a 9-month - old , 10-kg girl without any relevant medical history was presented at our emergency room because she had aspirated a peanut 5 hours previously . chest computed tomography showed a foreign body at the carina and the proximal right main bronchus , and emphysema in both lung fields ( fig . anesthesia was induced intravenously with thiopental 60 mg and rocuronium 6 mg after administering atropine 0.2 mg . approximately 25 minutes after the start of the operation , spo2 gradually decreased to 78% from 100% . accordingly , the surgeon was asked to stop the procedure , and an uncuffed endotracheal tube ( i d 4.0 , euromedical , denmark ) was intubated and fixed at 10 cm . left lung sounds were heard clearly , but no right lung sounds were evident on auscultation . spo2 did not improve despite manual ventilation with 100% o2 and an increased inspiratory pressure airway was detected . accordingly , a simple chest radiograph was taken . while waiting for the result of the chest radiograph , the otolaryngologist extubated the endotracheal tube and attempted to re - insert the rigid bronchoscope in order to check for possible causes of the airway obstruction , such as , residual foreign body . meanwhile , the heart rate decreased to 50 beats / min , and spo2 decreased to 57% ( blood pressure was not measured ) . atropine 0.2 mg and epinephrine 1 g were injected intravenously , but vital signs did not improve and no carotid artery pulse was palpable . external cardiac compression was performed and epinephrine 10 g was injected intravenously three times . heart rate and blood pressure then recovered , and thus , cardiac compression was stopped . a chest tube was immediately inserted into the right thorax and a massive air leak was observed . at this time , the sounds of both lungs were clearly heard and spo2 improved to 100% . follow up chest radiography showed a significant reduction of the right tension pneumothorax and a scattering of subcutaneous emphysema at the left upper chest and around the neck ( fig . the tension pneumothorax suggested major tracheobronchial injury and a subsequent bronchoscopic examination revealed three major sites of laceration , one in the mid trachea of length 1.5 cm , a second in the distal trachea of length 2 cm ( immediately above the carina ) ( fig . 4 ) , and a third in the right main bronchus of length 1 cm . an arterial line was placed in the left radial artery to monitor blood pressure continuously . arterial blood gas analysis showed ; ph 7.10 , paco2 63 mmhg , pao2 77 mmhg , hco3 19.6 mmol / l at fio2 1.0 , etco2 24 mmhg , and spo2 100% . after a rigid bronchoscope examination confirmed the absence of remaining foreign body , an uncuffed i d 4.5 endotracheal tube was inserted into the left main bronchus for single lung ventilation under fiberoptic bronchoscopic guidance . however , the patient did not tolerate single lung ventilation well and her spo2 decreased to 79% . in view of the facilitation of surgical approach and the risks of hypoxemia and hypoventilation , after 1,000 units of heparin was injected as a bolus , a 10 fr catheter ( fem - flex ii femoral cannula , edwards lifesciences , irvine , ca , usa ) was placed in the right internal jugular vein for drainage , and a 12 fr catheter was placed in the right femoral vein for perfusion using a sono - guided seldinger technique ( fig . 5 ) . ecmo flow was maintained at 0.7 - 0.8 l / min , and spo2 remained at 98 - 100% without mechanical ventilation . at the initiation of ecmo , anesthesia was maintained with continuous intravenous infusions of sufentanil 5 g / kg / h , midazolam 0.1 mg / kg / h , and vecuronium 0.1 mg / kg / h during ecmo . dopamine was infused at 5 g / kg / min and vital signs were stabilized . an activated clotting time ( act ) of approximately 200 seconds was maintained and arterial blood gas analysis under maximal ecmo support showed ; ph 7.34 , paco2 41 mmhg , pao2 81 mmhg , and hco3 22.1 mmol / l at fio2 1.0 . when the ecmo flow rate reduced , it was recovered by pulling the cannula in the internal jugular vein slightly . body temperature , measured using an oral thermometer , fell to as low as 35.0 after ecmo was initiated , and thus , a forced air warmer was applied to prevent further hypothermia . total anesthesia time was 8 hr 25 min , estimated blood loss was 300 ml , and urine output was 120 ml ; 250 ml of crystalloid solution and 1 unit of packed red blood cells were administered . ecmo was maintained postoperatively to minimize airway pressure . in the intensive care unit ( icu ) , the mechanical ventilation was performed using pressure control mode ( inspiratory airway pressure 10 cmh2o , pressure support 11 cmh2o , respiratory rate 20/min , fio2 0.5 and peep 3 cmh2o ) , which resulted in the expiratory tidal volume of 49 ml . vital signs were stable in the icu , and the patient awoke with no signs of respiratory or neurologic deficit on the first postoperative day . the simple chest radiograph taken in the icu showed reduced subcutaneous emphysema and no residual pneumothorax . ventilating bronchoscopy has the risk of severe complications , such as , infection , laryngeal edema , laryngospasm , bronchospasm , bleeding , hypoxia , pneumomediastinum , and pneumothorax . rothmann and boeckman   reported that the probability of pneumothorax during rigid bronchoscopy for the removal of a foreign body is approximately 1% . therefore , the possibility of pneumothorax should be suspected when ventilation worsens during ventilating bronchoscopy . however , an early diagnosis of pneumothorax during anesthesia is not easy because the symptom is masked by anesthesia . tension pneumothorax during surgery may manifest as a reduction in oxygen saturation , a rapid increase in airway pressure , hypotension , and/or tachycardia . in this case , the reasons for the delayed diagnosis in the present case were that the reduction in oxygen saturation and the diminished right lung sounds were mistakenly attributed to airway obstruction by a foreign body . in addition , if lung sounds had been checked more carefully , it might have been easier to determine whether the respiratory failure was due to foreign body obstruction or tension pneumothorax . furthermore , it would have been safer to evaluate airway with a fiberoptic bronchoscope inserted through the endotracheal tube under ventilation rather than attempt airway assessment using a ventilating bronchoscope after extubation . during surgery on the trachea and bronchus , a double lumen endotracheal tube or however , in small children , because conventional single lung ventilation methods are likely to fail to maintain adequate ventilation and oxygenation , the elective application of ecmo may be a good option . ecmo was also useful during the postoperative course in the described case because it can minimize inspiratory airway pressure during mechanical ventilation . during ecmo , heparin was administered as a single bolus of 100 unit / kg followed by continuous intravenous infusion at 20 - 60 unit / kg / min . anticoagulation was accomplished by titrating heparin administration to maintain an act of between 180 and 220 seconds . furthermore , levels of blood anticoagulation were monitored hourly , and the amount of heparin administered was carefully controlled to prevent bleeding complications . in addition , because the ecmo machine was not equipped with a sevoflurane vaporizer and almost no mechanical ventilation was performed during ecmo , intravenous opioids and midazolam were added for anesthesia . summarizing , the tension pneumothorax should be considered when inspiratory pressure is increased and oxygen saturation is decreased during ventilating bronchoscopy . effective communication between the operator and anesthesiologist is essential when unexpected complications are encountered to facilitate the prompt planning of coping strategies .
tension pneumothorax during ventilating bronchoscopy for foreign body removal is a rare but life - threatening complication . 
 the authors present a case of cardiac arrest caused by tension pneumothorax in a 9-month - old girl who underwent ventilating bronchoscopy for foreign body ( peanut ) removal . 
 tension pneumothorax was due to tracheobronchial lacerations caused by a bronchoscope . 
 the patient was successfully resuscitated by cardiopulmonary resuscitation and chest tube insertion . 
 the airway injury was effectively repaired by thoracotomy under extracorporeal membrane oxygenation .