928pH OPTIMIZATION AND INHALED NITRIC OXIDE THERAPY IN NEONATES WITH PERSISTENT PULMONARY HYPERTENSION: EVALUATING CLINICAL OUTCOMES AND RESPONSEAn empirical study conducted at Dhanalakshmi Srinivasan Medical College examined oxygenation issues in infants receiving inhaled nitric oxide (iNO) due to pH imbalances. The study tracked 142 infants over 98 hours, documenting demographic data, ventilation settings, arterial blood gases (ABGs) and interventions. It was observed that some infants required extracorporeal membrane oxygenation (ECMO) but ultimately survived until discharge. Key measurements included mean blood pressure (MBP) and mean airway pressure (MAP). The primary outcome of interest was the arterial/alveolar (a/A) ratio, used to assess clinical outcomes. Fisher’s exact test, simple linear regression and multiple linear regression analyses were applied. To define pH responsiveness, a correlation coefficient (CC) greater than 0.40 with a p-value of 0.05 was required. The mean gestational age was 35.5 weeks, and the mean birth weight was 3700 grams. All patients were clinically diagnosed with persistent pulmonary hypertension of the newborn (PPHN). The a/A ratio was not correlated with MAP or MBP in 82 of the 142 infants. Among the six responders, pH levels were greater than 7.41. Of the 26 patients who required ECMO, eight showed signs of responsiveness, with six of these responders requiring ECMO. This study suggests that the lack of response to inhaled nitric oxide may be attributed to an inability to optimize pH levels. It is not recommended to maintain pH levels above 7.5 by hyperventilation for this purposedrpebyreddy@gmail.comResearch1322022 Nitric oxide, ECMO, Hyperventilation, MAP, MBPpH OPTIMIZATION AND INHALED NITRIC OXIDE THERAPY IN NEONATES WITH PERSISTENT PULMONARY HYPERTENSION: EVALUATING CLINICAL OUTCOMES AND RESPONSEAssistant Professor, Department of Respiratory Medicine, Dhanalakshmi Srinivasan Medical College, Siruvachur, Tamil Nadu, India – 621113