Doppler血流计评价新生儿心脏功能的昼夜节律

Circadian rhythms in neonatal cardiac funciton evaluated by Doppler flowmeter

许多循环机能存在着昼夜节律的变化特性。该研究的目的是探索新生儿心脏功能的昼夜节律,采用Doppler血流计对88个新生儿的升主动脉的平均血流速度,血流加速度和射血距离作了24小时检测,每4小时测一次。其中新生儿在检测开始时的日龄小于24小时,大于24小时者分别被定为第一和第二组;有高血压家族史者是第三组,有心肌梗塞家族史的被定为第四组;第五组是足月小样儿;第六组是早产儿。所测数据用余弦法分析。结果是第二和五组的上述变量存在昼夜节律(P<0.01),其峰值在17:40左右。在第二组中,进一步按不同性别分组;以及随机分成亚组,再用余弦法分析证实这些节律仍存在。在第五组中,上述变量的昼夜节律振幅大于其他组。通过本研究进一步证实了人类的循环机能不但存在着昼夜变化,而且在新生儿就体现出来了。在相同环境下,新生儿循环机能的昼夜节律受到其遗传因素的影响;另外,还与其神经系统等调节机能的成熟度有关。

This study examines the circadian variation of aortic blood flow velocity, acceleration and distance of stroke assessed every 4 hours for 24 hours by Doppler ultrasound in 88 human newborns. Groups 1 and 2 involve neonates with a negative family history of high blood pressure or myocardial infarction monitored during the first day or between the second and tenth days postpartum, respectively; groups 3-6 are two- to ten-day-old babies with a positive family history of high blood pressure (group 3) or of myocardial infarction (group 4) or with a negative family history and intrauterine growth retardation (group 5) or born prematurely (group 6). Cosinor analyses demonstrate a circadian rhythm for all variables in groups 2 and 5 (P<0. 001), with overall high values occurring around 17:40. In group 2, a circadian rhythm remains demonstrable in boys and girls considered separately, and mostly so in arbitrary subgroups of different sizes, with only slight differences in rhythm parameters among them. These results show that, with relatively small samples, reproducible circadian rhythms of cardiac function can already be detected shortly after birth in neonates with a negative family history of high blood pressure or myocardial infarction.