Transcript Poster Presentation - Research

Pain Stimulator
Bryan
1
Eckerle ,
1
McFadden ,
1
Platt ,
2
Slyziuk ,
Katharine
Adam
Elizabeth
Jennifer
1
3
Advisors: Paul King, Ph.D. and Stephen Bruehl, Ph.D.
1
Wells
1Vanderbilt
University Department of Biomedical Engineering
2Vanderbilt University Department of Mechanical Engineering
3Vanderbilt University Medical Center Department of Anesthesiology
SYSTEM SCHEMATIC
Dr. Bruehl’s main objective is to understand endogenous pain regulatory mechanisms
in humans, with particular interest in the relationship between blood pressure, acute
pain sensitivity, and chronic pain. He is currently studying the effects of Yohimbine, a
selective α-2 adrenergic receptor antagonist, to understand the role of the adrenergic
system in regulation of pain pathways. He is using a device based on the original
Forgione-Barber Finger Pressure Stimulator to stimulate C-fibers. The device has a
fixed amount of weight attached to a lever with an unknown amount of pressure
being applied to the dorsal surface of the second phalanx of the index finger. It is
mounted on a table that does not allow for adjustments to accommodate variance in
subject height or forearm length. Additionally, the system does not include an
electronic output. The administrator asks the subject for a numerical pain rating on a
scale from 0 to 100, anchored with “no pain” and “worst pain imaginable,” thus
creating a numerical bias. Our objective is to create an adjustable, electronically
integrated, and standardized acute pain stimulus to compare responses under
placebo and under blockade of various receptors.
EXAMPLE OF PREVIOUS DATA
Circuit sensitivity
= .6V/cm @ Vs=5V
Potentiometer sensitivity
= 1500Ω/cm
USB DAQ
NI 6009
PC
Computer
LabVIEW 7.1
ADDITIONAL EQUIPMENT
PROJECT DELIVERABLES
•National Instruments USB-6009 Data Acquisition Device
•Modified version of Forgione-Barber Finger Pressure Stimulator
•Mouser Electronics 60mm Linear 10k Taiwan Alpha Slide Potentiometer
•National Instruments LabVIEW Version 7.1.1
PREVIOUS DEVICE
Insert
Cannula
Assess
Emotions
(EAS)
5 Min.
Seated Rest
Plasma
Sample
Assess Baroreceptor
Sensitivity (BRS)
Drug or Placebo
Infusion
Over 10 Min.
20 Min. Seated Rest
Assess EAS and
Side Effects
Plasma
Sample
Assess BRS:
5 Min. Seated Rest
Insert Finger
Adjust &
Apply Pressure
15s
Numerical
Pain Rating
15s
Numerical
Pain Rating
15s
30
35
40
45
50
55
60
6.34 12.2 19.4 29.7 39.8 53.7 64.2 76.3 88.1 98.2 100
100
80
60
40
20
0
0
10
20
30
40
50
60
Time (sec)
IMPROVED EXPERIMENTAL PROCEDURE
5 Min. Resting
BP Assessment
5 Min.
Rest
25
Design specifications were met so that the experiment is adjustable for subject
variance, automated, and electronically integrated. The study is improved as a result.
EXPERIMENTAL PROCEDURE
30 Min.
Adaptation
20
CONCLUSION
•Integrated system: device mounted to table, connected to sliding scale and software
15 Min.
Seated Rest
15
IMPROVED DEVICE
•Sliding scales to eliminate number bias
Screening and
Questionnaires
0
10
Pain Reading vs. Time
Subject 008
Vibration, thermal and electrical stimuli were considered, but ultimately rejected in
order to maintain pressure stimulus of C-fibers. A pneumatic pressure device was
also considered, but rejected for the stable and reliable lever system already in place.
•Vertically adjustable medical table
5
DEVICE
APPROACHES CONSIDERED
NO GRAPHICAL OUTPUT
MANUAL DATA ENTRY NECESSARY
RESULTS
Time, sec
Pain Level
Potentiometer Circuits
Contact Switch Circuit
•Software for data acquisition
Subject Number 008
Reported Pain Level: 30, 50, 65, 90
Pain Reading
PROBLEM STATEMENT
Numerical
Pain Rating
15s
Numerical
Pain Rating
Manual
Data Entry
& Analysis
15 Min.
Seated Rest
Screening and
Questionnaires
IMPROVEMENTS
•ELECTRONIC OUTPUT using LabVIEW 7.1
Automated Timer
Digital Data Storage
Digital Display
Ability to Export data for further statistical analysis
Graphical Output
Automated Start of Data Acquisition (contact switch)
Audiovisual Cues
•Adjustability
Hand Dominance
Forearm Length
Subject Height
Adjustable Weight Applied directly over Contact Point
•Pain Reading
Linear Potentiometers eliminate numerical bias
Insert
Cannula
30 Min.
Adaptation
5 Min. Resting
BP Assessment
Assess
Emotions
(EAS)
5 Min.
Seated Rest
Plasma
Sample
Assess Barorecptor
Sensitivity (BRS)
Drug Infusion
Over 10 Min.
20 Min. Seated Rest
Assess EAS and
Side Effects
Plasma
Sample
5 Min.
Rest
Assess BRS:
5 Min. Seated Rest
Insert Finger
Adjust &
Apply Pressure
LabVIEW collects data for 1 minute, data is saved and exported for future statistical analysis