CASO CLÍNICO 202 Revista Científca da Ordem dos Médicos www.actamedicaportuguesa.com RESUMO O pneumotórax é uma complicação pouco frequente da cirurgia laparoscópica. A maioria dos casos ocorrem em cirurgias da região abdominal superior, uma vez que a posição de Trendelenburg por empurrar o fígado e o peritoneu contra o diafragma, reduz a perda de gás. Quando a causa é a difusão de CO 2 através de um defeito diafragmático congénito, habitualmente resolve espontaneamente, após a desinsufação do pneumoperitoneu. Quando se exclui uma causa parenquimatosa pulmonar o aumento de positive end- -expiratory pressure para contrabalançar a pressão intra-abdominal é uma medida efcaz. O caso clínico que apresentamos refere-se a um caso de capnotórax hipertensivo que ocorreu devido à presença de um defeito diafragmático congénito, durante uma cirurgia abdominal inferior e que foi tratado com sucesso sem recorrer ao uso de dreno torácico. Este caso salienta a importância de manter uma vigilância ativa e alto indice de suspeição para o pneumotórax durante a cirurgia laparoscópica. Palavras-chave: Decúbito Inclinado com Rebaixamento da Cabeça/efeitos adversos; Laparoscopia; Pneumotórax/etiologia; Respira- ção com Pressão Positiva Capnothorax During Laparoscopy in Trendelenburg Position: A Rare Case Study Capnotórax Durante Laparoscopia em Trendelenburg: Um Caso Clínico Raro 1. Department of Anaesthesiology. Hospital de Santa Maria. Centro Hospitalar Lisboa Norte. Lisboa. Portugal. 2. Anestesi Operasjons Avdelingen. Universitetssykehuset Nor-Norge. Tromsø. Norway. 3. Department of Obstetrics, Gynecology and Medicine of Reproduction. Centro Hospitalar Lisboa Norte. Lisboa. Portugal.  Autor correspondente: Ana Margarida Damas. anadms@gmail.com Recebido: 27 de novembro de 2018 - Aceite: 11 de janeiro de 2019 | Copyright © Ordem dos Médicos 2020 Ana Margarida DAMAS 1 , Fátima GONÇALVES 1 , Marisa ANTUNES 2 , Sónia BARATA 3 Acta Med Port 2020 Mar;33(3):202-203 ▪ https://doi.org/10.20344/amp.11606 ABSTRACT Pneumothorax is an infrequent complication of laparoscopic surgery. Most cases occur during upper abdominal surgery, since a head- down position (Trendelenburg) pushes the liver and peritoneum against the diaphragm, reducing gas release. When it is due to CO 2 dif- fusion across congenital diaphragmatic defects, it usually resolves itself spontaneously after de-insuffation of the pneumoperitoneum. Increasing positive end-expiratory pressure to counteract intra-abdominal pressure is an effective measure when a pulmonary origin is excluded. We report a case of right-sided hypertensive capnothorax due to a diaphragmatic defect, during lower abdominal surgery, which was successfully managed without the need for chest drainage. This case highlights the importance of maintaining active vigi- lance and a high index of suspicion for pneumothorax during laparoscopic surgery. Keywords: Head-Down Tilt/adverse effects; Laparoscopy; Pneumothorax/etiology; Positive-Pressure Respiration INTRODUCTION Capnothorax is defned by the presence of carbon diox- ide in the pleural space, and its incidence is low. 1,2 It can be caused by direct injury or by passage through congenital defects, foramina or via the subperitoneal route. The in- creased abdominal pressure during laparoscopy can open weak points in the diaphragm, creating a pleuroperitoneal communication. The gas present in the abdominal compart- ment will then move into the pleural space due to a pressure gradient, usually resulting in right-side capnothorax. Unlike the pneumothorax caused by creation of bronchopleural conduit due to barotrauma, in the event of pneumothorax caused by CO 2 the use of positive end-expiratory pressure (PEEP) can be helpful. 3,4 Although most cases can be man- aged conservatively, capnothorax can be a life-threatening situation. Anesthesiologists should be aware of this compli- cation because successful management depends on early recognition and treatment. 5 CASE REPORT A healthy 30-year-old female patient, diagnosed with deep endometriosis was referred for elective intraabdomi- nal laparoscopic exploration, under general anesthesia. She had no surgical or medical history. General balanced anesthesia induction was performed, and rocuronium was administered to facilitate tracheal intubation. After 25 min- utes post-induction, the frst trocart was inserted and the abdominal cavity was insuffated at a pressure of 20 mmHg. Following this, a pneumoperitoneum of 12 mmHg was un- eventfully established. The patient was then placed in Tren- delenburg position for surgery. At that moment blood pres- sure and oxygen saturation decreased, ETCO 2 increased, while airway pressure rose suddenly to unacceptable lev- els. Moreover, auscultation revealed absent breath sounds on the right hemithorax. Endobronchial intubation was excluded, and we assumed a diagnosis of hypertensive pneumothorax. We then shifted to manual ventilation with 100% inspired oxygen and asked surgeons to release the pneumoperitoneum. This improved hemodynamics, oxygen saturation and ventilatory mechanics. With no further clini- cal events, surgeons slowly increased CO2 insuffation up to 10 mmHg, inspected the upper abdomen and were able to visualize a diaphragmatic defect of the right hemicupule. After laparoscopic aspiration of the capnothorax and increased PEEP, surgery was completed safely. Before