CPAP Remote Alarm System BME 272: Oral Report Three

1. CPAP Remote Alarm SystemBME 272: Oral Report Three Group 15 Kathleen Grunder Jessica Paulsen Molly Rice

2. Project Advisor Dr. Roberta Leu - Clinical Instructor in the Sleep Disorders Division of Neurology, Vanderbilt University Academic Advisor Dr. Paul King - Professor of Biomedical Engineering Emeritus, Professor of Mechanical Engineering Emeritus

3. Obstructive Sleep Apnea Most common form of sleep disorder breathing 2% of US children have been diagnosed with obstructive sleep apnea Results in partial or complete collapse of the upper airway Can lead to sleep deprivation, arrhythmia, high blood pressure, heart disease, stroke, or death  80% of children have apnea that can be treated with corrective surgery

4. Constant Positive Airway Pressure (CPAP) Therapy •  Used to treat sleep apnea in the 300,000 US children whose apnea cannot be corrected with surgery •  Holds airway open with continuous flow of air •  Effective when used correctly 

5. Analysis Problem Statement Continuous Positive Airway Pressure (CPAP) machine masks often slip off during the night; this can be especially dangerous for children, who are not compliant with wearing the mask

6. AnalysisPerformance Criteria There is currently no alarm to alert parents when their child's CPAP machine has failed "I'm very nervous about knowing when [the mask] comes off because I realize how important it is to keep [my son's] airway open." - Parent of a child with sleep apnea A patent search and literature review found mask displacement alarms none remote none with our proposed mechanisms

7. AnalysisPrimary Objective To develop a remote alarm system to wake parents when their child’s CPAP machine has failed

8. AnalysisFailure Modes Source power failure Disconnected power cord Internal machine failure Mask displacement Mask removal Hose disconnection From mask From machine Kinked hose Punctured hose

9. Mask is displaced PowerFailure Hose Failure Internal Failure Airflow increases Airflow Decreases Propeller spin rate falls outside of specified range Alarm sounds in parents’ room Parent replaces child’s mask Failure Mode Diagram

10. HypothesisGoals To improve pediatric compliance with CPAP masks To prevent complications from apneas that can occur when the machine fails To alert parents when the machine fails To provide parents with comfort in knowing that the machine is working properly

11. HypothesisSolution Description To use an airflow sensor (spinning propeller/ interrupter) to determine when the airflow is outside a determined range indicating that one of the failure modes has occurred May consider other sensors CO2 Concentration Pressure

12. Node C Node B Node A Preliminary Design 

13. HypothesisPerformance Metrics Sensitivity measurements How often does the machine sound when the mask is off? Functionality Does the alarm go off when the machine fails? Compliance Do parents and children use the alarm? Alarm Volume Does the alarm wake up the parents? Receiver Range Can the reciever get the signal all over a house?

14. ProgressCompleted Work Met with sales representatives from ResMed, a CPAP manufacturer Obtained CPAP machine and three masks from ResMed Consultation with Dr. Galloway 

15. ProgressCurrent Work Buy system components Begin building and testing sensor segment Begin building and testing alarm segment Build business plan