Clinical case: Penetration of the pericardium
They say that if you're an adrenaline junky, you should pick emergency medicine as your specialiity. Indeed, the emergency room is a place where you will encounter patients with life-threatening injuries and to successfully deal with them, you must be someone who knows a lot and thinks fast.
This clinical case of a man who got his thorax and pericardium penetrated by a rebar is something that will definitely give you a glance at what could be waiting for you, if you decide that the ER is your calling.
FAST exam | Focused Assessment with Sonography in Trauma (FAST) is an ultrasound procedure designated to quickly identify free fluid within pericardial, peritoneal and pleural spaces |
Pleural effusion | Presence of abnormal amount of fluid in the pleural cavity. Depending on the type of fluid, it can be hydrothorax (serous fluid), hemothorax (blood), chylothorax (lymph) and pyothorax (pus) |
Pericardial effusion | Presence of abnormal amount of fluid in the pericardial cavity. Similarily to its pleural analogue, it is called hemopericardium if the fluid is blood |
Pneumothorax | Presence of air in the pleural cavity |
After reviewing this case you should be able to describe the following:
- What is meant by a FAST exam? What is evaluated in such an exam?
- What is meant by a pleural effusion? How a pleural effusion is identified on a PA chest radiograph?
- What is meant by a pericardial effusion? How a pericardial effusion is associated with cardiac tamponade?
- What is meant by pneumothorax and how it is recognized radiologically?
This article is based on a case report published in the Journal "Case Reports in Surgery" in 2015, by Caroline C. Jadlowiec, Beata E. Lobel, Namita Akolkar, Michael D. Bourque, Thomas J. Devers, and David W. McFadden.
Case description
The patient (42 year-old-male) presented to the ED with a complete thoracic penetration trauma injury (Figure 1).
The patient had fallen onto a fixed rebar while working on a staircase. The spiral rebar, which was 60 cm long and 8 mm in diameter, penetrated entirely through the thoracic cavity with part of the bar extending beyond the body wall on both sides. The site of penetration was the right anterior axillary line at the seventh intercostal space, and the exit was on the other side at the intersection of the left anterior axillary line and the eighth intercostal space (Figures 1&2).
The patient’s blood pressure at presentation was 90/55 mmHg, his pulse was tachycardic at 120-130 beats/minute, and his oxygen saturation was 92% on room air. The patient, however, was uncommunicative. A FAST (focused assessment with sonography for trauma) ultrasound exam was performed and revealed pericardial effusion, pleural effusion and the possibility of splenic laceration. Accordingly, the patient was considered unstable and immediate surgery was recommended without waiting for any additional radiological investigation.
Management
Because of the thoracic injury and the possible splenic laceration, laparotomy and thoracotomy were performed simultaneously. The laparotomy revealed the absence of intra-abdominal organ injuries (thus, no splenic laceration) and that the diaphragm was completely intact. The extensive thoracotomy allowed the exploration of both hemithoraces and pericardial region concomitantly (Figure 3). It revealed that the rebar penetrated the pericardial cavity; however, no injury was found to either lung, the heart, or to major vessels. The rebar was slowly removed and the surgical procedure was completed. Thorax and mediastinal tubes were removed after postoperative days 2 and 3. The patient was discharged without complications four days after the surgery.
Surgical and anatomical considerations
Impalement thoracic injuries are usually fatal so this case is very unique. The lungs are the most injured organs in penetrating thoracic traumas. Pneumothorax and/or hemothorax are typically observed as a result of pleurae and/or lung injury.
When there is a penetrating wound into the pleural space that allows external air to enter it, the pressure of that air collapses the lung and prevents adequate ventilation (pneumothorax). If there were any air leaking into pleural space from outside or from damaged lungs, bilateral pneumothorax would have developed and have caused a very quick death in this patient. Further, the rebar penetrated the pericardial cavity and as such, it would seem the patient would have suffered cardiac damage and/or would have suffered from cardiac tamponade. Again, apparently, this did not happen. Additional possible causes of death could have been hemorrhage due to the damage to the great vessels in the mediastinum.
We now must attempt to explain why the patient did not die from any of these conditions. And we want to emphasize that we are speculating; but our speculation is based on both anatomical and physiological principles, plus the information provided in the case report.
Now let's try to project the patient's trauma into the lateral chest radiography and hypothesize the location and course of rebar penetration.
Questions to ponder
Why was there no significant damage to major viscera?
Figures 5&6 illustrate our hypothesized rendition of the path of the rebar relative to the thoracic wall and viscera. Note that as the rebar traversed the chest from right to left, it not only traveled transversely but also slightly inferiorly and then passed into the right hemithorax as it penetrated the pericardial cavity. This thus explains why there is no right lung damage. But of course, the parietal pleura was damaged, producing the pleural effusion.
The rebar appears to have actually penetrated the chest wall anterior to the right hemithorax (Figures 1&3). The reason we suspect that the heart was not damaged is either that as the rebar was traversing the pericardial cavity, its blunt end pushed the apex of the mobile heart out its way rather than piercing it, or the rebar simply passed through a fat layer overlying the epicardium. Thus, the absence of heart damage. However, the tearing of the fibrous pericardium does explain the pericardial effusion.
