McCulloch K M, Braun R J, Simms P E, Evans M A, Kelly D H
Department of Pediatrics, University of Illinois Medical Center, Chicago 60612.
Pediatr Pulmonol. 1989;7(2):66-70. doi: 10.1002/ppul.1950070203.
Cord blood caffeine concentrations were measured by high-pressure liquid chromatography in 79 preterm infants. Eleven infants (14%) had detectable caffeine concentrations ranging from 1.1 to 3.7 micrograms/mL (means +/- SD = 2.5 +/- 0.8), and 68 infants had no measurable caffeine. Seven infants with detectable caffeine (group 1) had impedance pneumograms recorded before 2 weeks of age. Each infant in group 1 was matched with two infants without detectable caffeine by birthweight, gestational age, and chronologic age at pneumogram recording to yield a control group (group 2) of 14 infants. Comparison of the groups using quantitative measures of apnea, bradycardia, and periodic breathing obtained from pneumogram analysis and the incidence of monitor alarms on bedside nursing records showed no significant differences. Thus, caffeine was present infrequently and at low concentrations at birth in 79 preterm infants. The amount of apnea, bradycardia, and periodic breathing experienced before 2 weeks of age in 7 preterm infants with detectable cord blood caffeine was not different from that in 14 similar infants without caffeine. Future studies are planned to examine the relationship between postnatal changes in transplacentally acquired methylxanthine concentrations and quantitative measures of apnea, bradycardia, and periodic breathing in a larger number of preterm infants without cardiorespiratory disease.
采用高压液相色谱法测定了79例早产儿脐血中的咖啡因浓度。11例婴儿（14%）的咖啡因浓度可检测到，范围为1.1至3.7微克/毫升（均值±标准差=2.5±0.8），68例婴儿未检测到可测量的咖啡因。7例咖啡因浓度可检测到的婴儿（第1组）在2周龄前记录了阻抗呼吸图。第1组的每例婴儿与2例在记录呼吸图时出生体重、胎龄和实际年龄与之匹配但咖啡因浓度未检测到的婴儿组成一个14例婴儿的对照组（第2组）。通过对呼吸图分析获得的呼吸暂停、心动过缓和周期性呼吸的定量测量结果以及床边护理记录中的监测警报发生率对两组进行比较，结果显示无显著差异。因此，79例早产儿出生时咖啡因出现频率低且浓度低。7例脐血咖啡因浓度可检测到的早产儿在2周龄前经历的呼吸暂停、心动过缓和周期性呼吸次数与14例类似的无咖啡因婴儿无差异。计划开展进一步研究，以检验大量无心肺疾病的早产儿经胎盘获得的甲基黄嘌呤浓度产后变化与呼吸暂停、心动过缓和周期性呼吸定量测量之间的关系。
