title: Negative effect of immediate hyperbaric oxygen therapy in acute acoustic trauma.
abstract: OBJECTIVE
  The functional evaluation of the effect of the hyperbaric oxygen therapy (HBOT) onset time on cochlea by using distortion product otoacoustic emission.
  
  
  METHODS
  Animal study.
  
  
  METHODS
  Twenty-four Wistar albino rats were divided into six groups and their right ears were directly exposed to a 110-dB sound pressure level (1-12 kHz) white noise for 25 minutes. The first group was considered the control group. HBOT was started at 1 hour postexposure for the second group, at 2 hours postexposure for the third group, at 6 hours postexposure for the fourth group, at 24 hours postexposure for the fifth group, and at 48 hours postexposure for the sixth group. Signal-to-noise ratios (SNRs) were recorded before the noise exposure; immediately after the noise exposure; and on the 3rd, 7th, and 10th day of postexposure.
  
  
  RESULTS
  SNRs at 6 to 8 kHz were significantly decreased after the acoustic trauma. The evaluation on the third day of postexposure showed that recovery begun in all groups except the group in which the HBOT was started at 1 hour postexposure. SNRs in the control group and HBOT groups were back to the preexposure levels at 10 days postexposure, except the 1- and 2-hour postexposure groups. However, in the group in which the HBOT was started at 1 hour postexposure, distortion product otoacoustic emissions were lost except at 4 kHz. The recovery of the SNRs in hyperbaric oxygen administration at 2 hours postexposure almost completed on the 10th day after noise exposure.
  
  
  CONCLUSIONS
  Immediate HBOT in acoustic trauma treatment is not necessary; on the contrary, it has an adverse effect.
authors.affiliation: 1st Department of Otorhinolaryngology-Head and Neck Surgery, Sişli Etfal Research and Training Hospital, and Department of Underwater and Hyperbaric Medicine, Istanbul Faculty of Medicine, Boğaziçi University, Istanbul, Turkey. burak_cakir@hotmail.com
authors.forename: Burak Omür
authors.initials: BO
authors.lastname: Cakir
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Ercan
authors.forename: Senol
authors.initials: S
authors.lastname: Civelek
authors.forename: Sefika
authors.initials: S
authors.lastname: Körpinar
authors.forename: Akýn Savaş
authors.initials: AS
authors.lastname: Toklu
authors.forename: Ozlem
authors.initials: O
authors.lastname: Gedik
authors.forename: Gökhan
authors.initials: G
authors.lastname: Işik
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Sayin
authors.forename: Suat
authors.initials: S
authors.lastname: Turgut
mesh_terms: D000208:Acute Disease; D000818:Animals; D006317:Hearing Loss, Noise-Induced / Q000503:physiopathology / Q000628:therapy*; D006931:Hyperbaric Oxygenation / Q000009:adverse effects* / Q000379:methods; D009622:Noise / Q000009:adverse effects*; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D017211:Treatment Failure