Team Members: Sara Karle Ashley Matsick Michele Lorenz Emily Maslonkowski Client: Dr. Mihai Teodorescu Advisor: Prof. Mitch Tyler

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Problem Statement Background Motivation Design Constraints Mechanical Design Circuit Design Future Work

Create a device: –for in-home use –to provide pulsed delivery of inhaled steroids –in line with commercial CPAP machines –using the ventilation circuit and flow generated by the CPAP

Obstructive Sleep Apnea: Cessation of breathing during sleep despite effort to breathe - Most common in obese adults - Muscles relax, causing airway to collapse - Side effect range: drowsiness to heart attack - Treated with Continuous Positive Airway Pressure (ASAA 2007) unobstructedobstructed

Continuous Positive Airway Pressure (CPAP) –Delivers steady pressure of room air Patients generally require a pressure b/t 6-14 cm H 2 O –Humidifier often integrated –Mask types can vary CPAP machine by Respironics NasalFull face Hybrid

Metered-dose Inhalers (MDIs): - Used to treat respiratory illnesses - Combine active ingredients with propellant -Require priming + moderate shaking before actuation -Upright actuation required -Most effective drug delivery occurs during inhalation (Dhand 2004)

Patients with obstructive sleep apnea also commonly have asthma Asthma symptoms worsen in early morning Chronic asthma symptoms treated with inhaled steroids Delivery with CPAP forces drug deeper into lungs Need for fast-acting inhaler during the day may be minimized by treatment at night (Teodorescu 2007)

Agitate MDI to mix drug and propellant Depress inhaler to deliver drug Detect breathing pattern to coordinate drug delivery with inhalation Interface with existing CPAP ventilation circuit Size, weight, and noise levels appropriate for in-home use

Design alternatives (cams): –Multi-ridge cam (vibration + actuation in single rotation) –Double spring + single cam (holding + actuation bumps) – Double cam design (Fall 2003/Spring 2004) Pros: Single motor, 1 rotation Cons: Large cam, inflexible Pros: Single motor, 1 rotation Cons: Spring dampening, need for complete testing

Adapted from previous BME 400 design group 2 rotating cams & 2 motors –1 each for shaking, actuation Pros: - Shaking, actuation can be finely controlled - Easy/inexpensive control system Cons: - Weight, size of 2 motors (limits location of integration) ~bme200/mdi/secure/ Testing performed (Fall ’03/Spring ‘04): - Effect of shaking amplitude/frequency on MDI dose delivery Demonstrated that automatic shaking approximated manual shaking

LabVIEW timer Vibration cam Thermistor Actuation cam Setpoint: 4:00 am Action: power on    Setpoint: “X” rotations Action: power off , power on  Setpoint: T° threshold Action: power off  power on    Setpoint: 1 rotation Action: power off  Detecting inhalation Thermocouple RTD Thermistor lower precision than inexpensive fast response less sensitive than

Machine cams and construct mechanical shaker/actuator Test drug delivery with UV spectroscopy Interface device with existing CPAP ventilation circuit Write LabVIEW program: detect inhalation, power to motors Human subjects testing

Dhand, R. “Basic Techniques for Aerosol Delivery During Mechanical Ventilation.” Respiratory Care, 49.6 (2004): Quinn K, Lam Y, Vanderpool R. “Automated MDI Vibrational Device,” Madison, WI: University of Wisconsin-Madison (2004): 44. “Sleep Apnea Information,” American Sleep Apnea Association. 3 Oct 2007 Teodorescu, Mihaela. Personal Interview. 13 Sept 2007 Teodorescu, Mihai. Personal Interview. 13 Sept 2007