The "Fish Tank".

A 66-year-old man with a history of diabetes mellitus, hypertension, and dyslipidemia presented with severe COVID-19 pneumonia, required high-flow nasal oxygen therapy and was admitted to the ICU. He was treated with dexamethasone and tocilizumab according to the institutional protocol. On day 7 of his admission, his hypoxic respiratory failure worsened. His oxygen requirements increased and his Po2 decreased to 35 mm Hg. The patient was then intubated, and invasive mechanical ventilation was initiated. On day 22 of his admission, the patient’s Po2/Fio2 ratio decreased to 70 mm Hg, and he was turned into prone position. An immediate hemodynamic and respiratory deterioration occurred. After prompt supination, emergent point-of-care cardiac ultrasound scanning with phased-array transducer showed hyperdynamic left ventricle, small right ventricle, and no pericardial effusion. Lung ultrasound scanning with linear probe exhibited normal “lung sliding” in the right lung, which represented the movement of the two layers of pleura directly against each other. In contrast, the left lung exhibited absence of lung sliding, which raised the suspicion of pneumothorax in this clinical scenario (Video 1). Because this finding is extremely sensitive but not specific, a confirmatory finding was obtained. Further scanning of the left lung revealed a “lung point” (Video 2), which is the subsequent lung sliding next to absence of sliding, which is the exact point where the two layers of pleura reattach. This finding is specific for pneumothorax and practically confirmed the diagnosis. At that point, a left chest pigtail drain was inserted that drained air, but surprisingly also bright red blood. A total of 1 L of blood was drained eventually, and the patient’s condition stabilized. Later that week, the patient was still ventilated invasively; evidence indicated ongoing air and fluid leaks in the chest tube set. Video 3 shows the follow-up left lung ultrasound scan with the use of a phased array probe that aimed to image deeper areas. Question: Based on the clinical picture and Video 3, what is the most probable diagnosis? Answer: The video shows a continuous air leak into the pleural space that was still filled with fluid that resembled air bubbles in a fish tank, probably suggestive of an alveolopleural fistula. Acute respiratory deterioration in patients with COVID-19 ARDS that requires invasive mechanical ventilation needs to be evaluated promptly. Main secondary pulmonary complications of critical COVID-19 pneumonia include secondary bacterial or fungal pneumonia,1Razazi K. Arrestier R. Haudebourg A.F. et al.Risks of ventilator-associated pneumonia and invasive pulmonary aspergillosis in patients with viral acute respiratory distress syndrome related or not to Coronavirus 19 disease.Crit Care. 2020; 24 ([published correction appears in Crit Care. 2021;25(1):118.]): 699Crossref PubMed Scopus (79) Google Scholar,2Maes M. Higginson E. Pereira-Dias J. et al.Ventilator-associated pneumonia in critically ill patients with COVID-19.Crit Care. 2021; 25 ([published correction appears in Crit Care. 2021;25(1):130.]): 25Crossref PubMed Scopus (147) Google Scholar pulmonary embolism,3Poissy J. Goutay J. Caplan M. et al.Pulmonary embolism in patients with COVID-19: awareness of an increased prevalence.Circulation. 