Article, Surgery

Pneumopericardium in blunt chest trauma after high-speed motor vehicle accidents

Pneumopericardium in blunt chest trauma after high-speed motor vehicle accidents

Roland Ladurner MD, Lars M. Qvick MD, Felix Hohenbleicher MD, Klaus K. Hallfeldt MD, Wolf Mutschler MD, Thomas Mussack MD*

Department of Surgery Innenstadt, Klinikum der Universita?t Mu?nchen, D-80336 Munich, Germany

Received and accepted 18 January 2004

Abstract Pneumopericardium is the presence of air in the pericardial space. In adults, it may be seen in the context with severe blunt chest trauma, pneumothorax, pneumoperitoneum, or other causes of pneumomediastinum. The diagnosis is made by computed tomography scan of the thorax and abdomen that allows the additional detection of concomitant injuries. Possible causes of the pneumopericardium such as tracheobronchial or oesophageal tears have to be excluded by bronchoscopy or esophagogas- troduodenoscopy. Usually, pneumopericardium is self-limiting requiring no specific therapy. However, a continuous monitoring of the electrocardiography and the blood pressure is necessary at an intermediate care unit. Tension pneumopericardium causing a life-threatening cardiac tamponade requires an immediate pericardial aspiration, the subsequent pericardial drainage via a pericardial window or emergent open subxyphoid approach to the pericardium.

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Introduction

Pneumopericardium in adults is a rare disorder and may be seen most commonly after blunt chest trauma in combination with pneumothorax or pneumomediastinum. Motor vehicle accidents (72.2%) and falls (17.1%) are reported to be the most frequent causes of these blunt chest injuries in polytraumatized patients [1,2]. More than 30% of cases with posttraumatic pneumopericardium displayed clear evidence of tension pathology [3,4]. Up to now, no

* Corresponding author. Tel.: +49 89 5160 2638; fax: +49 89 5160

4489.

E-mail address: [email protected] (T. Mussack).

data are available about how often a pneumopericardium is detected in case of blunt Thoracic trauma. The objective of this report is to discuss the adequate diagnosis and treatment of patients with pneumopericardium on a case series.

Case reports

Case 1

A 24-year-old man was involved in a high-speed motor vehicle accident with a resultant Glasgow Coma Scale score of 15 points, blood pressure of 110/80 mm Hg, and spontaneous breathing of 12/min. After extraction, he was admitted to an outside hospital because of blunt chest

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Fig. 1 The anteroposterior chest radiography shows suspicious streaks of air in the mediastinal fat.

trauma and discharged after unsuspicious clinical examina- tion and x-ray. Five hours later, he was readmitted to our hospital complaining increasing Thoracic pain. The ante- roposterior chest radiography showed suspicious streaks of air in the mediastinal fat (Fig. 1). The subsequent axial computed tomography (CT) scan demonstrated a pneumo- mediastinum and a nontension pneumopericardium with a maximum diameter of 8 mm (Fig. 2). The patient was transferred to the intensive care unit (ICU) for clinical surveillance and breathing training. All further examinations including Electrocardiography , bronchoscopy, gas- troscopy, ultrasound, and continuous monitoring of the blood pressure showed normal findings. The patient could be discharged again at day 5 after readmission in good healthy status.

Case 2

A 35-year-old man was transferred to our emergency room after a high-speed car accident. On scene, he was fully conscious (GCS, 15). Because of aggravating

Fig. 2 Axial spiral CT of the thorax demonstrates a pneumo- mediastinum and a nontension pneumopericardium with a maxi- mum diameter of 8 mm.

