Nitric Oxide Delivery by Neonatal Noninvasive Respiratory Support Devices

Unconventional delivery of inhaled nitric oxide during endoscopic laryngeal tracheal reconstruction in a child with pulmonary arterial hypertension: A case report

“…One case series demonstrated significant (>50%) discrepancies in iNO doses delivered with nasal cannula (NC) . In another in vitro study, the accuracy of iNO delivery was within 20% of the stated accuracy range for nasal continuous positive airway pressure, but there was a 40% discrepancy with high flow NC . The reason for wide discrepancies with NC delivery is that the actual inspired concentration is dependent on the fresh gas flow and relative balance of inspiration through the nose and mouth.…”

A bench study of inhaled nitric oxide delivery during high frequency percussive ventilation

“…The operation of the INOmax DSIR Plus® requires measurement of the entire gas flow being delivered to the patient to assure accuracy. Using a proportional flow delivery, this system has been shown to accurately deliver NO and prevent NO 2 production during volume and pressure targeted ventilation, high frequency oscillation, and continuous positive airway pressure (CPAP) …”

“…The FDA approved delivery system for INO, known as the INOmax DSIR Plus® (Mallinckrodt, St. Louis, MO), titrates nitric oxide into inspired gas in proportion to the delivered gas flow . Evaluations of the INOmax DSIR® have shown accurate delivery of INO dose, monitoring of inspired oxygen (FIO 2 ), and minimal nitrogen dioxide (NO 2 ) production during invasive and non‐invasive ventilation …”

An injection and mixing element for delivery and monitoring of inhaled nitric oxide

“…In practice, additional and potentially more significant reduction in NO 2 production would be afforded by positioning the injection and mixing element close to the patient, thereby reducing NO residence time in the breathing circuit. Such a reduction may be important when considering options to guard against NO 2 exposure [13, 19]. …”

“…First, while increased NO residence time in breathing circuits is beneficial for gas mixing, production of NO 2 increases with increased residence time as well. A recent bench investigation of NO delivery through neonatal noninvasive respiratory support devices measured potentially dangerous NO 2 concentrations (>2 ppm) in certain worst-case scenarios related to extended gas residence times in breathing circuits [13]. Second, for newer, noninvasive forms of respiratory support, such as high flow nasal cannula therapy [14, 15], gas delivery conduits may lack sufficient internal volume to ensure mixed samples, so that modifications are required at the device level to enable compatibility with NO delivery.…”