Neonatology Service, Hospital Clínic de Barcelona, Sabino de Arana 1, 08028 Barcelona, Spain.
BMC Pediatr. 2012 Jun 8;12:63. doi: 10.1186/1471-2431-12-63.
The aim of this study was to analyze the evolution from 1997 to 2009 of survival without significant (moderate and severe) bronchopulmonary dysplasia (SWsBPD) in extremely-low-birth-weight (ELBW) infants and to determine the influence of changes in resuscitation, nutrition and mechanical ventilation on the survival rate.
In this study, 415 premature infants with birth weights below 1000 g (ELBW) were divided into three chronological subgroups: 1997 to 2000 (n = 65), 2001 to 2005 (n = 178) and 2006 to 2009 (n = 172).Between 1997 and 2000, respiratory resuscitation in the delivery room was performed via a bag and mask (Ambu®, Ballerup, Sweden) with 40-50% oxygen. If this procedure was not effective, oral endotracheal intubation was always performed. Pulse oximetry was never used. Starting on January 1, 2001, a change in the delivery room respiratory policy was established for ELBW infants. Oxygenation and heart rate were monitored using a pulse oximeter (Nellcor®) attached to the newborn's right hand. If resuscitation was required, ventilation was performed using a face mask, and intermittent positive pressure was controlled via a ventilator (Babylog2, Drägger). In 2001, a policy of aggressive nutrition was also initiated with the early provision of parenteral amino acids. We used standardized parenteral nutrition to feed ELBW infants during the first 12-24 hours of life. Lipids were given on the first day. The glucose concentration administered was increased by 1 mg/kg/minute each day until levels reached 8 mg/kg/minute. Enteral nutrition was started with trophic feeding of milk. In 2006, volume guarantee treatment was instituted and administered together with synchronized intermittent mandatory ventilation (SIMV + VG). The complications of prematurity were treated similarly throughout the study period. Patent ductus arteriosus was only treated when hemodynamically significant. Surgical closure of the patent ductus arteriosus was performed when two courses of indomethacin or ibuprofen were not sufficient to close it.Mild BPD were defined by a supplemental oxygen requirement at 28 days of life and moderate BPD if breathing room air or a need for <30% oxygen at 36 weeks postmenstrual age or discharge from the NICU, whichever came first. Severe BPD was defined by a supplemental oxygen requirement at 28 days of life and a need for greater than or equal to 30% oxygen use and/or positive pressure support (IPPV or nCPAP) at 36 weeks postmenstrual age or discharge, whichever came first. Moderate and severe BPD have been considered together as "significant BPD". The goal of pulse oximetry was to maintain a hemoglobin saturation of between 88% and 93%. Patients were considered to not need oxygen supplementation when it could be permanently withdrawn. The distribution of the variables was not normal based on a Kolmogorov-Smirnov test (p < 0.05 in all cases). Therefore, quantitative variables were expressed as the median and interquartile range (IQR; 25th-75th percentile). Statistical analysis of the data was performed using nonparametric techniques (Kruskal-Wallis test and Mann-Whitney U test). A chi-square analysis was used to analyze qualitative variables. Potential confounding variables were those possibly related to BPD in survivors (p between 0.05 and 0.3 in univariate analysis). Logistic regression analysis was performed with variables related to BPD in survivors (p < 0.05) and potential confounding variables. The forward stepwise method adjusted for confounding factors was used to select the variables, and the enter method using selected variables was used to obtain the odds ratios.
There was an increase in the rate of SWsBPD (1997 to 2000: 58.5%; 2001 to 2005: 74.2%; and 2006 to 2009: 75.0%; p = 0.032). In survivors, the occurrence of significant BPD decreased after 2001 (9.5% vs. 2.3%; p = 0.013). The factors associated with improved SWsBPD were delivery by caesarean section, a reduced endotracheal intubation rate and a reduced duration of mechanical ventilation.While the mortality of ELBW infants has not changed since 2001, the frequency of SWsBPD has significantly increased (75.0%) in association with increased caesarean sections and reductions in the endotracheal intubation rate, as well as the duration of mechanical ventilation.
本研究旨在分析 1997 年至 2009 年极低出生体重儿（ELBW）中无显著（中度和重度）支气管肺发育不良（SWsBPD）生存率的演变，并确定复苏、营养和机械通气的变化对生存率的影响。
本研究纳入了 415 名出生体重低于 1000 g 的早产儿，分为三个时间亚组：1997 年至 2000 年（n=65）、2001 年至 2005 年（n=178）和 2006 年至 2009 年（n=172）。1997 年至 2000 年，产房内的呼吸复苏通过袋和面罩（Ambu®，Ballerup，瑞典）进行，氧浓度为 40-50%。如果此过程无效，始终进行经口气管内插管。从不使用脉搏血氧饱和度仪。从 2001 年 1 月 1 日起，为 ELBW 婴儿制定了产房呼吸政策的改变。通过连接到新生儿右手的脉搏血氧饱和度仪（Nellcor®）监测氧合和心率。如果需要复苏，通过面罩进行通气，并通过呼吸机（Babylog2，Draeger）控制间歇正压。2001 年，还启动了积极的营养政策，早期给予肠外氨基酸。我们在生命的头 12-24 小时内使用标准化的肠外营养喂养 ELBW 婴儿。第一天给予脂肪。给予的葡萄糖浓度每天增加 1 mg/kg/min，直到达到 8 mg/kg/min。开始经口喂养，给予微量喂养。2006 年，开始使用容量保证治疗，并与同步间歇强制通气（SIMV+VG）联合使用。整个研究期间，类似地治疗早产儿并发症。仅在存在血流动力学显著的情况下治疗动脉导管未闭。如果两疗程吲哚美辛或布洛芬不足以关闭动脉导管未闭，则进行手术关闭。轻度 BPD 定义为出生后 28 天需要补充氧气，中度 BPD 定义为出生后需要呼吸室气或在 36 周后出生或从 NICU 出院时需要氧浓度<30%，以先发生者为准。重度 BPD 定义为出生后 28 天需要补充氧气，需要大于或等于 30%的氧气使用和/或正压支持（IPPV 或 nCPAP）在 36 周后出生或出院，以先发生者为准。中度和重度 BPD 被认为是“显著 BPD”。脉搏血氧饱和度的目标是维持血红蛋白饱和度在 88%-93%之间。当可以永久停止吸氧时，患者被认为不需要补充氧气。基于 Kolmogorov-Smirnov 检验（所有情况下 p<0.05），变量的分布均不正常。因此，定量变量表示为中位数和四分位距（25%-75%分位数）。使用非参数技术（Kruskal-Wallis 检验和曼-惠特尼 U 检验）进行数据分析。使用卡方分析分析定性变量。幸存者中可能与 BPD 相关的潜在混杂变量（单变量分析中 p 在 0.05 到 0.3 之间）。使用与幸存者中 BPD 相关的变量和潜在混杂变量进行逻辑回归分析。使用向前逐步法调整混杂因素选择变量，并使用选定变量的进入法获得比值比。
SWsBPD 的发生率增加（1997 年至 2000 年：58.5%；2001 年至 2005 年：74.2%；2006 年至 2009 年：75.0%；p=0.032）。幸存者中，显著 BPD 的发生率在 2001 年后下降（9.5%比 2.3%；p=0.013）。与 SWsBPD 改善相关的因素包括剖宫产分娩、气管内插管率降低和机械通气时间缩短。自 2001 年以来，ELBW 婴儿的死亡率没有变化，但 SWsBPD 的发生率显著增加（75.0%），这与剖宫产率增加、气管内插管率降低以及机械通气时间缩短有关。
