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Dantas Gomes E.L.1, Malta dos Santos C.2, Veiga de Matos M.C.2, Santos A.3, Silva A.G.2, Malaquias França M.A.2, Romanini D.S.2, Leal A.2
1Nove de Julho University, Post Graduation Science Rehabilitation, São Paulo, Brazil, 2Nove de Julho University, São Paulo, Brazil, 3Hospital do Mandaqui, São Paulo, Brazil
Background: The environment of a NICU is characterized by various unpredictable noises added to the noise generated by the newborn and these external and internal noises can be further amplified by the incubator. The American Academy of Pediatrics stated that the noise level in a NICU must not exceed 45 dB in the day and 35dB at night. Persistent noises above this preset security level can cause deleterious effects to the central nervous system in preterm infants as well as in long-term development. Pre term infants presents autonomic self-regulation undeveloped and vulnerable to high levels of noise as a result of this inability to harmful stimuli processing. The manual restraint is a method used to organize the baby curl posture refers to positioning in intrauterine. The hypothesis is that the NICU noise exceeds the safety limit and these preterm babies has autonomic imbalance with sympathetic dominance and manual restraint may change this balance regardless of ambient noise.
Purpose: Evaluate the environmental noise and the autonomic balance with and without manual restraint.
Methods: Cross-sectional study in which it was evaluated the heart rate variability (HRV), in the time domain (RMSSD, SDNN, MeanHR) and the frequency domain (HF, LF and LF/HF) through the polar RS800CX, ambient noise was mesured by Dattalogger equipment (dB) with and without manual restraint for 10 minutes (random execution order).We included preemies with less than 37 weeks of gestational age (GA), with more than 1100 grams, clinically stable and with more than 72 hours of life.
Results: 20 infants were evaluated with an average correct age (CA) of 37.1 ± 2.8, average of GA 33 ± 2.6 weeks, weighing from 1837 ± 620 grams. Initial respiratory rate average 59 ± 16.37 without restraint, 51 ± 18.1 at the beginning of the manual restraint and 46.6 ± 12 (p = 0.03) at the end. The initial heart rate 156 ± 28, at the beginning of manual restraint 159 ± 26 and at the end of 140 ± 17 (p = 0.04).
As the autonomic variables there was a predominance of sympathetic activity before restraint LF 83.7 ± 4.84, HF 16.23 ± 3.54 and LF/HF 5.64 ± 2.0 with change in LF 78.5 ± 6.95, HF 21.45 ± 6.9 (p = 0.03) and LF/HF 4.15 ± 2.03. The peak of noise of the NICU was 91.5 ± 2.25 and 73 ± 3 dB average.
Conclusion(s): The noise reaches twice the considered safe by international standards, there is a predominance of sympathetic activity with imbalance on autonomic nervous system and interventions such as manual restraint interferes in this balance with clinical relevance even without reduction of noise levels.
Implications: A simple and non-pharmacological alternative to organize the baby can interfere so beneficial in homeostasis and contribute to less interference of the NICU environment deleterious in the development of premature infants.
Funding acknowledgements: FAPESP/ Capes/ CNPq/UNINOVE/ Mandaqui
Topic: Paediatrics
Ethics approval: The research protocol was approved by the COEP UNINOVE-1613732/2016.
All authors, affiliations and abstracts have been published as submitted.
