Thorax, 1977, 32, 91-97

Pneumopericardium and tension pneumopericardiumafter closed-chest injuryS. WESTABY

From Papworth Hospital, Cambridge

Westaby, S. (1977). Thorax, 32, 91-97. Pneumopericardium and tension pneumopericardiumafter closed-chest injury. Three recent cases of pneumopericardium after closed-chest injury aredescribed. The mechanism of pericardial inflation suspected in each was pleuropericardiallaceration in the presence of an intrathoracic air leak. Deflation of the pericardium wasachieved by underwater seal drainage of the right pleural cavity in the first patient, duringthoracotomy for repair of tracheobronchial rupture-in the second, and by subxiphoidpericardiotomy in the last. Haemodynamic changes after escape of air from the pericardiumof the second patient confirmed the existence of tension pneumopericardium and air tamponade.

Pneumopericardium after a non-penetrating chestinjury is rare. There are few previous reports ofthis lesion, and in the presence of additional in-jury its clinical importance remains poorly defined.This paper examines three recent cases in whichoperative deflation of the pericardium was per-formed. In one case release of air resulted inmarked haemodynamic changes leading to adiagnosis of tension pneumopericardium.

Case 1

On 21 August 1974 a 37-year-old constructionworker fell from scaffolding, bouncing from poleto pole and landing on a concrete floor 70 ft(21 m) below. He sustained multiple injuries.After resuscitation at the nearest hospital, wherea pneumopericardium was noted on the chestradiograph (Fig. 1), the patient was transferred tothe Birmingham Accident Hospital.He was fully conscious but cyanosed with a

raised jugular venous pressure, a blood pressureof 150/105 mmHg, and a tachycardia of 130 perminute. His many skeletal injuries included bi-lateral compound ankle fractures, fractures of thepelvis, crush fractures of LI and L5 vertebrae,and subluxation at the Li/2 disc with cord tran-section at this level.Examination of the chest revealed bilateral dis-

ruption of the first to fifth costochondral jointswith paradoxical movement of the left secondand third interspaces and an audible chondral

click. The right chest was resonant with decreasedbreath sounds. Precordial auscultation revealed aloud splashing sound or 'bruit de moulin'. Chestradiographs demonstrated a large pneumopericar-dium and a 50% pneumothorax on the right, withno mediastinal shift. Needle aspiration of thepericardium was performed through the fourthleft interspace and 40 ml of air with frothy bloodwas expelled in a pulsatile manner into thesyringe. This did not alter the size of the pneu-mopericardium radiologically. Insertion of anunderwater seal drain into the right chest, how-ever, resulted in expansion of the right lung anddeflation of the pericardium which was completein 24 hours.

Intermittent positive pressure ventilation withan initial inspired oxygen concentration of 50%was required to maintain adequate oxygenation,and 31 units of blood were transfused during thefirst 36 hours.To facilitate further management, a trache-

ostomy and internal fixation of the ankle fractureswere performed. His later course was complicatedby profound hypoxia with chest radiographicchanges of bilateral patchy consolidation. Recur-rent bouts of paroxysmal tachycardia were con-trolled with digoxin and practolol, and an ileus,present on admission, resolved slowly over severaldays. The pleural drain was removed on the sixthday, and after 26 days he was successfully weanedoff the ventilator. Unfortunately, the paraplegiashowed no signs of recovery, and five weeks after

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Fig. I Patient 1. (a) A posteroanterior chestradiograph showing the pneumopericardium shortlyafter admission to the Birmingham AccidentHospital. (b) Decubitus film showing shift of airwithin the pericardial sac, thus confirming itsintrapericardial location.

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Pneumopericardium and tension pneurnopericardium after closed-chest injury

the accident he was transferred to the spinal in-juries unit at Oswestry.

Case 2

On 22 October 1975 a 23-year-old motorist sus-tained chest and head injuries when his carcollided with a tree. Not wearing a seat belt hewas thrown forward on to the steering wheel andthrough the windscreen. Remarkably, he walkedone mile (16 km) to the nearest hospital wherehe complained of chest pain and bloodstainedsputum.

