Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.
Respir Res. 2014 Jan 7;15(1):1. doi: 10.1186/1465-9921-15-1.
Analysis of exhaled breath condensates (EBC) is a non-invasive technique to evaluate biomarkers such as antioxidants in the pediatric population, but limited data exists of its use in intubated patients, particularly newborns. Currently, tracheal aspirate (TA) serves as the gold standard collection modality in critically ill newborns, but this method remains invasive. We tested the hypothesis that glutathione status would positively correlate between EBC and TA collections in intubated newborns in the Newborn Intensive Care Unit (NICU). We also hypothesized that these measurements would be associated with alveolar macrophage (AM) glutathione status in the newborn lung.
Reduced glutathione (rGSH), glutathione disulfide (GSSG), and total GSH (rGSH + (2 X GSSG)) were measured in sequential EBC and TA samples from 26 intubated newborns via high performance liquid chromatography (HPLC). Additionally, AM glutathione was evaluated via immunofluorescence. Pearson's correlation coefficient and associated 95% confidence intervals were used to quantify the associations between raw and urea-corrected concentrations in EBC and TA samples and AM staining. Statistical significance was defined as p ≤ 0.05 using two-tailed tests. The sample size was projected to allow for a correlation coefficient of 0.5, with 0.8 power and alpha of 0.05.
EBC was obtainable from intubated newborns without adverse clinical events. EBC samples demonstrated moderate to strong positive correlations with TA samples in terms of rGSH, GSSG and total GSH. Positive correlations between the two sampling sites were observed in both raw and urea-corrected concentrations of rGSH, GSSG and total GSH. AM glutathione staining moderately correlated with GSSG and total GSH status in both the TA and EBC.
GSH status in EBC samples of intubated newborns significantly correlated with the GSH status of the TA sample and was reflective of cellular GSH status in this cohort of neonatal patients. Non-invasive EBC sampling of intubated newborns holds promise for monitoring antioxidant status such as GSH in the premature lung. Further studies are necessary to evaluate the potential relationships between EBC biomarkers in the intubated premature newborn and respiratory morbidities.
呼气冷凝物（EBC）分析是一种评估儿科人群中抗氧化剂等生物标志物的非侵入性技术，但在气管插管患者中，特别是新生儿中，其使用的数据有限。目前，气管抽吸（TA）是危重新生儿的金标准采集方式，但这种方法仍然具有侵入性。我们假设，在新生儿重症监护病房（NICU）中，EBC 和 TA 采集的谷胱甘肽状态在气管插管的新生儿中呈正相关。我们还假设，这些测量结果与新生儿肺部肺泡巨噬细胞（AM）的谷胱甘肽状态有关。
通过高效液相色谱法（HPLC）测量 26 名气管插管新生儿的 EBC 和 TA 连续样本中的还原型谷胱甘肽（rGSH）、谷胱甘肽二硫化物（GSSG）和总谷胱甘肽（rGSH+（2xGSSG））。此外，通过免疫荧光法评估 AM 谷胱甘肽。使用 Pearson 相关系数和相关的 95%置信区间来量化 EBC 和 TA 样本与 AM 染色之间的原始和尿素校正浓度之间的相关性。使用双侧检验定义统计学意义，p≤0.05。预计样本量允许相关系数为 0.5，功率为 0.8，alpha 为 0.05。
EBC 可从气管插管的新生儿中获得，无不良临床事件。EBC 样本在 rGSH、GSSG 和总 GSH 方面与 TA 样本具有中度至强的正相关性。在原始和尿素校正的 rGSH、GSSG 和总 GSH 浓度方面，两个采样部位均存在正相关性。AM 谷胱甘肽染色与 TA 和 EBC 中的 GSSG 和总 GSH 状态呈中度相关。
气管插管新生儿 EBC 样本中的 GSH 状态与 TA 样本中的 GSH 状态显著相关，反映了该队列新生儿的细胞 GSH 状态。气管插管新生儿的非侵入性 EBC 采样有望监测早产儿肺部的 GSH 等抗氧化剂状态。需要进一步研究来评估气管插管早产儿的 EBC 生物标志物与呼吸疾病之间的潜在关系。
