The impact of reduced duffusing capacity of the lung for carbon monoxide and fev1 on outcome after cardiac surgery

Introduction Impaired lung function is a well-known risk factor in cardiac surgery patients and reduced forced expiratory volume in one second (FEV1) is associated with increased mortality. However, there is limited knowledge regarding the influence of impaired diffusing capacity of the lungs for carbon monoxide (DLCO) in cardiac surgery patients. The aim of the study was to evaluate the impact of impaired DLCO and/or reduced FEV1 on postoperative mortality and morbidity in cardiac surgery patients. Methods In a prospective cohort study, 390 patients scheduled for elective cardiac surgery underwent a preoperative extended lung function test, including spirometry and DLCO measurements. We defined reduced FEV1 as FEV1 below lower limit of normal (LLN) and impaired DLCO as haemoglobin adjusted DLCO 72 hours) in intensive care unit (ICU) was used to evaluate impact also on morbidity. Results Mortality within one year (90-570 days) was significantly higher in patients with impaired DLCO (12% vs 3%, P=0.010) and with reduced FEV1 (9% vs 3%, P=0.028). Mortality was higher in patients with impaired DLCO, both in the presence and absence of FEV1 48 hours), postoperative tracheotomy, and postoperative pneumonia (Figure 1). Discussion In patients undergoing elective cardiac surgery, preoperative impaired FEV1 and DLCO were associated with increased mortality and morbidity. In multivariate analysis, only DLCO and age were independent predictors of a combined outcome with mortality and prolonged ICU stay.