Boston Children’s Hospital: Damping System for High-Frequency Oscillatory Ventilation

Presenter: Talia Favale

Research Category: Engineering and Technology
PI: Andrew Gouldstone

Boston Children’s Hospital uses High-Frequency Oscillatory Ventilation (HFOV) systems for pediatric and neonatal patients requiring intensive care. The air is pumped from the ventilator to the lungs, and from the lungs, the air flows to the Phillips NM3 and Capnostat 5 sensors. When the ventilator is set to a low amplitude and high frequency, CO2 measurements from the Capnostat 5 become variable and inaccurate. This inaccuracy makes it difficult to assess patient condition. The goal of the design team was to create a damping device that reduces vibrations from the HFOV system before the airflow reaches the flow rate and CO2 sensors, allowing for more accurate readings. Measuring the amount of CO­­2 exhaled by a neonatal patient on a mechanical ventilator is necessary to determine how much oxygen the body absorbs with each influx of air. This information helps the doctors and technicians understand the gravity of the condition of the patient’s lungs. The design team designed a device which successfully dampens the flow of exhaled air, called Balloon in Balloon (BIB). BIB utilizes a 0.5L balloon placed inside a 1L balloon. The 0.5L balloon has four-1” slits around the balloon and one-1” slit at the bottom to avoid collection of condensation. Oscillating air flows out of the patient, in through an adaptor to the 0.5L balloon, exits through the slits, fills the outer balloon, and exits through another adaptor. This device achieved a flow rate range of ±0.82L/min at the worst case conditions.