Assessment of prognosis in patients with community-acquired pneumonia who require mechanical ventilation.
OBJECTIVE
Knowing that mortality is high in patients who require mechanical ventilation patients with community-acquired pneumonia (CAP), we hypothesized that the severity of acute lung injury could be used along with nonpulmonary factors to identify patients with the highest risk of death. We formulated a prediction model to quantitate the risk of hospital mortality in this population of patients.


METHODS
Historical prospective study using data collected over the first 24 h of mechanical ventilation. We utilized a hypoxemia index-(1 - lowest [PaO(2)/PAO(2)]) x (minimum fraction of inspired oxygen to maintain PaO(2) at > 60 mm Hg) x 100], where PAO(2) is the alveolar partial pressure of oxygen-to grade the severity of acute lung injury on a scale from 0 to 100.


METHODS
Tertiary care university hospital ICU.


METHODS
One hundred forty-four adult patients mechanically ventilated for respiratory failure caused by CAP.


RESULTS
Hospital mortality was 46% (n = 66). Multivariate logistic regression analysis revealed five independent predictors of hospital mortality: (1) the extent of lung injury assessed by the hypoxemia index; (2) the number of nonpulmonary organs that failed; (3) immunosuppression; (4) age > 80 years; and (5) medical comorbidity with a prognosis for survival < 5 years. At a 50% mortality threshold, the prediction model correctly classified outcome in 88% of cases. All patients with > 95% predicted probability of death died in hospital.


CONCLUSIONS
Based on clinical parameters measured over the first 24 h of mechanical ventilation, this model accurately identified critically ill, mechanically ventilated patients with CAP for whom prolonged intensive care may not be of benefit.
Pascual
F E
FE
Cardiovascular Research Institute, Department of Medicine, University of California, San Francisco, USA. feppccm@usa.net
Matthay
M A
MA
Bacchetti
P
P
Wachter
R M
RM
D018806:APACHE; D000328:Adult; D000368:Aged; D002423:Cause of Death; D017714:Community-Acquired Infections / Q000401:mortality* / Q000628:therapy; D003422:Critical Care; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000209:etiology / Q000401:mortality* / Q000628:therapy; D018410:Pneumonia, Bacterial / Q000209:etiology / Q000401:mortality* / Q000628:therapy; D011175:Positive-Pressure Respiration; D011379:Prognosis; D011446:Prospective Studies; D012131:Respiratory Insufficiency / Q000401:mortality* / Q000628:therapy; D012306:Risk; D016019:Survival Analysis