Non-invasive positive pressure ventilation in acute hypercapnic respiratory failure: clinical experience of a respiratory ward

Background: Although a controlled trial demonstrated that non-invasive positive pressure ventilation (NIV) can be successfully applied to a respiratory ward (RW) for selected cases of acute hypercapnic respiratory failure (AHRF), clinical practice data about NIV use in this setting are limited. The aim of this observational study is to assess the feasibility and efficacy of NIV applied to AHRF in a RW in everyday practice. Methods: Twenty-two percent (216/984) of patients consecutively admitted for AHRF to our RW in Arezzo (years: 1996-2003) received NIV in addition to standard therapy, according to pre-defined routinely used criteria. Tolerance, effects upon arterial blood gases (ABG), success rate (avoidance a priori criteria for intubation) and predictors of failure of NIV were analysed. Results: Nine patients (4.2%) were found to be intolerant to NIV, while the remaining 207 (M: 157, F: 50; mean (SD) age: 73.2 (8.9) yrs; COPD: 71.5%) were ventilated for >1 hour. ABG significantly improved after two hours of NIV (pH: 7.32 (0.06) versus median (Interquartiles) 7.28 (7.24-7.31), p<0.0001; PaCO2: 71.9 (13.5) mmHg versus 80.0 (15.2) mmHg, p<0.0001; PaO2/FiO2: 212 (66) versus 184 (150-221), p<0.0001). NIV succeeded in avoiding intubation in 169/207 patients (81.6%) with hospital mortality of 15.5%. NIV failure was independently predicted by Activity of Daily Living score, pneumonia as cause of AHRF and Acute Physiology and Chronic Health Evaluation III score. Conclusions: In clinical practice NIV is feasible, effective in improving ABG and useful in avoiding intubation in most AHRF episodes that do not respond to the standard therapy managed in an RW adequately trained in NIV.