Division of Neonatology, Perrino Hospital, Brindisi, Italy; Clinical Physiology Institute (IFC-CNR), National Research Council of Italy, Lecce Section, Italy.
Early Hum Dev. 2013 Jun;89 Suppl 1:S69-73. doi: 10.1016/S0378-3782(13)70020-3.
Bronchopulmonary dysplasia (BPD) continues to represent a significant cause of morbidity among survivors of severe prematurity in the NICU. The increasing prevalence of BPD over the decades has been suggested to be related to the increased survival of extremely low birthweight infants.
To evaluate differences in prevalence of BPD (BPD28d and BPD36wk) and as a function of survival rate in extremely low birth weight (ELBW) infants over time, and to explore its relationship with known associated risk factors.
Survival rate and prevalence of oxygen-dependency =28 days (BPD28d) and oxygen-dependency =36 weeks postmenstrual age (BPD36wk) were evaluated in ELBW newborns (mean gestational age: 27.12.2 weeks; mean birth weight: 817142 g) consecutively admitted to the Brindisi NICU over the last 26 years. Two arbitrarily chosen time periods were compared: Period 1: July 1st, 1986 to June 30, 2002 vs. Period 2: July 1st, 2002 to December 31, 2012. Analyzed variables included gestational age, birth weight, intubation time, hours of O2 administration, NCPAP, and use of surfactant. Differences between the time periods were assessed by chi-square statistics, Fisher's tests or Mann-Whitney test, as appropriate. A two-tailed p value <0.05 was considered to indicate statistical significance.
Survival rate of ELBW infants over the examined time periods dramatically improved from 42.3% to 72.6% (p < 0.0001), whereas changes in the prevalence of BPD28d and BPD36wk were not statistically significant (30.5% vs. 39.3%, p = 0.2137 and 5.5% vs. 13.1%, p = 0.1452, respectively). Likewise, BPD severity was not significantly different between the two time periods (p = 0.1635). Gestational age and birth weight of surviving neonates did not significantly change between the two time periods (p = 0.8050 and p = 0.6986, respectively), whereas significantly increased intubation time (median values: 144 hours vs. 33 hours, p <0.0001) and use of exogenous surfactant (89.3% vs. 48.6%, p < 0.0001) was evidenced for the second time period, as well as NCPAP (median values: 600 hours vs. 377 hours, p = 0.0005). A statistically non-significant trend for a prolonged O2 administration in period 2 (p = 0.0850) was also observed.
Our findings indicate that a significantly increased survival is not necessarily associated with a significant difference in the prevalence of BPD among ELBW infants.
支气管肺发育不良（BPD）仍然是新生儿重症监护病房（NICU）中严重早产儿存活者的主要发病原因。几十年来，BPD 的发病率不断上升，这被认为与极低出生体重儿（ELBW）的存活率增加有关。
评估 ELBW 新生儿中 BPD（BPD28d 和 BPD36wk）的患病率随时间的变化以及与存活率的关系，并探讨其与已知相关危险因素的关系。
对过去 26 年来连续入住布林迪西 NICU 的 ELBW 新生儿（平均胎龄：27.1±2.2 周；平均出生体重：817±142g）的氧依赖 28 天（BPD28d）和氧依赖 36 周（BPD36wk）的存活率和患病率进行评估。比较了两个任意选择的时间段：时间段 1：1986 年 7 月 1 日至 2002 年 6 月 30 日与时间段 2：2002 年 7 月 1 日至 2012 年 12 月 31 日。分析的变量包括胎龄、出生体重、插管时间、氧疗时间、鼻塞持续气道正压通气（NCPAP）和表面活性物质的使用。通过卡方检验、Fisher 检验或曼-惠特尼检验评估两个时间段之间的差异，具体取决于适当性。双侧 p 值<0.05 被认为具有统计学意义。
ELBW 婴儿的存活率在研究期间从 42.3%显著提高到 72.6%（p<0.0001），而 BPD28d 和 BPD36wk 的患病率变化无统计学意义（30.5%vs.39.3%，p=0.2137 和 5.5%vs.13.1%，p=0.1452，分别）。同样，两个时间段之间 BPD 的严重程度也没有显著差异（p=0.1635）。两个时间段之间存活新生儿的胎龄和出生体重无显著变化（p=0.8050 和 p=0.6986，分别），而第二个时间段的插管时间（中位数：144 小时 vs.33 小时，p<0.0001）和外源性表面活性物质的使用（89.3%vs.48.6%，p<0.0001）显著增加，NCPAP（中位数：600 小时 vs.377 小时，p=0.0005）也显著增加。第二个时间段中，氧疗时间延长也呈统计学非显著趋势（p=0.0850）。
我们的研究结果表明，ELBW 婴儿存活率的显著提高不一定与 BPD 患病率的显著差异相关。
