Ventilation techniques: invasive versus noninvasive.

Conventional medical treatment of COPD patients with acute respiratory failure (ARF) was associated with an overall mortality ranging 12-29%. When conservative treatment fails, ARF is usually managed by means of mechanical ventilation (MV) via an endotracheal tube (ET) or tracheostomy. Mortality of COPD patients with ARF treated with invasive MV ranged 21-54%. Invasive MV is associated with several complications. Positive pressure ventilation (PPV) by means of facial or nasal masks have been used in place of endotracheal intubation in ARF: the results are promising. Advantages of mask ventilation include the possibility of intermittent delivery of ventilation, use of different modalities of ventilation, the ability to undertake normal swallowing, feeding and speech, the possibility of physiological air warming and humidification, the possibility of coughing, and an easier weaning whilst still maintaining possibilities of ET intubation. Reported side-effects during mask PPV include mask discomfort, skin reddening, dry nose, air leaks, eye irritation and gastric distension. Mortality of COPD patients treated with noninvasive PPV ranged 6-25%. The level of severity of basal acidosis and blood gas response to a short trial of noninvasive PPV were predictive of success of this modality of MV. Preliminary results suggest that one year mortality after MV is reduced with noninvasive PPV in comparison to ET ventilation.