Physical examination revealed lacerations of theface and scalp, tenderness over the lower third ofthe sternum, and gross surgical emphysema ex-tending from the upper chest into his neck. Hewas cyanosed but normotensive and had a tachy-cardia of 120 per minute. Chest radiographs(Fig. 2) showed a sternal fracture at the junctionof the middle and lower thirds and an extensivepneumopericardium and right pneumothorax. Theright lung failed to expand after insertion of anunderwater seal drain and there was a brisk airleak from the right pleural cavity. He was there-fore transferred to the Regional Cardio-ThoracicCentre at Papworth Hospital.On arrival his condition was found to have de-

teriorated; the blood pressure was 100/60 mmHgand pulse-rate 140 per minute. Surgical em-physema had spread into the face. On auscul-tation of the chest a loud splashing sound couldbe heard with muffling of heart sounds overthe precordium. There was a continued brisk airleak from the right pleural cavity. Bronchialrupture was diagnosed and bronchoscopy con-firmed a large tear at the origin of the right mainbronchus, extending into the carina and lowertrachea posteriorly. At thoracotomy extensivemediastinal emphysema was encountered and thepericardium was seen to be bulging and tenselyinflated with air. Incision of the pericardial sacresulted in expulsion of a large quantity of frothy,bloodstained fluid under considerable pressure,with a subsequent rise in blood pressure from110/70 to 130/90 mmHg. On inspection of thedeflated pericardial sac, a 3 mm tear on the pos-terior wall adjacent to the bronchial tear wasdemonstrated. It was postulated that a valvemechanism had resulted in pericardial inflationand air tamponade. After repair of both bronchialand pericardial tears the chest was closed withunderwater seal drainage of the right pleuralcavity. The patient continued to have a tachy-cardia of 120 per minute which gradually settled

over a 10-day period. Air was absent from thepericardium 24 hours after operation.

Case 3

On 29 November 1975 an 18-year-old motoristsustained multiple injuries after collision with anarticulated lorry. For an hour he remained trap-ped and unconscious in the driver's seat and onarrival at the nearest hospital was unresponsive,cyanosed, and profoundly hypotensive. Clinicalassessment revealed facial fractures with loss ofteeth and bleeding into the mouth and pharynx,bilateral fractured pubic rami, fractures of theleft ulna and radius, and several rib fractures onthe right side. Chest radiographs showed a smallright pneumothorax with diffuse, patchy shadow-ing throughout the right lung field and a largepneumopericardium. He was resuscitated withblood and dextran and ventilated artificially, andafter an initial improvement laparotomy was per-formed for suspected intra-abdominal bleeding.This revealed a large intrapelvic haematoma re-lated to the fractured pubic rami.

After this there was an improvement in his con-scious state but considerable deterioration in res-piratory function. Unfortunately, his lungs wereventilated with 100% oxygen for four days, dur-ing which time the chest radiograph (Fig. 3)showed increasing patchy opacities in both lungfields, the development of bilateral pneumo-thoraces, and a progressive increase in size of thepneumopericardium. He became restless, febrile,and increasingly hypoxic and developed surgicalemphysema of the chest and neck. At this stagebilateral intercostal underwater seal drains wereinserted and he was transferred to the Cardio-Thoracic Surgical Unit at Papworth Hospital.

His condition on arrival was critical, a tensionpneumothorax having developed en route due tokinking of the right intercostal drain. He wasdeeply cyanosed with tachycardia of 140 perminute and a blood pressure of 200/110 mmHg.Precordial auscultation revealed a loud splashingsound audible over the base of the heart, and theheart sounds were muffled. The chest radiographshowed a ground-glass appearance over both lungfields with a large pneumopericardium, medias-tinal emphysema, and peribronchial interstitialemphysema. A clinical diagnosis of rupturedbronchus was made but repeated attempts atbronchoscopy were interrupted due to profoundhypoxia and slowing of the heart rate. No bron-chial tear could be identified. In view of theballoon-like appearance of the pericardium on the

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chest radiograph, and a central venous pressure of18 cm of water, elective drainage of the pericar-dium was performed via a subxiphoid approach.On incision of the bulging pericardium, a largeamount of gas and yellow fluid was expelled underpressure. An underwater seal drain was left in situ

through which a brisk air leak persisted for 11days.

Further surgical intervention was deferred inview of his poor overall condition. His course wascomplicated by persistent severe hypoxia and de-creasing pulmonary compliance requiring ventila-

Fig. 2 Patient 2. (a) Posteroanterior radiograph taken shortly afterarrival at hospital showing a pneumopericardium, pneumomediastinum,right pneumothorax, and surgical emphysema of the neck and chestwall. (b) Detail of the pneumopericardium.

