The Effect of Intermittent. Negative Pressure Ventilation and Long-term Oxygen Therapy for Patients With COPD
The mortality rate of patients with chronic obstructive pulmonary disease (COPD) who are hospitalized for acute respiratory failure (ARF) averages 26 percent at 1 year when mechanical ventilation is not required, but increases up to 51 percent to 64 percent when a supportive ventilatory treatment by means of intubation is needed.
Long-term oxygen therapy (LTOT) is widely used in patients with COPD, and several studies” indicate that this form of treatment can improve patient survival. However, as yet no data have been reported on the effect of LTOT in a subgroup of patients with COPD whose acute exacerbations of ARF are treated with mechanical ventilation in addition to continuous 02 maintenance.
Intubation with positive pressure ventilation is the most widely used method for providing mechanical ventilation in patients with COPD. However, a recent report showed that a conservative ventilatory method, based on the use of an iron lung, can successfully be employed to overcome both the acute episode and the subsequent relapses of ARF; this therapeutic approach was found to improve the longterm prognosis of these patients. proventil inhaler
In the present study, we report the results obtained in patients with COPD using the combination of home LTOT with a noninvasive ventilatory system for treating the acute episode and the subsequent relapses of ARF. The study was aimed at assessing the long-term prognosis of patients with COPD who presented with a bout of ARF and who were given the combination of these two treatments.
We studied 79 patients with COPD with chronic respiratory insufficiency admitted to our respiratory intensive care unit for ARF from 1976 to 1986 who required, for the first time, ventilatory treatment and in whom ARF was not caused by the administration of central sedative agents. The ARF was defined as a condition of acute exacerbation of the chronic disease characterized by increase of dyspnea at rest, signs of right-sided heart failure (ankle edema), severe hypoxemia (Pa02 < 50 mm Hg), hypercapnia (PaC02 > 50 mm Hg), and pH < 7.30. This condition could be associated with consciousness loss or deteriorated sensorium. The diagnosis of COPD was established on the basis of the following: (1) spirometric measurements (FEV, < 70 percent predicted and FEVj/VC lower than 70 percent after bronchodilator therapy); (2) clinical history of productive chronic cough and dyspnea dating over 10 years in smokers or ex-smokers; and (3) radiographic evidence of hyperinflation.