Clinical Research Directory

Assessment of Continuous Measurement of Transcutaneous CO2 for Evaluation of Alveolar Dead Space During Exercise

The study aim is to monitor, during exercise tests carried out in various conditions, the alveolar dead space, by means of continuous transcutaneous measurement of Pt CO2, which would be used as a surrogate for arterial PaCO2. Validity of this measurement needs to be assessed against arterial sampling (either arterial, or arterialized capillary), especially with regards to the lag time required by the CO2 diffusion from the arterial compartment (PaCO2) to the cutaneous one (PtCO2), in particular when rapid changes of CO2 might be induced by exercise. The evaluation will be done in 2 different settings: * intensive care patients, equipped, for their routine clinical care, with an arterial line; this allows for a precise timed comparison between PaCO2 and PtCO2 readouts; * routine exercise test, where blood gas evaluation is done essentially by means of arterialized earlobe capillary sampling. Following assessment of validity of the measurement (and the lag time PaCO2-PtCO2 which might be necessary to introduce as a correction), evolution of dead space during excise test will be tested in different conditions: Healthy subjects, patients with Chronic Obstructive Pulmonary Disease (COPD), chronic heart failure (CHF), hyperventilation, Pulmonary artery hypertension (PAH), or interstitial lung disease (ILD)

Hyperventilation in Patients With Chronic Low Back Pain

Low back pain (LBP) is the leading cause of disability worldwide. Impaired postural control is a key factor in the development and maintenance of LBP. Moreover, the prevalence of LBP is associated with impairments in diaphragm function, symptoms of dyspnea, and dysfunctional breathing. However, the association between LBP (and more specifically postural control) and hyperventilation remains unknown. The main objective of this project is to investigate whether the presence of recurrent non-specific LBP is related to the presence of hyperventilation, when classified either objectively by decreased carbon dioxide values (demonstrating hypocapnia) or by symptoms while showing normal carbon dioxide values. Moreover, the investigators will explore whether psychosocial factors play a role in this relation. Subsequently, the investigators will examine whether hyperventilation in LBP patients is related to impaired postural control, and more specifically to a decreased postural contribution of the diaphragm.