Mechanical ventilation of patients on long-term oxygen therapy with acute exacerbations of chronic obstructive pulmonary disease: prognosis and cost-utility analysis.

OBJECTIVE

To analyze the prognosis and costs of mechanical ventilation in patients with exacerbations of chronic obstructive pulmonary disease (COPD) treated with long-term oxygen therapy.

DESIGN

A prospective cohort study. Follow-up at 1 and 5 years. Cost utility analysis.

SETTING

A medical-surgical intensive care unit (ICU) in a university hospital.

PATIENTS: 20 patients with previous COPD treated with long-term oxygen therapy and needing mechanical ventilation due to acute respiratory failure.

MEASUREMENTS AND MAIN

RESULTS

Mortality in the ICU, in-hospital mortality (ICU plus ward), and mortality at 1 and 5 years, and factors associated with prognosis and cost-utility were assessed. The mean Acute Physiology and Chronic Health Evaluation II score was 20 (median 20 range 12-36). Cumulative mortality was 35% in the ICU, 50% in hospital, 75% at 1 year, and 85% at 5 years. Factors significantly associated with mortality in the ICU were low levels of albumin (p = 0.05) and sodium (p = 0.01) at admission. Patients who died in hospital and in the first year after discharge had a lower forced expiratory volume in 1 s (FEV1) than survivors (p = 0.03 and p = 0.05, respectively). The cost per Quality Adjusted Life Year (QALY) was U.S. $26283 and U.S. $44602 in a "best" (cost/QALY calculated for the life expectancy in Spain) and a "worst case scenario" (cost/QALY calculated for a 68-year life expectancy), respectively.

CONCLUSIONS

Applying mechanical ventilation to COPD patients treated with long-term oxygen therapy carries a high mortality and cost. Factors significantly associated with mortality in the ICU were albumin and sodium concentrations and FEV1 in hospital and in the first year after discharge.