Chan G C, Lau Y L, Yeung C Y
Department of Paediatrics, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China.
J Paediatr Child Health. 1998 Oct;34(5):447-50. doi: 10.1046/j.1440-1754.1998.00270.x.
Endogenous carbon monoxide (CO) is produced mainly by heme catabolism. As CO is excreted solely by the lung, a simple technique for measuring the end tidal carbon monoxide (ETCO) level was assessed as a method for screening for haemolytic disease in children.
Two end expiratory breath samples were collected from normal children and from children with haemolytic disease using a one way valve connector between a mouth piece and an anaesthetic bag. The samples were analysed by gas chromatography for CO and carbon for dioxide (CO2). The CO2 value was used to normalise the CO value to an alveolar concentration. Carboxyhaemoglobin (HbCO) also was measured in the patient group for correlation analysis with ETCO.
A total of 21 children with beta thalassaemia major, 15 children with other haemolytic diseases (hereditary spherocytosis n=8, haemoglobin H disease n=3 and thalassaemia intermedia n=4) and 23 normal children were studied. The mean ETCO concentrations in the three groups were 3.21 p.p.m., 7.41 p.p.m. and 0.69 p.p.m., respectively, which were significantly different from each other (P<0.0001). There was a significant correlation between ETCO and HbCO in the patient groups (r=0.85; P<0.0001).
The end expiratory breath collection device is a simple and feasible sample collection method. The results confirm that ETCO can be used clinically to distinguish children with a variety of haemolytic disorders from normal subjects.
内源性一氧化碳（CO）主要由血红素分解代谢产生。由于CO仅通过肺部排出，一种用于测量呼气末一氧化碳（ETCO）水平的简单技术被评估为筛查儿童溶血性疾病的方法。
使用口件与麻醉袋之间的单向阀连接器，从正常儿童和溶血性疾病患儿中采集两份呼气末呼吸样本。通过气相色谱法分析样本中的CO和二氧化碳（CO2）。CO2值用于将CO值标准化为肺泡浓度。还测量了患者组中的碳氧血红蛋白（HbCO），以与ETCO进行相关性分析。
共研究了21例重型β地中海贫血患儿、15例其他溶血性疾病患儿（遗传性球形红细胞增多症8例、血红蛋白H病3例和中间型地中海贫血4例）以及23例正常儿童。三组的平均ETCO浓度分别为3.21 ppm、7.41 ppm和0.69 ppm，彼此之间有显著差异（P<0.0001）。患者组中ETCO与HbCO之间存在显著相关性（r=0.85；P<0.0001）。
呼气末呼吸采集装置是一种简单可行的样本采集方法。结果证实，ETCO可在临床上用于区分患有各种溶血性疾病的儿童与正常受试者。
