify 0.6 mm 2.55 mm 𝑭 = To maintain the high light intensity 22/30

PhO 2 Algorithms Detecting pressure Collecting raw data PPG 95 % Calculate peak-to- Identify the peaks ROI detection and create the and troughs PPG signals peak ratio 23/30

App overview PPG display Image frame 24/30

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In-lab experiments • 3 males, 3 females • 5 times performs the hyperventilation (a breath holding technique to reduce oxygen). • Totally 560 samples. 26/30

PhO2 vs. Existing apps DigiDoc iHealthCare SpO2 (%) SpO2 (%) Measurement Indices Measurement Indices PhO2 SpO2 (%) Time (s) 27/30

Experimental results 3.5% 28/30

In hospital experiment with patient. In clinic experiment 29/30

Fine-grained evaluation of the patient Low Oxygen Level Coughing 30/30

Heat Reduction Evaluation Hand multimeter Thermalcouple Probe 31/30

Output temperature of different add-on designs 58.9 60 45 38.5 40.3 50 37.6 36.8 Temperature (Celsius) 40 30 20 10 0 Without Banpass Filter With Bandpass Filter Large Tunnel Small Tunnel Multiple Small Tunnels 32/30

Conclusion ❑ Accurately measuring oxygen level using low-cost optical film filters . ❑ Detect the appropriate contact pressure between finger and phone’ camera . ❑ 3D-printed add-on to handle the problem of light scattering and finger movement . 34/30

Application for optical light based sensing Urea Lactate Optical light Cholest- Water erol based sensing Alcohol Glucose 35/30

PhO 2 Smartphone based Blood Oxygen Level Measurement using Near-IR and RED Wave-guided Light Nam Bui, Anh Nguyen, Phuc Nguyen, Hoang Truong, Ashwin Ashok, Thang Dinh, Robin Deterding, Tam Vu 37/30