Supplementary Material for: Measuring End-Tidal Carbon Monoxide of Jaundiced Neonates in the Birth Hospital to Identify Those with Hemolysis

<b><i>Background:</i></b> End-tidal breath carbon monoxide (ETCOc) levels correlate with catabolism of heme, but until recently, this measurement was not readily available for application to neonatology practice. <b><i>Objectives:</i></b> We performed a prospective, multihospital, test-of-concept study where ETCOc was measured during the birth hospitalization of neonates with a total bilirubin (TB) value &gt;75th percentile on the Bhutani bilirubin nomogram. This was done to test the feasibility and ease of use of this new device. <b><i>Methods:</i></b> Neonates with an elevated ETCOc (with a &gt;95th percentile reference interval previously established) were labeled as having ‘hemolytic jaundice'. We recommended a follow-up TB check &lt;24 h after hospital discharge to these families. <b><i>Results:</i></b> One hundred and fifteen neonates were eligible for the study, the parents of 103 provided consent, and measurements were obtained for 100. Sixty-three had normal and 37 had elevated ETCOc values. By means of a direct antiglobulin test (DAT; Coombs), 11 of these 37 were found positive for ABO hemolytic disease; the remaining 26 had other etiologies. Thirty-six of the 37 with an elevated ETCOc had repeat TB monitoring &lt;24 h after discharge home. None of the 100 were rehospitalized for jaundice treatment compared with a rate of 2.99 rehospitalizations per 100 control neonates who had a TB value &gt;75th percentile (p = 0.079). <b><i>Conclusion:</i></b> ETCOc measurement is a feasible means of assessing hemolysis in jaundiced neonates during the birth hospitalization. When hemolysis is identified, parents are likely to comply with instructions to bring the infant for a TB checkup &lt;24 h after discharge home.

<b><i>背景：</i></b> 呼末一氧化碳（End-tidal breath carbon monoxide, ETCOc）水平与血红素分解代谢密切相关，但直至近期，该检测手段尚未能便捷地应用于新生儿科临床实践。<b><i>研究目的：</i></b> 本研究开展了一项多中心前瞻性概念验证研究，针对出生住院期间总胆红素（total bilirubin, TB）水平高于Bhutani胆红素列线图第75百分位的新生儿，检测其呼末一氧化碳水平，以评估该新型检测设备的可行性与易用性。<b><i>研究方法：</i></b> 对于ETCOc水平高于既往确立的95百分位参考区间的新生儿，将其归类为"溶血性黄疸"。我们建议此类患儿的家属在患儿出院后24小时内复查总胆红素。<b><i>研究结果：</i></b> 本研究共纳入115名符合条件的新生儿，其中103名患儿家长签署了知情同意书，最终完成100例检测。63例新生儿的ETCOc水平正常，37例升高。通过直接抗球蛋白试验（direct antiglobulin test, DAT，又称库姆试验），37例ETCOc升高的新生儿中11例确诊ABO溶血病，其余26例存在其他致病原因。37例ETCOc升高的新生儿中，36例在出院后24小时内完成了总胆红素复查。100例研究对象均未因黄疸治疗再次住院，而同期总胆红素高于第75百分位的对照组新生儿再住院率为2.99/100例（p = 0.079）。<b><i>研究结论：</i></b> 呼末一氧化碳检测是在新生儿出生住院期间评估黄疸患儿溶血情况的可行手段。若确诊溶血，患儿家属大概率会遵循医嘱，在患儿出院后24小时内带其复查总胆红素。