Acute respiratory dysfunction after surgery for acute type A aortic dissection

Abstract

Objective: Acute respiratory dysfunction (ARD) can occur after acute type A aortic dissection, but relatively little is known about ARD in such patients. This study aims to analyse the clinical impact of ARD after surgery for acute type A aortic dissection and to assess possible treatment options.

Methods: We reviewed our institutional database to identify patients who underwent surgery for acute type A dissection between October 1994 and January 2008 (n=276). Postoperative ARD was defined as oxygenation impairment (PaO(2)/FiO(2) <150) that occurred within 72 h of surgery and was not related to other documented causes of acute respiratory failure.

Results: A total of 37 patients (13%) (27 male, mean age 60.7+/-11 years) experienced ARD after surgery for acute type A dissection. Intensive care unit stay was significantly longer for patients with ARD than those without (18+/-11 days vs 7.5+/-6 days, respectively, p<0.0001). However, hospital mortality was not significantly different between groups (16% for ARD patients vs 19% for patients without ARD, p=0.6). Logistic regression analysis identified preoperative multiple malperfusion as the only risk factor for ARD (OR 3.2, 95% confidence interval (C.I.): 2.2-4.9). Peak C-reactive protein levels were significantly higher in ARD patients (17.7+/-6.7 vs 9.6+/-5.4 mg dl(-1), p=0.04). Prone positioning ventilation was performed in 15 patients (40%) with severely impaired oxygenation and resulted in an immediate increase in mean oxygenation index from 71.6+/-8.8 to 138+/-92.6 (p<0.001). There was a tendency towards a shorter total time of mechanical ventilation (355+/-188 h vs 433+/-318 h, p=0.2) and shorter ICU stay (405+/-198 h vs 505+/-265 h, p=0.2) in the prone positioning subgroup.

Conclusions: ARD is a relatively common complication of surgery for acute type A dissection and is associated with increased morbidity and resource utilisation. Patients with preoperative malperfusion are at increased risk for development of ARD. Prone positioning is a viable treatment option that significantly improves pulmonary oxygenation.