Transfusion-related acute lung injury (TRALI) is potentially life-threatening adverse reaction associated with blood transfusion and can induce perioperative pulmonary secretion. TRALI that develops during cardiopulmonary bypass (CPB) may be difficult to detect; however, the pathophysiology might manifest as derangements in CPB operations. A 79-year-old man was scheduled to undergo partial replacement of the aortic arch with CPB. Two units of red blood cells were loaded into the priming solution. Although the vital signs, including oxygenation, remained stable in the prebypass period, perfusionists noticed a decreasing trend in the venous reservoir level early in the CPB operations. The trend continued even during circulatory arrest with selective cerebral perfusion, resulting in the termination of the modified hemofiltration. Surgical procedures were accomplished uneventfully; however, a large amount of fluid was required to maintain the minimal reservoir level and CPB flow. The total fluid balance during CPB was +8,233 mL, which was quite unusual in our practice. When 800 mL of massive pulmonary secretion was detected before CPB withdrawal, the etiology could not be determined simultaneously; nonetheless, systemic vascular hyperpermeability was speculated to be the underlying pathophysiology. Our therapeutic approach following the treatment of acute respiratory distress syndrome contributed to halting the deterioration of lung injury. Although the pneumothorax developed on the first postoperative day, the patient was treated with the insertion of a chest drainage tube. Subsequently, the patient had a good course and was discharged without respiratory complications. In conclusion, massive pulmonary secretion, probably due to TRALI type II, was associated with derangements in CPB operations. Prompt identification of the underlying pathophysiology and appropriate intervention is crucial.