Acute exacerbations of chronic obstructive pulmonary disease and mechanical ventilation: a reevaluation

Abstract

Objective: To review the intensive care unit (ICU) experience of patients admitted with acute exacerbations of chronic obstructive pulmonary disease.

Design: Retrospective case series.

Setting: University teaching hospital.

Patients: We reviewed the records of 100 consecutive ICU admissions of patients with acute exacerbations of chronic obstructive pulmonary disease over a period of 4.25 yrs.

Interventions: None.

Measurements and main results: Patients were characterized using a computerized prospective database and case note review. Multivariate analysis identified variables predicting ICU and hospital length of stay. The Cox proportional hazards model was used to analyze survival after hospital discharge. Seventy-five patients (24 female and 51 male, mean age 68.5 +/- 7 [SD] yrs) with 100 ICU admissions were identified. Premorbid airway obstruction was severe, with forced expiratory volume in 1 sec (FEV1)/forced vital capacity (FVC) of 0.7 +/- 0.34 L and FEV1/FVC of 39 +/- 16%. Thirty-two percent received home-administered oxygen and 42% were housebound. The pre-ICU admission PaCO2 was 86 +/- 28 torr (11.5 +/- 3.7 kPa), with a pH of 7.24 +/- 0.11 and a PaO2/FIO2 of 190 +/- 66. ICU admission Acute Physiology and Chronic Health Evaluation II score was 18 +/- 5. Forty-three patients were mechanically ventilated for a median of 4 days (range 0.08 to 30). Tracheostomy, in seven patients, was maintained for 21 +/- 7 days. Ventilation time and tracheostomy frequency predicted length of ICU stay (median 3 days; range 1 to 40) and hospital stay (17 days; 4 to 97), respectively. ICU and hospital case-fatality rates were 1% and 11%. Out-of-hospital (24-month) probability of survival was predicted by plasma albumin concentration at the time of ICU admission; this probability of survival was .64 at an albumin concentration of 38 g/L.

Conclusions: ICU admission of severely ill chronic obstructive pulmonary disease patients results in acceptable outcomes. Survival of < or =2 yrs is not affected by mechanical ventilation or tracheostomy requirement.