2020; 142 (Jul 14): 184-186Crossref PubMed Scopus (753) Google Scholar and spontaneous pneumothorax.4Ò Miró Llorens P. Jiménez S. et al.Frequency, Risk factors, clinical characteristics, and outcomes of spontaneous pneumothorax in patients with coronavirus disease 2019: a case-control, emergency medicine-based multicenter study.Chest. 2021; 159: 1241-1255Abstract Full Text Full Text PDF PubMed Scopus (53) Google Scholar Each one of these diagnoses requires different imaging modalities and/or laboratory tests. Pneumothorax has the potential to cause a sudden life-threatening clinical deterioration and can be confirmed promptly by bedside ultrasound scanning5Lichtenstein D.A. Mezière G.A. Relevance of lung ultrasound in the diagnosis of acute respiratory failure: the BLUE protocol.Chest. 2008; 134 ([published correction appears in Chest. 2013;144(2):721.]): 117-125Abstract Full Text Full Text PDF PubMed Scopus (1193) Google Scholar without the need to wait for a chest radiograph or CT scan. As presented in this case, timely diagnosis can be crucial, because these patients can exhibit respiratory and hemodynamic collapse; prompt chest drainage is a life-saving procedure. Two less-common complications of COVID-19 ARDS were encountered in this case. The first, spontaneous hemothorax,6Long A. Grimaldo F. Spontaneous hemopneumothorax in a patient with COVID-19.Am J Emerg Med. 2021; 40: e1-e2PubMed Google Scholar,7Guven B.B. Erturk T. Kompe Ö. Ersoy A. Serious complications in COVID-19 ARDS cases: pneumothorax, pneumomediastinum, subcutaneous emphysema and haemothorax.Epidemiol Infect. 2021; 149: e137Crossref PubMed Scopus (17) Google Scholar was diagnosed only after chest drain was inserted, and bright red blood was drained from the left pleural space. The second was prolonged air leak8Aiolfi A. Biraghi T. Montisci A. et al.Management of persistent pneumothorax with thoracoscopy and bleb resection in COVID-19 patients.Ann Thorac Surg. 2020; 110: e413-e415Abstract Full Text Full Text PDF PubMed Scopus (46) Google Scholar several days after the initial event. These were noticed on the chest tube and confirmed by the continuous air leak that was seen on the background of the left hemorrhagic pleural effusion (Fig 1). Air bubbles appear as echogenic circles in the fluid-filled pleural space. Echogenic findings in a pleural effusion can be divided into homogenous and heterogenous. Homogenous echogenic findings usually are the result of increased cellularity in cases of empyema or hemothorax. Heterogenous echogenic findings are usually the result of fibrinous stranding and septations or high malignant cellular content.9Soni N.J. Franco R. Velez M.I. et al.Ultrasound in the diagnosis and management of pleural effusions.J Hosp Med. 2015; 10: 811-816Crossref PubMed Scopus (106) Google Scholar Air bubbles have heterogenous appearance, originate from the lung tissue in both inspiration and expiration, and move upwards, as expected from air in fluid. Given the history of COVID-19 ARDS and spontaneous pneumothorax, with no history of invasive thoracic intervention, the most likely diagnosis was alveolopleural fistula (Narration Video). We believe this is the first visual description of alveolopleural fistula with the use of lung ultrasound scanning. The patient was treated conservatively and was discharged from the ICU to a medical ward 2 months later. 