Incubator Designed for Emerging Areas (iDEA)
University of PittsburghSenior Design – BioE 1160-1161
Areas (iDEA)
Ted Kastenhuber
Bradley H. Morneweck
Bailey M. Roche
Christopher E. Withers
Outline
• Overview• Project Objectives• Features & Benefits• Competitive Analysis• Quality System Considerations• Quality System Considerations• Regulatory Considerations• Our Design
• Considerations• Development
• Verification & Validation
Overview
• Infant Mortality in Developing Countries
• 98% of reported neonatal deaths occur in the developing world
• One of the leading causes is failure to keep babies warm, which leads to increased babies warm, which leads to increased hypothermia, decreased metabolism and infection
Zupan, Jelka “Perinatal Mortality in Developing Countries”, N ENGL J MED 352;20. 2005. 2047-2048
Overview
• Project contact: Dr. Ian Rawson, Hôpital Albert Schweitzer in Haiti
• Hospital requires a low-cost, low-maintenance neonatal incubator relevant to hospital situationhospital situation
• Projected intended to be a simple re-design of well-established incubation methods
Infantmortality:73 of 1,000
http://www.hashaiti.org/
Outline
• Overview• Project Objectives• Features & Benefits• Competitive Analysis• Quality System Considerations• Quality System Considerations• Regulatory Considerations• Our Design
• Considerations• Development
• Verification & Validation
Project Objectives
• Design functioning neonatal incubator
• Must be under $500
• Temporarily/semi-permanently operable outside of a variety of power gridsoutside of a variety of power grids
• Carry out four functions in accordance with FDA standards
• Thermoregulated heating
• Appropriate humidity maintenance
• Adequate ventilation maintenance
• Maintenance of sterility
Outline
• Overview• Project Objectives• Features & Benefits• Competitive Analysis• Quality System Considerations• Quality System Considerations• Regulatory Considerations• Our Design
• Considerations• Development
• Verification & Validation
Features & Benefits
• Thermoregulated System with alarm means that busy clinicians can go about their tasks assured that infant is safe
• Simple interface ensures that minimal training is required for operationis required for operation
• Low cost/accessible parts enable the device to be maintained on-site
• Compatibility with independent power supply ensures that device may be operable under conditions with limited or unreliable power supply
Outline
• Overview• Project Objectives• Features & Benefits• Competitive Analysis• Quality System Considerations• Quality System Considerations• Regulatory Considerations• Our Design
• Considerations• Development
• Verification & Validation
Competitive Analysis
• Modern Incubators (Dräger Medical)
• Extremely complex• Very expensive• Very expensive• Require extensive
maintenance by highly-trained technicians
http://www.gehealthcare.com/usen/perinatal/micro_environments/giraffe/images/giraffe_ph_prod_l.jpg
Competitive Analysis• HEBI
+ Cheap (€325 ~$510)+ Easy to use- Difficult to set up- No fine temperature control
• Kangaroo Mother Care (KMC)+ Cheap (free)
http://www.hebi-incubator.orghttp://www-conference.slu.se/KMCeurope08/bilder/Ylvasfoto5.jpg
Prasanga et. al., 2002
+ Cheap (free)
+ Easy
- Cumbersome
- Possibility of disease transmittal
• Phase Change Passive Incubator (PCPI)+ Lightweight
- Actual development is very meager
* Senior design project at MIT
Competitive Analysis
Parameter HEBI KMC PCPI iDEA
Cheap
User Friendly
Meets Modern Standards
Requires LessRequires LessNurse Attention
Safe
Baby Accessible for Procedures
Outline
• Overview• Project Objectives• Features & Benefits• Competitive Analysis• Quality System Considerations• Quality System Considerations• Regulatory Considerations• Our Design
• Considerations• Development
• Verification & Validation
Quality System Considerations
• Risk analysis• Significant risks
• Electrical failure causing fire• Loss of 1o C heat precision• Air infection• Loss of airflow• Loss of airflow
• General system responses• Failsafe systems respond• Alarm sounds• Device powers down (sounding alarm)
Regulatory Considerations
• Class II• FDA regulation 21 CFR 880.5400 – previous
incubators designated class II
• Also regulation: IEC 60601-2-19 1996-10: Amendment 1 - Medical electrical equipment Part Amendment 1 - Medical electrical equipment Part 2: Particular requirements for safety of baby incubators, which pertains to the 510(k) specifics.
