Inhaled nitric oxide therapy for preterm infants after 7 days of age: a scoping review protocol.

INTRODUCTION: Inhaled nitric oxide (iNO) use is recommended for persistent pulmonary hypertension of the newborn in term and late preterm infants. Recently, iNO therapy to prevent bronchopulmonary dysplasia (BPD) or rescue for hypoxic respiratory failure and pulmonary hypertension secondary to BPD has increasingly been used in preterm infants after 7 days of postnatal age (in the postacute phase), despite its off-label use. However, the initiation criteria of iNO therapy for preterm infants in the postacute phase are varied. The aim of this scoping review is to identify the clinical and/or echo findings at the initiation of iNO therapy in preterm infants in the postacute phase. METHODS AND ANALYSIS: We will search PubMed, Embase and the Japanese database 'Ichushi.' The following studies will be included in the review: randomised controlled trials, prospective/retrospective cohort studies, case-control studies and case series on iNO therapy for preterm infants in the postacute phase; studies published between January 2003 and August 2023; studies conducted in developed countries and studies written in English or Japanese. We will independently screen, extract and chart data using the population-concept-context framework following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews. We will summarise the characteristics and findings of the included studies. ETHICS AND DISSEMINATION: Obtaining an institutional review board approval is not required because of the nature of this review. A final report of review findings will be published and disseminated through a peer-reviewed journal and presentation at relevant conferences. TRIAL REGISTRATION NUMBER: UMIN000051498.

Therapeutic response of iNO in preterm infants with hypoxemic respiratory failure.

BACKGROUND: Inhaled nitric oxide (iNO) has been used as a rescue treatment for preterm infants with hypoxemic respiratory failure (HRF). However, its effectiveness remains debatable. Thus, in this study, we aimed to examine the impact of iNO therapy on HRF in extremely preterm infants. METHODS: A retrospective observational study was performed. Extremely preterm infants admitted to our neonatal intensive care unit who received iNO therapy later in their postnatal life were included. The oxygen saturation index (OSI) was used as an index of the severity of respiratory failure. RESULTS: In total, 30 extremely preterm infants were included in this study. Oxygenation was enhanced after the administration of iNO in infants with HRF. The OSI decreased by more than 20% in 12 patients (40%, positive responder) and did not decrease in 17 patients (57%, negative responder) within the first 6 h of treatment. The iNO initiation day was the significant independent factor associated with a positive response to iNO therapy in extremely preterm infants with HRF. CONCLUSIONS: iNO therapy was effective in enhancing oxygenation in extremely preterm infants with HRF. Earlier use of iNO was the significant factor associated with a positive therapeutic response to iNO, implying that iNO may be more effective in pulmonary vessels which are less damaged by shorter-term mechanical ventilation.

Changes in In-Hospital Survival and Long-Term Neurodevelopmental Outcomes of Extremely Preterm Infants: A Retrospective Study of a Japanese Tertiary Center.

OBJECTIVES: The objective of this study was to elucidate whether the survival and long-term neurodevelopmental outcomes of extremely preterm infants have improved in a Japanese tertiary center with an active treatment policy for infants born at 22-23 weeks of gestation. STUDY DESIGN: This single-centered retrospective cohort study enrolled extremely preterm infants treated at Saitama Medical Center, Saitama Medical University, from 2003 to 2014. Patients with major congenital abnormalities were excluded. Primary outcomes were in-hospital survival and severe neurodevelopmental impairment (NDI) at 6 years of age, which was defined as having severe cerebral palsy, severe cognitive impairment, severe visual impairment, or deafness. We assessed the changes in primary outcomes between the first (period 1; 2003-2008) and the second half (period 2; 2009-2014) of the study period and evaluated the association between birth-year and primary outcomes using multivariate logistic regression models. RESULTS: Of the 403 eligible patients, 340 (84%) survived to discharge. Among 248 patients available at 6 years of age, 43 (14%) were classified as having severe NDI. Between the 2 periods, in-hospital survival improved from 155 of 198 (78%) to 185 of 205 (90%), but severe NDI increased from 11 of 108 (10%) to 32 of 140 (23%). In multivariate logistic regression models adjusted for gestational age, birthweight, sex, singleton birth, and antenatal corticosteroids, the aOR (95% CI) of birth-year for in-hospital survival and severe NDI was 1.2 (1.1-1.3) and 1.1 (1.0-1.3), respectively. CONCLUSION: Mortality among extremely preterm infants has improved over the past 12 years; nevertheless, no significant improvement was observed in the long-term neurodevelopmental outcomes.