Fatigue and exercise intolerance after survived COVID-19-infection might be related to weakness of the respiratory muscles especially following invasive mechanical ventilation in the Intensive Care Unit.

The aim of the project is to measure respiratory muscle function and strength in our respiratory physiology laboratory (Respiratory Physiology Laboratory, Department of Pneumology and Intensive Care Medicine, Head: Professor Michael Dreher) in patients who survived a severe COVID-19-infection (25 with a severe course requiring mechanical ventilation in the intensive care unit, 25 with a moderate-severe course requiring administration of supplemental oxygen only, respectively).

Based on this data the aim is to develop a model which determines the severity, pathophysiology and clinical consequences of respiratory muscle dysfunction in patients who had been hospitalised for COVID-19.

This will potentially prove the importance of a dedicated pulmonologic rehabilitation with respiratory muscle strength training in patients who had been hospitalised for COVID-19.

The aim of the present project is to comprehensively measure respiratory muscle function and strength in patients who survived a hospitalisation for a severe COVID-19-infection (25 with a severe course requiring mechanical ventilation in the intensive care unit, 25 with a moderate-severe course requiring administration of supplemental oxygen only, respectively).

We intend to recruit 50 patients during their regular follow up appointments (12 months and 24 months after their discharge from the hospital) in our pulmonology outpatient-clinic. Patients fulfilling the criterions of inclusion and exclusion will be included.

Patients will undergo a series of measurements on one day in our respiratory physiology laboratory (Respiratory Physiology Laboratory, Department of Pneumology and Intensive Care Medicine, Head: Professor Michael Dreher). Patients will be asked to complete a questionnaire, followed by some examinations comprising spirometry by bodyplethysmography, exercise endurance, capillary blood gas analyses, measurement of maximum inspiratory and expiratory mouth pressures, dynamometric measurement of arm and leg strength, diaphragm ultrasound, magnetic stimulation of the phrenic and lower thoracic nerves with invasive recording of twitch transdiaphragmatic pressure and markers of systemic inflammation based on in depth analyses of blood samples that will be obtained.

Based on this data the aim is to develop a model which determines the severity, pathophysiology and clinical consequences of respiratory muscle dysfunction in patients who had been hospitalised for COVID-19.

This will potentially prove the importance of a dedicated pulmonologic rehabilitation with respiratory muscle strength training in patients who had been hospitalised for COVID-19.

Inclusion Criteria:

• 50 patients with survived COVID-19-infection (25 with a severe course requiring mechanical ventilation in the intensive care unit, 25 with a moderate-severe course requiring administration of supplemental oxygen only, respectively)
• Patients aged at least 18 years, who are mentally and physically able to consent and participate into the study

Exclusion Criteria:

• Diagnosis of another disease, which causes a permanent increase in carbon dioxide level in the blood (chronic hypercapnia) or a permanent combined lung weakness (particularly a neuromuscular disease)
• Body-mass-index (BMI) >40
• Expected absence of active participation of the patient in study-related measurements
• Alcohol or drug abuse
• Metal implant in the body that is not MRI compatible (NON MRI compatible pacemaker, implantable defibrillator, cervical implants, e.g. brain pacemakers etc.)
• Slipped disc
• Epilepsy
• Bound to a wheel chair
• Patients who are mentally and physically unable to consent and participate into the study
• Patients in an interdependence or with an employment contract with the principal investigator, Co-PI or his deputy.
• Emergency hospital stay in the last 4 weeks preceding the day of the measurements

The aim of the present project is to comprehensively measure respiratory muscle function and strength in patients who survived a hospitalisation for a severe COVID-19-infection (25 with a severe course requiring mechanical ventilation in the intensive care unit, 25 with a moderate-severe course requiring administration of supplemental oxygen only, respectively)