Objective:To investigate the association between blood pH measured by blood gas analysis during the first postnatal week and mortality in periviable extremely preterm infant (PEPI).Methods:This retrospective study analyzed 48 PEPIs (gestational age<24 weeks) admitted to the neonatal intensive care unit of Shenzhen Maternity and Child Healthcare Hospital, Southern Medical University between January 2021 and December 2023. According to the clinical outcomes during hospitalization, they were divided into two groups: death group ( n=12, including deaths despite active treatment and deaths due to treatment withdrawal) and survival group ( n=36, including cured and improved cases). Blood gas pH and base excess (BE) values during the first week were collected. Mann-Whitney U test and Chi-square test (or Fisher exact test) were used to compare maternal perinatal conditions and neonatal blood pH values between the two groups. The percentiles ( P3 and P90) of blood pH and BE values were described for the survival group by age. Results:(1) Among the 48 PEPIs, four were born at 21 weeks, 11 at 22 weeks, and 33 at 23 weeks of gestation. The clinical outcomes showed a cure rate of 60.4% (29/48), improvement rate of 14.6% (7/48), mortality due to poor prognosis with treatment withdrawal of 8.3% (4/48), and mortality under active treatment of 16.7% (8/48). (2) There was statistically significant difference in the death after treatment withdrawal among the PEPIs born at 21, 22, and 23 weeks of gestation [1/4, 2/11, and 3.0% (1/33); χ2=7.41, P=0.025]. The death group had higher proportions of infants with Apgar score≤3 at 1, 5, or 10 min after birth as compared with the survival group [7/12 vs. 25.0% (9/36), χ 2=4.50; 7/12 vs.16.7% (6/36), χ 2=7.91; 5/12 vs. 5.6% (2/36), χ 2=9.42; all P<0.05]. (3) The median blood pH values in the death group were lower than those in the survival group at 1-4, and 6 d after birth [7.13 (7.06-7.24) vs. 7.25 (7.23-7.31), Z=－3.44; 7.03 (7.00-7.18) vs. 7.21 (7.16-7.24), Z=－3.07; 7.02 (7.02-7.11) vs. 7.18 (7.13-7.21), Z=－3.51; 7.14 (7.13-7.20) vs. 7.18 (7.16-7.21), Z=－2.38; 7.15 (7.13-7.19) vs. 7.19 (7.17-7.22), Z=－2.08; all P<0.05].The pH value of the deceased infants rapidly declined within three days after birth, with the median pH values at two days and three days of age both falling below 7.05. In deceased infants due to poor prognosis, the median pH value at 4-7 days of age remained consistently at or below 7.15. In the survivors, the blood pH and BE values decreased after birth and hit the bottom at 3 and 5 days of age, respectively ( P3: pH=7.10, BE=－16.10 mmol/L) before gradual recovery. Conclusions:PEPI tend to present with low blood pH during the first postnatal week. However, excessively low blood pH warrants vigilance against adverse outcomes.

This report described a periviable extremely preterm infant who received Nirsevimab before discharge for preventing respiratory syncytial virus infection. The infant was born at 22?3 weeks' gestation with a birth weight of 360 g. Nirsevimab was administered on January 12, 2025 (110 days after birth, corrected gestational age of 38?2 weeks) at the Women and Children's Medical Center of Southern Medical University (Shenzhen Maternity & Child Healthcare Hospital). No local or systemic adverse reactions were observed following administration. Follow-up until 1 year and 2 months of age (November 2025) revealed no occurrence of respiratory syncytial virus infection.

