Скачать презентацию Non-Transcranial Electroanesthesia Group 2 Students Ryan Demeter Matt
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Non-Transcranial Electroanesthesia Group 2 Students: Ryan Demeter Matt Jackson Caroline Schulman Matthew Whitfield Advisors: Doctor Paul King and Doctor James Berry
Project Definition n n Design, build, and test a system for both administering and recording data related to vagal nerve stimulation. Topics to cover: Project Background, Design Ideas, Stimulation (production and application) Techniques, Testing, Overall Status, Current Status, and Key Issues 2
Project Background n n Advisor: Dr. James Berry (Dept. of Anesthesiology Multi-Specialty Division) Computer Engineering expertise from Dr. Andrew Dozier (Dept. of Electrical/Computer Engineering) 3
Project Background n n Currently, electroanesthesia devices are in use in Europe. In less developed countries where anesthesia technology is lacking, an electroanesthesia device would reduce both the cost of the procedure and the need for technical personal (anesthesiologist). n n S. Leduc --> Europe, Japan, Russia, and Germany Activation of a theoretical pain center n n 35 V, 4 m. A, 100 Hz, rectangular pulsating signal Alternative method n Descending mechanism and the interconnections within the brain 4
Background: Electroanethesia n n n n n Quicker recovery time and less biological effect during and after surgery (Photiades, 218 -225) Heal better (Sances and Larson, 21 -27) Less a build up of gases in the body (Sances and Larson, 218 -219) EEG and ECG Electrolyte levels in extracellular and intracellular fluid of the brain (Sances and Larson, 148 -175) Decreased gastric acid secretion (Sances and Larson, 3346) FDA Kano et al. (1976) Vagal Nerve Stimulation (Kirchner et al. , Ness et al. ) 5
Background: Nerve Information Vagal Nerve n n n n 10 th cranial nerve Location: both sides of the neck Composition: A, B, and C-fibers Function: motor and sensory (visceral afferent) signals C-fibers and Pain Not fully myelinated until adulthood (Koo et al. 429 -433) Shown to help control seizures and depression Best Route to the Central Nervous System Rutecki (1990) Facial Nerve n n n n 7 th cranial nerve Location: both sides of the head by the ear Composition: Branches of fibers Function: motor and sensory signals Facial Expression Myelinated NO research into therapeutic use Does lead into the Central Nervous System 6
Background: Vagal Nerve Fiber Information n A-fibers n n n B-fibers n n Adapt to constant stimulus and exhibit presynaptic inhibition Respond well to low stimulus (George et al. s 56 -s 61) Conduction Speed: 90 to 30 m/s 1 Selectively activated by low intensity VNS No effect on EEG recorded in the rats studied by Hammond et al. (1992) Respond well to low stimulus (George et al. s 56 -s 61) Conduction Speed: 20 to 10 m/s 1 No effect on EEG recorded in the rats studied by Hammond et al. (1992) C-fibers n n [1] Woodbury, Continue to fire with constant stimulus Conduction Speed: 1. 6 to. 3 m/s 1 7 DM and J. W. Woodbury. “Effects of Vagal Stimulation on Experimentally Induced Siezures in Rats. ” Epilepsia. 31. Suppl. 2 (1990): s 7 -s 19
Methods n n n Computer system Vital signs monitoring equipment Testing n n n Phase I: - Device components connected and tested to assure compatibility -Software integrated and tested to assure compatibility and properation -Test inputs and outputs of device Phase II: Applicator testing to assure proper outputs and operation Phase III: Testing of device operation with a rat 8
Design 1 n n Too Complex Un-needed components 9
Design 2 n n n Less Components Needed Laptop keyboard eliminates need for an additional keyboard Internal components dependent on stimulation method 10
Cost n n n Gas anesthesia n In the case of gas anesthesia, more is required for treatment and cost are around twenty to forty dollars a patient (Kurpiers et. al. , 69 -75). Liquids n between three and nine times as expensive as gas anesthesia per volume (Kurpiers et. al. , 69 -75). Electroanesthesia will reduce the high cost of anesthesia for surgery and other procedures by reducing the need to keep large quantities of liquid and gas anesthesia on hand. 11
Stimulation Parameters n n n Stimulation of both Vagal Nerves 20 Hz Rectangular pulse signal Pulse length of 250 µs (Liporace et al. 885 -886) 50 µA (Kirchner et al. 1167 -1171) 25 V Need to consult more with Dr. Berry to estimate best parameters 12
Soundcard n Virtins Sound Card Signal Generator 13
Lab. VIEW n n Lab. VIEW user interface DAQ controller buy DAQ controller Expensive to actually 14
Block Diagram View 15
Delivering Electroanesthesia n Option 1: Cortical Stimulator (Ojemann Cortical Stimulator) - Advantage: Add gain stage - Disadvantage: Knobs not computer compatible, gain stage 16
Delivering Electroanesthesia n Option 2: Gain Stage - Advantage: Computer compatible - Disadvantage: Noise, unforeseen circuitry problems 17
Recent Contacts n Ray Booker - Simulation engineer at Ctr. for Medical Simulation n Discussed head and neck phantoms Cost n Availability n Function n 18
Sim-man -Most expensive and limited funds (NEGATIVE) -Not immediately available (NEGATIVE) -Possible damage from device (NEGATIVE) 19
Airway Model -Relatively inexpensive (POSITIVE) -Immediately available (POSITIVE) -Thin, plastic head and neck (NEGATIVE) -No damage from electric shock (POSITIVE) 20
Plaster Cast n Inexpensive (POSITIVE) n Can be made and remade whenever needed (POSITIVE) n Dimensions somewhat flexible (POSITIVE) 21
Current Status n n n Sent out NCIIA report before winter break Laptop for project given by Dr. Berry and started programming in Lab. View Applied to BMEidea Divided tasks among group members Consulted Ray Booker for test subjects and materials Assigned weekly meeting times 22
Overall Status Month Description November 2004 Look into previous research done on VNS and Electroanesthesia. Develop schematics and possible device physical designs. Start design development. December 2004 Proceed with research and finalize our design approach. Assemble basic design components. Develop software and user interface. January 2005 Begin designing prototype model and testing. February 2005 Proceed with prototype design and testing. Obtain IRB approval to test our device. March 2005 Run experiments if approved and make modifications where necessary. Continue work-up and finalize design. April 2005 Continue to finalize Design and prepare paper and presentation poster. 23
Most Important References 10 of 31 Ammons, W. Steve, Robert W. Blair, and Robert D. Foreman. " Vagal Afferent Inhibition Ammons, of Primate Thoracic Spinothalamic Neurons. " Journal if Neurophysiology 50. 4 (October 1983): 926 -940. Bohning, DE, MP Lomarev, S Denslow, Z Nahas, A Shastri, and MS George. Bohning, Lomarev, Denslow, Nahas, Shastri, "Feasibility of vagus nerve stimulation-Feasibility of vagus nerve stimulationsynchronized blood oxygenation level-dependent functional MRI. " Investigative Radiology 36. 8 (2001): 470 -479. Fries, Richard. E-mail interview. 5 2005. “FDA: Significant Risk and Nonsignificant Risk Devices”. Mount Sinai School of Medicine. 1 September 2005.