Standardization of nitric oxide inhalation in extremely preterm infants in Japan

Clinical Analysis of Inhaled Nitric Oxide Therapy in Preterm Infants at Different Gestational Ages: A National Retrospective Multicenter Study

This study aimed to investigate clinical features of inhaled nitric oxide (iNO) in preterm infants with a gestational age (GA) < 34 weeks in China.The clinical data of 434 preterm infants with GA < 34 weeks, treated with iNO in the neonatology departments of eight Class A tertiary hospitals in China over a 10-year period from January 2013 to December 2022, were included in this retrospective multicenter investigation. The infants were divided into three groups based on GA: 24 to 27 weeks (extremely preterm infants), 28 to 31 weeks (very preterm infants), and 32 to 33 weeks (moderate preterm infants). The use of iNO, perinatal data, incidence and mortality of indication for iNO treatment, therapeutic effects of iNO, incidence of short-term complications for iNO treatment, and mortality were compared among these three groups.Over the past 10 years, the proportion of iNO use was highest in extremely preterm infants each year. The lower the GA, the higher the iNO use rate: 4.20% for GA 24 to 27 weeks, 1.54% for GA 28 to 31 weeks, and 0.85% for GA 32 to 33 weeks. There was no significant difference in the therapeutic effect of iNO among the three groups. The incidence of neonatal pulmonary hemorrhage, neonatal shock, late-onset diseases, retinopathy of prematurity requiring intervention, intracranial hemorrhage (grade 3 or 4), periventricular leukomalacia, neonatal necrotizing enterocolitis (≥stage II), and moderate to severe bronchopulmonary dysplasia was highest in extremely preterm infants and increased with decreasing GA. Mortality was negatively correlated with GA and birth weight. The highest rate of iNO treatment in 24 to 27 weeks' preterm infants was due to hypoxic respiratory failure (HRF), whereas the highest rate of iNO treatment in 32 to 33 weeks' preterm infants was due to documented persistent pulmonary hypertension of the newborn (PPHN). The rates of iNO treatment due to HRF and documented PPHN were 54.3 and 60.6%, respectively, in extremely preterm infants, significantly higher than in very preterm and moderate preterm infants (all p < 0.05). Within the same GA group, the proportion of preterm infants treated with iNO for HRF was lower than that for documented PPHN (all p < 0.05), but there was no statistically significant difference in mortality between HRF and documented PPHN treated with iNO (all p > 0.05).Among preterm infants with GA < 34 weeks, the rate of iNO usage was highest in extremely preterm infants. However, iNO failed to improve the clinical outcome of extremely preterm infants with refractory hypoxemia, and there was no significant difference in the therapeutic effect of iNO among preterm infants with different GAs.

Viability of Extremely Premature neonates: clinical approaches and outcomes

Viability refers to an infant's ability to survive outside the womb, which is influenced by both developmental maturity and the quality of medical care received. The concept of periviability, which has evolved alongside medical advancements, describes the stage between viability and nonviability, typically spanning from 200/7 to 25 6/7 weeks of gestation. While the chances of survival are extremely low at the earlier end of this range, the possibility of surviving without significant long-term complications improves towards the later end. The effectiveness of various antenatal and postnatal care practices, particularly those considered to be part of an active approach, plays a crucial role in influencing survival rates and mitigating morbidities. However, the decision to provide such active care is heavily influenced by national guidelines as well as international standards. The variability in guideline recommendations from one country to another, coupled with differences based on gestational age or accompanying risk factors, prevents the establishment of a standardized global approach. This variability results in differing practices depending on the country or institution where the birth occurs. Consequently, healthcare providers must navigate these discrepancies, which often leads to complex ethical dilemmas regarding the balance between potential survival and the associated risks. This review article explores the evolution of the definition of viability, the vulnerabilities faced by periviable infants, and the advancements in medical care that have improved survival rates. Additionally, it examines the viability and periviability definitions, the care and outcomes of periviable infants and recommendations in guidelines.

A multicenter epidemiological survey of iNO use in preterm infants in China

OBJECTIVE

To investigate the use of inhaled nitric oxide (iNO) in hospitalized preterm infants in China over 10 years and its clinical outcomes.

METHODS

A total of 616 premature infants who were administered iNO in the Neonatology Departments of 5 Class A tertiary hospitals in China for ten years from January 2013 to December 2022 were included retrospectively. Based on their enrollment periods, the patients were divided into two groups: Group 1 from January 2013 to December 2017 and Group 2 from January 2018 to December 2022, respectively. The perinatal characteristics, short-term clinical outcomes, and mortality rates were compared between these two groups.