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(a)

Fig. 3 Patient 3. (a) Anteroposterior chest radiographshowing pneumopericardium, pneumomediastinum, andbilateral pulmonary opacities four days after admission tohospZtal. Bilateral pleural underwater seal drains have beeninserted and a tracheostomy performed. Surgical emphysemahas spread into the neck. (b) Detail of thepneumopericardium.

(h))

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tion pressures in excess of 60 cm of water. Hesuffered recurrent pneumothoraces, bronchopneu-monia, and sputum retention requiring broncho-scopic clearance. Chest radiographs showedpulmonary interstitial emphysema with multipleair cysts throughout both lung fields. Two episodesof septicaemia were successfully treated with anti-biotics and he was resuscitated after cardiac arrest

18 days after the accident. Despite the severity ofthe lung changes-for which he received a highdosage of methyl prednisolone-he made a re-

markable recovery and was discharged fromhospital 12 weeks after admission.

Discussion

Pneumopericardium is a rare sequel to closed-chest injury and still rates highly in terms ofradiological curiosity. Shackelford (1931) collectednine such cases from the world literature. Peri-cardial laceration was present in five patients,suspected in one, but excluded by postmortemexamination in three. Cargill et al. (1973) reporteda further two cases, the first associated with rup-

ture of the thoracic aorta and the second dis-covered at necropsy with pericardium intact.McCaughey and King (1975) described one case

associated with tracheal rupture, and Borrie andLichter (1974), reporting four cases of pericardialrupture after non-penetrating chest injury, foundair in the pericardium of one. The latter authorsstate that pneumopericardium implies pleuroperi-cardial rupture, a potentially lethal conditionwhich may lead to herniation and strangulationof the heart.

Intrapericardial air in the absence of pericardiallaceration, a finding also reported after prolongedpositive pressure ventilation (Cohen and Lock-hart, 1970) and acute asthma (Toledo et al., 1972),led Rosen et al. (1963) to suggest that, followinga sudden rise in intrathoracic pressure such as

may result from a severe blow on the chest, alveolimay rupture, releasing air into the interstitialtissues of the lung. This air may track along thesheaths of the pulmonary vessels to the mediasti-num, neck, and retroperitoneal tissues and even

to the pericardial cavity itself. This pathway hasbeen demonstrated by anatomical dissection.There have been no previous reports of air

tamponade after closed-chest injury. The haemo-dynamic derangements caused by tensionpneumopericardium in the presence of multipleinjuries requiring resuscitation with large volumesof fluid are difficult to assess. Decreased atrial andventricular filling, leading to increased central

venous pressure and pulsus paradoxus, have beendemonstrated during experimental pericardial in-flation (Adcock et al., 1940), in pneumopericar-dium after positive pressure ventilation in hyalinemembrane disease (Sagel et al., 1973), and inpneumopericardium as a sequel to subtotal peri-cardiectomy (Khan, 1974). Adcock et al. (1940)showed that when intrapericardial pressure israised from 145-265 mm water a proportionaterise in venous pressure occurs. Above this levelthe rise is no longer proportional and signs oftamponade develop. In order to maintain thecirculation, venous pressure must exceed pericar-dial by 35-40 mm water.The second and third patients were observed

under the relatively controlled conditions ofgeneral anaesthesia with positive pressure ventila-tion. Inspection of the pericardium at operationin both cases revealed that it was bulging andtensely inflated with air. Incision was followed byexpulsion of gas and froth under pressure. In thesecond patient this resulted in marked haemody-namic changes, and there is little doubt that airtamponade existed in this case.The mechanism of pericardial inflation pro-

posed in the present series is pleuropericardiallaceration in the presence of tracheobronchial orpulmonary air leak, thus creating a pleuroperncar-dial fistula. Evidence for this process is the briskevacuation of pericardial air after intercostaldrainage of the right pleural cavity in the firstpatient, the operative findings of a pericardial tearadjacent to the tracheobronchial rupture in thesecond, and the persistent pleural and pericardialair leak after surgical drainage of the pericardiumin the third patient. As in tension pneumothorax,a valve mechanism may develop in a pericardiumalready distended with air, allowing inflation dur-ing inspiration and air trapping in expiration.Positive pressure ventilation must exacerbate thisproblem if the pericardium is not drained. Ana-tomically, the right main bronchus and transversesinus of the pericardium are closely related, andit is not surprising that traumatic laceration inthis region may result in communication.

