Bullous emphysema is typically observed in patients with chronic obstructive pulmonary disease, and when a bulla occupies more than 30% of the hemithorax, it is called a giant bulla . Non-thoracic surgery in patients with giant bullae is rare, and only a few case reports have described anesthetic management. When managing patients with giant bullae, the main anesthetic concern is avoiding PPV-induced rupture of the bulla and perioperative tension pneumothorax. Therefore, anesthetic management under spontaneous breathing is preferred for surgeries in which PPV is not essential, such as surgery of the extremities and lower abdomen [1, 2]. However, upper abdominal surgery usually requires general anesthesia and PPV to provide patient comfort and an excellent surgical field. Only one case report has described the successful anesthetic management of splenectomy with OLV using a bronchial blocker in a patient with a giant bulla . Because laparoscopic cholecystectomy is an upper abdominal surgery and pneumoperitoneum requires precise respiratory control, we decided to manage the patient with general anesthesia and OLV using a DLT. Consequently, general anesthesia with OLV successfully prevented giant bulla rupture in our patient. However, we unexpectedly found hyperinflation of the giant bulla and compression atelectasis of the entire right lung at the end of surgery.
As is often observed in video-assisted thoracic surgery, healthy lungs quickly collapse when the pleura is opened, and ambient air freely enters the thoracic cavity . Conversely, emphysematous lungs and bullae are reluctant to collapse because of reduced elastic recoil and expiratory limitation . Although the pleura was not open in our case, the right lumen of the DLT was open to ambient air throughout the OLV. It is likely that the open right-sided lumen of the DLT allowed ambient air to flow into the giant bulla, thereby enabling the right upper lobe to collapse.
Several measures could have been taken to prevent right upper lobe atelectasis and giant bulla hyperinflation during general anesthesia and OLV. Providing an OLV with a closed right-sided lumen may be the most straightforward option, although its effectiveness remains uncertain. It may be more effective if a Jackson-Rees circuit or another ventilator is connected to the right lumen of the DLT to apply a mild positive end-expiratory pressure to the right lung. Intubating a single-lumen tube and placing a bronchial blocker in the right intermediate bronchus may enable ventilation of the right upper lobe and left lung while preventing PPV of the giant bulla. Although laparoscopic cholecystectomy is typically performed under general anesthesia and PPV, recent studies have shown that it can be performed safely under neuraxial block and spontaneous breathing [7, 8]. Spinal anesthesia or combined spinal and epidural anesthesia with spontaneous breathing may have been a good alternative in our case.
Differentiating the hyperinflated giant bulla from pneumothorax was challenging on chest radiography. Generally, a giant bulla sometimes mimics a tension pneumothorax, and some case reports have described unnecessary chest tube insertion in patients with giant bullae [9, 10]. In such cases, CT is required to avoid misdiagnosis. On CT imaging, the lung collapses toward the ipsilateral hilum in the case of pneumothorax, whereas it is draped around the bulla in the case of a giant bulla [4, 9]. CT imaging effectively differentiated the hyperinflated giant bulla from pneumothorax in our case and enabled us to avoid unnecessary chest tube insertion.