RESULTS

The utilization of iNO in preterm infants grew annually over the past10 years; the utilization of iNO in Group 2 infants increased approximately one-fold when compared with Group 1 (1.52% vs. 0.80%, p < .001), and the increase was greater in gestational age (GA) < 34 weeks compared with 34-36 weeks preterm infants. Moreover, the iNO usage in Group 1 infants with GA < 34 weeks increased from 1.14% to 2.46% and 0.60% to 0.99% in 34-36 weeks preterm infants (p < .001) in Group 2, respectively. Apart from a smaller GA (32.9 w vs. 33.5 w, p < .001) and birth weight (BW, 1900 g vs. 2141 g, p < .001), the initial [14 parts per million (ppm) versus 10 ppm, p < .001] and maximum (15 ppm vs. 10 ppm, p < .001) doses of Group 2 were larger; however, their recent clinical outcomes did not improve with increasing iNO utilization (p > .05)as compared to Group 1, respectively. Although the overall iNO preterm mortality rates over the past 10 years were 25.8%, the mortality rates for preterm infants at 34-36 weeks were significantly lower than for preterm infants at GA < 34 weeks (15.4% vs. 33.8%, p < .001). Nonetheless, no improvement in mortality was observed in Group 2 preterm infants with GA < 34 weeks for the past 5 years when compared with Group 1 (32.9% vs. 35.8%, p > .05) infants, and significantly lower mortality rates were noticed in preterm infants with 34-36 weeks (11.2% vs. 22.7%, p < .001). Patients with hypoxic respiratory failure (HRF) or persistent pulmonary hypertension of the newborn (PPHN) iNO preterm infants did not show lower mortality rates with the increase of iNO use rate (p > .05). The overall mortality rates of preterm PPHN infants with iNO were lower than that of HRF (20.2% vs. 36.5%, p < .001), while the mortality rates of Group 2 preterm PPHN infants with iNO significantly lower than that of HRF (17.7% vs 36.0%, p < .001).

CONCLUSION

The iNO has been extensively used in Chinese preterm infants over the past 10 years, this increase was more significant in preterm infants with GA < 34 weeks. Moreover, preterm infants using iNO have lower GA and BW, larger initial and maximum doses, and more aggressive strategies in the last past 5 years. Although iNO use in preterm infants with GA of 34-36 weeks has significantly reduced mortality, mortality rates and short-term clinical outcomes of iNO in preterm infants <34 weeks of GA has no obvious improvement. Further studies are required to investigate the efficacy and safety of iNO in preterm infants <34 weeks of GA.

[Recent research on inhaled nitric oxide in preterm infants with a gestational age of <34 weeks]

Nitric oxide is a messenger molecule for vasodilation of vascular smooth muscle cells, and inhaled nitric oxide (iNO) can dilate pulmonary blood vessels and reduce pulmonary vascular resistance, thereby reducing pulmonary artery pressure, but with no influence on systemic circulation pressure. Guidelines in China and overseas recommend the use of iNO in full-term infants and late preterm infants, and it has been proved that it has a marked effect on persistent pulmonary hypertension and hypoxic respiratory failure in such infants. However, recent studies have shown that there is an increase in the off-label use of iNO in preterm infants with a gestational age of <34 weeks. This article reviews the research progress on the efficacy, safety, timing, dose, and withdrawal mode of iNO and its combination with vasoactive drugs in the treatment of preterm infants with a gestational age of <34 weeks in China and overseas, so as to provide a reference for clinical application.

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.

Inhaled Nitric Oxide Therapy in the Post-Acute Phase in Extremely Preterm Infants: A Japanese Cohort Study

OBJECTIVE

To determine the trends in inhaled nitric oxide (iNO) utilization in the late phase of hospitalization in a large Japanese cohort of extremely preterm infants and evaluate its benefit on long-term outcomes.

STUDY DESIGN

This was a retrospective multicenter cohort study of 15 977 extremely preterm infants born at <28 weeks of gestational age between 2003 and 2016, in the Neonatal Research Network, Japan. Demographic characteristics, morbidity, and mortality were compared between extremely preterm infants with and without post-acute iNO therapy. Multivariable logistic analysis was performed to determine factors associated with post-acute iNO and its impact on neurodevelopmental outcomes at 3 years of age.

RESULTS

Post-acute iNO utilization rates increased from 0.3% in 2009 to 1.9% in 2016, even under strict insurance coverage rules starting in 2009. Gestational age (1-week increment; aOR 0.82, 95% CI 0.76-0.88), small for gestational age (1.47, 1.08-1.99), histologic chorioamnionitis (1.50, 1.21-1.86), 5-minute Apgar score <4 (1.51, 1.10-2.07), air leak (1.92, 1.30-2.83), and bubbly/cystic appearance on chest X-Ray (1.68, 1.37-2.06) were associated with post-acute iNO. Post-acute iNO was not associated with neurodevelopmental outcomes at 3 years of age.

