1. Neonatal Chest Compression Device Courtney Gallagher 1, Jillian Zeber 1 Advisors: Paul King 1, PhD; William Walsh 2, MD Vanderbilt University, Biomedical Engineering 1, Monroe Carell Jr. Children’s Hospital 2 INTRODUCTION DESIGN APPROACH RESULTS ACKNOWLEDGEMENTS PROTOTYPE EVALUATION CALCULATIONS OBJECTIVES DESIGN/SAFETY CRITERIA Figure 1. Dr. Walsh demonstrates how to provide manual chest compressions on the NICU simulation baby, Isabel. COST BREAKDOWN Chest compressions to restart the heart may need to be performed simultaneously with abdomen or neck surgery on a 0-30 day old infant. Since the surgeons cannot stop the surgery, another surgeon must perform the compressions. There is limited space around the infant due to their size and there isn’t any room for another person to provide compressions. 2 occurrences in the Vanderbilt NICU this past year (as seen by Dr. Walsh) Must perform adequate chest compressions to the standards of Dr. Walsh: Take up little space in the NICU Provide compressions at least as effective as the traditional, manual method of chest compressions Be safe, non-harmful to the baby Used in Vanderbilt NICU and other hospital NICU’s Design Criteria: Reduce the chest width by one third (2-3 cm) Provide 80-100 compressions per minute Apply 11-12 pounds of force Be portable with quick/easy set up Solutions to Safety Issues: Completed DesignSafe Develop instruction manual and training program Sterilization with plastic drapes No more than 12 lbs of force can be applied MaterialCost per Unit Air Cylinder $15 3-Way Solenoid Valve $109 Electronic Timer $80 Coiled Air Hose $33 25’ Tubing $12 Air Compressor $200 Wall Plug $7 TOTAL UNIT COST: $456 Table 2. Cost evaluation per unit of material, which is significantly lower than adult devices currently on the market. 1.1”diameter plunger attached to 2”bore- piston to displace chest 2-3 cm Wheel-up cart supporting electronic components & air compressor Stand with base and adjustable arm holds the cylinder directly above the infant’s chest Figure 2. Compressed air travels through the hose to actuate the air cylinder during the on-position of the solenoid valve. Figure 3. The solenoid valve is controlled by an electronic timer and power is supplied via a wall outlet. Air Cylinder Mechanics: F = p A = p π d 2 /4 F = force exerted (N) p = gauge pressure (N/m 2, Pa) A = full bore area (m 2 ) d = full bore piston diameter (m) From testing: F = 11 lbs = 50 N p = 100 psi = 689.5 kPa d = 10 mm ≈ 7/16” 80/min90/min100/min Cycle Frequency (s -1 )1.3331.501.667 Cycle Length (s)0.7500.6670.600 On/Off time (s)0.3750.3350.300 Table 1. A rate of 80-100 compressions per minute results in on/off times of 0.3-0.375 seconds. Timer On/Off time: Cycle Length = 1/Cycle Frequency On/Off time = Cycle Length/2 Figure 4. The prototype is tested on Isabel with the air cylinder positioned directly above the center of the chest right beneath the nipples. The device was tested on the NICU SimNewB simulation baby, Isabel. The SimNewB supplies lifelike clinical feedback, determining whether the chest compressions provided by the device are adequate by measuring blood flow rate. Single-acting spring return pneumatic cylinder actuated by compressed air via an air compressor with coil hose Air flow controlled via 3-way solenoid valve with an electronic timer Power supplied via a wall outlet (120 V, 60 Hz) FUTURE DIRECTIONS Create instruction manual Evaluate the effectiveness against traditional method Build a permanent support structure with a wide base Implement feedback via force sensitive resistors Try for FDA approval REFERENCES " Cost Effective Comprehensive Training Program Targets Rural Community Hospitals." Laerdal: Helping save Lives. Laerdal Medical, 2011. Halperin, MD, MA, Henry R et al. "Cardiopulmonary Resuscitation with a Novel Chest Compression Device in a Porcine Model of Cardiac Arrest: Improved Hemodynamics and Mechanisms." Journal of the American College of Cardiology 44 (2004): 2214-220. "Pneumatic Air Cylinders - Force Exerted." Engineering Toolbox. Web. 18 Apr. 2011. We would like to thank the following for their support and help with our senior design project: Mary Lee Lemley, MSN, RNCKent Meeks, GE John DunbarVU Dept. of Chemistry Joel Barnett, PhD Comparison: 1.Lucas: $14,500 2.Thumper: $5,000 3.Autopulse: $13,000 Figure 6. The 11-lb cut-off equals a minimum of 72 psi of compressed air. Figure 5. When tested on Isabel only applied forces greater than 11 lbs. were adequate.