[Prognostic factors for COPD patients with chronic hypercapnic respiratory failure and home ventilation]

The prevalence of patients with severe COPD and chronic hypercapnic respiratory failure (CHRF) receiving non-invasive home ventilation has greatly increased. With regard to disease severity, a multidimensional assessment seems indicated. Base excess (BE), in particular, reflects the long-term metabolic response to chronic hypercapnia and thus constitutes a promising, easily accessible, integrative marker of CHRF. Infact, BE as well as nutritional status and lung hyperinflation have been identified as independent predictors of long-term survival. In addition and in a review with the literature, a broad panel of indices including frequent comorbidities are helpful for assessment and monitoring purposes of patients with CHRF. Accordingly, in view of the patients' individual risk profile, the decision about the initiation of NIV should probably not rely solely on symptoms and chronic persistent hypercapnia but include a spectrum of factors that specifically reflect disease severity. Owing to the physiologically positive effects of NIV and according to retrospective data, patients with COPD and recurrent hypercapnic respiratory decompensation and patients with prolonged mechanical ventilation and/or difficult weaning could also be considered for long-term non-invasive ventilation. This, however, has to be corroborated in future prospective trials.