Transepithelial nasal potential difference in patients with, and at risk of acute respiratory distress syndrome.

Rob Mac Sweeney, Kiran Reddy, Jane C Davies, Mike Parker, Barry Kelly, J Stuart Elborn, John Conlon, Rejina M Verghis, Carolyn S Calfee, Michael A Matthay, Eric W F W Alton, Daniel F McAuley

Journal: Thorax 2022;76(11):1099-1107

PMID: 33888572

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Abstract

BACKGROUND

Impaired alveolar fluid clearance, determined in part by alveolar sodium transport, is associated with acute respiratory distress syndrome (ARDS). Nasal sodium transport may reflect alveolar transport. The primary objective of this prospective, observational study was to determine if reduced nasal sodium transport, as measured by nasal potential difference (NPD), was predictive of the development of and outcome from ARDS.

METHODS

NPD was measured in 15 healthy controls and in 88 patients: 40 mechanically ventilated patients defined as 'at-risk' for ARDS, 61 mechanically ventilated patients with ARDS (13 who were previously included in the 'at-risk' group) and 8 ARDS survivors on the ward.

RESULTS

In at-risk subjects, maximum NPD (mNPD) was greater in those who developed ARDS (difference -8.4 mV; 95% CI -13.8 to -3.7; p=0.005) and increased mNPD predicted the development of ARDS before its onset (area under the curve (AUC) 0.75; 95% CI 0.59 to 0.89). In the ARDS group, mNPD was not significantly different for survivors and non-survivors (p=0.076), and mNPD was a modest predictor of death (AUC 0.60; 95% CI 0.45 to 0.75). mNPD was greater in subjects with ARDS (-30.8 mV) than in at-risk subjects (-24.2 mV) and controls (-19.9 mV) (p<0.001). NPD values were not significantly different for survivors and controls (p=0.18).

CONCLUSIONS

Increased NPD predicts the development of ARDS in at-risk subjects but does not predict mortality. NPD increases before ARDS develops, is greater during ARDS, but is not significantly different for controls and survivors. These results may reflect the upregulated sodium transport necessary for alveolar fluid clearance in ARDS. NPD may be useful as a biomarker of endogenous mechanisms to stimulate sodium transport. Larger studies are now needed to confirm these associations and predictive performance.

Address: Intensive Care Unit, Royal Victoria Hospital, Belfast, UK.; Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK.; Department of Anaesthesia, Intensive Care, and Pain Medicine, Mater Misericordiae University Hospital, Dublin, Ireland.; Department of Medicine, University College Dublin, Dublin, Ireland.; National Heart and Lung Institute, Imperial College London, London, UK.; Department of Paediatric Respiratory Medicine, Royal Brompton and Harefield NHS Foundation Trust, London, UK.; Department of Computing and Information Science, Anglia Ruskin University, Chelmsford, Essex, UK.; Department of Medicine, Division of Pulmonary, Critical Care, Allergy and Sleep Medicine, University of California, San Francisco, San Francisco, California, USA.; Department of Anesthesia, University of California, San Francisco, San Francisco, California, USA.; Department of Respiratory Medicine, Royal Brompton Hospital, London, UK.; Intensive Care Unit, Royal Victoria Hospital, Belfast, UK [email protected].

DOI: 10.1136/thoraxjnl-2020-215587

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MeSH Terms: Area Under Curve, Humans, Prospective Studies, Respiratory Distress Syndrome, Risk Factors