title: [A Randomized Controlled Trial on the Effect of Earmuffs on Intermittent Hypoxia and Bradycardia in Preterm Infants].
abstract: BACKGROUND
  Irregular breathing causing hypoxia and bradycardia is a common problem of preterm infants but its pathophysiology is incompletely understood. Agitation provoked by environmental noise may play a role. We wanted to know if earmuffs can at least halve the rate of intermittent hypoxia in premies.
  
  
  METHODS
  In this randomized controlled trial 31 infants (14 male; median [min.-max.] birth weight and gestational age: 1 323 g [560-1 990] and 30(1/7) weeks [25(5/7)-33(0/7)]) had the effect of earmuffs on the frequency of pulse oximeter desaturations (SpO(2) <80%) and bradycardia events (<80 beats per minute) tested, documented via a standard home monitor. Infants were measured 2 h each with or without earmuffs; the sequence of intervention was randomised. Measurement conditions were kept constant while a noise meter recorded sound pressure levels at a 1 Hz sampling rate.
  
  
  RESULTS
  Median sound pressure level was 46.8 dB(A). In a pre-study, ear muffs yielded a sound reduction by 7.2 dB. 19 infants had a total of 474 desaturations. The median (25.-75. percentile) number of desaturations was 1 (1-10.5) without, and 1 (1-10) with earmuffs. The amount of infants with at least one desaturation was equal in both treatment protocols. Only 7 bradycardias occurred.
  
  
  CONCLUSIONS
  The earmuffs had, in a rather quiet environment, no effect on intermittent hypoxia in these infants.
authors.affiliation: Universitätsklinikum Tübingen, Abteilung für Neonatologie.
authors.forename: T S
authors.initials: TS
authors.lastname: Bott
authors.affiliation: Institut für Medizinische Biometrie, Epidemiologie und Informatik der Universitätsmedizin der Johannes Gutenberg-Universität Mainz.
authors.forename: M S
authors.initials: MS
authors.lastname: Urschitz
authors.affiliation: Universitätsklinikum Tübingen, Abteilung für Neonatologie.
authors.forename: C
authors.initials: C
authors.lastname: Poets
authors.affiliation: Universität Tübingen, Institut für Arbeitsmedizin, Sozialmedizin und Versorgungsforschung.
authors.forename: N
authors.initials: N
authors.lastname: Blomberg
authors.affiliation: Universitätsklinikum Tübingen, Abteilung für Neonatologie.
authors.forename: A
authors.initials: A
authors.lastname: Poets
mesh_terms: D001919:Bradycardia / Q000175:diagnosis*; D004430:Ear Protective Devices; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000175:diagnosis*; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000175:diagnosis*; D019102:Infant, Very Low Birth Weight; D007363:Intensive Care Units, Neonatal; D008297:Male; D010092:Oximetry; D013018:Sound Spectrography