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 IO 2 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 H 2 O. 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 IO 2 range of 0.34-0.98.

Delivery of Nitric Oxide in the Cardiovascular System: Implications for Clinical Diagnosis and Therapy

“…The main limitation of inhaled NO therapy is that the optimal dose threshold remains unclear, which can lead to long-term impairment, such as neurodevelopmental disabilities [113]. It is with this backdrop that Carter et al designed an MRI-compatible NO delivery device, which realized simultaneous NO inhalation and measurement of vasodilation [114]. Schafer et al further quantitatively investigated the correlation between inhaled NO and hemodynamic changes in intracardiac flow with four-dimensional-flow MRI [115].…”

The Delivery of Nitric Oxide in the Cardiovascular System: Implication for Clinical Diagnosis and Therapy

“…The main limitation of inhaled NO therapy is that the optimal dosed threshold remains unclear, which would lead to the long-term impairments, such as the neurodevelopmental disability [84]. It is with this backdrop that, Carter et al designed a MRI-compatible NO delivery device, which realized the simultaneous nitric oxide inhalation and measurement of vasodilation [85]. Schafer et al further quantitatively investigated the correlation between the inhaled NO and hemodynamic changes in the intracardiac flow with four-dimensional-flow MRI [86].…”