Objective
To define the incidence, risk factors, and clinical outcome of early pulmonary dysfunction after cardiovascular surgery for adults.
Study
Inception cohort.
Setting
Adult cardiovascular intensive care unit (ICU).
Patients
All adult admissions after cardiovascular surgery without preoperative pulmonary parenchyma or vascular disease over a period of 12 consecutive months.
Intervention
Collection of data on demographics, preoperative organ insufficiency, emergency surgery, type of surgical procedure, cardiopulmonary bypass time, transfusion of blood products, postoperative arterial blood gases, and systemic hemodynamics on admission to the cardiovascular ICU.
Measurements and Main Results
Early postoperative pulmonary dysfunction was defined by mechanical ventilation with a PaO2/FIO2 ratio of <or=to150 torr (<or=to20 kPa) and chest radiography on admission to the cardiovascular ICU. Secondary outcome included postoperative renal and neurologic dysfunction, nosocomial infections, length of mechanical ventilation, hospitalization, and death.
A total of 3,122 patients were evaluated and 1,461 patients satisfied the entry criteria of the study. Early postoperative pulmonary dysfunction was present in 180 (12%) patients on admission to the cardiovascular ICU. Preoperative variables: age of >or=to75 yrs (odds ratio 1.69, 95% confidence interval [CI] 1.06 to 2.65), body mass index of >or=to30 kg/m2 (odds ratio 1.60, 95% CI 1.09 to 2.32), mean pulmonary arterial pressure of >or=to20 mm Hg (odds ratio 1.60, 95% CI 1.13 to 2.28), stroke volume index of <or=to30 mL/m2 (odds ratio 1.57, 95% CI 1.08 to 2.26), serum albumin (odds ratio 0.71, 95% CI 0.49 to 0.97), history of cerebral vascular disease (odds ratio 1.81; 95% CI 1.08 to 2.96); operative variables: emergency surgery (odds ratio 2.12, 95% CI 1.01 to 4.51), total cardiopulmonary bypass time of >or=to140 mins (odds ratio 1.54, 95% CI 1.0 to 2.34); and postoperative variables (on admission to cardiovascular ICU): hematocrit of >or=to30% (odds ratio 2.46, 95% CI 1.71 to 3.56), systemic mean arterial pressure of >or=to90 mm Hg (odds ratio 1.67, 95% CI 1.13 to 2.42), and cardiac index of >or=to3.0 L/min/m2 (odds ratio 2.09, 95% CI 1.44 to 3.01) were predictors of early postoperative pulmonary dysfunction. Pulmonary dysfunction was associated with a postoperative increase of serum creatinine (1.36 +/- 0.4 vs. 1.24 +/- 0.4 mg/dL, p <.02), neurologic complications (3% vs. 1.6%, p <.001), nosocomial infections (3% vs. 1.6%, p <.001), prolonged mechanical ventilation (2.2 +/- 5.9 vs. 1.7 +/- 5.6 days, p <.001), length of stay in the cardiovascular ICU (4.4 +/- 12.2 vs. 2.6 +/- 6.2 days, p <.001) and hospital (14.8 +/- 13.1 vs. 10.5 +/- 8.0 days, p <.001), and death (4.4% vs. 1.6%, p <.001).
Conclusions
The incidence of early postoperative pulmonary dysfunction is uncommon; however, once developed, it is associated with increased morbidity and mortality after cardiovascular surgery. Advanced age, large body mass index, preoperative increased pulmonary arterial pressure, low stroke volume index, hypoalbuminemia, history of cerebral vascular disease, emergency surgery, and prolonged cardiopulmonary bypass time are risk factors for early onset of severe pulmonary dysfunction after surgery. Postoperative hematocrit and systemic hemodynamics suggest that early postoperative pulmonary dysfunction can be a component of a generalized inflammatory reaction to cardiovascular surgery. (Crit Care Med 1997; 25:1831-1839)