Objective:To investigate the association between blood pH measured by blood gas analysis during the first postnatal week and mortality in periviable extremely preterm infant (PEPI).Methods:This retrospective study analyzed 48 PEPIs (gestational age<24 weeks) admitted to the neonatal intensive care unit of Shenzhen Maternity and Child Healthcare Hospital, Southern Medical University between January 2021 and December 2023. According to the clinical outcomes during hospitalization, they were divided into two groups: death group ( n=12, including deaths despite active treatment and deaths due to treatment withdrawal) and survival group ( n=36, including cured and improved cases). Blood gas pH and base excess (BE) values during the first week were collected. Mann-Whitney U test and Chi-square test (or Fisher exact test) were used to compare maternal perinatal conditions and neonatal blood pH values between the two groups. The percentiles ( P3 and P90) of blood pH and BE values were described for the survival group by age. Results:(1) Among the 48 PEPIs, four were born at 21 weeks, 11 at 22 weeks, and 33 at 23 weeks of gestation. The clinical outcomes showed a cure rate of 60.4% (29/48), improvement rate of 14.6% (7/48), mortality due to poor prognosis with treatment withdrawal of 8.3% (4/48), and mortality under active treatment of 16.7% (8/48). (2) There was statistically significant difference in the death after treatment withdrawal among the PEPIs born at 21, 22, and 23 weeks of gestation [1/4, 2/11, and 3.0% (1/33); χ2=7.41, P=0.025]. The death group had higher proportions of infants with Apgar score≤3 at 1, 5, or 10 min after birth as compared with the survival group [7/12 vs. 25.0% (9/36), χ 2=4.50; 7/12 vs.16.7% (6/36), χ 2=7.91; 5/12 vs. 5.6% (2/36), χ 2=9.42; all P<0.05]. (3) The median blood pH values in the death group were lower than those in the survival group at 1-4, and 6 d after birth [7.13 (7.06-7.24) vs. 7.25 (7.23-7.31), Z=－3.44; 7.03 (7.00-7.18) vs. 7.21 (7.16-7.24), Z=－3.07; 7.02 (7.02-7.11) vs. 7.18 (7.13-7.21), Z=－3.51; 7.14 (7.13-7.20) vs. 7.18 (7.16-7.21), Z=－2.38; 7.15 (7.13-7.19) vs. 7.19 (7.17-7.22), Z=－2.08; all P<0.05].The pH value of the deceased infants rapidly declined within three days after birth, with the median pH values at two days and three days of age both falling below 7.05. In deceased infants due to poor prognosis, the median pH value at 4-7 days of age remained consistently at or below 7.15. In the survivors, the blood pH and BE values decreased after birth and hit the bottom at 3 and 5 days of age, respectively ( P3: pH=7.10, BE=－16.10 mmol/L) before gradual recovery. Conclusions:PEPI tend to present with low blood pH during the first postnatal week. However, excessively low blood pH warrants vigilance against adverse outcomes.

This report described a periviable extremely preterm infant who received Nirsevimab before discharge for preventing respiratory syncytial virus infection. The infant was born at 22?3 weeks' gestation with a birth weight of 360 g. Nirsevimab was administered on January 12, 2025 (110 days after birth, corrected gestational age of 38?2 weeks) at the Women and Children's Medical Center of Southern Medical University (Shenzhen Maternity & Child Healthcare Hospital). No local or systemic adverse reactions were observed following administration. Follow-up until 1 year and 2 months of age (November 2025) revealed no occurrence of respiratory syncytial virus infection.

Objective:To investigate the current status, trends, and differences among institutions in the application of delivery room continuous positive airway pressure (DRCPAP) for very preterm infants treated in the institutions in the Chinese Neonatal Network (CHNN). Also, to explore the impact of DRCPAP on the outcomes of very preterm infants in China.Methods:A retrospective cohort study was conducted. Based on the CHNN very preterm infant cohort, very preterm infants (gestational ages ranging from 25 weeks +0 to 31 weeks +6) born in-hospital and treated in 79 tertiary neonatal intensive care units (NICUs) participating in the CHNN from 2019 to 2021 were included. The usage rates of DRCPAP in different hospitals, as well as gestational ages and years, were described. Data were analyzed using the Chi-square test (or Fisher's exact test) or t-test. A multivariate logistic regression model was established to explore the correlation between DRCPAP and clinical outcomes. Results:(1) A total of 18 048 very