1. Summary
• Vaso-occlusion, which is the obstruction of
blood flow in a vessel, leads to ischemia,
chronic pain, and, if left untreated, tissue
death (Yale et. al. 1349-1356)
• Caregivers are routinely unable to correlate the
magnitude of a vaso-occlusive event and pain
in patients with sickle cell disease.

2. Summary
The subjective pain scale is the primary method of
detection
• Patient ranks his/her pain on a scale of 1-10
• Contains no biometric data that relates severity of
vaso-occlusion to pain

3. Summary
• Purpose: develop a modified pulse oximeter that
will measure oxygen saturation or perfusion
levels in tissue.
• Goal: determine a correlation between the
oxygen levels and/or perfusion within the region
of pain and the level of pain the patient is
experiencing
• The device will, hopefully, lead to more efficient
treatment

4. Sickle Cell Disease
• Malformation of hemoglobin
• Results in sickle-shaped red blood cells with
altered function and lifespan
• Complications include painful vaso-occlusive
episodes, ACS, stroke, pulmonary
hypertension, multi-organ damage, decreased
life-span (Conran 1-2)
• Affects 70,000-100,000 individuals in the US
(SCDAA.com)

5. Vaso-Occlusion
• Most common complication of sickle cell
disease
• Painful
• Can occur in arms, legs, chest, abdomen
(American Family Physician 1027)

6. Vaso-Occlusion
• Sickled cells cannot
deform to pass
through small vessels
• Endothelial wall
damage(Conran 4-8)

7. Pain
• Caused by infection and/or ischemia
• Pain occurs in legs, arms, lower back, knees,
chest, abdomen
• 5% of patients with sickle cell disease have 3-10
pain episodes per year
• Pain crises are the primary reason for ER visits

8. Pain Management
Drug Therapy
• Mild Pain : NSAIDs
(acetaminophen, aspirin, ibuprofen, naproxen)
• Moderate-Severe Pain: Opioids

9. Pain Management
Common Opioids Used to Treat Mild to Moderate Pain in Sickle Cell Disease
Drug Usual oral starting dosage in adults Comments and precautions
Codeine 30 to 60 mg Every 3 or 4 hours Available in liquid or tablet form,
alone or in combination with
acetaminophen
Side effects: impaired ventilation
(histamine release possibly
triggering bronchospasm) and
increased intracranial pressure
as a result of carbon dioxide
retention
Oxycodone (Roxicodone) 10 to 30 mg every 4 hours Often used in combination with
acetaminophen, which limits
safe dosage to 12 tablets per day
(about 4 g of acetaminophen)
Side effects: similar to those of
codeine
IM = intramuscular; IV = intravenous; SC = subcutaneous.
*—Single-dose studies determined that the relative potency is 6:1; with repetitive doses, this ratio changes to 3:1.

10. Pain Management
Equianalgesic dosages Usual starting dosage in adults
Drug Oral/IM potency IM Oral Oral Parenteral
Morphine 6* 10 mg 60 mg 15 to 30 mg every 0.1 to 0.15 mg per
(Duramorph) 4 hours kg every 3 or 4
hours
Hydromorphone 5 1.5 mg 7.5 mg 2 to 4 mg every 4 1 to 2 mg every 4
(Dilaudid-Hp) to 6 hours to 6 hours
Meperidine 4 75 mg 300 mg 50 to 150 mg 75 to 100 mg
(Demerol) every 3 or 4 hours every 3 or 4 hours
Levorphanol 2 2 mg 4 mg 2 to 4 mg every 6 Up to 1 mg IV
(Levo-Dromoran) to 8 hours every 3 to 6 hours;
1 to 2 mg IM or SC
every 6 to 8 hours
IM = intramuscular; IV = intravenous; SC = subcutaneous.
*—Single-dose studies determined that the relative potency is 6:1; with repetitive doses, this ratio changes to 3:1.

11. Reluctance of Pain
Treatment
• Narcotic addiction & tolerance
• Excessive sedation
• Respiratory depression
• ‘Drug-seeking’ behavior
• Addiction in sickle cell patients = ~3% (Yale et. al)

12. Pain Validation
• Pain scale—subjective
• CT*
• Chest X-Ray*
*Not ordered regularly—very expensive
Need: A reliable, non-invasive, and inexpensive device
to provide correlating data between the occurance and
severity of vaso-occlusion and the pain that the patient
is experiencing

13. Specifications
• Vaso-occlusion reduces the flow of oxygenated
blood, which leads to a reduction of oxygen within
the tissue.
• Reduced oxygenation leads to tissue damage and
pain.
• The device proposed will adapt the principles of
photoplethysmography to measure the oxygen
saturation level at the site of pain.

