The Effect of Earmuffs on Physiological Parameters in Preterm Infants: A Systematic Review.

Noise may cause stress responses such as apnea, hypoxemia, changes in oxygen saturation and augmented oxygen consumption secondary to elevated heart and respiratory rates. Moreover, stress results in increased intracranial pressure, abnormal sleep patterns, hearing impairment, and bronchopulmonary dysplasia, retinopathy of prematurity, intraventricular hemorrhage, periventricular leukomalacia, retardate development and alterations in the neuroendocrine system. Herein, this study aimed to discuss the effects of earmuffs on physiological parameters in preterm infants. The relevant and available peer-reviewed publications from 2012 to 2018 from various databases were analyzed. For the assessment of the studies, the full-text accessible studies were included for analysis. The retrieved documents were analyzed using VOSviewer regarding the geographical distributions of the documents with their numbers and citations, keywords proposed by the researchers. All records with the term "earmuffs OR earmuff" in the "article title, abstract, keywords" were retrieved from different databases. Accordingly, 396 documents containing the word "earmuffs OR earmuff" were recorded. The search was then restricted for publications that contain the words "noise AND nursing AND preterm" in the title and abstracts (TITLE-ABS-KEY (earmuffs OR earmuff)) AND (noise AND nursing AND preterm) (Scopus=390; Web of Science=1, Medline=2; Cochrane=1; Embase=1= Pubmed=1=n=396). After inclusion and exclusion criteria, 7 documents were recorded and then evaluated for the present study. As a conclusion, the effects of earmuffs on physiological parameters of preterm infants have not been clearly understood and reported yet. Along with the present documents, it is not clear that the use of earmuffs reduces stress and provides physiological stability in preterm infants born between approximately 28-32 weeks. The studies with a larger sample size are needed for validation of information reported in the articles analyzed herein.