title: B-type natriuretic peptide in healthy subjects after exposure to hyperbaric oxygen at 2.5 ATA.
abstract: BACKGROUND
  B-type natriuretic peptide (BNP) is a cardiac hormone used as a marker of cardiac dysfunction with diuretic and vasodilating properties secreted by the ventricles in response to wall stress. Hyperbaric oxygen (HBO) exposure is known to induce hemodynamic effects in humans which can be complicated by acute pulmonary edema. The aim of this study was to investigate if HBO has any effects on the secretion of BNP in healthy human subjects.
  
  
  METHODS
  Eight healthy volunteers underwent the following HBO protocol in a hyperbaric chamber: compression to 2.5 atmospheres absolute (ATA); 45 min breathing 100% oxygen; 5 min breathing air; another 45 min in 100% oxygen; then decompression to atmospheric pressure. A venous blood sample was drawn before entering the chamber (To), immediately at the end of the treatment (T1), and at 5 h from To (T2). BNP concentration was determined using a rapid point-of-care immunoassay. Non-parametric statistics were used to analyze data.
  
  
  RESULTS
  No difference in BNP levels was found between T0 and T1 or T2.
  
  
  CONCLUSIONS
  The findings of this preliminary study show that in healthy subjects a single HBO exposure does not significantly modify BNP plasma levels. We hypothesize that this can be the net result between the stimulating effect of the HBO-induced vasoconstriction and the direct inhibitory effect on BNP secretion of myocyte hyperoxia. We conclude that HBO does not modify BNP secretion in healthy volunteers and that the direct effect of extreme hyperoxia on BNP secretion deserves further investigation.
authors.affiliation: Department of Anesthesia and Intensive Care, Cattinara Hospital, Trieste, Italy. paolo.grassi@aots.sanita.fvg.it
authors.forename: Paolo
authors.initials: P
authors.lastname: Grassi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Buscema
authors.forename: Adriano
authors.initials: A
authors.lastname: Rinaldi
authors.forename: Pietro E
authors.initials: PE
authors.lastname: Gobbato
authors.forename: Giorgio
authors.initials: G
authors.lastname: Berlot
mesh_terms: D000328:Adult; D001274:Atmospheric Pressure; D015415:Biomarkers; D003664:Decompression; D005260:Female; D006801:Humans; D006931:Hyperbaric Oxygenation / Q000009:adverse effects*; D018496:Hyperoxia / Q000209:etiology*; D008297:Male; D020097:Natriuretic Peptide, Brain / Q000097:blood / Q000378:metabolism*; D011446:Prospective Studies; D014661:Vasoconstriction
chemical_list: D015415:Biomarkers; D020097:Natriuretic Peptide, Brain