CPAP Remote Alarm System
BME 272: Oral Report Four
Group 15Kathleen Grunder
Jessica PaulsenMolly 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
• 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
Obstructive Sleep Apnea
• 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
Constant Positive Airway Pressure (CPAP) Therapy
• 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
Analysis Problem Statement
• 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 alarmso none remoteo none with our proposed mechanisms
AnalysisPerformance Criteria
• To develop a remote alarm system to wake parents when their child’s CPAP machine has failed
AnalysisPrimary Objective
• Source power failure• Disconnected power cord• Internal machine failure• Mask displacement • Mask removal • Hose disconnectiono From mask o From machine
• Kinked hose• Punctured hose
AnalysisFailure Modes
Failure Mode Diagram
Hose FailureMask
DisplacementInternal Failure Power Failure
Airflow Decreases
Airflow Increases
Propeller Spin Rate Breaches Specific Range
Alarm Sounds in Parents’
Room
Parent Replaces
Child’s Mask
• 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 failso To provide parents with comfort in knowing that
the machine is working properly
HypothesisGoals
• 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
HypothesisSolution Description
Preliminary Design
• Sensitivity measurementso How often does the machine sound when the mask is off?
• Functionalityo Does the alarm go off when the machine fails?
• Complianceo Do parents and children use the alarm?
• Alarm Volumeo Does the alarm wake up the parents?
• Receiver Rangeo Can the reciever get the signal all over a house?
HypothesisPerformance Metrics
• 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
Progress Completed Work
• Finish constructing circuit• Design corresponding LabView VI• Begin testing sensor segment
ProgressCurrent Work
• Begin building and testing alarm segment
• Perform cost analysis• Build business plan
ProgressFuture Work