preterm infants were included. Among them, 3 666 (20.3%) received DRCPAP, and 14 382 (79.7%) did not. (2) The usage rate of DRCPAP for very preterm infants among different institutions is from 0.0% to 94.5%. Fourteen institutions did not use DRCPAP, and 55 institutions had a usage rate below 30%. The usage rate of DRCPAP in very preterm infants increased annually, from 13.8% (818/5 916) in 2019 to 26.0% (1 583/6 097) in 2021 ( χ2trend=122.00, P<0.001). (3) The DRCPAP group had higher rates of maternal assisted reproductive technology pregnancy, chorioamnionitis, a full course of antenatal corticosteroids, gestational diabetes, fetal distress, antenatal magnesium sulfate use, and cesarean delivery compared to the non-DRCPAP group [20.3% (744/3 665) vs. 17.6% (2 529/14 369), χ2=14.45; 23.0% (695/3 021) vs. 16.4% (1 956/11 926), χ2=72.57; 57.1% (2 090/3 660) vs. 54.3% (7 766/14 302), χ2=9.55; 23.0% (844/3 669) vs. 20.7% (2 969/14 342), χ2=9.77; 8.7% (319/3 666) vs. 7.0% (1 006/14 371), χ2=12.51; 87.1% (3 186/3 657) vs. 82.0% (11 736/14 312), χ2=81.38; 63.5% (2 327/3 664) vs. 60.7% (8 722/14 369), χ2=9.59; all P<0.05]. While the incidence of hypertensive disorders of pregnancy and the proportion of infants not using antenatal corticosteroids were lower in the non-DRCPAP group [17.1% (626/3 660) vs. 22.6% (3 183/14 084), χ2=44.70; 14.2% (520/3 661) vs. 19.7% (2 814/14 284), χ2=57.34; all P<0.05]. The DRCPAP group had lower birth weight and gestational age, higher 1 min and 5 min Apgar scores, and lower neonatal transport stabilization index scores [(1 308±314) g vs. (1 325±315) g, t=2.90; (29.5±1.7) weeks vs. (29.7±1.6) weeks, t=3.96; (7.9±1.8) scores vs. (7.6±1.9) scores, t=－9.80; (9.0±1.1) scores vs. (8.7±1.3) scores, t=－13.01; (11.0±9.4) scores vs. (13.1±9.8) scores, t=11.31; all P<0.05]. The incidence of early-onset sepsis was higher in the DRCPAP group than in the non-DRCPAP group [1.8% (68/3 578) vs. 1.3% (193/14 296), adjusted OR (95% CI): 1.417 (1.028-1.955)], while the rates of tracheal intubation within 72 hours, PS use, invasive mechanical ventilation, mortality, admission hypothermia, grade Ⅲ-Ⅳ intracranial hemorrhage, and stage≥3 ROP were all lower in the DRCPAP group compared to the non-DRCPAP group [22.6% (830/3 666) vs. 36.9% (5 310/14 374), adjusted OR (95% CI): 0.499 (0.448-0.555); 53.1% (1 947/3 666) vs. 58.3% (8 388/14 377), adjusted OR (95% CI): 0.764 (0.697-0.836); 30.1% (1 104/3 662) vs. 43.9% (6 307/14 366), adjusted OR (95% CI): 0.539 (0.487-0.595); 7.4% (274/3 666) vs. 10.6% (1 526/14 342), adjusted OR (95% CI): 0.709 (0.601-0.836); 57.5% (2 103/3 657) vs. 66.5% (9 501/14 287), adjusted OR (95% CI): 0.722 (0.661-0.788); 3.0% (101/3 366) vs. 5.9% (763/12 932)], adjusted OR (95% CI): 0.525 (0.412-0.669); 2.2% (65/2 954) vs. 3.3% (367/11 121), adjusted OR (95% CI): 0.692 (0.505-0.947); all P<0.05]. There were no statistically significant differences between the two groups in the incidence rates of BPD at a corrected gestational age of 36 weeks, patent ductus arteriosus ligation, spontaneous intestinal perforation, and pneumothorax. Conclusions:Domestically, the application of DRCPAP might be related to a decrease in the demand for invasive ventilation, the use of surfactants, and mortality, but it might not reduce the occurrence of bronchopulmonary dysplasia, at a corrected gestational age of 36 weeks. In recent years, the use of DRCPAP in very premature infants in China has increased, but the overall usage rate is still low, and there are significant differences between units, requiring continuous quality improvement.

This case report described the sucussful treatment of a male infant born at 21 weeks and 4 days through assisted reproductive technology. After prenatal consultation and with the strong desire of the parents, active resuscitation and treatment were performed. The infant received 52 days of mechanical ventilation and was extubated to non-invasive ventilation at a corrected gestational age of 28 weeks and 6 days. During hospitalization, no vasoactive drugs were used, and necrotizing enterocolitis did not occur. The gastric tube was removed at a corrected gestational age of 37 weeks and 4 days. At a corrected gestational age of 40 weeks, cranial MRI showed no abnormalities. The infant was discharged at a corrected gestational age of 42 weeks after 143 days of treatment, without the need for any respiratory support. Follow-up until a corrected age of 6 months showed good growth and development.