• Third world application, bypasses FDA
Outline
• Overview• Project Objectives• Features & Benefits• Competitive Analysis• Quality System Considerations• Quality System Considerations• Regulatory Considerations• Our Design
• Considerations• Development
• Verification & Validation
Our Design
• Adequate Warmth
• Adequate Humidity
• Infant Visibility• Infant Visibility
• Infant Accessibility
• Air Filtration
• Sterility Maintenance
Our Design
Thermoregulation Unit
12V Battery (Thermoregulation
unit dedicated)
Surgical Mask Filtration
Access Ports
Humidity Chamber
Temperature Chart1
12V Battery
1. Kloesz, Jennifer L. Personal interview. 6 Oct. 2007.
Humidity Chamber and Power Supply
Housing
Bassinet
Access and Visibility
• Access Ports
• Sliding platform
• Transparent faces• Transparent faces
PowerAC DC
ePOWER EP-520XP-C1B ATX12V 520W Power Supply (x2)
Autocraft 12V Marine/RV Deep Cycle battery
(Supplied by HAS)
Power Supply (x2)
9 V Battery for independent alarm circuit
Heat
Rally 12V Heater (200W)$5.99
CE PTC Ceramic Heater & Fan (300W)$25.00
Circuit
MaxxTronic – MX052 –Digital Thermoregulator$39.95
Alarm Circuit1 -- $1.00
1. Stetten, George. "Comparators, Photoresistor, Thermoregulation, Hysteresis." University of Pittsburgh. Benedum Hall, Pittsburgh. 6 Apr. 2008 <http://www.stetten.com>.
Humidifier
PC fan~$7.99 ea.
Oven Pan$5.00
Ventilation
12V CoolerMaster computer fan (x2)
Active outtake, passive intakeActive outtake, passive intake
Cost Analysis
Material Cost (USD)
Wood 75
Plexiglass 40
Hardware 50
Power supplies 70
PC fans 10PC fans 10
Heaters 31
Maxtronic Thermoregulatory circuit 40
Misc. electronic supplies 70
Caulk, sealant, etc. 20
Bulb Thermometer 31
Water pan 5
Total 442*
*Note: The above prices reflect prototype production. During mass production, unit prices will be markedly lower.
Cost Analysis
$442.00 $510.22 $40,0001
iDEA
HEBI
Dräger1. Kloesz, Jennifer L. Personal interview. 6 Oct. 2007.
User input
• Set point temperature
• On/off
• Battery or AC power• Battery or AC power
• Alarm circuit on/off
Outline
• Overview• Project Objectives• Features & Benefits• Competitive Analysis• Quality System Considerations• Quality System Considerations• Regulatory Considerations• Our Design
• Considerations• Development
• Verification & Validation
Thermoregulation
*Note: Resolution of data logger is 0.5°C.(set point = 37.0°C)
Thermoregulation
• Initial tests indicate that servo control is possible
Humidity
60.00%
65.00%
70.00%
75.00%
80.00%
Rel
ativ
e H
um
idit
y (%
)Relative Humidity over Time
Red Squares -- starting water temp = 52 deg C
Blue Diamonds -- starting water temp = 30 deg C
Green Triangles -- included water heater
30.00%
35.00%
40.00%
45.00%
50.00%
55.00%
0 10 20 30 40 50 60
Rel
ativ
e H
um
idit
y (%
)
Time (min)
Ventilation
Ethanol Candle Test
14.335 g / 30 minutes==
232.7 mL O2/min
A baby requires 2.48 mL O2/min*
Oxygen requirements of candle exceed neonate by nearly 100, thus validating ventilation
*Libert JP, Bach V, Farges G. 1997. Neutral temperature range in incubators: performance of equipment in current use and new developments. Crit Rev Biomed Eng 25(4-5):287-370.
