Pressure support ventilation via face mask in acute respiratory failure in hypercapnic COPD patients

Objective To test whether non-invasive ventilation via facial mask could reduce the need for tracheal intubation via when mechanical ventilation must be initiated in COPD patients.Design Open prospective interventional study.Setting General Intensive Care Service of a County Hospital.Patients We have studied 12 COPD patients during 14 episodes of acute exacerbation of chronic respiratory failure who failed to improve with intensive medical therapy and showed impairements in severe respiratory acidosis and/or hypercapnic encephalopathy leading their attending physicians to order mechanical ventilationInterventions In these circumstances, a trial of pressuresupport (PS) ventilation (Servo Ventilator 900C) via facial mask Vital Signs Inc.) was performed. The level of pressure support was adjusted to obtain a tidal volume>400 ml. If the patient deteriorated, tracheal intubation and standard mechanical ventilation were performed.Measurements and results Measurements are presented as means±SEM. A pressure-support level of 14±3 cmH₂O was used during a period of 8±4 h. Low levels of external PEEP were used in 4 patients, while it generated excessive leaks in the others. Significant differences (p<0.05 ANOVA for repeated measures) in data obtained on admission, when patients deteriorated and after pressure support was administered were only observed in PaCO₂ (68±3 versus 92±3 versus 67±3 mmHg), arterial pH (7.27±0.03 versus 7.19±0.02 versus 7.31±0.01). SaO₂ (60±4 versus 86±3 versus 92±1%) and respiratory rate (35±2 versus 32±2 versus 23±1 breaths·min^–1). Three patients needed intubation and one of them died in the ICU.Conclusion Non-invasive ventilation (pressure-support) via face mask may reduce the need for tracheal intubation in the severe hypercapnic failure of COPD patients.Presented in part at the 6th European Congress on Intensive Care Medicine. Barcelona October 1992. Supported by grant 93/0623 from Fondo de Investigationes Sanitarias