Objective:To observe the impacts of using heated and humidified gas sources for delivery room resuscitation on the short-term outcomes of extremely preterm infants.Methods:A retrospective study was conducted on 231 extremely preterm infants admitted to the neonatal intensive care unit of Shenzhen Maternity & Child Healthcare Hospital, the First School of Clinical Medicine, Southern Medical University, from January 2020 to December 2022. The infants were divided into two groups based on whether heated and humidified gas sources were used during delivery room resuscitation: the heated and humidified group (103 cases) and the non-heated and humidified group (128 cases). Independent sample t-tests, Chi-square tests, and Mann-Whitney U tests were used to compare general conditions and short-term outcomes between the groups. Multivariate logistic regression analysis was used to assess the impact of using heated and humidified gas sources during delivery room resuscitation on the short-term outcomes of extremely preterm infants. Results:Compared to the non-heated and humidified group, the heated and humidified group had a lower incidence of intubation resuscitation [28.2% (29/103) vs. 41.4% (53/128), χ 2=4.38], moderate to severe bronchopulmonary dysplasia (BPD)/death [22.3% (23/103) vs. 39.1% (50/128), χ 2=7.39] and low rectal temperature upon admission (<36.7 ℃) [57.3% (59/103) vs. 79.7% (102/128), χ 2=13.57], while the rectal temperature upon admission was higher [36.3 ℃ (36.0-36.7 ℃) vs. 35.9 ℃ (35.5-36.3 ℃), U=－5.05], with all differences being statistically significant (all P<0.05). After adjusting for gender, gestational age, mode of delivery, amniotic fluid condition, weight on admission, maternal premature rupture of membranes, assisted reproductive technology, and full course of prenatal steroid use, multivariate logistic regression analysis showed that the use of heated and humidified gas sources during delivery room resuscitation could increase the hospital admission rectal temperature ( β=0.46, 95% CI: 0.28-0.64), and decrease the risks of severe BPD/death ( aOR=0.39, 95% CI: 0.20-0.75), and low rectal temperature upon admission ( aOR=0.29, 95% CI: 0.16-0.55)(all P<0.05). Compared to the non-heated and humidified group, the heated and humidified group showed no statistically significant differences in the use of pulmonary surfactant [37.9% (39/103) vs. 43.8% (56/128), χ 2=1.45], incidence of stage Ⅲ or higher necrotizing enterocolitis [2.0% (2/103) vs. 5.5% (7/128), χ 2=2.06], grade Ⅲ or higher intracranial hemorrhage [2.9% (3/103) vs. 3.9% (5/128), χ 2=0.22], and retinopathy of prematurity requiring surgical treatment [3.9% (4/103) vs. 10.2% (13/128), χ 2=3.60] (all P>0.05). Conclusion:The use of heated and humidified gas sources during resuscitation of extremely preterm infants can reduce the risk of moderate to severe BPD/death, help maintain warmth during resuscitation, and do not adversely affect other short-term outcomes.

Objective:To describe the current status and trends in the outcomes and care practices of extremely preterm infants at 22-25 weeks′ gestation age from the Chinese Neonatal Network (CHNN) from 2019 to 2021.Methods:This cross-sectional study used data from the CHNN cohort of very preterm infants. All 963 extremely preterm infants with gestational age between 22-25 weeks who were admitted to neonatal intensive care units (NICU) of the CHNN from 2019 to 2021 were included. Infants admitted after 24 hours of life or transferred to non-CHNN hospitals were excluded. Perinatal care practices, survival rates, incidences of major morbidities, and NICU treatments were described according to different gestational age groups and admission years. Comparison among gestational age groups was conducted using χ2 and Kruskal-Wallis tests. Trends by year were evaluated by Cochran-Armitage and Jonckheere-Terpstra tests for trend. Results:Of the 963 extremely preterm infants enrolled, 588 extremely preterm infants (61.1%) were male. The gestational age was 25.0 (24.4, 25.6) weeks, with 29 extremely preterm infants (3.0%), 88 extremely preterm infants (9.1%), 264 extremely preterm infants (27.4%), and 582 extremely preterm infants (60.4%) at 22, 23, 24, and 25 weeks of gestation age, respectively. The birth weight was 770 (680, 840) g. From 2019 to 2021, the number of extremely preterm infants increased each year (285, 312, and 366 extremely preterm infants, respectively). Antenatal steroids and magnesium sulfate were administered to 67.7% (615/908) and 51.1% (453/886) mothers of extremely preterm infants. In the delivery room, 20.8% (200/963) and 69.5% (669/963) extremely preterm infants received noninvasive positive end-expiratory pressure support and endotracheal intubation. Delayed cord clamping and cord milking were performed in 19.0% (149/784) and 30.4% (241/794) extremely preterm infants. From 2019 to 2021, there were significant increases in the usage of antenatal steroids, antenatal magnesium sulfate, and delivery room noninvasive positive-end expiratory pressure support (all P<0.05). Overall, 349 extremely preterm infants (36.2%) did not receive complete care, 392 extremely preterm infants (40.7%) received complete care and survived to discharge, and 222 extremely preterm infants (23.1%) received complete care but died in hospital. The survival rates for extremely preterm infants at 22, 23, 24 and 25 weeks of gestation age were 10.3% (3/29), 23.9% (21/88), 33.0% (87/264) and 48.3% (281/582), respectively. From 2019 to 2021, there were no statistically significant trends in complete care, survival, and mortality rates (all P>0.05). Only 11.5% (45/392) extremely preterm infants survived without major morbidities. Moderate to severe bronchopulmonary dysplasia (67.3% (264/392)) and severe retinopathy of prematurity (61.5% (241/392)) were the most common morbidities among survivors. The incidences of severe intraventricular hemorrhage or periventricular leukomalacia, necrotizing enterocolitis, and sepsis were 15.3% (60/392), 5.9% (23/392) and 19.1% (75/392), respectively. Overall, 83.7% (328/392) survivors received invasive ventilation during hospitalization, with a duration of 22 (10, 42) days. The hospital stay for survivors was 97 (86, 116) days. Conclusions:With the increasing number of extremely preterm infants at 22-25 weeks′ gestation admitted to CHNN NICU, the survival rate remained low, especially the rate of survival without major morbidities. Further quality improvement initiatives are needed to facilitate the implementation of evidence-based care practices.

Objective:To investigate the current status, trends, and differences among institutions in the application of delivery room continuous positive airway pressure (DRCPAP) for very preterm infants treated in the institutions in the Chinese Neonatal Network (CHNN). Also, to explore the impact of DRCPAP on the outcomes of very preterm infants in China.Methods:A retrospective cohort study was conducted. Based on the CHNN very preterm infant cohort, very preterm infants (gestational ages ranging from 25 weeks +0 to 31 weeks +6) born in-hospital and treated in 79 tertiary neonatal intensive care units (NICUs) participating in the CHNN from 2019 to 2021 were included. The usage rates of DRCPAP in different hospitals, as well as gestational ages and years, were described. Data were analyzed using the Chi-square test (or Fisher's exact test) or t-test. A multivariate logistic regression model was established to explore the correlation between DRCPAP and clinical outcomes. Results:(1) A total of 18 048 very preterm infants were included. Among them, 3 666 (20.3%) received DRCPAP, and 14 382 (79.7%) did not. (2) The usage rate of DRCPAP for very preterm infants among different institutions is from 0.0% to 94.5%. Fourteen institutions did not use DRCPAP, and 55 institutions had a usage rate below 30%. The usage rate of DRCPAP in very preterm infants increased annually, from 13.8% (818/5 916) in 2019 to 26.0% (1 583/6 097) in 2021 ( χ2trend=122.00, P<0.001). (3) The DRCPAP group had higher rates of maternal assisted reproductive technology pregnancy, chorioamnionitis, a full course of antenatal corticosteroids, gestational diabetes, fetal distress, antenatal magnesium sulfate use, and cesarean delivery compared to the non-DRCPAP group [20.3% (744/3 665) vs. 17.6% (2 529/14 369), χ2=14.45; 23.0% (695/3 021) vs. 16.4% (1 