Sterility
• Swabbed for bacterial growth
• Time points: t0 = after ethanol cleansing; tF = after 5 hour run
• Positive control outside• Positive control outside
• Swabbed• Inside bassinet
• Inside humidity bay
• Inside water pan
Sterilityt0 = right after cleaning with ethanol
+ Control
Humidity Bay
Water Pan
Bassinet
tF = after 5 hours of running incubator
BassinetWater Pan
Humidity Bay
+ Control
Clinician Feedback
• Initial Impressions• Received well by Dr. Mahmood, Magee-
Women’s Hospital
• “I could see this device in my part of the • “I could see this device in my part of the world being used”
• Survey:• Scale 1-5:
• Ease of use, Utility, Safety
Survey
Ease of Use 1 2 3 4 5
Responsiveness 1 2 3 4 5
Mechanical Operability 1 2 3 4 5
4.67
3.67
4.67
Ergonomic and Aesthetic Quality 1 2 3 4 5
Three participants of backgrounds:1. MD, Neonatologist fellow2. High school equivalent3. B.S., Bioengineering
4.33
Project ManagementDec Jan Feb Mar Apr
3D Design
Heating/Humidityelement design
Alarm Circuitry
Device assembly
Verification/Verification/Validation
Send to Haiti
Each group member contributed equally to each aspect of the design process
Comparison to PDS
• Cost less than $500
• Must regulate temperature at set points 29-35˚ C
• Must alert staff if the temperature falls • Must alert staff if the temperature falls out of range
• Patient must be visible in the device
Comparison to PDS
• Noise < 47 dB (via Audacity™)
• Dimensions < (2m x 2m x 2m)
• Access to infant in less than 5s• Access to infant in less than 5s
• Easily portable
• Humidity > 40%
Moving Forward
• Immediate (Through April)
• Come up with production plan
• Long term (Early June?)
• Create final product (kit)
• Send and install device in HAS
Acknowledgements
• Ian Rawson, MD• Burhan Mahmood, MD • Jack Patzer, PhD• Rich Stoner• Andy Alexander• Andy Alexander• Shawn Burton• Sources of funding
• Generous gift of Drs. Hal Wrigley and Linda Baker• Department of Bioengineering• NCIIA BMEidea stipend award
??
Failure Mode Effect Analysis
Hazard Risk Index Acceptance Criteria
1 to 5 Unacceptable
6 to 9 Undesirable
10 to 16 Acceptable upon completion of quality assurance review
17 to20 Acceptable without review
Function or Component
Failure Mode Effect on System Possible HazardsRisk
IndexUser Detection Means Applicable Controls
Electrical thermoregulation unit
Incomplete/short circuit, thermistor malfunction
Temperature of the system deviates from set value
Over or underheating of the infant, dehydration; shock from circuit itself
10Monitoring of temperature shows system is not being moderated adequately; alarm sounds
Utilize circuit components with low voltage demands
Electrical thermosensitive alarm unit
Incomplete/short circuit, thermistor malfunction; incorrect input to alarm
Alarm failsInfant remains in an over or under-heated state for an amount of time that is fatal
10Monitoring of system shows temperature reads too high or low and no alarm has sounded
Utilize circuit components with low voltage demands; provide detailed, clear schematics for repair
Auditory Alarm Burnout or loss of functionAlarm fails to sound in the event of large deviation from set value
Infant remains in an over or under-heated state for an amount of time that is fatal
15Monitoring of system shows temperature reads too high or low and no alarm has sounded
Provide instructions for replacement; recommend regular tests
Table & legsFailure to provide adequate support
Device falls unexpectedly Trauma to infant 12 Visual observation.Ensure that device platform is structurally sound, provide warnings for incubator placement
Box/insulation component
Insufficient capacity to retain heat; puncture
Device is unable to reach set temperature value
Infant temperature too low, hypothermia
14 Alarm sounds.Warnings and detailed instructions for leak repair
Doors and hinges Unable to easily openInfant trapped inside of incubator
Asphyxiation, overheating, dehydration of infant
17 The door resists opening.
Enable hinges to be manually detached, provide warnings for proper handling of doors + hinges; recommend regular tests
Holes OcclusionAir ceases to be able to pass through device
Oxygen depletion, asphyxiation of infant
12Visual inspection of occlusion, unable to feel air flow placing hand over the hole
Ensure hole diameters are at a value that minimizes both occlusion occurrence and heat loss
FanMechanical failure, circuit failure
Air ceases to be pushed through device
Overheating of infant, oxygen depletion, asphyxiation
14 Visual or auditory recognition of fan failureEnsure fan component is easily replaceable, provide warnings for use
Heating lamps/bulbsBurnout, improper connection
Air ceases to be heatedHypothermia; shock, burns, broken glass hazards
9 Visual recognition or alarm sounds.
Use low wattage light bulbs; suggest having readily available back-up; use shatter-proof spotlight.
Redesigns• Bassinet
• Plexiglas vs. wood
• Added features
• Humidifier• Humidifier
• Simple
• Capillary action
• Enclosed pan
• Open chamber with forced air
Redesigns• Thermoregulation circuit
• Op Amp comparator
• PIC controller
• MaxxTronic
• Alarm Circuit
• Data logger
• Op Amp Comparator
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