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Fig. 3 Spiral CT of the thorax shows bilateral pulmonary contusions, a right Tension pneumothorax, and a pneumopericar- dium with a maximum diameter of 15 mm.

dyspnea, thoracic pain, subcutaneous emphysema, and reduced breathing sounds over the right hemithorax, the patient was intubated and a chest tube was placed on the right side. Primary clinical and CT examination (Injury Severity Score, 50 points; Revised Trauma Score, 7.55) showed bilateral pulmonary contusions, right tension pneu- mothorax, pneumopericardium with a maximum diameter of 15 mm (Fig. 3), multiple rib fractures of the right side (C1-C12), grade I liver and grade I right kidney rupture, and a stable fracture of the pelvis. Two additional CT- guided Chest tubes were inserted to treat right tension pneumothorax. Bronchoscopy and esophagogastroduode- noscopy revealed no evidence of tracheobronchial or Esophageal rupture. The ECG showed a normal myocardial function without suspicious abnormalities of the wall motion. During the next 2 days on ICU, we registered slightly increased Creatine phosphokinase -MB isoen- zyme and troponin T levels that decreased below threshold values at day 3. After 2 weeks of artificial ventilation, the

Fig. 4 Spiral CT of the thorax reveals a left tension pneumo- thorax, bilateral pulmonary contusions, multiple left rib fractures, and air in the pericardial sac.

Pneumopericardium in blunt chest trauma after high-speed motor vehicle accidents 85

Fig. 5 Intraoperative view of a pericardial tear as the origin of the pneumopericardium.

patient was extubated and transferred to an outside rehabilitation center 1 week later.

Case 3

A 23-year-old man was admitted to our hospital after being involved in a motor vehicle accident. On scene, he presented a GCS score of 15 points, blood pressure of 130/ 80 mm Hg, and spontaneous breathing with 14/min. How- ever, he suffered from a complete sensomotoric neurological deficit below the fourth thoracic spinal nerve. Primary CT evaluation demonstrated Le Fort II fracture, left tension pneumothorax bilateral hematothoraces, bilateral pulmonary contusions, multiple left rib fractures C1-C7, air in the pericardial sac (Fig. 4), unstable thoracic spine fracture (fourth and fifth dorsal vertebra), grade III liver rupture, and grade I spleen injury (Injury Severity Score, 45 points; Revised Trauma Score, 7.84). After insertion of a left chest tube, the patient had been transferred to the ICU. During the first 3 days, he showed ECG alterations and elevated CK-MB isoenzyme and troponin T levels. Bronchoscopy showed no evidence of a tracheobronchial tear as the origin of the pneumopericardium. Ten days after admission, the unstable thoracic spine fracture has been stabilized by anterior thoracic fusion (vertebrae T3 – T7) with a titanium plate and an Iliac crest bone graft through a transthoracic approach. During this operation, we identified a pericardial tear as the origin of the pneumopericardium (Fig. 5). Three weeks after admission, the patient was transferred to rehabilitation center for patients with spinal cord injuries.

Discussion

Pneumopericardium in blunt chest trauma is suggested to be caused by an abrupt increase of the intrathoracic pressure

with the rupture of the alveoli. In this case, the severity of the trauma must be great enough to cause pleuropericardial and bronchial tears.

If the visceral pleura is disrupted, the air will escape into the pleural space causing a pneumothorax. If the visceral pleura remains intact, the air reaches the interstitial tissue of the lung. From the pleural space, the air can expand into the pericardium if there exists a pericardial tear. In this context, congenital pleuropericardial connec- tions have also been discussed [3,5]. Without having a pneumothorax, the air can also reach the pericardial space along the pulmonary vessels. Finally, a direct tracheobron- chial pericardial communication might be another cause of pneumopericardium.

Initially, every pneumopericardium is a nontension pneumopericardium. Presumably, under conditions of elevated pleural and intrapulmonary pressure such as mask valve ventilation or intubation and controlled artificial ventilation, air can be forced from the ruptured alveoli or the pleural space into the pericardial sac leading to a tension pneumopericardium [6]. Capizzi et al [3] noticed in 10 of 12 patients with blunt chest trauma the development of tension pneumopericardium after endotracheal intuba- tion, suggesting the iatrogenic barotrauma to contribute the tension effect.

The diagnosis of a pneumopericardium is made by a Plain radiography of the chest. In the anteroposterior or lateral projection, the heart may be partially or completely surrounded by air with the pericardium sharply outlined by air density on either side [6]. Pneumopericardium can usually be distinguished from pneumomediastinum, be- cause air in the pericardial sac should not rise above the anatomical limits of the pericardial reflection on the proximal great vessels. In plain radiographs obtained in decubitus patient’s position, air in the pericardial sac will shift in location immediately, whereas air confirmed to the mediastinum will not move during a short interval.

