High-frequency sound field and bubble formation in a rat decompression model

Avi Shupak, Yehuda Arieli, Haim Bitterman, Vera Brod, Ran Arieli, Giora Rosenhause

Research output: Contribution to journalArticlepeer-review


High-frequency sound might cause bubble enlargement by rectified diffusion. The purpose of the present study was to investigate gas bubble formation in the immersed diving animal during exposure to high-frequency sound. Anaesthetised rats were subjected to a simulated diving profile while immersed inside a hyperbaric chamber. An acoustic beacon (pinger) was placed ventral to the animal's abdomen, transmitting at an intensity of 208.9 dB re 1 μPa and a frequency of 37 kHz. Six groups of eight animals were included in the study as in Table 1, breathing air (n = 4) or Nitrox 72/28 (n = 2), at a depth of 0 m, 30 m or 40 m. Immediately after decompression, the intestinal mesenterium was imaged, and frames were acquired digitally. The number of bubbles and their radii were analysed and compared among the groups. The mean bubble density for group 1 was 1.35 ± 0.18 bubbles/mm2, significantly higher when compared with the other groups (p < 0.0001). The average bubble radius for groups 1 and 2 was similar (12.57 ± 4.1 and 10.63 ± 1.8 μm, respectively), but significantly larger than in the other groups (p < 0.0002). The percentage of bubbles with a radius greater than 50 μm was significantly higher in group 1 (p < 0.0001). The results suggest that commercially available underwater pingers might enhance bubble growth during deep air diving.

Original languageEnglish
Pages (from-to)655-660
Number of pages6
JournalUltrasound in Medicine and Biology
Issue number5
StatePublished - 2002
Externally publishedYes

Bibliographical note

Funding Information:
The authors are grateful to Richard Lincoln for his help in editing the manuscript. This study was supported financially by a research grant from the office of the IDF Surgeon General Scientific Council.


  • Bioeffect
  • Decompression
  • Diving
  • Gas bubble
  • High-frequency sound
  • Immersion
  • Rectified diffusion

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Biophysics
  • Acoustics and Ultrasonics


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