Once in the left hemithorax the rebar was slightly lower than it was on the right and actually passed inferior to the left lung but superior to the diaphragm. Remember that the left hemidiaphragm is lower than the right hemidiaphragm. So in this specific location, again there was parietal pleural damage, but no damage to lung tissue or diaphragm. Had the rebar been traveling right to left in eighth intercostal space on both sides (instead of entering through seventh on right and exiting on eighth on left), it is very likely there would have been severe liver and IVC damage.
Why was there not a clinically significant bilateral pneumothorax that caused the patient’s death?
The absence of a pneumothorax would seem explainable by the soft tissues surrounding the entrance and exit wounds sealing around the rebar. Note in Figures 2&5 the concave and convex orientations of the entrance and exit wounds, respectively. Note also in Figure 2 the puckering of skin surrounding the exit wound. We suggest that the rebar and the soft tissue around it sealed the entrance and exit wounds, preventing significant external air from entering the thoracic cavity.
If the rebar was removed at the accident site, a bilateral pneumothorax would have been very likely. This case highlights the importance of not removing any penetrating injury objects before a patient with an impalement injury is taken to surgery. Similarly, because there was virtually no lung damage, there was not any leakage of air into the pleural cavity from the tracheobronchial tree.
Why was there no damage to the great vessels or the diaphragm?
As noted in the case description, the rebar entered and exited the chest near the anterior axillary lines. At this location, the rebar would pass anterior to the great vessels (Figure 6).
With the following learning materials you can learn everything about the heat in situ and the diaphragm.
Explanations to objectives
Objectives
- What is meant by a FAST exam? What is evaluated in such an exam?
- What is meant by a pleural effusion? How a pleural effusion is identified on a PA chest radiograph?
- What is meant by a pericardial effusion? How a pericardial effusion is associated with cardiac tamponade?
- What is meant by a pneumothorax and how it is recognized radiologically?
FAST exam
It is common in trauma patients for internal injuries not to be apparent upon initial physical exam. Further, trauma patients may not have sufficient cognitive awareness to relate areas of pain, and major hemorrhage into the peritoneal, pleural, or pericardial spaces. Thus, an ultrasound procedure has been developed that is designed to rapidly identify free fluid (usually blood) in the peritoneal, pericardial, or pleural spaces. This procedure is known as the FAST (Focused Assessment with Sonography in Trauma) exam and it has now become the initial imaging test of choice for trauma care.
Ultrasound is the ideal initial imaging modality for trauma cases because it can be performed simultaneously with other resuscitative procedures, providing critical information without the time delay associated with other radiologic procedures such as radiography or CT. Additionally, ultrasound devices are relatively small and portable, which allow their use in the ER without transporting the patient to the radiology unit. That is why the FAST exam was used in this case. Physicians should thus understand the potential benefit of trauma ultrasound but also be aware of their own technical limitations in sonographic exams. Ultrasound exam proficiency requires significant practice and skill to perform well and the images are more difficult to interpret than most other radiographic images such as CT and MRI.
Pleural effusion
A pleural effusion is an abnormal collection of fluid within the pleural cavity. Pleural space normally contains only 5-20 ml of serous fluid. If the production of this fluid increases and absorbance of the fluid decreases, pleural effusion develops. This collection, if accumulates to a significant amount, can impair respiration by limiting the capacity of the lungs to expand. Pleural effusion can be either transudative or exudative based on its protein and LDH content (Light’s Criteria). In the case discussed here mention of pleural effusion in FAST exam was only for the radiological appearance of a fluid in the pleural space. Because the fluid was most likely blood, it would be called hemothorax. In addition to blood, the fluid could be chyle from the thoracic duct injury (chylothorax). Fluid is gravity dependent so a pleural effusion or hemothorax is recognized on a chest radiograph by the blunting of the sharp edges of the costodiaphragmatic (costophrenic) sulci (Figure 7). The sulci are blunted because the gravity dependent fluid, when the patient is upright, collects in the costophrenic recesses.
Pericardial effusion
A pericardial effusion is when there is excess fluid in the pericardial cavity (Figure 8). Similar to pleural space, if the liquid is blood, it is called hemopericardium. Most pericardial effusions are small and not clinically significant but large effusions can impede cardiac action, producing cardiac tamponade, in which the pumping action of the heart is reduced or prevented. Most pericardial effusions are associated with inflammation of the pericardium and uncommonly result in tamponade. However, penetrating cardiac injuries and subsequent hemorrhage are likely to develop tamponade quickly.
Pneumothorax
A pneumothorax occurs when there is air in the pleural cavity. This can occur via an external wound or via air being released from the tracheobronchial tree. Because in a pneumothorax there is air on both sides of the visceral pleura, this layer becomes visible as a line on chest radiographs (Figure 9). The particular patient depicted in Figure 9 had a rib fracture that resulted in a right pneumothorax and also a right hemothorax.
Clinical case: Penetration of the pericardium: want to learn more about it?
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