Glotzbach S F, Edgar D M, Ariagno R L
Department of Pediatrics, Stanford University School of Medicine, CA 94305-5119.
Pediatrics. 1995 Feb;95(2):231-7.
The study of biological rhythms and the influence of environmental factors in the timing and synchronization of different rhythmic events have important implications for neonatal health. Preterm infants in the neonatal intensive care unit (NICU) are deprived of the patterned influences of maternal sleep, temperature, heart rate, and hormonal cycles. The impact of the NICU and nursing interventions on the development of the circadian system was studied in 17 stable preterm infants in the Intermediate Intensive Care Nursery at Stanford University for three consecutive days at about 35 weeks postconceptional age.
Rectal temperature, abdominal skin temperature, heart rate, and activity were simultaneously recorded at 2-minute intervals during each 3-day study by a small microcomputer (Vitalog).
Very low amplitude circadian rhythms were found for rectal and skin temperatures (maximum range 36.8 to 37.0 degrees C); population mean values for heart rate (158 bpm) and activity (3.5 counts per 2-min bin) did not differ significantly as a function of time of day. Rectal temperature, averaged in 6-hour bins over the 24-hour day as a function of both postconceptional age and postnatal age, was significantly higher during the first part of the circadian cycle. In all infants, rhythmicity in each variable was dominated by ultradian periodicities that were coincident with feedings and related interventions; moreover, several physiological variables charted during feeding differed significantly from values obtained during periods in which caregiving interventions did not occur.
Quantitative data on the preterm infant circadian system may facilitate evaluation of factors that improve therapeutic responses, recovery, and outcome of neonatal intensive care patients.
研究生物节律以及环境因素对不同节律事件的时间安排和同步性的影响，对新生儿健康具有重要意义。新生儿重症监护病房（NICU）中的早产儿被剥夺了母亲睡眠、体温、心率和激素周期的模式化影响。在斯坦福大学中级重症监护病房，对17名孕龄约35周的稳定早产儿连续三天进行研究，以探讨NICU和护理干预对昼夜节律系统发育的影响。
在为期3天的每项研究中，通过小型微型计算机（Vitalog）每隔2分钟同时记录直肠温度、腹部皮肤温度、心率和活动情况。
直肠温度和皮肤温度的昼夜节律幅度极低（最大范围为36.8至37.0摄氏度）；心率（158次/分钟）和活动（每2分钟时段3.5次计数）的总体平均值在一天中的不同时间没有显著差异。以受孕后年龄和出生后年龄为函数，将24小时内的直肠温度按6小时时段进行平均，在昼夜周期的第一部分显著更高。在所有婴儿中，每个变量的节律性都以与喂食及相关干预同时出现的超日周期为主；此外，喂食期间记录的几个生理变量与未进行护理干预期间获得的值有显著差异。
关于早产儿昼夜节律系统的定量数据可能有助于评估改善新生儿重症监护患者治疗反应、恢复情况和预后的因素。
