Distensão de bolha pulmonar por malformação adenomatoide cística durante viagem aérea

Abstract

Emphysematous bullae are defined as functionally inert, air-filled blebs that are larger than 1 cm and are covered by a thin outer layer that is either translucent or opalescent and is less than 1 mm thick, as well as consisting primarily of visceral pleura. (1) Under low pressure, lung bullae can either expand and lead to mediastinal compression or burst and cause hypertensive pneumothorax, massive hemorrhage, or gas embolism, characterizing an uncommon type of barotrauma. (2) Cases of gas embolism in divers who ascend too rapidly from great depths constitute the most common example of barotrauma, cases of barotrauma during air travel being rare. Therefore, we report the case of a 62-year-old male patient who experienced acute respiratory failure due to expansion of a lung bulla during air travel.The patient was admitted to an emergency room with intense chest pain and sudden-onset dyspnea during air travel. Immediately after admission, electrocardiography was performed and cardiac enzyme levels were determined. The electrocardiogram and cardiac enzyme levels were found to be normal. A chest X-ray revealed a round hypertransparent area located in the middle third of the left lung and compressing the lung parenchyma ( Figure 1). An axial CT scan of the chest confirmed the presence of a hypertransparent area occupying the entire anterior segment of the left upper lobe and measuring 12.2 × 9.0 cm, as well as containing a fine liquid layer. No other changes were found. The patient underwent left thoracotomy with selective lung intubation. We found a lung bulla located in the upper lobe and occupying the entire mediastinal surface of the lung. The affected area was resected and stapled with a mechanical stapler, and abrasion pleurodesis was performed. No other macroscopic changes were observed during the surgical procedure. After the surgical procedure, the patient was transferred to the ICU, where he was woken and extubated. The postoperative evolution was favorable, the chest tube having been removed on postoperative day 5. A follow-up chest X-ray revealed re-expansion of the left lung and hypotransparent areas in the middle third, which were attributed to the edema and the hematoma at the suture site. The histopathological features of the surgical specimen were found to be consistent with cystic adenomatoid malformation.Cystic adenomatoid malformation of the lung is generally asymptomatic in adults, the diagnosis being incidental. (3) Changes in the atmospheric pressure can lead to rupture of previously asymptomatic lung bullae. This can be explained by Boyle's Law, according to which the volume of a gas is inversely proportional to its pressure. (4,5) During commercial flights, the pressure in the passenger cabin varies according to the altitude. At an altitude of approximately 9,000 m, the airplane is pressurized in order to maintain an internal pressure of 2,400 m. During ascent, that change causes the pressure to drop from 760 mmHg (sea level) to 564 mmHg, a pressure that is reached within approximately 20 mi...