Supplementary Material for: Safely Inserting Neonatal Chest Drains

<b><i>Background:</i></b> Inserting a chest drain for a left-sided neonatal pneumothorax carries a risk of penetrating the pericardium. We identified reference ranges for the chest wall thickness (CWT) and distance between the pericardium and parietal pleura to improve safety of chest tube insertion. <b><i>Method:</i></b> We prospectively measured the CWT using ultrasound in 20 neonates (body weight [BW] 640–2,700 g, age &lt;10 days) at the usual site of puncture in the 4th and 5th intercostal space (ICS). Furthermore, we measured the minimal distance between the parietal pleura and the cardiac silhouette in 131 neonatal chest X-rays (birth weight, 420–4,930 g [divided into 11 weight groups]; age &lt;10 days). Both data sets were transformed into weight-dependent percentiles (Ps). We considered the difference between the sum of P 2.5 for the CWT plus P 2.5 for pleura-heart distance minus P 97.5 for the CWT as a safe corridor for placing the tip of the needle. <b><i>Results:</i></b> At both ICSs, curves for the above metrics did not cross, indicating a narrow but safe corridor for each BW with at least 97.5% probability. This safety corridor was 4.6–5.2 mm wide for the 4th and 2.8–3.4 mm for the 5th ICS. <b><i>Conclusion:</i></b> These data offer a reference for left-sided chest drain insertion for BW &lt;2,700 g, which may help to improve safety of the procedure.<b><i>背景：</i></b> 为左侧新生儿气胸置入胸腔引流管存在穿透心包的风险。本研究明确了胸壁厚度（Chest Wall Thickness, CWT）以及心包与壁层胸膜之间距离的参考范围，以提升胸腔置管术的安全性。<b><i>方法：</i></b> 本研究采用超声，于第4、5肋间间隙（intercostal space, ICS）的常规穿刺位点，对20名体重[BW]为640~2700g、年龄<10天的新生儿前瞻性测量胸壁厚度。此外，本研究对131例新生儿胸部X线片（出生体重420~4930g，分为11个体重组；年龄<10天），测量了壁层胸膜与心脏轮廓间的最小距离。将两组数据转换为体重相关百分位数（percentiles, Ps）。本研究将「胸壁厚度的P2.5与胸膜-心包距离的P2.5之和减去胸壁厚度的P97.5」的差值作为针尖置入的安全通道。<b><i>结果：</i></b> 在两个肋间间隙中，上述指标的曲线均未出现交叉，表明各体重组均存在狭窄但安全的操作通道，置信度至少达97.5%。第4肋间间隙的该安全通道宽度为4.6~5.2mm，第5肋间间隙为2.8~3.4mm。<b><i>结论：</i></b> 本研究数据为体重<2700g的新生儿左侧胸腔引流置管术提供了参考依据，有助于提升该操作的安全性。