Use of Home Ventilators for Ventilatory Support during Magnetic Resonance Imaging

Purpose: Magnetic Resonance Imaging (MRI) is a valuable diagnostic tool for neuroimaging in the Emergency and Critical Care setting, but its use may be limited in acutely and chronically ventilated patients, who cannot maintain the supine position in spontaneous breathing for the duration required for the procedure, as it may be the case in acute and chronic neurological and neuromuscular diseases with diaphragm involvement. We aimed to evaluate the performance of home life support ventilators used with a longer circuit, allowing the application of ventilatory support during MRI. The study hypothesis was that home ventilators are accurate in delivery the set ventilatory parameters despite a modified circuit. Materials and Methods: Four non-MRI-compatible life-support home ventilators were tested on a bench using 3 circuits of 4.8 m length and 3 ventilation settings. Results: We found measurable differences in the efficacy of the ventilation delivered to the test lung, which was influenced from the used ventilator, the type of circuit and the ventilation parameters. In the volumetric setting with unvented circuit, the difference between set VT and delivered VT ranged between -10% and +3%. In the barometric setting, only the ventilators providing automatic compensation for circuit compliance and resistance were reliable in the delivery of the set inspiratory and end-expiratory pressures. Conclusion: The use of home ventilators during MRI may represent a valuable alternative when a MRI-compatible ventilator is not available, but may require an adjustment of the ventilatory setting, and a systematic verification of the parameters effectively delivered to the patient.