14. Specifications
Product Specification Design Specification
Pulse oximetry will be used to detect the varying levels of
1. Detecting varying levels of blood oxygen
blood oxygen saturation. This must be able to read blood
saturation
oxygen saturation between 70% and 100% (ISO).
The device will be able to detect a fraction of the light that
2. The device must be able to obtain is originally emitted into the arm. The fraction will be
measurements through 5 inches of flesh determined using Beer’s Law and the optical properties of
human tissue.
No exposed wires will be present in the device, and the
3. Electrical components must be isolated
leakage current will meet IEC standards (under 300µA).
This includes the time taken to attach the device to the
patient, the time required for the device to take
4. Data acquisition must take less than 5 minutes
measurements, and the time for the device to interpret
the measurements taken
This device must be reliable with no false negatives. This
5. Reliability
will follow ISO Standard 80601-2-61-2011.
The device should not cause any discomfort during use. It
6. Comfort/Ease of Use should be easy to place on the patient and should be
easily removed

15. Alternative Methods
Method Specifications Met Pros Cons
Non-invasive May be time consuming to find the exact
location of the vaso-occlusion
Pulse Oximetry All inexpensive
If the occlusion is too great, a signal may not be
easily adaptable for our use determined
Non-invasive
All May be time consuming to find the exact
Perfusion Index location of the vaso-occlusion
inexpensive
Expensive (Camera > $5002)
Non-invasive
Fast Frame
1,3
“SpO2 Camera”1 Only measures O2 at surface
Non-invasive Expensive (Camera>$10003)
Gives a general view of temperature in the Only measures temperature at surface
Thermal Imaging 1,3
body
Can only work if vaso-occlusion causes a
Fast data acquisition temperature difference in skin
Sources: 1(Kamshillin 996-1006); 2EdmundOptics.com; 3Neo-Bits.com

16. Method Chosen
• Modified Pulse Oximeter
• Meets all specifications
• Low Cost

17. Further Research
Further research is needed in the following areas:
• Pathology of vaso-occlusion
• Location of vaso-occlusion
• Frequency of vaso-occlusion
• Size of affected area
• Time in which ischemia occurs
• Treatments for vaso-occlusion
(not pain treatment)

18. Specific Aims
1. Confirm that a Vaso-Occlusive Crisis Can be
Detected
– Blood Oxygen Saturation
– Pulse Oximetry
– Photoplethysmography

19. Specific Aims
2. Develop a Device that Can Measure the
Varying Oxygenation Levels
– The device will be developed using various
programming software and hardware
–LabView
–LEDs
–Photodetector

20. Specific Aims
3. Design the Device so that it can be Attached
to a Patient’s Arm of Varying Sizes
– This device should be able to adjust to
varying thicknesses.
–Adjustable armband

21. Specific Aims
4. Find a Correlation Between Oxygen
Saturation in the Blood and Pain
– A pain scale can be created that ranges
from one to ten.
– Each number on the pain scale can correlate
to a specific range of oxygen saturation
levels.

22. Preliminary Results
(Figure 1adopted from Ahmed et. al.)

23. Preliminary Data
• Methods of Data Collection
– Vaso-occlusive crisis was simulated
• A tourniquet was used to do this
– Different pulse oximeters were used
• Nano Tracker
• Medtronic Lifepak 12 Clinical Pulse Oximeter
• AD Instruments MLT321 Pulse Oximeters

24. Preliminary Data
Table 1 - DATA FROM PHOTOPLETHYSMOGRAPH (NANO TRACKER)
Normal O2 Normal O2 O2--V-O Mimic O2--V-O Mimic
Left Arm Right Arm Left Right
Subject 1 n/a 0.93 n/a 0.74
Subject 2 0.95 0.97 0.76 0.8
Subject 3 0.97 0.97 0.78 0.82
STDV L 0.11030 STDV R 0.09786
n=2
p=0.0035 - Right Arm
n=3
p=0.0055 - Left Arm

