Problem Statement

1. Aerosolized Drug Delivery Using Continuous Positive Airway Pressure Device Joe Decker Patrick Kurkiewicz Annie Loevinger Steve Welch Problem Statement Budget 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 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. Background • Sleep Apnea • Occurs when the trachea of the subject closes during sleep, repeatedly waking the subject and causing chronic sleep deprivation • Affects over 12 million Americans • 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. Final Design • 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. Future Work Nebulizer Column Breathing Cycle Waveform • 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. Inhale Exhale Piezoelectric Plate Image from Webster, J.G. 2009. Medical Instrumentation. Hoboken, NJ: John Wiley & Sons, Inc. • Nebulizer devices • Aerosolizes liquid medication into a mist of many small liquid droplets (1 – 10 m) • Often used with albuterol sulfate, a bronchodilator. • Ultrasonic Nebulizer (above right) • Uses high-frequency piezoelectric crystal to aerosolize drug for patient delivery • Program • 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 Threshold • Ultrasonic Nebulizer • Uses ultrasonic waves • Efficiency ~ 86+/-5%** • Jet Nebulizer • Uses pressurized air • Efficiency ~ 39+/-3%** patient References Testing Image from www.mece.ualberta.ca/arla/tutorial.htm Image from www.sonozap.com/nebulizer.htm 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. Design Specifications • 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 • 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. Acknowledgements Dr. Mihai Teodorescu—Department of Geriatrics, Gerontology and Sleep Medicine Dr. John Webster—Department of Biomedical Engineering Jim Maynard – Department of Chemistry CPAP Nebulized Albuterol Sulfate