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.
目的： 描述2019—2021年中国新生儿协作网（CHNN）各单位收治的出生胎龄22~25周超早产儿的出院预后和治疗现状以及3年变化趋势。 方法： 基于CHNN极早产儿队列的横断面研究，纳入2019—2021年CHNN各单位新生儿重症监护病房（NICU）收治的963例出生胎龄22~25周的超早产儿。排除出生24 h后入院及转运至非CHNN医院治疗的超早产儿。根据出生胎龄和入院年份分组，描述不同组超早产儿围生期救治、存活率、并发症发生率及NICU治疗情况。采用χ2检验、Kruskal-Wallis秩和检验进行组间比较，采用Cochran-Armitage和Jonckheere-Terpstra趋势检验进行不同年份间趋势分析。 结果： 963例超早产儿中男588例（61.1%），出生胎龄25.0（24.4，25.6）周，出生体重770（680，840）g。出生胎龄22、23、24、25周的超早产儿分别有29例（3.0%）、88例（9.1%）、264例（27.4%）、582例（60.4%）。2019—2021年3年间超早产儿病例数量逐年增加（分别为285、312、366例）。母亲产前激素和硫酸镁的应用率分别为67.7%（615/908）和51.1%（453/886）。产房中无创呼气末正压和气管插管应用率分别为20.8%（200/963）和69.5%（669/963），延迟脐带结扎和脐带挤压应用率分别为19.0%（149/784）和30.4%（241/794）。2019—2021年3年间母亲产前激素、产前硫酸镁应用、产房无创呼气末正压应用率均有增加趋势（均P<0.05）。349例（36.2%）超早产儿未接受完整治疗自动出院，392例（40.7%）接受积极治疗存活，222例（23.1%）接受积极治疗后死亡。积极治疗后存活率在出生胎龄22、23、24、25周超早产儿中分别为10.3%（3/29）、23.9%（21/88）、33.0%（87/264）和48.3%（281/582）。2019—2021年3年间自动出院率、积极治疗后存活率和病死率变化趋势均无统计学意义（均P>0.05）。积极治疗后存活超早产儿中，仅11.5%（45/392）出院时无并发症存活。中重度支气管肺发育不良［67.3%（264/392）］和严重早产儿视网膜病［61.5%（241/392）］是常见的两类并发症，重度脑室内出血或脑室旁白质软化、坏死性小肠结肠炎和败血症的发生率分别为15.3%（60/392）、5.9%（23/392）和19.1%（75/392）。积极治疗后存活超早产儿中，83.7%（328/392）接受有创机械通气治疗，时长为22（10，42）d。存活超早产儿的住院时长为97（86，116）d。 结论： CHNN各单位NICU收治的出生胎龄22~25周超早产儿数量2019—2021年逐年增加，但出院时存活率尤其是无并发症存活率仍有很大的提升空间；多项可改善超早产儿预后的最佳临床实践实施情况有待改进。.