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Anesthesiology Neuromuscular Monitoring System. ANTS. #25. Group Information. Greg Angelotti (EE) Otto Cruz ( CpE ) Kristin “Zaza” Soriano ( CpE /EE) Sponsor: Dr. Thomas Looke (Anesthesiologist/EE). Current Methodology. Administer Neuromuscular Blocking Agents (NMBA)
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Group Information Greg Angelotti (EE) Otto Cruz (CpE) Kristin “Zaza” Soriano (CpE/EE) Sponsor: Dr. Thomas Looke (Anesthesiologist/EE)
Current Methodology • Administer Neuromuscular Blocking Agents (NMBA) • Blocks Acetylcholine (ACh) • Trivial neuromuscular stimulating • Subjective muscle response monitoring (if any at all) • Pen and paper record keeping
Current Methodology *Courtesy of nursingcrib.com
Current Methodology * Research shows not as reliable as the first two sites
Objectives • To safely stimulate targeted sites • To effectively obtain patient signals • To accurately record patient feedback • To create a more organized environment
Requirements • Must consist of safe modular subsystems • Must obtain objective quantitative muscular responses • Must produce individual patient feedback and logging • Must reduce operating room clutter
Current Control • PWM to produce the 200us square wave form. • 10 Bit Serial SPI Dual Output DAC to control current output. • 2^10 taps (1024) with a 10 bit DAC • Issues deciding between Digital Potentiometer (voltage) and DAC (voltage & current).
Current Op amp • Current input varies between 0 to 150 uA. • Current output 0 to 750 mA. • Availability and price is the reason for this part.
DC to DC Converter • Optional part • Input 3.1 to 75 volts • Frequency Synchronization
Negative Feedback • DC Converter to ADC port on MCU • Digital Integral controller to regulate the stimulation current. • Using the formula above will allow us to control the stimulators output.
Power Supply • Voltage buck/boost regulator dual output 3.7 volts supplies processor & 5 volts supplies DAC • Boost Voltage regulator supplies op amp at 8 volts • The power supply is a 3.7 volt 2200 mAh lithium ion polymer.
Surface EMG • Pick targeted sites • Prepare the site • Place Ag/Cl reference electrodes • Ring Electrodes [preferred] • Disc Electrodes [<10 mm] • Ready to read patient action potentials • 0-6 mV [Typical]
Pressure Sensor Conditioning Inverting Amplifier • Standard Resistance from sensor (FSR): • Appr. 1 MOhm • VREF should be negative • Appr. -5 Volts • The smaller RG is the more sensitive the sensor becomes Vout = (Vref)*(RG/Sensor)
Bend Sensor Conditioning Inverting Amplifier • Standard Resistance from sensor (FSR): • Appr. 10 KOhm • VREF should be negative • Appr. -5 Volts • The more the sensor bends the more the greater the impedance Vout = (Vref)*(RG/Sensor)
Touchscreen Controller Custom I2C Voltage-level Shifter GND SCL SDA VIO Pandaboard ES J6 Expansion Header
LCD Controller LED Backlight Control I/O Pandaboard ES J3/J4 30-pin LVDS Connection LCD I/O
Tablet Power • 6 volts 10000 mAh • 23 x 99 x 71 mm • $15-17
Tablet Software • Ubuntu • C++ • qT