Auto-adjusted versus fixed positive airway pressure in patients with severe OSA: A large randomized controlled trial.

BACKGROUND AND OBJECTIVE: Continuous positive airway pressure (CPAP) in the treatment of severe obstructive sleep apnoea (OSA) can be used in fixed CPAP or auto-adjusted (APAP) mode. The aim of this prospective randomized controlled clinical study was to evaluate the 3 month-efficacy of CPAP used either in fixed CPAP or APAP mode. METHODS: Eight hundred one patients with severe OSA were included in twenty-two French centres. After 7 days during which all patients were treated with APAP to determine the effective pressure level and its variability, 353 and 351 patients were respectively randomized in the fixed CPAP group and APAP group. After 3 months of treatment, 308 patients in each group were analysed. RESULTS: There was no difference between the two groups in terms of efficacy whatever the level of efficient pressure and pressure variability (p = 0.41). Exactly, 219 of 308 patients (71.1%) in the fixed CPAP group and 212 of 308 (68.8%) in the APAP group (p = 0.49) demonstrated residual apnoea hypopnoea index (AHI) <10/h and Epworth Score <11. Tolerance and adherence were also identical with a similar effect on quality of life and blood pressure evaluation. CONCLUSION: The two CPAP modes, fixed CPAP and APAP, were equally effective and tolerated in severe OSA patients.

Prognostic value of exercise pulmonary haemodynamics in pulmonary arterial hypertension.

The aim of the study was to investigate the prognostic value of right heart catheterisation variables measured during exercise. 55 incident patients with idiopathic, familial or anorexigen-associated pulmonary arterial hypertension (PAH) underwent right heart catheterisation at rest and during exercise and 6-min walk testing before PAH treatment initiation. Patients were treated according to recommendations within the next 2 weeks. Right heart catheterisation was repeated 3-5 months into the PAH treatment in 20 patients. Exercise cardiac index decreased gradually as New York Heart Association (NYHA) functional class increased whereas cardiac index at rest was not significantly different across NYHA groups. Baseline 6-min walk distance correlated significantly with exercise and change in cardiac index from rest to exercise (r=0.414 and r=0.481, respectively; p<0.01). Change in 6-min walk distance from baseline to 3-5 months under PAH treatment was highly correlated with change in exercise cardiac index (r=0.746, p<0.001). The most significant baseline covariates associated with survival were change in systolic pulmonary artery pressure from rest to exercise and exercise cardiac index (hazard ratio 0.56 (95% CI 0.37-0.86) and 0.14 (95% CI 0.05-0.43), respectively). Change in pulmonary haemodynamics during exercise is an important tool for assessing disease severity and may help devise optimal treat-to-target strategies.

Lack of correlation between the ventilatory response to CO2 and lung function impairment in myotonic dystrophy patients: evidence for a dysregulation at central level.

Myotonic dystrophy Type 1 (DM1) is the most common muscular dystrophy in adults. Respiratory failure is common but clinical findings support a dysregulation of the control of breathing at central level, furthermore contributing to alveolar hypoventilation independently of the severity of respiratory weakness. We therefore intended to study the relationship between the ventilatory response to CO2 and the impairment of lung function in DM1 patients. Sixty-nine DM1 patients were prospectively investigated (43.5 ± 12.7 years). Systematic pulmonary lung function evaluation including spirometry, plethysmography, measurements of respiratory muscle strength, arterial blood gas analysis and ventilatory response to CO2 were performed. Thirty-one DM1 patients (45%) presented a ventilatory restriction, 38 (55%) were hypoxaemic and 15 (22%) were hypercapnic. Total lung capacity decline was correlated to hypoxaemia (p = 0.0008) and hypercapnia (p = 0.0013), but not to a decrease in ventilatory response to CO2 (p = 0.194). Ventilatory response to CO2 was reduced to 0.85 ± 0.67 L/min/mmHg and not correlated to respiratory muscle weakness. Ventilatory response to CO2 was neither different among restricted/non-restricted patients (p = 0.2395) nor among normoxaemic/hypoxaemic subjects (p = 0.6380). The reduced ventilatory response to CO2 in DM1 patients appeared independent of lung function impairment and respiratory muscle weakness, suggesting a central cause of CO2 insensitivity.

[Impact of COPD: from disability to exacerbations]. / Impact de la BPCO: du handicap aux exacerbations.

COPD is a common disease characterized by health status impairment and disability that is usually progressive. Exacerbations of COPD, an acute event in the course of the disease, have effects on symptoms and patient's quality of life. Assessment of symptoms and risk of exacerbations is useful to guide strategy management of the disease. COPD disability includes different aspects. Its assessment needs to consider the classification of severity of airflow limitation, symptoms, comorbidities and impairment of patient's health-related quality of life. The rate at which exacerbations occur varies between patients. History of previous exacerbations and severity of airflow limitation are the best predictors of the frequency and severity of exacerbations. Severity of the symptoms is associated with an increased risk of exacerbations. Exacerbations increase deterioration in health status and leads to severe disability, inducing a vicious circle from disability to exacerbations. At an individual patient level, an understanding of the impact of COPD requires to assess the patient's disability, the risk of future exacerbations, and the identification of comorbidities.