Delivery characteristics of a combined nitric oxide nasal continuous positive airway pressure system

• Published in: Pediatric anesthesia Vol. 12; no. 6; pp. 530 - 536
• Main Authors: Lindwall, R., Frostell, C.G., Lönnqvist, P.A.
• Format: Journal Article
• Language: English
• Published: Oxford UK Blackwell Science Ltd 01.07.2002; Blackwell
• Subjects: Administration, Inhalation; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Cardiovascular system; dosage; Emergency and intensive respiratory care; Humans; Infant; Infant, Newborn; infant, newborn: lung diseases, therapy; Intensive care medicine; Medical sciences; Medicin och hälsovetenskap; newborn: lung diseases; Nitric Oxide - administration & dosage; Nitric Oxide - therapeutic use; nitric oxide: administration; NO2: monitoring; NO2: monitoring, positive‐pressure respiration; Pharmacology. Drug treatments; positive-pressure respiration; Positive-Pressure Respiration - instrumentation; therapy; Vasodilator agents. Cerebral vasodilators; Human; Delivery system; Respiratory disease; Continuous; Artificial ventilation; Vasodilation; Inhalation; Chemotherapy; Newborn; Treatment; Respiratory failure; Positive pressure; Nitric oxide; Pulmonary circulation; Nasal route; Technical equipment
• ISSN: 1155-5645; 1460-9592
• DOI: 10.1046/j.1460-9592.2002.00898.x

Summary Background: Nitric oxide (NO), when inhaled, has a synergistic effect with airway recruitment strategies such as positive endexpiratory pressure (PEEP) or continuous positive airway pressure (CPAP) in improving oxygenation in lung injury. Methods: We modified a commercially available nasal CPAP (nCPAP) system to enable the concomitant delivery of inhaled NO (iNO) and nCPAP to neonates and term babies. Oxygen, NO and nitrogen dioxide (NO2) concentrations were measured, comparing the effects of using 50 or 1000 parts per million (p.p.m.) NO stock gas cylinders. Results: Stable and accurate delivery of iNO was found for both stock gas concentrations. Using a 50 p.p.m. NO stock gas resulted in limited NO2 formation, with a maximum inspired NO2 concentration of ≤ 0.3 p.p.m. (dose range up to 37 p.p.m. iNO), which was interpreted as the result of progressive dilution with nitrogen. In contrast, using a 1000 p.p.m. NO stock gas cylinder, inspired NO2 levels increased nonlinearly as expected with an increasing inspired concentration of NO. Conclusions: Inhaled NO can be safely and reliably delivered by the system we describe. The NO2 levels generated by the system are low, at least up to a dose of 37 p.p.m. NO, regardless of a stock gas concentration of 50 or 1000 p.p.m. NO. Using a 50 p.p.m. NO stock gas concentration, up to 80% oxygen can be given at 10 p.p.m. iNO.