Diagnosis in suspected pneumopericardium isnot difficult. The loud precordial splashing or

'bruit de moulin', as described by Bricheteau(1844), with muffled heart sounds is characteristic.Radiography provides confirmation. Cimmino(1967), however, suggested that pneumopericar-dium was overdiagnosed and mistaken for pneu-momediastinum. In pneumopericardium air doesnot rise above the upper border of the pericardiumin the erect film, and decubitus films are useful to

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show shift of air in the pericardial sac. Medi-astinal air will not move in the short intervalbetween films (Fig. 1).

Air tamponade must be suspected if the chestradiograph shows marked ballooning of the peri-cardium and the venous pressure is raised. Inthese circumstances evacuation of the pericardialair is advisable, particularly if positive pressureventilation is required.The dangers of pleuropericardial laceration

must be considered since herniation with strangu-lation of the heart may occur several days afterthe initial injury. Bronchoscopy and thoracotomymay be required for diagnosis and repair of bron-chial and pericardial tears.

Exposure of the pericardial sac to damaged airpassages may result in infection and suppurativepericarditis. The patients described received anti-biotics for reasons other than their pericardialtear, and pericardial infection did not occur. Intwo patients troublesome supraventricular tachy-cardia followed release of air, and in one this re-quired digitalisation and beta blockade. In thepresence of anoxia and cardiac trauma the signifi-cance of this arrhythmia is difficult to define.

I am grateful to Mr. P. S. London, Mr. T. A. H.English, and Mr. B. B. Milstein for permission topublish details of these patients; also to Miss S.Dean for secretarial services.

References

Adcock, J. D., Lyons, R. H., and Barnwell, J. B.(1940). The circulatory effects produced in a patientwith pneumopericardium by artificially varying theintrapericardial pressure. American Heart Journal,19, 283-291.

Borrie, J. and Lichter, I. (1974). Pericardial rupturefrom blunt chest trauma. Thorax, 29, 329-337.

Bricheteau, I. (1844). Observation d'hydropneumo-pericarde accompagnee d'un bruit de fluctuationperceptible a l'oreille. Archives Generales deMedecine, 4, 334-339.

Cargill, A. 0. R., Galasko, C. S. B., and Gunning,A. 1. (1973). Pneumopericardium following closedchest injury: a report of two cases. Injury, 4,221-224.

Cimmino, C. V. (1967). Some radio-diagnostic noteson pneumomediastinum, pneumothorax, and pneu-mopericardium. Virginia Medical Monthly, 94,205-212.

Cohen, S. and Lockhart, C. H. (1970). Pneumoperi-cardium: a complication of prolonged ventilation.Anesthesiology, 32, 465-467.

Khan, R. M. A. (1974). Air tamponade and tensionpneumopericardium: an unusual complication ofsubtotal pericardiectomy. Journal of Thoracic andCardiovascular Surgery, 68, 328-330.

McCaughey, W. and King, R. (1975). Pneumoperi-cardium associated with tracheal rupture: manage-ment of a case complicated by the shock lungsyndrome. Anaesthesia, 30, 199-205.

Rosen, A., Vaudagna, J., and Jamplis, R. W. (1963).Spontaneous pneumopericardium. American Reviewof Respiratory Diseases, 87, 764-765.

Sagel, S. S., Wimbush, P., and Goldenberg, D. B.(1973). Tension pneumopericardium followingassisted ventilation in hyaline membrane disease.Radiology, 106, 175-178.

Shackelford, R. T. (1931). Hydropneumopericardium.Journal of the American Medical Association, 96,187-191.

Toledo, T. M., Moore, W. L., Nash, D. A., andNorth, R. L. (1972). Spontaneous pneumopericar-dium in acute asthma. Chest, 62, 118-120.

Requests for reprints to: Dr. S. Westaby, Depart-ment of Surgery, Addenbrooke's Hospital, Cambridge.

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after closed-chest injury.tension pneumopericardium Penumopericardium and

S Westaby

doi: 10.1136/thx.32.1.911977 32: 91-97 Thorax

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