Chapter 13 – Pulmonary Trauma




Abstract




Chest trauma is present in almost two thirds of all trauma patients, varying in severity from a simple rib fracture to penetrating injury to the heart.1 Blunt chest trauma accounts for 90% of cases, where less than 10% require surgical intervention.1 Understanding chest trauma mechanism is key to the approach when evaluating and managing an individual with potential chest trauma.





Chapter 13 Pulmonary Trauma


Manpreet Singh and Dennis Kim


Chest trauma is present in almost two thirds of all trauma patients, varying in severity from a simple rib fracture to penetrating injury to the heart.1 Blunt chest trauma accounts for 90% of cases, where less than 10% require surgical intervention.1 Understanding chest trauma mechanism is key to the approach when evaluating and managing an individual with potential chest trauma.


The primary survey should focus on excluding or treating the life-threatening injuries in Box 13.1.




Box 13.1 Primary Survey





  1. 1 – Airway obstruction



  2. 2 – Tension pneumothorax



  3. 3 – Open pneumothorax



  4. 4 – Massive hemothorax



  5. 5 – Flail chest



  6. 6 – Cardiac tamponade*





* These entities will be discussed in Chapter 14.


The secondary survey should focus on excluding or treating the potential life-threatening injuries in Box 13.2.




Box 13.2 Secondary Survey





  1. 7 – Pulmonary contusion



  2. 8 – Myocardial contusion*



  3. 9 – Aortic disruption*



  4. 10 – Traumatic diaphragmatic rupture



  5. 11 – Tracheobronchial disruption



  6. 12 – Esophageal disruption





* These entities will be discussed in Chapter 14.



Airway Obstruction




  • Pathophysiology: Airway obstruction is a major cause of death and morbidity, where the mantra of airway management with in-line cervical spine stabilization is key.



  • Presentation: Details on airway obstruction presentation discussed in Chapter 2.



  • Treatment: Details on airway obstruction management discussed in Chapter 2.



Procedure – In-Line Stabilization


This is key to maintain a neutral position so the head is not inadvertently moved due to a concern for cervical spine injury, which may be unstable. There is a 2–12% risk of cervical spine injury in major trauma, where 7–14% may be unstable.2 Approximately 10% of comatose trauma patients have a cervical spine injury.2


To perform in-line stabilization, an assistant crouches at the head of the bed beside the intubator, with the assistant’s hands on the patient’s trapezius muscles, supporting the patient’s head between the forearms. Alternatively, standing beside the patient in the front, the assistant can hold the head with his/her hands while anchoring at the trapezius.



Tension Pneumothorax




  • Pathophysiology: This injury is associated with the presence of intra-pleural air under positive-pressure from the respiratory cycle. Air enters the chest in a one-way valve type manner, but it cannot leave. As a result, with build-up of intra-pleural air there is reduced blood return to the heart (decreased preload), leading to decreased cardiac output (Figure 13.1).3



  • Presentation: Prompt recognition is key, so always consider this in a rapidly deteriorating patient with signs of pneumothorax, which include worsening tachycardia and respiratory distress, eventually leading to cardiac collapse. Findings such as tracheal deviation, distended neck veins, and displaced PMI are late findings, where there is considerable variability of their presence.3



  • Diagnosis: This can be difficult, as mentioned above, so reliance on history alone may be key in the correct clinical context. It can present in an intubated traumatic patient, where ventilation becomes progressively difficult, leading to high peak airway pressures.3 Ultrasound can provide rapid diagnosis by demonstrating a lung point due to absent lung sliding.



  • Treatment: Management requires immediate chest decompression, through either needle decompression or finger thoracostomy followed by chest tube placement.3






(A) Illustration showing mechanism of tension pneumothorax. Extrapulmonary air under tension collapses the lung, depresses the diaphragm, and pushes the heart toward the opposite side. The normal lung is compressed in the contralateral pleural cavity. These changes cause cardiorespiratory failure.





(B) Chest x-rays showing a large tension pneumothorax on the left side, mediastinal shift to the opposite side, and downward displacement of the left hemidiaphragm. Arrows point to tension pneumothorax.





