Neonatal Chest
Compression Device
Courtney Gallagher
Jillian Zeber
Advisor: Dr. Walsh, Vanderbilt NICU
Problem Statement
• When performed in
conjunction with operations of
the neck and lower abdomen,
there is limited space for
manual chest compressions.
• Manual chest compressions
require both hands to be
wrapped around the chest.
• 2 occurrences at the Vanderbilt
NICU this past year.
Project Goal
• Small, easy to setup device that will perform
automatic chest compressions on a 0-30 day old
infant for use in the OR during a simultaneous
procedure.
Performance Criteria
• Small but adjustable to fit the size of the baby.
• Provide enough force for sufficient chest compressions to
reduce the width to one third, 2 to 3 cm.
• Apply the 11-12 lbs of force directly below the nipples in the
center of the chest.
• Verified with bathroom scale and free weights.
• Maintain a rate of 80-100 compressions per minute for blood
pumping.
• Simple and easy to use by Dr. Walsh in the NICU
Force Required for Chest
Compressions
Applied Force (lbs)
Adequate Compression
11.1
Yes
11.6
Yes
12.3
Yes
13.1
Yes
14.7
Yes
18
Yes
10.8
No
10.1
No
9.9
No
Desired Force Range: 11 – 12 lbs
Solution Proposal
Solenoid Valve
Electronic Timer
Power Supply
15
cm
2-3
cm
6-9
cm
Adjustable depending on size of the baby
Solution Proposal
Solenoid Valve
Electronic Timer
Power Supply
15
cm
5 cm
4-6
cm
Adjustable depending on size of the baby
Solution Proposal
Exhaust
3- WAY
Air Cylinder
Air Compressor
Device Components
• Single-acting spring return pneumatic cylinder
• Air compressor with coil hose
• Solenoid valve controlled by electronic timer
• On/off time range: 0.1 s to 99 hr
• Power supply: wall outlet
• 1.1 inch diameter plunger to displace chest 2-3 cm
• Wheel-up cart supporting electronic components & air
compressor
• Support structure:
• Currently: stand with base and adjustable arm
• Ideally: Swivel arm connected to side panel of GE
OmniBed
Calculations
Air Cylinder Specs
Timer Settings
• Bore size:
F = p A = p π d2/4
where
F = force exerted (N)
p = gauge pressure (N/m2, Pa)
A = full bore area (m2)
d = full bore piston diameter (m)
F = 11 lbs = 50 N
p = 100 psi = 689.5 kPa
d = 10 mm ≈ 7/16”
• Stroke length:
> 3 cm with extra space
5 cm ≈ 2”
• On/Off time:
Cycle Length = 1/Cycle Freqency
On/Off time = Cycle Length/2
80/min
90/min
100/min
Cycle Frequency
(s-1)
1.333
1.50
1.667
Cycle Length (s)
0.750
0.667
0.600
On/Off time (s)
0.375
0.335
0.300
Factors
•
•
•
•
•
•
•
Provide necessary but not excessive force (11-12 lbs = 5 kg)
Materials that can be sterilized
Comfortable
Quick setup
Potentially portable
Safety
Adjustable
Implementation of Factors into Design
• Sterilizing plunger and
stopper with plastic drapes
• Dr. Walsh
• Vary force applied with the psi
of compressed air applied to
cylinder
• Variable rate with micro-timer
• Adjustable with flexible arm
coming out of NICU bed
Evaluation
• Isabel in the NICU Simulation Lab
• Responds like an alive baby
• Provides vitals
• Can determine if chest compression are adequate
Previous Work
• Researched existing adult compression devices
• AutoPulse, Lucas, Thumper
• Established goals and criteria that must be met
• Discussed with advisors
• Measured force required to provide chest compressions
• Decided on a prototype design
• Pneumatic cylinder
• Researched and purchased materials to build prototype
• Pneumatic cylinder and Air compressor
• Solenoid valve, timer
• All necessary connections
• Tested simplified version of prototype
• Verified applied force was correct
• Ordered more parts
Current Work
• Finishing DesignSafe
• Getting in touch with GE contact
• Kent Meeks
• Building complete version of prototype
• Testing full prototype
Future Work
• After testing, make modifications and re-test
• Build flexible arm
• Test
• Make Demo
• Evaluate effectiveness against traditional method
References
• http://www.zoll.com/medical-products/cardiac-supportpump/autopulse/
• http://content.onlinejacc.org/cgi/content/full/44/11/2214/FIG2
• http://www.omega.com/auto/pdf/SimpValvesguide.pdf
• http://www.gehealthcare.com/euen/maternal-infantcare/products/microenvironments/giraffe_omnibed/index.html
• http://www.engineeringtoolbox.com/pneumatic-cylinder-forced_1273.html