Negative pressure breathing enhances nitrogen elimination

Timothy B. Curry, Claes E.G. Lundgren

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Background: The rate of nitrogen elimination during decompression is primarily dependent on tissue perfusion and, therefore, cardiac output (CO). Negative pressure breathing (NPB) is thought to increase CO by enhancing venous return and, consequently, the rate of nitrogen elimination. This notion was investigated in the present study. Methods: Nitrogen elimination was measured in five subjects lying supine while breathing a nitrogen free gas (79% Ar, 20% O2) supplied at -15 cm H2O (-1.5 kPa) or at atmospheric pressure. Results: Over a 2-h washout period, NPB increased nitrogen elimination by 39.2 ± 21.7% (mean ± SD), increased calf blood flow by 34.1 ± 34.6%, and elevated BP slightly during the last half of the experiment. Negative pressure breathing did not significantly change CO; the increase in nitrogen elimination may have been due to redistribution of blood flow. Conclusions: Negative pressure breathing appears to be a useful means of increasing nitrogen elimination and should be considered in situations such as decompression or treatment of decompression sickness where this effect may be beneficial.

Original languageEnglish (US)
Pages (from-to)1034-1039
Number of pages6
JournalAviation Space and Environmental Medicine
Volume74
Issue number10
StatePublished - Oct 1 2003

Keywords

  • Blood circulation
  • Cardiography
  • Decompression sickness
  • Impedance
  • Plethysmography
  • Respiratory mechanics

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health

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