25. Preliminary Data
Table 2 - DATA FROM MEDTRONIC LIFEPAK 12 PULSE OX
Normal O2 Left O2--V-O Mimic
Perfusion Index
Arm Left
Subject 1 0.97 0.86 Decreased
Subject 2 0.96 0.88 No Change
Subject 3 0.98 0.88 Decreased
STDV 0.053821
p=0.0004
n=3

26. Preliminary Data
Table 3 - DATA FROM AD INSTRUMENTS PULSE OX
O2 Experimental
Normal O2
Arm
O2--Experimental
(Normal
Control Arm
Conditions)
Subject 1 0.97 0.97 0.92
Subject 2 0.95 0.96 0.91
Subject 3 0.974 0.983 0.953
Subject 4 0.99 0.99 0.96
p=0.0540—Control vs. Experimental
STDV Exp 0.028116
p=0.0285—Experimental (Normal Conditions) vs.
n=4
Experimental Conditions

27. Preliminary Data
• T-test Values
– Table 1
• p=0.0035 - Right Arm
• p=0.0055 - Left Arm
– Table 2
• p = 0.0004
– Table 3
• p = 0.054 – Control vs. Experimental
• p = 0.0285 – Experimental (Normal Conditions) vs.
Experimental Conditions

28. Purpose
• Detect Low oxygen concentration in
extremities.
• Easy and cheap diagnostic technique for vaso-
occlusion patient.
• Early diagnosis ease the treatment and
prevent further damage.

29. Working Principle
• Pulse Oxymetry consist of Red(R) and
infra red (IR) light emitting LEDs and a
photo detector/s.
• Oxygenated and de-oxygenated
hemoglobin have differential light
absorption rate.
– Oxygenated hemoglobin absorbs more
infrared light and deoxygenated
hemoglobin absorbs more red light.
• Photo detector measures the
transmitted lights and calculate R/IR
ratio.
• R/IR ratio determines the oxygen blood
concentration.

30. Modification
• The pulse Oxymetry will be modified to fit in
the extremities.
• High power LEDs will be used for larger parts.
• Two oximeters will be used for control and
experimental data.
• Multi-array detector will be used if needed

31. Proposed Solution
• Single source multiple detector can be
used.
• Uneven distribution on the detector can
be analyzed mathematically.
• The output in the detector can be
averaged out to find the occlusion.
• Non-linear transmission of the light can
result the uniform result.
• Experiment can be conducted to test the
linear behavior of the device.

32. Proposed Solution
• Rotating LEDs with aligned
detectors can be designed.
• Signal from detector can be
reconstructed using convolution.
• Complicated design but it can
be promising solution.
• CT scan uses same mechanism
to create the cross sectional area.

33. Testing
• The device has to be calibrated for each
individual.
• The device uses its data and compares with
the control data.
• Device will correlate the severity of the vaso-
occlusion measuring the blood oxygen
concentration.

34. Design Specification
• Our device
will utilize an
adjustable arm-
band design.
• We will use
multiple LEDs
and detectors

35. Benefits of a Multiple LED system
• Produces more light which allows
detector to see dark spots better
• Even if the crisis occurs outside of the
emitance of the LED, our detectors can
identify a crisis

36. Technique
• We will use two pulse oximeters
• This can allow us to get a
baseline reading while
simultaneously attempting to
identify a crisis
• Preliminary testing has proven
this method to be viable

37. Recreating a vaso-occlusion
• Vaso-occlusion causes less blood to
reach tissue
• We were able to slow blood flow to
the extremities using a
sphygmomanometer

38. Pain scale
Numbers from device Pain Scale
<0.82 9-10
.82-.86 6-8
.86-.90 4-5
.90 1-3

39. Cost Structure
Per Unit Price in Number of Number of Total Our Cost
Components
Price ($) bulk($) pieces in Bulk units used Price ($) ($)
Op Amp 0.92 12 11.04 11.04
Resistors 0.05 2.33 50 20-40 13.98 13.98
Capacitor 0.12 2.9 25 4-8 29.00 29.00
LED 660/940 4.64 5 25.00 25.00
Bread Board 18.00 1 18.00 18.00
ArmBand 60.00 1 60.00 60.00
Photodetector 44.00 5 220.00 220.00
Analog to Digital
280.00 1 280.00 Donated
Converter
Computer with
3200.00 Donated
Software
Travel 150.00 150.00
Total Price 4007.00 527.02

40. Ghantt Chart