(C) Tension pneumothorax on the CT scan (arrow). Note the deviation of the heart to the right.





(D) Photograph showing a thoracostomy needle in place, below the middle of the clavicle.





(E) CT scan shows that the thoracostomy needle is located into the subcutaneous tissues, outside the pleural cavity. This is a common technical problem


(reproduced with permission from Color Atlas of Emergency Trauma, Second Edition, illustration at (A) by Alexis Demetriades)


Figure 13.1 Tension pneumothorax.



Procedure – Needle Decompression


Traditional treatment includes placement of a large bore angiocatheter in the second intercostal space at the mid-clavicular line.4 Incorrect placement can lead to vascular (internal mammary or subclavian) or cardiac damage. However, it may only be effective 20–50% of time due to chest wall thickness.4


Longer angiocatheters have been advocated as they tend to increase the success rate, but the risk/benefits should be weighed.4 Iatrogenic vascular, visceral, and parenchymal injuries have been reported using longer ones. Recently, many have advocated the fifth intercostal space at the mid-axillary line as a location of decompression, where there is a thinner chest wall and no major blood vessels nearby.4 Though potentially safer, the major downsides of this include dislodgement in transport with movement of the patient arms on the side (Figures 13.2 and 13.3).


Figure 13.2



(A) Illustration showing the sequence of open chest tube insertion. The patient is in the supine position, and the arm is abducted at 90 degrees (a). The insertion site should be in the midaxillary line, at the fourth or fifth intercostal space (b). Abduction and internal rotation of the arm is a suboptimal position because of the interposition of the latissimus dorsi muscle (c). The tube is directed posteriorly toward the apex (d).





(B) Photograph showing thoracostomy tube being secured in place with horizontal mattress suture


(reproduced with permission from Color Atlas of Emergency Trauma, Second Edition, illustrations by Alexis Demetriades)




Figure 13.3 Illustration depicting step-by-step the insertion of a chest tube with the percutaneous dilational technique (illustration, photograph of procedure, thoracoscopic view): The needle, attached to a syringe containing sterile water, is inserted through the fourth to fifth intercostal space, close to the superior border of the rib, in order to avoid injury to the intercostal vessels. (A) Aspiration of air or blood confirms the intrathoracic position of the needle. (B) A guidewire is inserted though the needle into the thoracic cavity. Serial dilatation over the wire (C) is followed by insertion of the chest tube over the guidewire (D)


(reproduced with permission from Color Atlas of Emergency Trauma, Second Edition, illustrations by Alexis Demetriades)


Procedure – Pleur-Evac Setup and Troubleshooting


All chest tube collection systems are based on three chambers: (1) Collection Bottle, (2) Water Seal, and (3) Suction Control. Fluid from the chest drains into the first bottle, whether it is serous or sanguineous fluid. The collection chamber is graduated and measured.5 Bottle one is for chest tube fluid control. Bottle two is for chest tube air control. Air from the chest tube bubbles into bottle two, which is the water seal and usually 2 cm. This is called the “air leak” monitor, and it also prevents air from entering back into the chest tube system. The water seal should show bubbling, which should diminish over time once a pneumothorax is resolving. A persistent leak suggests a leak at the insertion site or bad chest tube, or tracheobronchial injury. Obstruction usually results in no bubbling. When no suction is applied, it is set to water seal.5 Bottle three is the vacuum or suction control, which allows for precise control on suction. There is an atmospheric vent, which is the safety valve of the system, submerged in 20 cm of water.



