Abstract
Background The concentration of exhaled octane has been postulated as a reliable biomarker of acute respiratory distress syndrome (ARDS) using metabolomics analysis with gas chromatography mass spectrometry (GC-MS). A point-of-care (POC) breath test was developed in recent years to accurately measure octane at the bedside.
Aim To validate the diagnostic accuracy of exhaled octane for ARDS using a POC test in invasively ventilated intensive care unit (ICU) patients.
Methods This was an observational cohort study of consecutive patients receiving invasive ventilation for at least 24 h, recruited in two university ICUs. GC-MS and POC tests were used to quantify the exhaled octane concentration. ARDS was assessed by three experts following the Berlin definition and used as reference standard. The area under the receiver operating characteristics curve (AUROCC) was used to assess diagnostic accuracy.
Results 519 patients were included and 190 (37%) fulfilled the criteria for ARDS. The concentration of octane using the POC breath test was not significantly different between patients with ARDS (0.14ppb; IQR: 0.05–0.37) and without ARDS (0.11ppb; IQR: 0.06–0.26; p=0.64). The AUROCC for ARDS based on the octane concentration in exhaled breath using the POC breath test was 0.52 (95%CI: 0.46–0.57). Analysis of exhaled octane with GC-MS showed similar results.
Conclusion Octane in exhaled breath has insufficient diagnostic accuracy for ARDS. This disqualifies the use of octane as a biomarker in the diagnosis of ARDS and challenges most of the research performed up to now in the field of exhaled breath metabolomics.
Footnotes
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Conflict of interest: LDJB reports grants from: Dutch lung foundation (Young investigator grant), Dutch lung foundation and Health Holland (Public-Private Partnership grant), Dutch lung foundation (Dirkje Postma Award), IMI COVID19 iniative, grants from Amsterdam UMC fellowship, ZonMW COVID-19 Urgency grant, ERS Gold Metal for ARDS. LDJB reports participating in an advisory board for Sobi, Exvastat, Santhera, Pfizer and Astra Zeneca, all paid to institution. LDJB reports consultancy for Scailyte, Santhera and Janssen en Janssen, all paid to institution, outside the submitted work.
Conflict of interest: ARMV, TMEN, IG, CNP and RR are employees at Philips Research.
Conflict of interest: LAH, NFLH, MRS, DWF, PB, MJS, DCJJB, and RMS have no conflict of interest regarding this manuscript.
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- Received April 5, 2023.
- Accepted August 3, 2023.
- Copyright ©The authors 2023
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