Noninvasive Ventilation in Hypercapnic Patients

A prospective randomized controlled trial was conducted in 162 mechanically ventilated patients who tolerated a spontaneous breathing trial after recovery from an acute hypercapnic respiratory failure episode, but had increased risk for respiratory failure after extubation. Patients were randomly allocated after extubation to receive noninvasive positive pressure ventilation (NPPV) for 24 hours or conventional management with oxygen therapy.

The study was conducted by Dr. Miquel Ferrer and colleagues at the Pneumology Service of the Hospital Clinic of the Universitat de Barcelona (Barcelona, Spain). The results were published in the January 15, 2006 issue of the American Journal of Respiratory and Critical Care Medicine (AJRCCM).

In the noninvasive ventilation group, respiratory failure after extubation was less frequent and the intensive care unit mortality was lower. However, 90 day survival rate did not change significantly between the different groups. Separate analyses of patients with and without hypercapnia (defined as arterial CO2 tension greater than 45 mm Hg) during the spontaneous breathing trial showed that noninvasive ventilation improved intensive care unit mortality and 90-day survival rate in hypercapnic patients only; of these, 98% had chronic respiratory disorders.

Respiratory failure after extubation and reintubation is associated with increased morbidity and mortality. In noninvasive positive pressure ventilation, a mask or mouthpiece is used. NPPV avoids some of the complications of intubation, such as pneumonia, sinusitis, and trauma to the airway.

The researchers concluded that the beneficial effect of noninvasive ventilation in improving survival of hypercapnic patients with chronic respiratory disorders warrants a new prospective clinical trial.




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