Post COVID-19 Condition Patients with Dyspnea Show Diaphragm Dysfunction in Sonographic Imaging – a Prospective Observational Study

Abstract

Objective

Around 6.2% of patients report symptoms as fatigue, muscle pain and dyspnea more than three months after SARS-CoV-2 infection, defined as post COVID-19 condition (PCC). Non-hospitalized patients with PCC often show normal pulmonary functioning tests and imaging but suffer from respiratory symptoms. On clinical examination, PCC with dyspnea show signs of diaphragmatic dysfunction. The study aimed to objectively visualize and quantify the diaphragmatic function using sonographic parameters in PCC patients with and without dyspnea.

Materials and Methods

Adult PCC patients were prospectively assessed for dysfunctional breathing and diaphragmatic stiffness using sonographic imaging. Multiparametric sonography evaluated diaphragm thickness, mobility, stiffness and elasticity in different breathing cycles using B-mode imaging, M-mode and quantitative shear wave elastography. PCC patients were stratified into two groups with and without dyspnea.

Results

Fifty-four post-COVID patients were assessed, of whom n=24 (44.4%) reported dyspnea and presented dysfunctional breathing, while 30 PCC without dyspnea served as control. PCC with dyspnea compared to PCC without dyspnea showed a less deep first breath (5.8 mm vs. 6.5 mm, p=0.044), reduced diaphragm thickness on inspiration (3.4 mm vs. 3.9 mm, p=0.030), as well as less increase of diaphragmatic elasticity (108% vs. 146%; p=0.027) and diaphragmatic stiffness (40% vs. 53%; p=0.022) during inspiration.

Conclusions

Diaphragm dysfunction as a possible origin of dyspnea in PCC can be assessed and objectively quantified using multiparametric sonography and may help evaluate therapeutic interventions that are otherwise overlooked.

Zusammenfassung

Hintergrund und Ziel

Etwa 6,2% der Patienten berichten mehr als drei Monate nach einer SARS-CoV-2-Infektion über Symptome wie Müdigkeit, Muskelschmerzen und Atemnot, die als Post-COVID-19-Zustand (PCC) definiert werden. Nichthospitalisierte Patienten mit PCC weisen häufig normale Lungenfunktionstests und bildgebende Verfahren auf, leiden aber unter Atemwegssymptomen. Bei der klinischen Untersuchung zeigen PCC mit Dyspnoe Anzeichen einer Zwerchfelldysfunktion. Ziel der Studie war es, die Zwerchfellfunktion bei PCC-Patienten mit und ohne Dyspnoe anhand sonografischer Parameter objektiv darzustellen und zu quantifizieren.

Material und Methoden

Erwachsene PCC-Patienten wurden prospektiv auf dysfunktionale Atmung untersucht. Sonografisch wurden Zwerchfelldicke, -beweglichkeit, -steifigkeit und -elastizität in verschiedenen Atemzyklen mittels B-Mode, M-Mode und Scherwellenelastografie untersucht. Die PCC-Patienten wurden in zwei Gruppen mit und ohne Dyspnoe eingeteilt.

Ergebnisse

54 PCC-Patienten wurden untersucht, von denen 24 (44,4%) Dyspnoe und dysfunktionale Atmung aufwiesen, während 30 PCC-Patienten ohne Dyspnoe als Kontrolle dienten. PCC-Patienten mit Dyspnoe zeigten im Vergleich zurKontrollgruppe einen weniger tiefen ersten Atemzug (5,8 mm vs. 6,5 mm, p=0,044), eine geringere Zwerchfelldicke in Inspiration (3,4 mm vs. 3,9 mm, p=0,030) sowie eine geringere Zunahme der Elastizität (108% vs. 146%; p=0,027) und Steifigkeit (40% vs. 53%; p=0,022) in Inspiration.

Schlussfolgerungen

Eine Zwerchfelldysfunktion als mögliche Ursache der Dyspnoe bei PCC kann sonografisch beurteilt und quantifiziert werden und dazu beitragen weitere therapeutische Interventionen zu evaluieren.

Keywords

diaphragm dysfunction - post COVID-19 condition - dyspnea - functional disturbance - ultrasound

Schlüsselwörter

Diaphragma - Funktionelle Störung - Post-COVID Syndrom - Dyspnoe - Ultraschall

Publication History

Received: 04 October 2024

Accepted after revision: 07 January 2025

Article published online:
06 February 2025

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