title: Elective haemodialysis increases exhaled isoprene.
abstract: BACKGROUND
  Uraemic odour is a characteristic feature of patients with end-stage renal disease (ESRD). However, few investigations have been carried out into the composition of exhaled air in ESRD patients undergoing haemodialysis (HD). Increases of exhaled isoprene levels by a factor of up to 2.7 following HD have been reported.
  
  
  METHODS
  We attempted to confirm these findings in 50 patients undergoing HD using haemophan (n=23) or polysulphone (n=27) dialysis membranes. Parallel evaluation of ambient air, calorie intake, medication and haemodynamic variables was performed. Samples were analysed using proton transfer reaction-mass spectrometry (PTR-MS).
  
  
  RESULTS
  Significant changes in breath isoprene concentration were observed when comparing patients before [39.14+/-14.96 parts per billion (ppbv)] and after (63.54+/-27.59 ppbv) dialysis (P<0.001). The quotient of values before and after dialysis was 1.84 (SD 1.41). No significant differences in isoprene kinetics were found between the use of haemophan and polysulphone membranes. No significant correlations were observed between isoprene quotients and variations in blood pressure during HD, calorie intake, ingestion of lipid-lowering drugs or serum lipid levels.
  
  
  CONCLUSIONS
  Isoprene concentration was higher in the exhaled air of patients after HD as compared with values before HD. Large interindividual variability existed in isoprene kinetics. Oxidative stress appears to be an unlikely cause for this rise. An alternative hypothesis is an influence of respiratory variables on isoprene exhalation based upon Henry's law constant. We therefore propose to perform online monitoring of isoprene exhalation by PTR-MS during the HD session to investigate the possible influence of respiratory variables.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Leopold Franzens University of Innsbruck, Anichstrasse 35, A-6020 Innsbruck, Austria.
authors.forename: Philipp
authors.initials: P
authors.lastname: Lirk
authors.forename: Florian
authors.initials: F
authors.lastname: Bodrogi
authors.forename: Hartmann
authors.initials: H
authors.lastname: Raifer
authors.forename: Karin
authors.initials: K
authors.lastname: Greiner
authors.forename: Hanno
authors.initials: H
authors.lastname: Ulmer
authors.forename: Josef
authors.initials: J
authors.lastname: Rieder
mesh_terms: D000328:Adult; D000368:Aged; D002070:Butadienes / Q000378:metabolism*; D002482:Cellulose / Q000031:analogs & derivatives*; D045853:Exhalation; D045782:Hemiterpenes / Q000378:metabolism*; D006801:Humans; D007688:Kidneys, Artificial; D008875:Middle Aged; D008954:Models, Biological; D009812:Odorants; D018384:Oxidative Stress; D010420:Pentanes / Q000378:metabolism*; D011108:Polymers; D006435:Renal Dialysis / Q000009:adverse effects*; D013450:Sulfones; D014511:Uremia / Q000378:metabolism / Q000628:therapy
chemical_list: D002070:Butadienes; D045782:Hemiterpenes; D010420:Pentanes; D011108:Polymers; D013450:Sulfones; C005059:isoprene; C054645:Hemophan; C017662:polysulfone P 1700; D002482:Cellulose