Influence Of Difference NICU Environment On Physiological Response And The Stress Hormones Of The Preterm Infants

Objective: To study the influence of improved NICU environment in which noise,light and infant handling were reduced on the infant' physiological and movement response, sleep and the levels of the stress hormones and to estimate the possibility and significance to improve the NICU environment. MethodsrWe selected Sam-9am and 10am-11am as the observation periods. Each studied subject was observed 2-3 periods which included a mornal period (Sam-9am) and a quiet period (10am-lam) in the same day or a mornalperiod(8am-9am) in a day and a quiet period(8am-9am)in another day ora mornal period(8am-9am) and a quiet period(10am-1am) in a day , anotherquiet period(8am-9am) next day. The study group comprised 30 preterminfants. We observed and compared NICU' noise,light and handling events.At the same time, we recorded and compared infants' physiological response(Heart rate, respiratory rate, transcutaneous oxygen saturation, systolic blood pressure, diastolic blood pressure, mean blood pressure and body temperature), sleep time and the levels of the stress hormones (cortisol,epinephrine and norepinephrine).Results:The noise levels of incubators is 55~65dB under the normal NICU environment. Incubators, which themselves generated considerable noise, actually muffle external sounds.The noise levels in incubators were lower 5-10dB than the environment levels. The noises mainly came from all kinds of activities of the stall, the sound which the medical equipments generated and alarm events. The mean noise levels were 59. 7dB and 53. 8dB(P<0.01) in normal periods and quiet periods, respectively. The light of NICU was difference in the day when there were curtains or not. When there were curtains,the mean light was 24, OOOlux and near the windows it was 50,0001ux;when there were not curtains, the mean light was 88, OOOlux and near the windows it was much brighter than 200, OOOlux. The light of NICU at night was 76001ux. In quiet periods, the mean light only had 181ux and near the windows it only had 24. 51ux.The handling to the infants was 4.4 events/hour. Because the quiet periods began after all activities of care were finished, this ensured that infants could be handledas few as possible. Under the improved NICU environment, the levels of the stress hormones, heart rate(P<0. 01), blood pressure(P<0. 05) and movement events (P<0. 01)descreased;sleep time(P<0.01) and transcutaneous oxygen saturation (P<0. 05) increased.Conclusions:NICU environment was a stress one in which there were big noise, bright light and too much handling to infants. It made the levels of the stress hormones increase, affected on the infant' physiological and movement response and altered the infant' sleep state, which did harm to the high risk infant very much. When NICU environment was improved, the pain and stress of infants wre relieved. It was helpful to the restore of illness and the development.