Chronic Lung Disease and Mortality after Cardiac Surgery: A Prospective Cohort Study.

OBJECTIVE: To investigate the 1-year survival in cardiac surgical patients with lung disease, including previously undiagnosed cases. DESIGN: Prospective cohort study. SETTING: Tertiary hospital. PARTICIPANTS: Patients scheduled for elective coronary artery bypass graft (CABG) surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Pulmonary function tests (PFTs) were performed in 454 patients before surgery. Abnormal respiratory patterns were defined as follows: obstructive (forced expiratory volume in 1 second/forced vital capacity <0.70), restrictive (forced expiratory volume in 1 second/forced vital capacity ≥0.70 and forced vital capacity <80% of predicted), and mixed. Overall 1-year mortality was 3.3%. Among 31 patients with documented chronic obstructive pulmonary disease (COPD), mortality was 9.6%, hazard ratio (HR) 1.28, 95% confidence interval (CI) 1.02-12.80, p = 0.04. Of 423 patients without history of COPD, 57 obstructive, 46 restrictive, and 4 mixed abnormal patterns were identified. Of a total of 72 with obstructive lung disease confirmed by PFT (ie, 15 of COPD patients and 57 newly identified cases), 6.9% died, HR 2.75, 95% CI 0.98-8.07, p = 0.06. When combined with cases of COPD where a respiratory abnormality was confirmed (26 patients), newly diagnosed obstructive lung disease (57 patients) was significantly associated with 1-year mortality, HR 4.13, 95% CI 1.50-11.42, p = 0.006. The adjustment for EuroSCORE II did not change the results. CONCLUSIONS: Combination of confirmed preexisting lung disease and newly diagnosed cases provides a clear link to mid-term mortality.

Prevalence and Implications of Abnormal Respiratory Patterns in Cardiac Surgery: A Prospective Cohort Study.

OBJECTIVE: To investigate the prevalence and impact of abnormal respiratory patterns in cardiac surgery patients. DESIGN: Prospective cohort study. SETTING: Tertiary hospital. PARTICIPANTS: Patients scheduled for elective coronary artery bypass graft surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Pulmonary function tests were performed in 454 patients before surgery. Abnormal respiratory patterns were defined as follows: obstructive (forced expiratory volume in 1 s [FEV1]/forced vital capacity [FVC]<0.70), restrictive (FEV1/FVC≥0.70 and FVC<80% of predicted), and mixed (FEV1/FVC<0.70 and both FEV1 and FVC<80% of predicted). Of the 31 patients with a history of chronic obstructive pulmonary disease, no abnormal respiratory pattern was confirmed in 5. Of the 423 patients without a history of lung disease, the authors newly identified 57 obstructive, 46 restrictive, and 4 mixed patterns. Therefore, lung disease was reclassified in 24.7% of cases. Independent predictors of obstructive pattern were age, male sex, history of smoking, and chronic obstructive pulmonary disease. Obstructive lung disease was associated with 16 hours or longer ventilation. A reduced FEV1 was associated with a likelihood of atrial fibrillation (1-L decrement, odds ratio: 1.38, 95% confidence interval: 1.01-to-1.90, p = 0.04) and hospitalization time (regression coefficient: 1.23, 95% confidence interval: 0.54-to-1.91, p<0.001). CONCLUSIONS: Abnormal respiratory patterns are common and often underdiagnosed in the cardiac surgery setting. Pulmonary function tests help reveal patients at risk of complications and may provide an opportunity for intervention.