title: Volatile compounds in health and disease.
abstract: OBJECTIVE
  To summarize the recent progress made in noninvasive monitoring of volatile compounds in exhaled breath and above biological liquids, as they are becoming increasingly important in assessing the nutritional and clinical status and beginning to provide support to conventional clinical diagnostics and therapy. To indicate the potential of these developments in medicine and the specific areas which are currently under investigation.
  
  
  RESULTS
  The significance of the following breath gases and their concentrations are reported: acetone and the influence of diet; ammonia confirmed as an indicator of dialysis efficacy; hydrogen and the (13)CO(2)/(12)CO(2) ratio (following the ingestion of (13)C-labeled compounds) as related to gastric emptying and bowel transit times; hydrogen cyanide released by Pseudomonas and its detection in breath of children with cystic fibrosis; and multiple trace compounds in breath of patients with specific pathophysiological conditions and 'metabolic profiling'.
  
  
  CONCLUSIONS
  Advanced analytical methods, especially exploiting mass spectrometry, are moving breath analysis towards the clinical setting; some trace gas metabolites are already being exploited in diagnosis and therapy. Much effort is being given to the search for biomarkers of tumours in the body. HCN as an indicator of the presence of Pseudomonas in the airways has real potential in therapeutically alleviating the symptoms of cystic fibrosis.
authors.affiliation: J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic. spanel@jh-inst.cas.cz
authors.forename: Patrik
authors.initials: P
authors.lastname: Španěl
authors.forename: David
authors.initials: D
authors.lastname: Smith
mesh_terms: D000096:Acetone / Q000378:metabolism; D000641:Ammonia / Q000378:metabolism; D001944:Breath Tests / Q000379:methods*; D002245:Carbon Dioxide / Q000378:metabolism; D006304:Health Status; D006801:Humans; D006859:Hydrogen / Q000378:metabolism; D006856:Hydrogen Cyanide / Q000378:metabolism; D013058:Mass Spectrometry; D009752:Nutritional Status; D012137:Respiratory System / Q000378:metabolism*; D014131:Trace Elements / Q000378:metabolism; D055549:Volatile Organic Compounds / Q000378:metabolism*
chemical_list: D014131:Trace Elements; D055549:Volatile Organic Compounds; D000096:Acetone; D002245:Carbon Dioxide; D006856:Hydrogen Cyanide; D000641:Ammonia; D006859:Hydrogen