1.Spontaneous pneumothorax is a common and potentially life-threatening complication of COVID-19 ARDS.2.A prompt diagnosis of pneumothorax may be crucial and can be made at the bedside with the use of ultrasound scanning seconds after a sudden respiratory and/or hemodynamic deterioration.3.Alveolopleural fistula is another possible complication for patients with invasively ventilated COVID-19.4.Alveolopleural fistula in the presence of pleural effusion/hemothorax can be diagnosed with the use of lung ultrasound scanning by identification of the “fish tank” sign. None declared. Disclaimer: This submission is exempted from an REB approval according to the University Health Network’s REB guidance on case reports. The patient’s substitute decision maker gave consent to publish this case with no identifying details. Other contributions: CHEST worked with the authors to ensure that the Journal policies on patient consent to report information were met. Additional information: Videos for this case are available under "Supplementary Data." eyJraWQiOiI4ZjUxYWNhY2IzYjhiNjNlNzFlYmIzYWFmYTU5NmZmYyIsImFsZyI6IlJTMjU2In0.eyJzdWIiOiJkYmM1MzA0YWIxMGFkMTI4MTExNTU2OTJmNzVhYmYwYyIsImtpZCI6IjhmNTFhY2FjYjNiOGI2M2U3MWViYjNhYWZhNTk2ZmZjIiwiZXhwIjoxNjg4NDQxNjk1fQ.ZLYtebk0uDMSVjDRMY_iUK64LFtZpjkJwukGwpbGJAg4VkUZrP4ua0G4HQzn60E6waTFgmGFEs5rcrYz2CCSXYTwTFrQ5YwwdlpOM6a-e9WrzEO4TbTRk4kV9TtpSggnCkmIzCHjxFQyyomgl156u5kQJh_XAAEUpSr75NaADI5K6rd7K7nPKKhDP137AZjObiLowjZC57Y1g7jUBHf6D2wKumT80gt4xzx9Smt6Ihd9M_25Vcw6EkgOlsU3ediSlSS0Op3Q-t5km4U9xh2W_gD1N742JTAzi_bn2j94a3SKVQ7p-i3vTuO0DLGjpGWHV4SA-KB-jZtGgONmjr224g Download .mp4 (1.47 MB) Help with .mp4 files Video 1Ultrasound of the right and the left upper anterior lungs.eyJraWQiOiI4ZjUxYWNhY2IzYjhiNjNlNzFlYmIzYWFmYTU5NmZmYyIsImFsZyI6IlJTMjU2In0.eyJzdWIiOiJjNWNjMGM1MjE1YzExZjAyM2ViNDZhMjlmYThhZmRjNyIsImtpZCI6IjhmNTFhY2FjYjNiOGI2M2U3MWViYjNhYWZhNTk2ZmZjIiwiZXhwIjoxNjg4NDQxNjk1fQ.skpJgWgHb-XtCRRv2F82ZoBJmsxclEzRvhApCu4-QkyeKPTPbMlwb5u7WDguBuhh1-veI7AY5ecB3paR18SAL5GtpEtcdosQVG2x-tcdaXPLjWFTPlLQRfiTOQARnl_xqMlrnr2gWiBo5LQGQiZbWR-Sm3xU6cNiDpOhEOIqZA04JZySBOae9pS7A58LjHP6xSin0PBn6o5dpDogdrFHNqJZoSDBq0ut7vLkB6k78WwZJ5ty3vlQ2ZzkHqXKqqfWqW6Qzvej6O6FR2ShYZOChT7VB-JKv4cziOPIOiEcyKhWKmM8_nYu4m_SoH_8OziUeB3_BP65DCCiXHI24sCwGg Download .mp4 (0.62 MB) Help with .mp4 files Video 2Ultrasound of the upper lateral left lung depicting a “Lung Point.”eyJraWQiOiI4ZjUxYWNhY2IzYjhiNjNlNzFlYmIzYWFmYTU5NmZmYyIsImFsZyI6IlJTMjU2In0.eyJzdWIiOiJmODBhMzNkMjAzZTQ5NmQyYzEwMjlmODhhMDE2YzIzOSIsImtpZCI6IjhmNTFhY2FjYjNiOGI2M2U3MWViYjNhYWZhNTk2ZmZjIiwiZXhwIjoxNjg4NDQxNjk1fQ.njkclaePq_19_zU2gi3TMKuIvnLUDiU9tQs96KTwQmmbKQ7iJ2GLkGhKVdn6c7WVd0k_1JCj4Cl1vmiYPdKG6ox3Z6gTfsTtzeBen_Xet1KRPyQr1-zBJ7CrrSKHHYAu9tG1dbgD_OfUcUIrsIRsn7Ls8Yin1yJD6PhAWDJGTKxHe9fRUY9BhvPsgrp6ZbQNluAcQorppFjfQN84jYeD3RJvTcskMc5Fl1Sbzw20dKYx286thWKfj-fqMYtVHmKs3ma3N-EP6rdU0oXQh0Q9CMOjhrh7dRxyD-GVJClnLYvwTTHhh3BEEyzk_Y0qVFSSRsPeXnloGpnlzmRQsk1WMA Download .mp4 (2.74 MB) Help with .mp4 files Video 3Ultrasound of the left lung shows continuous (inspiratory and expiratory) air leak into a blood-filled pleural space. The collapsed lung is seen on the right side of the video.eyJraWQiOiI4ZjUxYWNhY2IzYjhiNjNlNzFlYmIzYWFmYTU5NmZmYyIsImFsZyI6IlJTMjU2In0.eyJzdWIiOiI5Yzk1M2RiMjM3NTBiOGU3ZjA3Yjk1YTlkOTE0MzNhZSIsImtpZCI6IjhmNTFhY2FjYjNiOGI2M2U3MWViYjNhYWZhNTk2ZmZjIiwiZXhwIjoxNjg4NDQxNjk1fQ.QwIBAL-hqO2bfXtJ5XYqDirW-VomCz_jMOCv7yVfr13bnvpCZZZdtjL_60TtKjRh7jEeDbG8Kh52jcjKXy8Xn-aup-xuyBT0WqkLHHJvRMB7pJolQWCe6AP63tKQLHiQPNBz2WWB7J1qLTDCgsNSpgmUyPx8GzCCk0jwTUUpo2gBKw9aXNPSkKAA7KifDz2PrQ4joxcwHDAQHDc9poXPN3zme1eougT_J1sEBdLiZaGa5qgQxuBapho2O0piJE-cYB5EEKwsVq2oghZYoONseAhM509w4zmIZKuO4TOVbxjNfBc8SXP6VQTiZMRVR6oDsO0rUrgtA5m5gc-ISdJDZQ Download .mp4 (67.55 MB) Help with .mp4 files Narration Video