In this post I will attempt to give an account of the indications for an emergency thoracotomy in chest trauma. The discussion will focus on penetrative chest injuries causing haemodynamic instability, and when CT scan preoperatively cannot be obtained safely. I will then discuss factors that may influence the surgeon’s decision for the choice of incision. The step by step technique for each approach will be covered separately. Dealing with major chest trauma is often stressful for doctors. Knowing when and how to perform an emergency thoracotomy quickly but safely can be life-saving.
Indications for Surgery
Most patients in need of emergency thoracotomy are often too unstable to go through a CT scan. What makes a patient cardiovascularly too unstable to undergo a CT scan depends on a combination of two factors: 1) the patient’s blood pressure and 2) the ease of access to the scanner. It is important to highlight that not all accident and emergency departments have rapid access to an on-site CT scanner. Instead, it is the bedside clinical judgement that is the decider. It is also fair to say that emergency thoracotomy has almost no role in the management of blunt decelerating injuries, since most of these patients unfortunately either die on route or die shortly after arrival at the hospital.
The vast majority of patients in need of emergency thoracotomy are those with penetrating trauma. In the UK penetrating chest trauma is most commonly caused by stab injuries and less commonly by gun shots. When compared to a gun shot injury, a knife injury often involves fewer injured organs, and unlike a gun shot, a knife injury does not involve both an entry wound and an exit wound.
The most urgent of all penetrating chest injuries is a stabbed heart. This should be suspected in any penetrating injury to the anterior thoracic wall. The patient could be showing clinical signs of tamponade, including muffled heart sounds, raised JVP, low BP, and pulsus paradoxus (a drop of at least 10 mmHg in arterial blood pressure with inspiration). FAST scan could be very useful when available, but these patients often require urgent surgical exploration.
Many patients would have had a chest drain(s) soon after their arrival at the emergency department and the volume of blood aspirated from any drain would have been recorded. A volume of 1.5 litres or more is often taken as an indication for a thoracotomy. However, this should be put in the context of the individual patient’s clinical picture. If such a patient is clinically stable without ongoing blood loss through the drain, an emergency thoracotomy may be deferred, pending the results of a CT scan.
Choice of Incisions
For most clinical scenarios, and when no pre-operative imaging is available, the default is a clamshell incision. The incision often starts as a left antero-lateral thoracotomy through the 4th intercostal space. At times this my be started from the right side if the problem clearly stems from the right chest. The surgeon should have a very low threshold for extending this incision to the contralateral intercostal space for a full clamshell. This provides excellent exposures of aorta, heart, lungs and oesophagus, however it provides less optimal views of the superior mediastinum particularly for injuries to the base of the neck and the superior thoracic aperture. If required, a sternotomy can be added to a clamshell. However in a known injury to the superior mediastinum, a midline sternotomy may be the best approach initially. A special mention is due for injuries over the right thoracoabdominal area. This area extends from the right 5th intercostal space superiorly and a horizontal line crossing the most inferior aspect of the rib cage inferiorly. In this case, and when no preoperative imaging can be obtained due to patient’s condition, a midline laparotomy is often the starting point to look for any liver trauma. Occasionally a pericardial window can be made from the cephalad end of the laparotomy incision, for a rapid inspection of the pericardial space to check for cardiac tamponade. The laparotomy can then be extended into the left chest over the 7th intercostal space for a left thoracoabdominal incision for a more definitive approach to the heart. A laparotomy can always be abandoned and a clamshell incision made instead, in case of unexplained hypotension but a negative laparotomy. You notice that the trauma surgeon should continuously reassess the adequacy of any exposure and change tacks as required.