Breath Markers and Soluble Lipid Peroxidation Markers in Critically Ill Patients

Abstract

Free radical-mediated inflammatory processes account for a great portion of morbidity and mortality in critically ill patients. The purpose of this study was to determine two plasma peroxidation markers and three volatile markers related to lipid peroxidation, metabolic activity and cholesterol metabolism, and to explore relationships between the different markers and patients' clinical status. Substances were analyzed in whole blood and in exhaled air in patients with head injury, acute respiratory distress syndrome (ARDS) and in those being at risk of developing ARDS. These results were compared with the baseline measurements in healthy individuals. Additionally, patients were assessed according to their inflammatory status. Concentrations of malondialdehyde and thiobarbituric acid-reactive substances in plasma as well as pentane concentrations in breath increased with increasing inflammatory status. Although these compounds are generated through peroxidation of fatty acids, concentrations of these markers were significantly different in patient groups. Isoprene concentrations were lowest in the ARDS group. Acetone concentrations were not different between patient groups. We conclude that for the assessment of lipid peroxidation and other inflammatory reactions a set of parameters has to be defined. More detailed insights into inflammatory processes can be obtained when the volatile markers and the serum markers are considered together.

Study of Ethane Level in Exhaled Breath in Patients with Age-Related Macular Degeneration: Preliminary Study

“…Measuring volatile hydrocarbons in exhaled breath is thought to be a highly sensitive method for determining the body's oxidation and lipid peroxidation in vivo [3,4,7] . Ideally, lipid peroxidation should be evaluated by monitoring oxygen consumption and the loss of polyunsaturated fatty acids.…”

“…However, since this is virtually impossible, tests measuring lipid peroxidation are based on the analysis of products of reaction. At the end of the reaction of lipid peroxidation there are volatile organic hydrocarbons [3][4][5] .…”

“…Many of them can serve as markers of the lipid peroxidation induced by free radicals and, in some cases, of the damage to certain amino acid compounds in vivo [3] . Measurement of these respiratory markers is a method that has often proved to be a very sensitive index of free radical-induced lipid peroxidation in vivo [4,5] . This test provides an index of the patients' overall oxidative stress level.…”

Volatile Organic Compound and Metabolite Signatures as Pathogen Identifiers and Biomarkers of Infectious Disease

“…Thirdly, the human body mounts an inflammatory response against pathogen infection, potentially leading to a change in bacterial and host metabolism. Future studies should address the metabolic differences between infectious and non-infectious inflammatory responses [65]. Fourthly, VOCs derived from exogenous sources, such as the host environment and diet, can easily contaminate a sample [66].…”

Breath Analysis: Potential for Clinical Diagnosis and Exposure Assessment

“…These compounds are therefore regarded as in vitro and in vivo markers of lipid peroxidation. Breath markers are often more sensitive than the serum markers MDA and thiobarbituric acidreactive substances (26 ). Hydrocarbons as stable end products of lipid peroxidation show only low solubility in blood and are excreted into the breath within minutes of their formation in tissues.…”