The risk factors for late failure of non-invasive mechanical ventilation in acute hypercapnic respiratory failure

Non-invasive mechanical ventilation provides early improvement in most of the patients with acute hypercapnic respiratory failure. The aim of our study was to determine the risk factors for late failure of non-invasive mechanical ventilation in patients with acute hypercapnic respiratory failure.

Ninety three patients were prospectively evaluated. Non-invasive mechanical ventilation was accepted to be successful if the patient was discharged from the hospital without the need for intubation (group 1) and to be late failure if a deterioration occurred after an initial improvement of blood gases tension and general conditions (group 2).

Non-invasive mechanical ventilation was successful in 62 (66.7%) patients. In 25 (26.9%) patients a late failure was observed. There was no difference between groups 1 and 2 in terms of pretreatment pH, PaCO2 and PaO2/FiO2. However, serum C-reactive protein level, Acute Physiology and Chronic Health Evaluation II (APACHE II) score and frequency of bronchiectasis and pneumonia were significantly higher and serum albumin level, Glasgow Coma Score, cough strength and compliance to non-invasive mechanical ventilation were significantly lower in group 2.

The pretreatment high APACHE II Score and C-reactive protein level, low Glasgow Coma Score, albumin level, cough strength, bad compliance to non-invasive mechanical ventilation, the presence of bronchiectasis and pneumonia and absence of significance improvement in PaO2/FiO2 after treatment were determined as risk factors for non-invasive mechanical ventilation late failure.