Pain Stimulator Adam Platt Biz Slyziuk Bryan Eckerle Jen Wells Kalee Mc. Fadden April 13, 2004
Dr. Stephen Bruehl o Research Interests o Endogenous Pain Regulatory Systems, Psychobiology of Emotions o Focus: Understanding endogenous pain regulatory systems and dysfunction associated with chronic pain. o Interaction between cardiovascular and pain regulatory systems to maintain homeostasis during painful stimuli compared to interaction in chronic pain patients
Baroreceptor Input Intermediolateral Cell Column (SNS Preganglionic Neurons) Nucleus Tractus Solitarius NE Neurons and α-2 receptors Periaqueductal Gray α-2 receptors Locus Coeruleus NE Neurons and α-2 receptors A 5 Cell Group NE Neurons and α-2 receptors Caudal Ventrolateral Medulla NE Neurons Nucleus Raphe Magnus Dorsal Horn Laminae I-IV α-2 Postsynaptic Rostal Ventrolateral Medulla NE Neurons and α-2 receptors Primary Afferent Fiber Terminals α-2 Presynaptic Spinal Sites of Descending Modulation Rostal Ventromedial Medulla α-2 receptors Peripheral SNS Terminals (α-2 Presynaptic Autoreceptors) Blood Pressure
Experimental Importance o NIH funded o 120 subjects o Two research sessions one week apart o Stimulation of C-fibers o Placebo vs. drug n Measures level of activity of receptors o Draw conclusions on natural pain systems in humans
Experimental Method o Dinamap Compact-T automated oscillometric BP monitor o Finapres 2300 o ECG o Cannula inserted into dominant arm o Blood drawn to assess natural stress hormones and inflammatory substances o Forgione-Barber Finger Pressure Stimulator o Mc. Gill Pain Questionnaire
Drugs to be Tested o Yohimbine n Blocks 2 adrenergic receptors which inhibit release of norepinephrine n Used clinically for erectile dysfunction (orally) n For Dr. Bruehl’s purposes, the FDA has only approved injections o Naloxone n Blocks opiate receptors n Used clinically for heroine overdose n Injected into patient
Problems with Existing Device o No electronic output p Oral reading o No accurate measurement of pressure o Lever system with constant weight o No adjustability for height or hand dominance n Adjustable only for finger placement
Our Design o Device o. Maintain lever system §Most stable design o Reposition weight to be placed vertically above finger o. Adjustable Weight o 2 – 5 lbs o Contact Point o Between top two joints on index finger of dominant hand o Middle Phalanx #2
Our Design… Cont. o Table n Provided by Dr. Bruehl n Transportation n Positioning p Adjustable Height p Sliding Tracks p Forearm length o Slider scale mounted to table displaying “No Pain” to “Worst Pain Imaginable” n Scale mounted on each side of device
Schematic Slider Scale Device (Pressure Transducer) PC Computer A/D Converter Lab. VIEW
Device with Measurements
Materials o Aluminum o Lucite o Steel
Device Construction o In process o Featheringill machine shop
Lab. View o Timer o Sliding Scale o Digital Display o Graphical Output o Audiovisuals o Digital Data Storage n Patient n Administrator n Date n Experimental Data
Lab. VIEW Interface
Potentiometers o Circuit sensitivity ≈. 62 V/cm @ Vs=5 V o Potentiometer sensitivity ≈ 1500Ω/cm
Questions?
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