Real-Time Coagulopathy Measurement 1 Development Team Justin - - PowerPoint PPT Presentation

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Real-Time Coagulopathy Measurement 1 Development Team Justin - - PowerPoint PPT Presentation

Apr 03, 2023 31 likes •452 views

Real-Time Coagulopathy Measurement 1 Development Team Justin Hemphill Trenton Rochelle Ziming Qi Overview Coagulopathy of Trauma A hypo-coagulable state caused by trauma, resulting in increased bleeding or clotting, heightened

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Real-Time Coagulopathy Measurement

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Development Team

Trenton Rochelle Justin Hemphill Ziming Qi

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Overview

  • Coagulopathy of Trauma – A hypo-coagulable state

caused by trauma, resulting in increased bleeding or clotting, heightened resuscitation requirements, and a 4x increased rate of mortality.

  • Car accidents, shootings, bad falls...
  • To minimize mortality, coagulopathy must be assessed

and addressed nearest to the time of injury and monitored throughout the course of care.

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Problem with Current Solutions

  • Measurements can only be taken in a hospital/lab setting
  • Can take up to an hour
  • Seconds matter when treating a critically injured person
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Aptitude’s Solution

  • Proprietary molecule that binds to receptors in a person’s
  • blood. Electrochemical signals produced by the molecular

binding give coagulopathy measurement.

  • Developed a handheld sensor analogous to a blood

glucose meter

  • 30 second test
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Location Hospital/Lab Portable Time ~ 1 hour < 2 minutes Size Stationary Machines Handheld User Doctor/Lab Technician First Responder

Current Solution Aptitude’s Solution

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Alpha Prototype

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Our New System

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Main Product Requirements

  • Handheld and field-ready during an emergency
  • Blood within the sensor needs to be stable at various goal

temperatures (15-60°C) ○ Needed for different tests + future development

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Goals

  • Temperature control
  • Integrate modules into a PCB
  • Provide future feature expandability
  • Device charging in-use
  • Redesign enclosure
  • Quick and reliable readings
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Design Limitations

  • No bluetooth
  • Long battery life
  • Handheld
  • Work while charging
  • Work with Android
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Simplified Block Diagram

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Core Modules

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Central Processor

  • SAMD21 Cortex-M0+
  • Low power 32-bit
  • 48MHz Clock
  • SPI/UART/USB + GPIO + PWM
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Emstat Pico

  • Highly compact potentiostat used for

electrochemical measurements

  • Provides coagulopathy measurement
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Power System

Battery:

  • PKCELL Li-Po rechargeable battery
  • 3.7V
  • 2500mAh
  • 50mm x 50mm x 7mm
  • Use: Supply system power

Battery Controller:

  • PowerBoost 1000C
  • Boosts output to 5V
  • Battery level reading
  • Safely charges Li-Po Battery from USB
  • Charge + Use simultaneously.
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Temperature Control

Peltier Module:

  • Heats + Cools the blood chip
  • 25mm x 12mm x 3mm
  • 6.0-9.0V operating voltage
  • 800mA draw
  • Voltage changes as temperature changes
  • H-Bridge device alternates current
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Temperature Readings

Surface Mount Thermistor (PT100):

  • Responsive thermal equilibrium
  • Thin Film

Digital Amplifier (MAX31865):

  • Read temperature every 100ms
  • 0.02℃ resolution
  • Connected to Thermistor

Thermistor atop Peltier Side View

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Peltier Control Function

  • 1. Input: Temperature (℃)
  • 1. Output: PWM Duty Cycle (0-100%)
  • 1. Using two PID controller objects

i. One for heating

  • ii. One for cooling
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Proportional-Integral-Derivative (PID)

  • Control loop mechanism employs feedback
  • Continuously calculates an error value e(t) as the difference

between a desired setpoint y(t) and a measured process variable r(t)

  • Applies a correction based on proportional, integral, and

derivative terms

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PID Tuning - Kp, Ki, Kd

Target Amplitude Time

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Heating PID - No Enclosure Results

Converges to +10℃ in around 7-8 seconds!

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Cooling (more difficult)

Working against ambient temperature Created an enclosure for thermal isolation Heat from bottom side diffuses into colder side High temperature gradient reduces efficiency Attached heat sinks } ΔT = temperature gradient

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Enclosure Design

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Enclosure Design

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Heating Improvement

25°C to 37°C in 4 seconds (50%) 25°C to 60°C in 20 seconds

4

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Putting It All Together

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PCB Revision 1

  • 2-Layer
  • Single-sided
  • 45mm x 75mm
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PCB Revision 2

  • 4-Layer
  • Double-sided
  • 45mm x 63mm (12mm shorter)
  • Blood reading system included
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Top Bottom

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Android Application

  • Microprocessor-Android communication while also

charging

  • Microprocessor data can be changed in-app with JSON

messages ○

{"mode":"set","modeType":"isTempControlling","modeData":[1]}

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Developer Settings

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Scanning App

  • Scan Start
  • Status Info
  • Temperature
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Acknowledgements

Scott Ferguson, PhD, CEO and Founder, Aptitude Inc. Radhey Patel, Electronics Engineer, Aptitude Inc. Yoga Isukapalli, Professor and Capstone Chair, UCSB ECE. Aditya Wadaskar, Teaching Assistant, UCSB ECE. Kyle Douglas, Teaching Assistant, UCSB ECE.