956/11 926), χ2=72.57; 57.1% (2 090/3 660) vs. 54.3% (7 766/14 302), χ2=9.55; 23.0% (844/3 669) vs. 20.7% (2 969/14 342), χ2=9.77; 8.7% (319/3 666) vs. 7.0% (1 006/14 371), χ2=12.51; 87.1% (3 186/3 657) vs. 82.0% (11 736/14 312), χ2=81.38; 63.5% (2 327/3 664) vs. 60.7% (8 722/14 369), χ2=9.59; all P<0.05]. While the incidence of hypertensive disorders of pregnancy and the proportion of infants not using antenatal corticosteroids were lower in the non-DRCPAP group [17.1% (626/3 660) vs. 22.6% (3 183/14 084), χ2=44.70; 14.2% (520/3 661) vs. 19.7% (2 814/14 284), χ2=57.34; all P<0.05]. The DRCPAP group had lower birth weight and gestational age, higher 1 min and 5 min Apgar scores, and lower neonatal transport stabilization index scores [(1 308±314) g vs. (1 325±315) g, t=2.90; (29.5±1.7) weeks vs. (29.7±1.6) weeks, t=3.96; (7.9±1.8) scores vs. (7.6±1.9) scores, t=－9.80; (9.0±1.1) scores vs. (8.7±1.3) scores, t=－13.01; (11.0±9.4) scores vs. (13.1±9.8) scores, t=11.31; all P<0.05]. The incidence of early-onset sepsis was higher in the DRCPAP group than in the non-DRCPAP group [1.8% (68/3 578) vs. 1.3% (193/14 296), adjusted OR (95% CI): 1.417 (1.028-1.955)], while the rates of tracheal intubation within 72 hours, PS use, invasive mechanical ventilation, mortality, admission hypothermia, grade Ⅲ-Ⅳ intracranial hemorrhage, and stage≥3 ROP were all lower in the DRCPAP group compared to the non-DRCPAP group [22.6% (830/3 666) vs. 36.9% (5 310/14 374), adjusted OR (95% CI): 0.499 (0.448-0.555); 53.1% (1 947/3 666) vs. 58.3% (8 388/14 377), adjusted OR (95% CI): 0.764 (0.697-0.836); 30.1% (1 104/3 662) vs. 43.9% (6 307/14 366), adjusted OR (95% CI): 0.539 (0.487-0.595); 7.4% (274/3 666) vs. 10.6% (1 526/14 342), adjusted OR (95% CI): 0.709 (0.601-0.836); 57.5% (2 103/3 657) vs. 66.5% (9 501/14 287), adjusted OR (95% CI): 0.722 (0.661-0.788); 3.0% (101/3 366) vs. 5.9% (763/12 932)], adjusted OR (95% CI): 0.525 (0.412-0.669); 2.2% (65/2 954) vs. 3.3% (367/11 121), adjusted OR (95% CI): 0.692 (0.505-0.947); all P<0.05]. There were no statistically significant differences between the two groups in the incidence rates of BPD at a corrected gestational age of 36 weeks, patent ductus arteriosus ligation, spontaneous intestinal perforation, and pneumothorax. Conclusions:Domestically, the application of DRCPAP might be related to a decrease in the demand for invasive ventilation, the use of surfactants, and mortality, but it might not reduce the occurrence of bronchopulmonary dysplasia, at a corrected gestational age of 36 weeks. In recent years, the use of DRCPAP in very premature infants in China has increased, but the overall usage rate is still low, and there are significant differences between units, requiring continuous quality improvement.

Objective:To study the early use of inhaled nitric oxide (iNO) as a rescue therapy in extremely premature infants (EPIs) with refractory hypoxic respiratory failure (HRF).Methods:Between January 2021 and December 2021, EPIs with refractory HRF receiving iNO within the first week of life in our NICU were enrolled. Their clinical characteristics and outcomes were retrospectively analyzed.Results:A total of 11 EPIs were included with 5 males and 6 females. The median gestational age (GA) was 24(22.6, 25.2) weeks. The median birth weight (BW) was 580(490, 770) g. The most common primary diagnoses were moderate/severe respiratory distress syndrome (RDS) (5/11) and early-onset sepsis (3/11). The median age starting iNO therapy was 6.5(4.5, 34.0)h and the median duration of iNO was 24(12, 36)h. The median iNO starting dose was 5(5, 8) ppm and the therapeutic range was 5-20 ppm. Therapeutic efficacy was defined as ≥30% FiO 2 reduction after 6 h of iNO treatment. The treatment was effective in 8 cases. The oxygenation index (OI) decreased more than 10% from baseline 1 h after initiation in 9 patients and in all 11 patients after 12 h of iNO. The reduction of OI was more prominent in EPIs with a higher OI at baseline. Of the 11 patients, 8 survived, 1 died and 2 abandoned further treatments. Conclusions:As an early rescue therapy for EPIs with refractory HRF, iNO can improve oxygenation without obvious short-term adverse effects.