Case Report

Adolescent pneumopericardium and pneumomediastinum after motor vehicle crash and ejection

Abstract

A 15 year old male was an unrestrained passenger in a high speed motor vehicle crash followed by ejection. The patient was noted to have evidence of bilateral pneumothorax upon arrival in the Emergency Department. Bilateral chest tubes were placed under sterile conditions; however, the left pneumothorax remained, and a second left chest tube was placed. Repeat chest radiographs revealed extensive sub- cutaneous emphysema, pneumomediastinum, and pneumo- pericardium. Needle aspiration of the pericardium returned significant quantities of air, an immediate improvement in blood pressures followed. An 18-gauge triple lumen catheter was placed into the pericardial space for additional with- drawal of air via syringe.

Mechanisms have been proposed to explain the develop- ment of Tension pneumopericardium after chest trauma. Early diagnosis is crucial, and may be found on initial chest radiographs. Computed tomography is also an effective method for evaluating the presence of air in the pericardial space and may assist in establishing the diagnosis. Tension pneumopericardium requires immediate recognition and decompression to prevent cardiac tamponade with a fatal circulation collapse, an entity that is as serious as the tamponade resulting from hemopericardium.

Traumatic pneumopericardium is rare, but can be a complicated finding associated with high-speed blunt chest trauma. Patients with evidence of pneumopericardium should be closely monitored, particularly those supported by positive pressure ventilation.

A 15 year old male was an unrestrained passenger in a high speed motor vehicle crash with ejection. The patient had a Glasgow Coma Scale of 14 when paramedics arrived; however, the patient reportedly lost consciousness en route to the closest receiving medical facility. Emergency Medicine physicians noted bilateral pneumothoraces and placed bilateral chest tubes. The left pneumothorax did not resolve. A second chest tube was placed on that side. The patient was then transferred to the regional trauma center by helicopter flight paramedics.

Upon arrival to the trauma center, the patient was noted to be hypotensive with blood pressure 90/60 and hypoxemic by

face mask ventilation. Chest radiographs were taken and shown (Fig. 1) revealing extensive subcutaneous emphysema, pneumomediastinum, and pneumopericardium. Additional bilateral 36 French chest tubes were placed. Diagnostic peritoneal lavage was also performed and was unremarkable. Needle aspiration of the pericardium was performed and returned significant quantities of air with noted immediate improvement in blood pressures to 140/90. An 18 gauge triple lumen catheter was thread over a guide-wire into the pericardial space for additional withdrawal of air via syringe (Fig. 2). Transthoracic echo-cardiogram and Electrocardiogram revealed no abnormalities as did Telemetry monitoring while in the resuscitation bay.

Pneumopericardium is both unusual and rare. Case reports have documented tension pneumopericardium from events such as laparoscopy, endoscopy, neonatal ventilation as well as blunt and penetrating chest trauma [1-4]. Pneumopericardium may also be associated with and complicate high-speed blunt chest trauma as seen in this case. Patients with evidence of pneumopericardium should be monitored frequently and closely, particularly those on positive pressure ventilation as their symptoms may develop suddenly and their condition may deteriorate rapidly.

Traumatic pneumopericardium, although extensively examined and reviewed, remains a poorly recognized diagnosis due to the instability and Hemodynamic compromise found in critically ill and severely injured trauma patients [5,6].

Fig. 1 Large-scale air leak with pneumothoraces, extensive subcutaneous emphysema and pneumopericardium.

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Fig. 2 Improved pneumopericardium. Tiny pneumothoraces still present. Stable subcutaneous emphysema over the chest. Pneumo- mediastinum extends into the neck.

Levin et al. [1] also reported hemodynamic compromise in 37% of their 263 reported cases of pneumopericardium [1]. Hypotension can result from multiple injuries that typify the scenario in a trauma patient such as those found with intra- abdominal bleeding or Tension pneumothorax. Hypotension may also be secondary to the beta-blockers used to treat concomitant aortic injury, seen in deceleration injuries.

Several mechanisms have been proposed to explain the development of tension pneumopericardium after chest trauma:

1. Increase in intra-alveolar pressure produces a rupture of the alveolar walls, and air can travel down peribronchial and vascular sheaths to gain access into the pericardium and then enter the mediastinum [4]. In these cases, pericardial tissue is not contiguous at the reflection of the parietal and visceral pleura near the osteopulmonary veins leading to pneumopericardium. These connec- tions may also explain the phenomena of Free air in the abdomen after severe thoracic pathology [3].
2. In patients with positive-pressure ventilatory support, air could be forced along perivascular sheaths into the pericardium. A one-way valve mechanism may develop in the pericardium, and the air can enter the pericardial sac but cannot exit [7].
3. Another possible mechanism is air dissecting into the pericardial sac and free disruption of the tracheobronchial tree with direct communication of the pericardium via fibrous attachment [7].
4. Direct communication may also develop between a tension pneumothorax and pericardial space [7].

Early diagnosis is crucial. In our case, the diagnosis was initially established by chest radiograph; however, computed tomography is an effective method for evaluat-

ing the presence of air in the pericardial space and may permit the diagnosis of tension pneumopericardium [8]. Ultrasound imaging may obscure cardiac views due to subcutaneous emphysema.

Tension pneumopericardium requires immediate recogni- tion and decompression to prevent cardiac tamponade with a fatal circulation collapse, an entity that is as serious as the tamponade resulting from hemopericardium.

Mark K. Markarian MD, MSPH

Texas Tech University Health Sciences Center

Department of Surgery Lubbock, TX 79430, USA

E-mail address: [email protected]

David A. MacIntyre DO Benjamin J. Cousins MD John J. Fildes MD

University of Nevada School of Medicine

Department of Surgery Division of Trauma and Critical Care University Medical Center/UMC

Las Vegas, NV 89102, USA

Alexander Malone MD University of Nevada School of Medicine Department of Emergency Medicine University Medical Center/UMC

Las Vegas, NV 89102, USA

doi:10.1016/j.ajem.2007.08.008

References

1. Levin S, et al. Cardiac tamponade without pericardial infusion after blunt chest trauma. Am Heart J 1996;131:198-200.
2. Capizzi PJ, et al. Tension pneumopericardium following blunt injury. J Trauma 1995;39:775-80.
3. Siplovich L, Bar-Ziv J, Karplus M, et al. The pericardial “window”: a rare etiologic factor in neonatal pneumopericardium. J Pediatr 1979; 94:975.
4. Macklin CC. Transport of air along sheaths of pulmonic blood vessels from alveoli to mediastinum: clinical implications. Arch Intern Med 1939;64:913-26.
5. Gorecki PJ, et al. Tension pneumopericardium in chest trauma. J Trauma 1999;46:854-956.
6. Swanson J, et al. Trauma to chest wall, pleura, and thoracic viscera. In: Shields TW, editor. General thoracic surgery. Philadelphia: Lea and Febiger; 1989. p. 461-73.
7. Wetsby S. Pneumopericardium and tension pneumopericardium after closed chest injury. Thorax 1977;32:91-7.
8. Hernandez-Luyando L, et al. posttraumatic tension pneumorpericar- dium. Am J Emerg Med 1997;15:686-7.