Inhaled Nitric Oxide Delivery With a Noninvasive Single-Limb Circuit

Abstract

Background: Invasive mechanical ventilation is associated with costly complications such as ventilator-associated pneumonia, muscle atrophy, and line sepsis.¹ For patients with persistent need for inhaled nitric oxide (INO), extubation may be delayed by limited options for noninvasive ventilation (NIV) compatibility with INO. Studies suggest that NIV with INO may be appropriate and effective.² There is insufficient data on NIV INO delivery via systems with leaks. Our current standard of practice is to utilize a non-vented mask (NVM) in conjunction with F&P Evaqua dual-limb circuit on a Maquet Servo-U ventilator in NIV mode to accommodate Mallinckrodt INOMax DSIR recommendations. The need for a leakless system enhances restrictions for appropriate mask options in pediatrics. We aimed to evaluate INO delivery in a NIV bench model with a single limb circuit and leak to assess feasibility of INO delivery for our pediatric population.

Methods: INO delivery was evaluated using three NIV models. In all models a Michigan test lung (infant 0.005 compliance) was interfaced with the pediatric head mannikin (open nostrils) via Philips PerforMax XS mask and spontaneous breathing was simulated via ventilator (RR 30). INO injector module was placed immediately after the NIV outlet filter and INO was sampled proximal and distal to the patient interface. Both a Philips Respironics V60 and the EV300 were trialed with three models: the mask with non-vented adapter (NV) and distal exhalation port (DEP), the mask with NV and Respironics Whisper Swivel, and the mask with the Philips vented port. NIV settings were S/T, IPAP 20, EPAP 10, RR 10, Ti 0.7, % FIO₂ 1.0. NIV leak was maintained at <60 L/min and NIV pressures were allowed to stabilize and verified prior to trials. Each trial was 30 min, with recordings every 10 min.

Results: In all models evaluated NO and NO₂ showed no statistical significance in set, delivered, or measured values (Table 1). INO PSI showed no change over the trial period in a system with leaks.

Conclusions: In our bench analysis of INO and a NIV system with leaks INO delivery remained consistent and reliable. More studies should be done to assess implications related to INO D-cylinder tank duration, patient response, and potential caregiver exposure. References: 1. Cooke C. Economics of mechanical ventilation and respiratory failure. 2021;28(1):39-55. 2. Priyanka Patel, et al. Safety and efficacy of noninvasive inhaled nitric oxide in pediatric cardiac intensive care unit. Pediatrics 2019;144:403.