Abstract
The objective of this study was to evaluate the risk factors associated with mortality in interstitial lung disease patients. We performed a retrospective study of 722 consecutive patients submitted for lung biopsy during the 1986–1990 period. Twenty-two (3%) died within the 30 days following surgery. Forty-four patients who survived after the surgery for the same time span were randomly chosen as control group. Dyspnea at rest was present in 18/44 of surviving group (SG) and in 18/22 of the nonsurviving group (NSG) (OR 6.5, 95% CI 1.8–22.4,p=. 001). Systemic diseases (i.e., diabetes, systemic arterial hypertension) were mainly present in the NSG (OR 7.2, 95% CI 2.3–22.8,p<. 001). The SG displayed significantly less respiratory insufficiency with a PaO2of 52.2 ± 8.4 versus 38.5 ± 9.4 mm Hg, and PaCO2of 28.8 ± 4.5 versus 38.5 ± 9.2 mm Hg, respectively (p<. 001). Likewise, the SG exhibited a PaCO2/PaO2ratio of 0.5 ± 0.1, while in the NSG it was of 1 ± 0.4 (p<. 001), showing a sensitivity of 84% and specificity of 93% for mortality. Multiple logistic regression analysis for these variables showed that log likelihood was still significant for PaCO2> 34 mm Hg, PaO2< 48 mm Hg, and comorbid diseases. Logistic regression analysis of these three variables showed the greatest sensitivity and specificity (84 and 75%, respectively) for prediction of mortality. However, the strongest association was found when PaCO2/PaO2ratio was analyzed alone (OR 21,073, CI 95% 28–15,946,357,p<. 005). These data suggest that PaCO2/PaO2ratio appears to be a predictor of mortality in this subset of patients. Its prospective use has reduced early mortality after surgery less than 1%in the last decade.