The CT examination usually allows a more accurate assessment of the pneumopericardium and concomitant injuries of the chest. This evaluation is 4 to 5 times more sensitive than supine chest radiography at detecting intrathoracic injuries [7-9]. In a prospective study includ- ing 93 patients after blunt chest trauma, 27% had a primary normal chest radiography. Nevertheless, 52% of these patients revealed pathological CT scans showing additional aortic lacerations (n = 2), Pleural effusions (n = 3), or pericardial effusions (n = 1). The authors recommended the routine use of CT scans in all patients with blunt chest trauma [10].

Usually, the pneumopericardium is self-limiting requir- ing no therapy. However, if the process causes a cardiac tamponade, an immediate pericardial aspiration will be a life-saving maneuver. Clinical signs of a cardiac tampon- ade are paradoxical pulse, tachycardia, low-voltage ECG, increasing central venous pressure with decreasing cardiac output, muffled heart sounds, and worsening pulmonary

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function. The picture of increasing cardiac tamponade may be confused by concurrent conditions such as cardiac contusion, shock lung, hemorrhage, or tension pneumo- thorax. The approach for pericardial aspiration is usually the subxyphoid or the left parasternal route. An 8- to 12- cm needle is attached to a syringe and under Continuous ECG monitoring directed upward and backward at an angle of 458. Suggested direction is toward the left scapula tip [11]. After this procedure, all patients have to be transferred to the operating room where a subxyphoid pericardial window with a percutaneously placed pericar- dial drainage should be performed. The window can be made by an open subxyphoid approach, by open thora- cotomy, or by video-assisted thoracoscopic pericardial approach [5].

Because of the risk of cardiac tamponade, heart failure, or arrhythmias, all trauma patients with pneumopericar- dium should be admitted to the ICU with continuous ECG and Blood pressure monitoring. Especially, patients with concomitant pulmonary contusions and the need of intubation and increased ventilation pressure are at high risk to develop a tension pneumopericardium [3,12]. Diagnostic bronchoscopy is necessary to exclude a tracheobronchial rupture. In cases of pneumopericardium and pneumomediastinum, one should also consider an esophageal injury as the cause of air leakage and perform an immediate esophagogastroduodenoscopy. A concomi- tant pneumothorax is treated by a chest tube connected to low pressure suction.

The diagnosis of a myocardial contusion can be made on the basis of pathological ECG findings, arrhythmias, progressive heart failure, impaired cardial function (ie, reduced ejection fraction), as well as increased CK-MB isoenzyme and troponin T levels. Especially, the ECG allows to determine wall motion abnormalities, to differ- entiate between right- and left-side heart contusion, to check the valve integrity, and to visualize pericardial fluid. However, ECG alterations in pneumoperitoneum are rather unspecific. If significant changes are not observed within the first 24 hours after trauma, it is unlikely that these alterations will develop later [13]. Enzymes such as CK, serum aspartate aminotransferase, and lactate dehydroge- nase are often elevated in patients with severe Blunt chest injury because of the associated trauma of the liver and skeletal muscles. In this context, CK-MB isoenzyme and troponin T levels are more specific [14]. In case of acute myocardial contusion, CK-MB isoenzyme reaches the maximum peak 18 to 24 hours after trauma. However, normal CK-MB isoenzyme levels as well as normal ECG findings may not exclude a myocardial contusion [15,16].

Conclusion

Pneumopericardium is a rare disorder after a blunt thoracic trauma. In most cases, the pneumopericardium is self-limiting requiring no additional therapy. Concomitant injuries of the lung, heart, trachea, bronchus, and esophagus have to be primarily excluded by CT scan, bronchoscopy, esophagogastroduodenoscopy, and echocardiography. Patients are admitted to the ICU with continuous ECG, blood pressure, as well as CK-MB isoenzyme and troponin T monitoring. In cases of cardiac tamponade caused by tension pneumopericardium, a Needle aspiration is required immediately, and a pericardial window with pericardial drainage is to be performed in the operating room.

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