Increased extravascular lung water index (EVLWI) reflects rapid non-cardiogenic oedema and mortality in COVID-19 associated ARDS

Sebastian Rasch,Tobias Lahmer,Fabian Geisler,Sengül Sancak,Ulrich Mayr,Roland M Schmid,Paul Schmidle,Christoph D Spinner,Christina Huberle,Wolfgang Huber,Alexander Herner,Jochen Schneider,Dominik Schulz

doi:10.1038/s41598-021-91043-3

Abstract

Nearly 5% of patients suffering from COVID-19 develop acute respiratory distress syndrome (ARDS). Extravascular lung water index (EVLWI) is a marker of pulmonary oedema which is associated with mortality in ARDS. In this study, we evaluate whether EVLWI is higher in patients with COVID-19 associated ARDS as compared to COVID-19 negative, ventilated patients with ARDS and whether EVLWI has the potential to monitor disease progression. EVLWI and cardiac function were monitored by transpulmonary thermodilution in 25 patients with COVID-19 ARDS subsequent to intubation and compared to a control group of 49 non-COVID-19 ARDS patients. At intubation, EVLWI was noticeably elevated and significantly higher in COVID-19 patients than in the control group (17 (11–38) vs. 11 (6–26) mL/kg; p < 0.001). High pulmonary vascular permeability index values (2.9 (1.0–5.2) versus 1.9 (1.0–5.2); p = 0.003) suggested a non-cardiogenic pulmonary oedema. By contrast, the cardiac parameters SVI, GEF and GEDVI were comparable in both cohorts. High EVLWI values were associated with viral persistence, prolonged intensive care treatment and in-hospital mortality (23.2 ± 6.7% vs. 30.3 ± 6.0%, p = 0.025). Also, EVLWI showed a significant between-subjects (r = − 0.60; p = 0.001) and within-subjects correlation (r = − 0.27; p = 0.028) to Horowitz index. Compared to non COVID-19 ARDS, COVID-19 results in markedly elevated EVLWI-values in patients with ARDS. High EVLWI reflects a non-cardiogenic pulmonary oedema in COVID-19 ARDS and could serve as parameter to monitor ARDS progression on ICU.

Highlights

5% of patients suffering from COVID-19 develop acute respiratory distress syndrome (ARDS)
74 patients with ARDS were included in the study (25 with COVID-19 and 49 without)
Patients with COVID-19 were more frequently male compared to nonCOVID-19 patients (20/25 (80%) vs. 26/49 (53%); p = 0.041; Table 1)

Summary

Material and methods

The study protocol was approved by the Institutional Review Board (Ethics committee of Technical University of Munich; Approval No 178/20S) as part of the register study CORRECT: COVID Registry REChts der Isar intensive care Trial. To derive EVLWI, GEDVI, SVI, GEF and all other parameters provided by the PiCCO, we used the most recent software V3.1, which corrects GEDVI for femoral CVC indicator injection[23]. See Huber et al for further d etails[14] For this analysis TPTD and respiratory parameters were routinely registered in included all patients on ICU at intubation and on day 3,7,10 and 14. The control group consists of 49 consecutive patients with TPTD monitoring and non-COVID-19 ARDS19. All patients of this cohort were treated in the same ICU as the COVID-19 patients before 2019 (see Clinical Study Registration No ISRCTN32938630; Institutional Review Board (Ethics committee of Technical University of Munich), Approval No 343/18 S). To assess whether ELVWI can be used to monitor respiratory function and ARDS progression over time we calculated betweensubject and within-subject correlations to Horowitz index as proposed by Bland et al.[25,26]

Results

Discussion

Conclusion