In contemporary clinical practice concerning the administration of inhaled nitric oxide (iNO) within neonatal intensive care units (NICUs), a stepwise reduction approach is frequently employed in accordance with established neonatal guidelines. Nonetheless, the comparative advantages of a linear reduction strategy-characterized by a gradual decrease in inhalation concentration-over the traditional stepwise method in terms of efficacy and safety have yet to be conclusively established. Furthermore, existing iNO delivery devices necessitate that healthcare professionals manually adjust parameters at intervals dictated by the patient's condition. This reliance on subjective clinical judgment often results in variability and a lack of standardization in the duration of the weaning process. Additionally, the protracted and intricate nature of the weaning procedure considerably heightens the workload for healthcare staff. Importantly, the development of a scientifically grounded, standardized, and real-time feedback mechanism for weaning may enhance clinical outcomes for patients and mitigate the risks associated with inappropriate weaning practices or inconsistent manual interventions. Consequently, this study seeks to leverage the newly introduced "intelligent closed-loop weaning" feature of the latest generation of iNO devices to facilitate automated linear concentration reduction during the weaning process. This innovation aims to alleviate the burden on healthcare personnel while establishing a more standardized and scientifically robust weaning protocol. However, it is noteworthy that there is currently a lack of clinical evidence, both domestically and internationally, regarding the safety and efficacy of this device's weaning protocol, underscoring the urgent need to validate its safety and effectiveness in real-world clinical settings.

Inclusion Criteria:

1. The administration of inhaled nitric oxide (iNO) has commenced or is anticipated to commence for a duration of 24 hours or more, based on a clinical diagnosis of persistent pulmonary hypertension of the newborn (PPHN);
2. There is a demonstrable positive response to iNO treatment;
3. The iNO delivery system employed is appropriate and meets the conditional requirements, featuring an intelligent closed-loop offline functionality;
4. The guardian or legal representative possesses a comprehensive understanding of the potential benefits and risks associated with participation in this study and has expressed a willingness to consent by signing the informed consent document.

Exclusion Criteria:

1. There are established contraindications associated with the use of nitric oxide, which include the following conditions:

   1. Severe hypoplasia of the left heart or duct-dependent congenital heart disease;
   2. Life-threatening congenital anomalies and congestive heart failure;
   3. Congenital methemoglobinemia;
   4. Significant hemorrhagic events, such as intracranial hemorrhage, intraventricular hemorrhage, and pulmonary hemorrhage.

2. Patients with chronic pulmonary conditions and other refractory diseases are not permitted to initiate withdrawal from the inhaled nitric oxide (iNO) treatment within a seven-day period following its administration.

3. In cases where there is no observable response to iNO or if the duration of use is less than 30 minutes, a strict tapering protocol for withdrawal is not required.

4. If the concentration of iNO treatment exceeds 20 parts per million (ppm) during the initiation phase or if the starting concentration for withdrawal is below 20 ppm, specific considerations must be taken into account.

5. Participation in concurrent clinical trials involving other pharmacological agents or medical devices is prohibited.

6. The investigator may determine that participation in this study is not appropriate for certain individuals.