pericardiocentesis is an invasive procedure which is usually performed in a patient who has pericardial effusion to resolve the pressure in the pericardial sac . in 1653 , riolanus ( 1 ) first described as a trephination of the sternum to relieve fluid surrounding the heart . due to frequent complications this procedure was out of interest until ultrasound guided technique emerged ( 2 ) . herein , we report a case of iatrogenic tension pneumopericardium , which exhibit impending cardiac arrest . a 70-year - old male presented with severe dyspnea and general weakness on march 8 , 2013 . he was referred from a local hospital for pericardiocentesis and further work - up due to a large pericardial effusion . he had a past medical history of ischemic stroke 15 years prior to his visit to the hospital and of syncope a day before his visit to the hospital . the vital signs of the patient in the emergency room ( er ) were as follows : blood pressure of 163/93 , heart rate of 135 beats per minute , respiratory rate of 30 breaths per minute , body temperature of 37.0c , and oxygen saturation of 91% . the patient had distended neck veins and muffled heart sounds but did not have low blood pressure . echocardiography was performed by an emergency physician , and a right ventricle ( rv ) free wall collapse in was observed in the diastolic phase . an emergency pericardiocentesis was indicated , and it was performed by a subxiphoid approach . approximately 700 ml of serous effusion was drained through a catheter ; the patient s heart rate dropped to 110 and his blood pressure was maintained above 130 . a water - sealed chest tube bottle was connected at the end of the catheter for further drainage . the patient was transferred to a computerized tomography ( ct ) room for a chest ct to examine the cause of his pericardial effusion . before he left after the patient returned to the er from the ct room , his heart rate fell to 30 , and he exhibited impending cardiac arrest . an intravenous dose of 0.5 mg atropine was given , and the patient was hydrated with crystalloid solution . the patient s chest ct confirmed tension pneumopericardium , and imaging showed that pericardial air was compressing the right ventricle and that the catheter tip was placed behind the left ventricle ( lv ) ( fig . 1 ) . approximated 500 ml of pericardial air was evacuated rapidly through the previously implanted catheter , and the patient s vital sign became stable . the patient was admitted to the intensive care unit and subsequently transferred to a long - term care hospital . a contrast - enhanced computed tomography scan of the chest . ( a ) axial view showed the air compressing the right ventricle ( arrows ) and tip of the catheter inside pericardium ( arrow head ) . pneumopericardium is defined as the presence of air inside the pericardial space . in 1910 , wenkebach first described the x - ray findings of pneumopericardium , and in 1967 , cimmino ( 6 ) described the diagnostic features of pneumopericardium . in a review of the literature , toledo et al . ( 7 ) classified the etiology of pneumopericardium into four categories : iatrogenic , pericarditis , fistula formation between the pericardium and an adjacent air - containing organ , and trauma . ( 8) reported that trauma and positive pressure ventilation are the major causes of pneumopericardium . iatrogenic cases of pneumopericardium associated with various procedures , such as thoracentesis , paracentesis , poststernal bone marrow aspiration , postcauterization of esophageal webs , pericardiocentesis , radiofrequency ablation , and pacemaker insertion , have been reported ( 7910 ) . if the patient has tension pneumopericardium , physical examination may show tachycardia , distended neck veins , and hypotension . in 1844 , bricheteau was the first to describe the mill wheel murmur in auscultation , which is a characteristic churning or splashing auscultatory sound due to blood mixing with air in the pericardial sac . a chest x - ray showing air surrounding the heart and the  small heart sign pericardial air can be mistaken for mediastinal air , but the air in the pericardial sac does not rise above the pericardial reflection of the proximal great vessels . also a chest x - ray taken from the decubitus position may show a shift of air if the air is in the pericardium , but mediastinal air does not shift ( 12 ) . a small amount of air in the pericardial sac is indistinguishable by plain chest x - ray but can be detected by ct scan . bedside echocardiography in the er is an alternative method for detecting air in the pericardial sac , but a large amount of air may hinder the penetration of the ultrasound beam , so diagnosis by this method may be challenging . the needle should be placed 1 cm inferior to the left xiphocostal angle at a 30-degree angle to the skin . it should be aimed toward the left shoulder and advanced while maintaining negative pressure ( 13 ) . after the insertion of the catheter , a drainage tube is connected to a water sealed device . in our case , a conventional chest tube bottle was used , and during transportation to the ct room , the drainage device was not clamped . , the water in the bottom of the bottle could have swung back and forth . originally , the tube connected to the catheter would have been sealed with water , but this swinging motion would have provided the opportunity for air to enter the catheter and , subsequently , the pericardial sac . iatrogenic pneumopericardium is rarely reported after pericardiocentesis , but it can lead to tension pneumopericardium , which is a life threatening condition . physicians should be aware of this serious complication of pericardiocentesis and take extra precautions in handling drainage devices because this iatrogenic complication can lead to cardiac arrest and a medical dispute .
pneumopericardium is defined as the presence of air inside the pericardial space . 
 usually , it is reported as a complication of blunt or penetrating chest trauma , but rare iatrogenic and spontaneous cases have been reported . 
 pneumopericardium is relatively stable if it does not generate a tension effect on the heart . 
 however , it may progress to tension pneumopericardium , which requires immediate pericardial aspiration . 
 we report a case of iatrogenic pneumopericardium occurred in a 70-year - old man who presented dyspnea at emergency department . 
 the patient underwent pericardiocentesis for cardiac tamponade due to large pericardial effusion , and iatrogenic tension pneumopericardium occurred due to misuse of the drainage device . after evacuating the pericardial air through the previously implanted catheter , the patient became stable . 
 we report this case to increase the awareness of this fatal condition and to help increase the use of precautions against the development of this condition during emergency procedures .