Ventilator-associated Injury (VAI) in Chronic Home Mechanical Ventilation

Rationale:

Chronic Obstructive Pulmonary Disease (COPD) is a progressive inflammatory disease characterised by airway and lung parenchyma damage. At end-stage disease patients may develop chronic hypercapnic respiratory failure, a disease characteristic that is however not uniformly seen in other end-stage lung diseases, such as in patients with pulmonary fibrosis. The underlying process for the development of chronic hypercapnic respiratory failure is incompletely understood and the role of respiratory muscle alterations is unclear.

Home noninvasive ventilation with high-intensity ventilatory settings (HI-NIV) has been shown to be effective in these severe COPD patients. However, in patients being mechanically ventilated on the intensive care unit for diverse reasons, high-intensity ventilation, especially high tidal volumes, has been shown to result in ventilator associated lung and diaphragm injury. Whether this occurs in home high-intensity NIV, is however completely unknown.

Objective: The aims of the study are to get insight in:

A. changes respiratory muscles in end-stage respiratory disease, comparing COPD with restrictive lung disease (RLD) due to pulmonary fibrosis B. the effects of long-term HI-NIV in severe COPD patients on the respiratory muscles; i.e. the contractile strength and the structure of single diaphragm and intercostal muscle fibres and the lungs; i.e. alveolar structure and damage and inflammation, by comparing COPD patients that had been treated with long-term NIV to COPD patients that were not treated with long-term NIV.

Study design: In order to investigate this, the investigators will include in a small pilot cohort study patients being lung transplanted. In these patients there is lung tissue available and respiratory muscle biopsies will be performed during lung-transplant surgery.

Study population: Patients that are listed for lung transplantation for an underlying diagnosis of COPD or RLD will be asked to participate. Three groups will be included: patients with a RLD due to pulmonary fibrosis, COPD patients that had been treated with long-term NIV prior to being lung transplanted and COPD patients that were not treated with long-term NIV. Patients will be included definitely once being lung transplanted.

Main study parameters/endpoints: The study is an exploratory pilot study. The study aims to get data on respiratory muscle and lung and airway pathology in order to, if important results are observed, set up a larger prospective trial investigating both clinical outcomes and pathology of the respiratory muscles/lungs. Both contractile strength and the structure of single diaphragm and intercostal muscle fibres as well as lung injury; i.e. alveolar structure and damage and inflammation in the alveoli, will be investigated.

Inclusion criteria

• RLD: probable or confirmed diagnosis of interstitial pulmonary fibrosis (IPF) or other fibrotic lung disease of unknown origin.
• COPD: GOLD stage III or IV
• Being listed for lung transplantation

Exclusion criteria

• Concomitant neuromuscular or systemic/collagen-vascular disease
• Prior lung surgery (except for lung biopsies) or lung volume reduction treatment
• Being unable to understand the patient information and consent for the study