Noninvasive ventilation in acute hypercapnic respiratory failure caused by obesity hypoventilation syndrome and chronic obstructive pulmonary disease.

RATIONALE: Noninvasive ventilation (NIV) is widely used in episodes of acute hypercapnic respiratory failure (AHRF) in patients with chronic obstructive pulmonary disease (COPD). However, there is no evidence on the efficacy of NIV during similar episodes in obesity hypoventilation syndrome (OHS). OBJECTIVES: To compare the efficacy of NIV in episodes of AHRF caused by OHS and COPD. METHODS: We prospectively assessed 716 consecutive patients (173 with OHS and 543 with COPD) with AHRF (arterial pH < 7.35 and Pa(CO(2)) > 45 mm Hg) treated with a similar protocol of NIV. We defined successful NIV as avoidance of intubation and intensive care unit survival at least 24 hours in the ward. Hospital survivors were followed for 1 year to assess hospital readmission and survival. MEASUREMENTS AND MAIN RESULTS: Both groups had similar (mean ± SD) baseline respiratory acidosis (arterial pH, 7.22 ± 0.08; Pa(CO(2)), 86 ± 21 mm Hg). Patients with OHS were older (74 ± 11 vs. 71 ± 10 yr; P < 0.001); were more frequently female (134, 77% vs. 66, 12%; P < 0.001); had less late NIV failure (12, 7% vs. 67, 13%; P = 0.037); had lower hospital mortality (10, 6% vs. 96, 18%; P < 0.001); and had higher 1-year survival (odds ratio, 1.83; 95% confidence interval, 1.24-2.69; P = 0.002). However, survival adjusted for confounders (adjusted odds ratio, 1.41; 95% confidence interval, 0.70-2.83; P = 0.34), NIV failure (11, 6% vs. 59, 11%; P = 0.11), length of stay, and hospital readmission were similar in both groups. Among patients with COPD, obesity was associated with less late NIV failure and hospital readmission. CONCLUSIONS: Patients with OHS can be treated with NIV during an episode of AHRF with similar efficacy and better outcomes than patients with COPD.

Non-invasive ventilation in community-acquired pneumonia and severe acute respiratory failure.

PURPOSE: The use of non-invasive ventilation (NIV) in severe acute respiratory failure (ARF) due to community-acquired pneumonia (CAP) is controversial, and the risk factors for NIV failure in these patients are not well known. We assessed the characteristics and predictors of outcome of patients with CAP and severe ARF treated with NIV. METHODS: We prospectively assessed 184 consecutive patients; 102 had "de novo" ARF, and 82 previous cardiac or respiratory disease. We defined successful NIV as avoidance of intubation and intensive care unit (ICU) survival at least 24 h in the ward. We assessed predictors of NIV failure and hospital mortality in multivariate analyses. RESULTS: Patients with "de novo" ARF failed NIV more frequently than patients with previous cardiac or respiratory disease (47, 46% versus 21, 26%, p = 0.007). Worsening radiologic infiltrate 24 h after admission, maximum Sepsis-Related Organ Failure Assessment (SOFA) score and, after 1 h of NIV, higher heart rate and lower PaO(2)/FiO(2) and bicarbonate independently predicted NIV failure. Likewise, maximum SOFA, NIV failure and older age independently predicted hospital mortality. Among intubated patients with "de novo" ARF, NIV duration was shorter in hospital survivors than non-survivors (32 ± 24 versus 78 ± 65 h, p = 0.014). In this group, longer duration of NIV before intubation was associated with decreased hospital survival (adjusted odds ratio 0.978, 95% confidence interval 0.962-0.995, p = 0.012). This association was not observed in patients with previous cardiac or respiratory disease. CONCLUSIONS: Successful NIV was strongly associated with better survival. If predictors for NIV failure are present, avoiding delayed intubation of patients with "de novo" ARF would potentially minimise mortality.