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Review
. 2024 May 7;14(10):972.
doi: 10.3390/diagnostics14100972.

Particles in Exhaled Air (PExA): Clinical Uses and Future Implications

Thomas Roe  1 , Siona Silveira  2   3 , Zixing Luo  2   4 , Eleanor L Osborne  4 , Ganapathy Senthil Murugan  4 , Michael P W Grocott  1   2   3 , Anthony D Postle  2   3 , Ahilanandan Dushianthan  1   2   3
Affiliations
Review

Particles in Exhaled Air (PExA): Clinical Uses and Future Implications

Thomas Roe et al. Diagnostics (Basel). .

Abstract

Access to distal airway samples to assess respiratory diseases is not straightforward and requires invasive procedures such as bronchoscopy and bronchoalveolar lavage. The particles in exhaled air (PExA) device provides a non-invasive means of assessing small airways; it captures distal airway particles (PEx) sized around 0.5-7 μm and contains particles of respiratory tract lining fluid (RTLF) that originate during airway closure and opening. The PExA device can count particles and measure particle mass according to their size. The PEx particles can be analysed for metabolites on various analytical platforms to quantitatively measure targeted and untargeted lung specific markers of inflammation. As such, the measurement of distal airway components may help to evaluate acute and chronic inflammatory conditions such as asthma, chronic obstructive pulmonary disease, acute respiratory distress syndrome, and more recently, acute viral infections such as COVID-19. PExA may provide an alternative to traditional methods of airway sampling, such as induced sputum, tracheal aspirate, or bronchoalveolar lavage. The measurement of specific biomarkers of airway inflammation obtained directly from the RTLF by PExA enables a more accurate and comprehensive understanding of pathophysiological changes at the molecular level in patients with acute and chronic lung diseases.

Keywords: PExA; acute respiratory distress syndrome; asthma; particles in exhaled air.

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Conflict of interest statement

All authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
PExA device and principles. (A) Photograph of the external surface of PExA including the flow director level and opening for mouthpiece. (B) PExA impaction tray. (C) Schematic of PExA air flow. Note the smaller (0.5–7 μm) particles are selected by bypassing the initial tray and are impacted on the second. (D) Principle of a 50% particle size cut-off (PExA impactor cut-off curve is not determined).
Figure 2
Figure 2
Representation of PExA in 2.0 configuration, connected to a mechanical ventilator. Blue arrows indicate inhaled air. Orange arrows are for exhaled air.
Figure 3
Figure 3
Analytical techniques utilized for PExA samples are highlighted above, with some potential clinical applications.
See this image and copyright information in PMC

References

    1. NHS England Respiratory Disease. [(accessed on 11 November 2023)]. Available online: https://www.england.nhs.uk/ourwork/clinical-policy/respiratory-disease/
    1. Soriano J.B., Kendrick P.J., Paulson K.R., Gupta V., Abrams E.M., Adedoyin R.A., Adhikari T.B., Advani S.M., Agrawal A., Ahmadian E., et al. Prevalence and Attributable Health Burden of Chronic Respiratory Diseases, 1990–2017: A Systematic Analysis for the Global Burden of Disease Study 2017. Lancet Respir. Med. 2020;8:585–596. doi: 10.1016/S2213-2600(20)30105-3. - DOI - PMC - PubMed
    1. Intensive Care National Audit and Research Centre INCARC Reports. [(accessed on 1 March 2024)]. Available online: https://www.icnarc.org/Our-Audit/Audits/Cmp/Reports.
    1. Chang R., Elhusseiny K.M., Yeh Y.-C., Sun W.-Z. COVID-19 ICU and Mechanical Ventilation Patient Characteristics and Outcomes—A Systematic Review and Meta-Analysis. PLoS ONE. 2021;16:e0246318. doi: 10.1371/journal.pone.0246318. - DOI - PMC - PubMed
    1. Campling J., Jones D., Chalmers J., Jiang Q., Vyse A., Madhava H., Ellsbury G., Rabe A., Slack M. Clinical and Financial Burden of Hospitalised Community-Acquired Pneumonia in Patients with Selected Underlying Comorbidities in England. BMJ Open Respir. Res. 2020;7:e000703. doi: 10.1136/bmjresp-2020-000703. - DOI - PMC - PubMed