CPAP Remote Alarm System BME 272: Oral Report Four

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

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

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

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

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

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

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

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

Internal Failure Power Failure Hose Failure Mask Displacement Airflow Increases Airflow Decreases Propeller Spin Rate Breaches Specific Range Alarm Sounds in Parents’ Room Parent Replaces Child’s Mask Failure Mode Diagram

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

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

Preliminary Design

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?

ProgressCompleted Work • Met with sales representatives from ResMed, a CPAP manufacturer • Obtained CPAP machine and three masks from ResMed • Consultation with Dr. Galloway • Obtained parts • Began constructing circuit

ProgressCurrent Work • Finish constructing circuit • Design corresponding LabView VI • Begin testing sensor segment

ProgressFuture Work • Begin building and testing alarm segment • Perform cost analysis • Build business plan

CPAP Remote Alarm System BME 272: Oral Report Four