Delivery of Inhaled Nitric Oxide During MRI to Ventilated Neonates and Infants

Abstract

BACKGROUND:

Many pediatric and neonatal ICU patients receive nitric oxide (NO), with some also requiring magnetic resonance imaging (MRI) scans. MRI-compatible NO delivery devices are not always available. We describe and bench test a method of delivering NO during MRI using standard equipment in which a NO delivery device was positioned in the MRI control room with the NO blender component connected to oxygen and set to 80 ppm and delivering flow via 12 m of tubing to a MRI-compatible ventilator, set up inside the MRI scanner magnet room.

METHODS:

For our bench test, the ventilator was set up normally and connected to an infant test lung to simulate several patients of differing weight (ie, 4 kg, 10 kg, 20 kg). The NO blender delivered flows of 2–10 L/min to the ventilator to achieve a range of NO and oxygen concentrations monitored via extended tubing. The measured values were compared to calculated values.

RESULTS:

A range of NO concentrations (12–41 ppm) and F_IO2 values (0.67–0.97) were achieved during the bench testing. The additional flow increased delivered peak inspiratory pressure and PEEP by 1–5 cm H₂O. Calculated values were within acceptable ranges and were used to create a lookup table.

CONCLUSIONS:

In clinical use, this system can safely generate a range of NO flows of 15–42 ppm with an accompanying F_IO2 range of 0.34–0.98.