CONCLUSIONS

The increasing post-acute iNO utilization rate among extremely preterm infants has been concurrent with improved survival rates of extremely preterm infants in Japan. Infants treated with post-acute iNO had more severe disease and complications than the comparison group, but there were no differences in neurodevelopmental outcome at 3 years. This suggests post-acute iNO may benefit extremely preterm infants.

Controversies in neonatology: The efficacy of inhaled nitric oxide in preterm infants with persistent pulmonary hypertension

Introduction: There is limited and conflicting information in literature regarding use of inhaled nitric oxide (iNO) in preterm infants. In this study we examined the characteristics of preterm infants with persistent pulmonary hypertension (PHT) who responded and did not respond to iNO therapy . Material and Method: We retrospectively reviewed data of infants

Use of Inhaled Nitric Oxide in Preterm Infants: Is There Sufficient Evidence?

Nitric oxide (NO) is a potent vasodilator. The inhaled form (iNO) improves outcomes in term infants with persistent pulmonary hypertension of the newborn (PPHN) or bronchopulmonary dysplasia-associated pulmonary hypertension in preterm infants. However, in preterm infants, the risks and benefits of iNO use are controversial. Substantial evidence reveals no significant impact on survival or other morbidities in preterm infants with iNO treatment, independent of indication, timing, or duration of use. Many scientific organizations do not recommend the use of iNO in preterm infants, except in unique clinical circumstances with echocardiographic findings of PPHN in the setting of presumed pulmonary hypoplasia.

Creating experiences from active treatment towards extremely preterm infants born at less than 25 weeks in Japan

Treatment for extremely preterm infants born at less than 25 weeks of gestation in Japan was initiated mainly due to the amendment of the Maternal Health Act lowering the upper limit of abortion from 24 weeks to 22 weeks in 1990. Five years after the amendment, the Japanese national government started a nationwide project to improve the perinatal care system. Once selected perinatal centers reported improvements in survival rates, more centers have adopted aggressive treatments. They have accumulated their knowledge by experiencing the treatment of infants with a limit of viability. As a result, more than 50% of infants born even at 22 weeks of gestation can survive to discharge currently. This progress has resulted from the accumulation of experience at each perinatal center rather than the results from clinical trials. Furthermore, these experiences have been standardized to some extent through sharing information.

Serum vitamin A levels as a novel predictor for respiratory distress syndrome in neonates: is it beneficial?

BACKGROUND

Neonatal respiratory distress syndrome (RDS) is a very important dangerous disease in neonates and is accompanied by neonatal complications and death.

OBJECTIVE

Early determination of neonatal serum vitamin A levels as a possible novel predictor for neonatal RDS.

PATIENTS AND METHODS

A case-control study, with the identification number TCTR20210206001 was done on 100 neonates who were admitted to the neonatal intensive care unit (NICU) of Tanta University Hospital (TUH) suffering from RDS (patient group) and 100 healthy neonates (control group). Estimation of serum vitamin A (retinol) was occurred for all neonates of this study within the first four hours after birth before any nutrition or therapies.

RESULTS

Showed no significant difference between serums retinol (RT) levels in grade 1&2 RDS neonates (patient group) and the serum RT levels in the control group while there was significant difference between serums retinol levels in grade 3&4 RDS neonates (patient group) and the serum retinol levels in the control group where the P-value was 0.006, 0.002 respectively.

CONCLUSION

Serum vitamin A levels in neonates were decreased in RDS neonates and could be used as a predictor for the development and severity of RDS.

RECOMMENDATION

Routine estimation of serum vitamin A levels in neonates as a novel predictor for neonatal RDS.

Nitric oxide and the brain. Part 2: Effects following neonatal brain injury-friend or foe?

Nitric oxide (NO) has critical roles in a wide variety of key biologic functions and has intricate transport mechanisms for delivery to key distal tissues under normal conditions. However, NO also plays important roles during disease processes, such as hypoxia-ischemia, asphyxia, neuro-inflammation, and retinopathy of prematurity. The effects of exogenous NO on the developing neonatal brain remain controversial. Inhaled NO (iNO) can be neuroprotective or toxic depending on a variety of factors, including cellular redox state, underlying disease processes, duration of treatment, and dose. This review identifies key gaps in knowledge that should prompt further investigation into the possible role of iNO as a therapeutic agent after injury to the brain. IMPACT: NO is a key signal mediator in the neonatal brain with neuroprotective and neurotoxic properties. iNO, a commonly used medication, has significant effects on the neonatal brain. Dosing, duration, and timing of administration of iNO can affect the developing brain. This review article summarizes the roles of NO in association with various disease processes that impact neonates, such as brain hypoxia-ischemia, asphyxia, retinopathy of prematurity, and neuroinflammation. The impact of this review is that it clearly describes gaps in knowledge, and makes the case for further, targeted studies in each of the identified areas.