Brazy J E
Department of Pediatrics, Duke University Medical Center, Durham, North Carolina 27710.
J Pediatr. 1988 Mar;112(3):457-61. doi: 10.1016/s0022-3476(88)80336-6.
To determine if crying alters cerebral hemodynamics and oxidative metabolism in the brain, near infrared spectrophotometry was used to assess relative changes in cerebral blood volume and the oxidation-reduction state of cytochrome aa3. Thirty-six crying episodes were observed, 20 in healthy infants and 16 in infants with respiratory problems. Throughout all crying episodes cerebral blood volume and oxidized cytochrome aa3 demonstrated oscillatory fluctuations every 10 to 20 seconds, with maximum changes during prolonged exhalations. In 86% of episodes baseline blood volume rose and remained elevated during the cry. The relative content of deoxyhemoglobin in cerebral blood also rose, indicating that venous blood is the major contributor to the increase in blood volume. Changes in baseline cytochrome aa3 oxidation varied with the presence of lung disease and with the chronologic age of the infant. Cytochrome reduction with crying occurred significantly more often in infants with respiratory problems than in healthy infants. Cytochrome aa3 became more oxidized in 82% of crying episodes in healthy infants older than 3 days of age, but no change in cytochrome oxidation was usually noted in those younger than 3 days. Thus crying alters cerebral blood volume in all neonates in a pattern consistent with cyclic obstruction to cerebral venous return; it decreases cerebral oxygenation in infants with respiratory problems.
为了确定哭泣是否会改变大脑的脑血流动力学和氧化代谢，采用近红外分光光度法评估脑血容量和细胞色素aa3氧化还原状态的相对变化。观察到36次哭泣事件，其中20次发生在健康婴儿身上，16次发生在有呼吸问题的婴儿身上。在所有哭泣事件中，脑血容量和氧化型细胞色素aa3每10至20秒出现一次振荡波动，在长时间呼气时变化最大。在86%的事件中，基线血容量在哭泣期间上升并保持升高。脑血中脱氧血红蛋白的相对含量也上升，表明静脉血是血容量增加的主要贡献者。基线细胞色素aa3氧化的变化因肺部疾病的存在和婴儿的实际年龄而异。与健康婴儿相比，有呼吸问题的婴儿在哭泣时细胞色素还原的情况明显更频繁。在3日龄以上的健康婴儿中，82%的哭泣事件中细胞色素aa3氧化程度增加，但在3日龄以下的婴儿中，通常未观察到细胞色素氧化的变化。因此，哭泣会改变所有新生儿的脑血容量，其模式与脑静脉回流的周期性阻塞一致；它会降低有呼吸问题婴儿的脑氧合。
