Abstract
Rev Bras Ter Intensiva. 2019;31(3):296-302
DOI 10.5935/0103-507X.20190054
Evaluate the physiological and autonomic nervous system responses of premature newborns to body position and noise in the neonatal intensive care unit.
A quasi-experimental study. The autonomic nervous system of newborns was evaluated based on heart rate variability when the newborns were exposed to environmental noise and placed in different positions: supine without support, supine with manual restraint and prone.
Fifty premature newborns were evaluated (gestational age: 32.6 ± 2.3 weeks; weight: 1816 ± 493g; and Brazelton sleep/awake level: 3 to 4). A positive correlation was found between environmental noise and sympathetic activity (R = 0.27, p = 0.04). The mean environmental noise was 53 ± 14dB. The heart rate was higher in the supine position than in the manual restraint and prone positions (148.7 ± 21.6, 141.9 ± 16 and 144 ± 13, respectively) (p = 0.001). Sympathetic activity, represented by a low frequency index, was higher in the supine position (p < 0.05) than in the other positions, and parasympathetic activity (high frequency, root mean square of the sum of differences between normal adjacent mean R-R interval and percentage of adjacent iRR that differed by more than 50ms) was higher in the prone position (p < 0.05) than in the other positions. The complexity of the autonomic adjustments (approximate entropy and sample entropy) was lower in the supine position than in the other positions.
The prone position and manual restraint position increased both parasympathetic activity and the complexity of autonomic adjustments in comparison to the supine position, even in the presence of higher environmental noise than the recommended level, which tends to increase sympathetic activity.
Abstract
Rev Bras Ter Intensiva. 2010;22(4):369-374
DOI 10.1590/S0103-507X2010000400010
OBJECTIVE: The several multidisciplinary team personnel and device alarms make intensive care units noisy environments. This study aimed to measure the noise level of a medical-surgical intensive care unit in Recife, Brazil, and to assess the noise perception by the unit's healthcare professionals. METHODS: A decibel meter was used for continuous every five seconds one week noise levels recording. After this measurement, an interview shaped noise perception questionnaire was applied to the healthcare professionals, approaching the discomfort level and noise control possibilities. RESULTS: Mean 58.21 ± 5.93 dB noise was recorded. The morning noise level was higher than at night (60.85 ± 4.90 versus 55.60 ± 5.98, p <0.001), as well as work-days versus weekend (58. 77 ± 6.05 versus 56.83 ± 5.90, p <0.001). The evening staff shift change noise was louder than by daytime change (62.31 ± 4.70 versus 61.35 ± 5.08 dB; p < 0.001). Of the 73 questionnaire respondents, 97.3% believe that the intensive care unit has moderate or intense noise levels; 50.7% consider the noise harmful; and 98.6% believe that noise levels can be reduced. CONCLUSION: The measured noise levels were above the recommended. Preventive and educational programs approaching the importance of noise levels reduction should be encouraged in intensive care units.