Supplementary Material for: Duration of Mechanical Ventilation and Extubation Success among Extremely Premature Infants

Objective: The objective of this study was to examine the duration of mechanical ventilation (MV) in days until the first successful extubation and the cumulative duration of MV until discharge of infants with gestational age (GA) <26 weeks. We also aimed to explore associations between early clinical variables and the cumulative duration of MV. Design and Setting: This population-based study analysed data reported to the Norwegian Neonatal Network on extremely premature infants admitted between January 1, 2013, and December 31, 2018. Results: A total of 406 infants were included, of which 293 (72%) survived to discharge. The proportion successfully extubated on their first attempt was 34% of the infants born at GA 22–23 weeks, 50% at GA 24 weeks, and 70% at GA 25 weeks. Median postmenstrual age (PMA) at the first successful extubation was 27 weeks. The median duration of MV was 35, 24, and 12 days for infants born at GA 22–23, 24, and 25 weeks, respectively. Male sex and low 5-min Apgar score were independent early predictors for prolonged MV duration adjusted for GA in regression analyses. Conclusions: Most of the infants born at GA 25 weeks were successfully extubated on the first attempt. However, half of the infants born <26 weeks experienced unsuccessful extubations, indicating a lack of useful clinical predictors of successful extubation. The median duration of MV in survivors was 4 weeks longer for infants at GA 22–23 weeks than for infants born at GA 25 weeks, while the difference in median PMA at the first successful extubation was 2 weeks.

【研究目的】本研究旨在探讨胎龄（gestational age, GA）<26周的早产儿首次成功拔管前的机械通气（mechanical ventilation, MV）时长（以天计），以及直至出院时的累计机械通气时长；同时探索早期临床变量与累计机械通气时长之间的关联。

【研究设计与场景】本项基于人群的研究，分析了2013年1月1日至2018年12月31日期间收入挪威新生儿网络的极早早产儿相关上报数据。

【研究结果】本研究共纳入406例早产儿，其中293例（72%）存活至出院。胎龄22~23周出生的早产儿中，首次尝试拔管成功的比例为34%；胎龄24周者为50%；胎龄25周者为70%。首次成功拔管时的校正胎龄（postmenstrual age, PMA）中位数为27周。胎龄22~23周、24周、25周出生的早产儿，其机械通气中位时长分别为35天、24天和12天。经校正胎龄的回归分析显示，男性性别与5分钟Apgar低分是机械通气时长延长的独立早期预测因素。

【研究结论】多数胎龄25周出生的早产儿可首次尝试即成功拔管。然而，胎龄<26周的早产儿中有半数拔管失败，提示目前缺乏可用于预测拔管成功的有效临床指标。存活早产儿中，胎龄22~23周者的机械通气中位时长较胎龄25周者长4周，二者首次成功拔管时的校正胎龄中位数相差2周。