Objective: Postoperative respiratory failure is a frequent and serious complication in patients with type A acute aortic dissection operated on with deep systemic hypothermia. Interaction between neutrophils and pulmonary endothelium along with ischemic insult and reperfusion are the major determinants of lung injury. The aim of this prospective study was to evaluate the effect of continuous pulmonary perfusion during retrograde cerebral perfusion on lung function.
Methods: Twenty-two patients referred for acute type A aortic dissection, who were free from preoperative respiratory dysfunction, were assigned prospectively and alternately to one of 2 treatment groups. Pulmonary perfusion was performed during retrograde cerebral perfusion in group B (11 patients), whereas the conventional Ueda technique was applied in group A (11 patients). Lung function was evaluated on the basis of intubation time, scoring of chest radiographs at 12 hours after cardiopulmonary bypass, and Pao(2)/fraction of inspired oxygen ratio assessed from immediately before the operation to 72 hours after termination of cardiopulmonary bypass.
Results: Study groups were homogeneous for age, sex, interval between symptom onset and surgical operation, previous aortic surgery, preoperative ejection fraction and pulmonary gas exchange function, extent of aortic repair, and concomitant procedures. Cardiopulmonary bypass time, length of retrograde cerebral perfusion, operation time, need for blood substitutes, and surgical revision for bleeding did not differ between treatment groups. Postoperative Pao(2)/fraction of inspired oxygen ratios were higher in group B than in group A, and the difference remained statistically significant throughout the study period. The incidence of prolonged ventilator support (>72 hours) and the severity of the radiographic pulmonary infiltrate score were lower in the perfused group (18.2% vs 72.7% [P =.015] and 0.81 +/- 0.75 vs 1.8 +/- 0.78 [P =.028], respectively).
Conclusions: Continuous pulmonary perfusion provided a better preservation of lung function in patients operated on with deep systemic hypothermia.