Interface strategy during noninvasive positive pressure ventilation for hypercapnic acute respiratory failure.

OBJECTIVE: To assess the influence of initial mask choice on the clinical effectiveness and tolerance of noninvasive positive pressure ventilation (NIPPV) in the management of hypercapnic acute respiratory failure. DESIGN: A prospective randomized controlled clinical study. SETTING: A medical intensive care unit at a university hospital. INTERVENTION: Randomization between two NIPPV interfaces. PATIENTS: Initial mask choice was randomized between two standard masks: face (NIPPVf group) and nasal (NIPPVn group). The main end point was mask failure (i.e., mask change and/or intubation). Secondary end points were tolerance of NIPPV, change in respiratory parameters during the first 3 days, and patient outcome. Results were analyzed on an intent to treat basis. A per protocol analysis was also conducted. MAIN RESULTS: Ninety patients with underlying chronic lung disease were included, 46 in the NIPPVf group and 44 in the NIPPVn group. The overall success rate of NIPPV was 83%. Mask failure occurred significantly more often in the NIPPVn group (32/44 vs. 9/46; p < 0.0001), mainly because of the need for mask change (32/44 vs. 0/46; p < 0.0001) because of the occurrence of major buccal air-leaks in 94% of cases. Improvement in respiratory parameters was similar in the two groups. Whereas air-leaks were more frequent in the NIPPVn group (p < 0.05), respiratory comfort was assessed as lower and complications more frequent by the staff in the NIPPVf group from day 2 (p < 0.05). CONCLUSIONS: A face mask should be the first-line strategy in the initial management of hypercapnic acute respiratory failure with NIPPV. However, if NIPPV has to be prolonged, switching to a nasal mask may improve comfort by reducing face mask complications.

Noninvasive mechanical ventilation in clinical practice: a 2-year experience in a medical intensive care unit.

OBJECTIVE: To evaluate the feasibility and outcome results of noninvasive mechanical ventilation (NIV) in daily clinical practice outside any prospective protocol-driven trial. DESIGN: An observational retrospective cohort study. SETTING: A 22-bed medical intensive care unit in a university hospital. PATIENTS: A consecutive cohort of 124 patients who underwent 143 NIV trials, regardless of the indication, over two consecutive years (1997-1998). INTERVENTIONS: None. RESULTS: A total of 604 acute respiratory failure patients underwent mechanical ventilation, and 143 NIVs were performed in 124 patients. The overall prevalence of NIV use was 143 of 604 patients (24%) in three groups: hypoxemic acute respiratory failure (29.5%), hypercapnic acute respiratory failure (41%), and weaning/postextubation (29.5%). Intubation was avoided in 92 of 143 of the NIVs performed (64%), 19 (13%) after changing the initial NIV mode (i.e., a success rate of 62%, 51%, and 86% in the three groups, respectively). A total of 35 of 51 intubated patients (69%) required intubation during the first 24 hrs of NIV. Intensive care unit stay was 12 +/- 10 days for the overall population, and mortality, when NIV failed, was 13 of 124 patients (10.5%). Arterial pH (p =.0527) and the Pao2/Fio2 ratio (p =.0482) after 1 hr were the only independent predictive factors for NIV failure by multivariate analysis. CONCLUSIONS: This study confirms the results of controlled trials and demonstrates the feasibility and efficacy of NIV applied in daily clinical practice. These results suggest that NIV should be considered as a first-line ventilatory treatment in various etiologies of acute respiratory failure and as a promising weaning technique and postextubation ventilatory support. However, NIV should certainly be performed by a motivated and sufficiently trained care team.