Central Control of Breathing in Patients With Chronic Obstructive Pulmonary Disease: Identification and Dynamics With Cerebral Functional Magnetic Resonance Imaging

Chronic obstructive pulmonary disease (COPD) is a chronicle inflammatory disease with a non reversible diminution of the airway flow. COPD is caused most commonly from tobacco smoking, which triggers an abnormal inflammatory response in the lung. Worldwide, COPD ranked as the sixth leading cause of death in 1990. It is projected to be the fourth leading cause of death worldwide by 2030 due to an increase in smoking rates and demographic changes in many countries. COPD is responsible for 16000 deaths per year in France, 100 000 hospitalizations per year and the health care expenditure of COPD in France is 3.5 billion of Euros. Classical markers of the disease severity, the forced expiratory volume in one second, poorly correlates with dyspnea and prognosis. Therefore, many studies focused on the control of breathing in an attempt to understand the pathophysiological mechanisms involved in the progression of the disease. Breathing control is enhanced in patients with COPD due to the progressive failure of respiratory muscles (airflow obstruction, static and dynamic hyperinflation, positive intrinsic end expiratory pressure), the ventilation/ perfusion ratio abnormalities leading to the loss of the gaz exchange efficiency. Inspiratory command depends on the medulla automatic pathway and the voluntary corticospinal command. Indirect method of breathing control estimation suggested in COPD patients an increased excitability of neurons involved in the voluntary diaphragm activation and a reduced cortical reserve. This may represent an increase risk factor for acute respiratory failure. Until now, no study reported the central breathing control with cerebral fMRI in COPD patients. This pilot study also aims in estimating if the absence or diminution of the cortical reserve is a marker of disease severity. In addition correlations will be performed between activated neuronal signals with fMRI and ventilatory flow output recordings (chaotic analysis).