Procedure – Chest Tube Removal


A suture removal set and dressing material should be ready, along with proper dressing (glove, gown, mask, and eye shield). Explain to the patient the procedure. The goal is to pull the tube before any air can enter the thorax and have the patient increase intra-thoracic pressure by holding his/her breath and bearing down doing a valsalva maneuver. If the patient is ventilated, perform an inspiratory pause. Pull the chest tube and put a dressing on the site. Keep this on for 48 hours, and keep dry and clean.1



Open Pneumothorax




  • Pathophysiology: This is described as a “sucking chest wound,” which occurs when the wound is greater than two thirds of the diameter of the trachea. At a wound this size, air will enter a chest wall wound, preferentially leading to pneumothorax.6



  • Presentation: Besides visible “sucking” of air into the wound, there is rapid, shallow, and labored breathing with reduced hemithorax expansion accompanied by decreased breath sounds and hyperresonance on physical exam.6



  • Diagnosis: Visible “sucking” of air or dressing overlying the wound is often visible on exam cueing the diagnosis.



  • Treatment: Cover the wound with an occlusive 3-sided dressing that acts as a flutter valve to allow air out, but prevents “sucking in.”6 After this, a formal tube thoracostomy is placed, while the wound is formally explored at another time.



Massive Hemothorax




  • Pathophysiology: This condition may result in exsanguination from blunt or penetrating injury, originating from major vessels, intercostal vessels, heart, or lungs (Figures 13.4 and 13.5).1



  • Presentation: Signs of hemorrhagic shock based on vitals and physical exam may be present, where the patient may become anxious or agitated. Massive hemothorax that meets the following indications may need thoracotomy urgently:1, 7




    • Initial output >1500 cc (approximately 1/3rd blood volume)



    • Output >200 cc/h for 2–4 hours




  • Diagnosis: Though diagnosis is partly based on chest tube output, always consider it with a large volume hemothorax diagnosed on exam (difficult to appreciate) or imaging (i.e. CXR or ultrasound) in a dyspneic, hemodynamically unstable patient.1



  • Treatment: Resuscitation is key to rapidly restore blood volume lost while definitive management is taken by the trauma surgeon. Large bore IV access is recommended through upper extremity peripherals, humeral IO, or central access. Using autotransfusions, as well as activating the massive transfusion protocol, may be required for resuscitation.






(A) Chest radiograph with extensive opacification of the left hemithorax due to massive hemothorax with mediastinal shift to the opposite side and retained fragments of a missile.





(B) Gunshot wound to the left chest with suspected “residual hemothorax” on chest x-ray (left) 2 days after injury. Residual hemothorax is confirmed by CT scan (right).





(C) Thoracoscopic evacuation of the residual hemothorax. The procedure should be performed within the first 5 days of injury, before organization of the clot and fibrin encapsulation of the lung.





(D) Photograph of material removed during decortication for persistent residual hemothorax and lung entrapment, a few weeks after injury. Delayed evacuation of a clotted hemothorax is difficult and requires thoracotomy and decortication


(reproduced with permission from Color Atlas of Emergency Trauma, Second Edition)


Figure 13.4 Hemothorax.





Figure 13.5 Image demonstrating arterial blush in a patient with massive hemothorax following chest tube insertion


(image: Dennis Kim, MD)


Procedure – Autologous Transfusion


Most chest tube collection systems have optional autotransfusion canisters, which are used to collect blood and hung like a bag of blood from the blood bank.7 It is key to heparinize the collection system prior to this, though some state the blood may be retransfused up to 6 hours. Ultimately, the manufacturer’s instructions should be followed (Figure 13.6).





Figure 13.6 Autotransfusion system utilization in hemothorax. The collection chamber of the drainage system (circle) is connected to a negative pressure autotransfusion bag and the blood is actively sucked into the bag (A). (1 mL of citrate per 10 mL of blood is added to the collection system before drainage.) The collected blood is autotransfused using standard techniques (B)


(reproduced with permission from Color Atlas of Emergency Trauma, Second Edition)

Though autologous transfusion has been shown to provide immediate blood for resuscitation and pose no serious complications,8 it is associated with pro-inflammatory cytokines, is depleted of coagulation factors compared to venous blood, and one “unit” of autologous transfused blood is less than one unit of pRBC.9, 10 Further research is required to evaluate patient outcomes with autologous transfusion.

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Jan 10, 2021 | Posted by in EMERGENCY MEDICINE | Comments Off on Chapter 13 – Pulmonary Trauma
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