Transcript Final Poster 1508 kb Sunday, December 6, 2009

Aerosolized Drug Delivery Using Continuous
Positive Airway Pressure Device
Joe Decker
Patrick Kurkiewicz
Problem Statement
A method is needed for automated delivery of
respiratory anti-inflammatory drugs, like albuterol,
to patients as they use continuous positive airway
pressure (CPAP) device.
Annie Loevinger
Steve Welch
Client: Dr. Mihai Teodorescu, MD 1
Advisor: John Webster, PhD2
1 Department
of Geriatrics, Gerontology and Sleep Medicine – School of Medicine and Public Health
and Center for Sleep Medicine and Sleep Research - University of Wisconsin Madison
2Department of Biomedical Engineering – University of Wisconsin Madison
Background
Sleep Apnea
Final Design
• Occurs when the trachea of the subject closes during sleep,
repeatedly waking the subject and causing chronic sleep
deprivation
• Affects over 12 million Americans
Function
•Detects breathing cycle from
microphone attached to CPAP
machine and amplifies/filters signal.
•Uses LabJack U3 to process
breathing cycle and determines
when to turn switch on.
•Switch activates ultrasonic
nebulizer, which delivers drug to
patient.
Continuous Positive Airway Pressure (CPAP) devices
• Includes a pressure source, a circuit, and tubing to a mask
worn by a patient
• Provides positive pressure to assist in patient breathing.
• Used for sleep apnea or in ambulatory situations for
patients with asthma.
Nebulizer
Column
Inhale
• Aerosolizes liquid medication into a mist of many small
liquid droplets (1 – 10 m)
• Often used with albuterol sulfate, a bronchodilator.
Jet Nebulizer
• Uses pressurized air
• Efficiency ~ 39+/-3%**
Ultrasonic Nebulizer
• Uses ultrasonic waves
• Efficiency ~ 86+/-5%**
Microphone Circuit Output (V)
Nebulizer devices
Exhale
2
Image from Webster, J.G. 2009. Medical Instrumentation. Hoboken, NJ: John Wiley & Sons, Inc.
Piezoelectric
Plate
1.5
Ultrasonic Nebulizer (above right)
•Uses high-frequency piezoelectric crystal to
Threshold aerosolize drug for patient delivery
1
Program
0.5
patient
0
Image from www.mece.ualberta.ca/arla/tutorial.htm
Image from www.sonozap.com/nebulizer.htm
Design Specifications
The drug delivery device should:
• Deliver nebulized medication within the CPAP circuit.
• Be compatible with any CPAP device currently on the
market.
• Be capable of daily use, for at least 8 hours at a time.
• Deliver up to three 3 mL doses of medication during usage.
• Allow the user to sleep comfortably and safely during use.
• Include a user-programmable feature to specify dosage and
delivery timing.
CPAP
Nebulized Albuterol Sulfate
0
5
10
15
20
Time (s)
25
30
Item
Vendor
Purpose
Cost
Ultrasonic Humidifier
Wal-Mart
For ultrasonic piezoelectric component
$30.56
Ultrasonic Humidifier
Home Depot
To replace broken piezoelectric component
from first ultrasonic humidifier
$31.64
PVC pipe fittings/ piping
ACE Hardware
For connection of piezoelectric component to
the CPAP circuit
$6.50
DAQ Board
LabJack
For processing of signals to and from
microphone and piezoelectric component.
$111.99
Microphone
Radio Shack
Detection of CPAP flow and subject’s
breathing for more efficient use of Albuterol.
$4.00
DC Voltage Adapter
Prime Electronic
Components
To provide the required power to the DAQ
board / microphone
$11.83
PC tubing 1.25” I.D.
US Plastic
To serve as a clear reservoir to hold liquid to
be nebulized
$9.87
Pipe Fittings
McMaster-Carr
To replace PVC pipe fittings purchased earlier
with something less bulky.
$14.14
120 V Switch
DigiKey
Will switch power to piezoelectric component
on and off to control nebulization amount
$4.15
CPAP unit
UW-Hospital
Used to test feasibility of prototype ideas
Donated
Albuterol Nebulizer Doses
UW-Hospital
Used to test feasibility of prototype ideas
Donated
Total
Breathing Cycle Waveform
2.5
Budget
35
40
•Detects breathing rate waveform (left) from
microphone amplifier/filter circuit
•Averages past 3 breathing cycles to estimate
next cycle
•Can program when to turn on/off ultrasonic
nebulizer based on estimated breathing rate
Testing
•Left: Spectrophotographic
curve for albuterol at 269
nm.
•Right: Observed albuterol
concentration of the bulk
solution during nebulization
and theoretical albuterol
concentration if no albuterol
were nebulized.
•Data indicates that
observed albuterol
concentration was lower
than theoretical
concentration if no albuterol
were nebulized
$224.68
Future Work
• R&D work will continue in January, 2010.
• Change design of Albuterol reservoir so that the following
problems are solved:
– Heating of Albuterol Solution
– Inadequate mixing of nebulized drug with CPAP flow
• Acquire data pertaining to % nebulized drug that makes it to
the CPAP mask
• Automate nebulization and create user interface with
adjustable dosage settings based on this information.
• Conduct “Stage I” trials in Dr. Teodorescu’s sleep research
lab.
References
American Sleep Apnea Association (ASAA). www.sleepapnea.org
Dhand, R. 2004. Basic Techniques for Aerosol Delivery During Mechanical Ventilation. Respiratory Care. Vol. 49, No. 6: June
2004.
Estes, M. C., Fiore, J., Mechlenburg, D. M., Ressler, H., and Kepler, J. 2005. Method and Apparatus for Providing Positive
Airway Pressure to a Patient. US Patent, 6,932,084. Assigned to RIC Investments, Inc.
Franca, E.E.T., Dornelas de Andrade, A. F., Cabral, G., Filho, P. A., Silva, K.C., Filho, V. C. G., Marinho, P. E. M., Lemos, A.,
and Parreria, V.F. 2006. Nebulization associated with bi-level noninvasive ventilation: Analysis of pulmonary radioaerosol
deposition. Respiratory Medicine. Is. (2006) 100, 721-728.
**Gessler T; Schmehl T; Hoeper M M; Rose F; Ghofrani H A; Olschewski H; Grimminger F; Seeger W. 2001. Ultrasonic versus
jet nebulization of iloprost in severe pulmonary hypertension. The European respiratory journal : official journal of the European
Society for Clinical Respiratory Physiology 2001;17(1):14-9.
Hess, D. R. 2007. The Mask for Noninvasive Ventilation: Principles of Design and Effects on Aerosol Delivery. J. Aerosol
Med. Vol. 20, Supplement 1.
LabJack U3. 2009. U3 Specs. [Onine] www.labjack.com/u3/specs
Sanders, M. H. and Zdrojkowski, R. J. 1992. Method and Apparatus for Maintaining Airway Patency to Treat Sleep Apnea and
Other Disorders. US Patent, 5,148,802.
Webster, J.G. 2009. Medical Instrumentation. Hoboken, NJ: John Wiley & Sons, Inc.
Acknowledgements
Dr. Mihai Teodorescu—Department of Geriatrics, Gerontology and Sleep Medicine
Dr. John Webster—Department of Biomedical Engineering
Jim Maynard – Department of Chemistry