Risk of respiratory failure after repair of thoracoabdominal aortic aneurysms

Multiple complications occur after repair of a thoracoabdominal aortic aneurysm, the most common of which is respiratory failure.

One hundred consecutive thoracoabdominal aneurysm repairs were studied retrospectively using univariate, bivariate, and multiple logarithmic regression analyses to identify factors associated with respiratory failure.

The mean of days of intubation was 5.8 +/- 0.8 (mean +/- SEM), with a median of 2 days. Patients who developed respiratory failure (21%) had a 42% mortality compared with a 6% mortality in patients who did not develop respiratory failure (P < 0.001). Statistical analysis demonstrated a significant (P < 0.01) age difference between those with respiratory failure (71.9 +/- 1.6 years) and those without (65.5 +/- 1.3 years). Type II aneurysms occurred in 32% of patients, a 3.2-fold increase in relative risk compared with all other types of aneurysm. Seventy-nine percent of patients had a significant smoking history. Low forced vital capacity and forced expiratory volume were both significant variables in predicting respiratory failure, but neither chronic obstructive pulmonary disease nor emphysema was a predictive variable. Intraoperative blood transfusion (mean 10.5 +/- 0.8 units) was associated with respiratory failure (P = 0.05). Postoperative complications associated with respiratory failure were creatinine elevation and pneumonia.

We conclude that the independent variables affecting respiratory failure after thoracoabdominal aneurysm repair are age, type of aneurysm, excessive intraoperative blood transfusions, creatinine elevation, and postoperative pneumonia.