Finally, the chest is open and the tamponade has been relieved. But your patient has little volume. In order to conserve any circulating blood and pump it only to the heart and the head, it’s time to cross clamp the aorta. This task is best left to the surgeon, because it is not a simple matter.
First, you have to locate the aorta, ideally somewhere just above the diaphragm. Unfortunately, if the patient is hypovolemic it’s very difficult to distinguish the aorta from the esophagus, which lie right next to each other (see picture above). In order to make them feel different, insert a gastric tube through the mouth or nose.
Next, separate the aorta and esophagus. They are both covered by pleura. The structure nearest you without the tube in it will be the aorta. Sometimes it’s possible to use a finger to dissect through the pleura and around the aorta. However, the younger the patient, the tougher this tissue is. It may be necessary to incise the pleura with scissors while your assistant holds the lung anteriorly, our of the way.
Finally, once you can pass a finger completely around the aorta, use it to guide the placement of a gently curved DeBakey type clamp (see picture on the left). Squeeze it until it clicks once, and you are done! Now rapidly infuse warmed blood into the patient and run to the OR!
Once the chest is open, the first item of business is to check the heart. In some patients, the inferior pulmonary ligament may prevent you from pushing the lung laterally and superiorly, out of the way. This ligament is a piece of pleura that attaches the lower lobe to the medial diaphragm and mediastinum. Locate it with your fingers and carefully cut it (blindly) with your scissors.
Now look at the heart. What is the rhythm? Put your hands around it. What is the patient’s volume status? If there is the possibility of a penetrating injury, open the pericardium. This structure is tough, and if tamponade is present it will be stretched tight. I find it very difficult to grab the pericardium with forceps and make the initial incision with scissors. Toothed forceps may work, but I just make a very small nick, carefully and directly, with a scalpel. The incision should be placed anterior to the phrenic nerve and vessels, which are usually plainly visible. See the picture on the left, above. The color of the pericardial fluid will immediately indicate whether a cardiac injury is present.
Next, extend the incision (parallel to the bed) to the top and bottom of the ventricle and eviscerate the heart. This will allow careful inspection of all but the atria. If an injury is present, a finger can be used to occlude it until preparations for a repair are made.
Holding the heart is both diagnostic and potentially therapeutic. The “fullness” of this organ is an excellent indicator of the volume status, and if a finger is being used to plug a hole, the temperature of the blood and infused fluids can be determined quickly. All volume resuscitation in this situation should be warmed fluids. And if need be, open cardiac massage is very effective for augmenting circulation.
Performing a proper emergency thoracotomy is more difficult than you think. There are lots of details to consider, and the learning curve is steep. I’m going to split the process into three parts: getting in, dealing with the heart, and clamping the aorta.
The most important part of getting in is setting up your team. Someone has to be assigned to make sure the chemical and volume resuscitation part is carried out, because the person actually doing the thoracotomy is going to be busy. The most experienced person in the room will actually perform the procedure, or assist the physician who will be learning the procedure.
Next, protect yourself! This is a dangerous procedure. Emotions run high, and people are holding sharp objects. You don’t know where your patient has been or what is circulating in the little blood they may have left, so be careful and make sure you are wearing your personal protective equipment.
Finally, make the incision. This is usually placed along the fifth intercostal space, which is just under the nipple in men. Don’t start too close to the sternum, or you may cut the internal mammary artery. This won’t bleed until circulation is restarted, but it takes some effort to stop it later. Some people prefer a straight incision down toward the table, but I prefer a curved incision that follows the ribs, as illustrated.
Use the scalpel to incise skin, subcutaneous tissue and muscle. However, stop short of the pleura while you are incising the intercostal muscles. If you try to cut through the pleura with the knife, it’s alarmingly easy to injure the lung, or even the diaphragm. Use scissors instead.
Now it’s time to insert the retractor. I prefer to place it with the handle pointing down toward the feet so it doesn’t get jammed against the arm. This is not nice, polite thoracic surgery. You don’t open it a few turns and wait, trying to avoid rib fractures. Open it fast and all the way. Ribs will break, so be careful from this point onward so you don’t cut yourself on their sharp edges.
I still encounter a quite a bit of confusion about ED thoracotomy: when to do it, when to stop. A nice set of guidelines was developed by the Subcommittee on Outcomes of the American College of Surgeons Committee on Trauma about 10 years ago. And really, things haven’t changed very much since then.
In general, the literature on this topic has been all over the place. Most studies are retrospective with very little statistical validation. But there’s a lot of it out there. The subcommittee used fairly standard methods to evaluate the literature and come up with some recommendations.
The overall survival rate for all comers was 8% (11% for penetrating, 1.6% for blunt). About 15% of survivors (no breakdown of blunt vs penetrating) suffered from neurologic impairment. Penetrating cardiac injury had the best survival (31%). In the 4 studies on children, the survival numbers paralleled the adults.
Because of the relatively weak quality of the data, only level II recommendations were given. They were:
Don’t consider ED thoracotomy in blunt trauma patients unless the patient arrests in front of you. Otherwise, meaningful survival is almost nonexistent.
Consider ED thoracotomy for penetrating chest injury if there were witnessed signs of life and a short transport time (5-10 minutes max, in my opinion). Look for pupillary response, spontaneous respirations, palpable pulse, or a narrow complex cardiac rhythm.
ED thoracotomy for penetrating abdominal injuries has a low survival rate, but can be considered if the injury may involve the chest.
Consider thoracotomy for suspected abdominal vascular injury, but survival is also very low.
The guidelines above apply equally to children.
Practical tips: ED thoracotomy is a seldom used and dangerous procedure. There are many opportunities for injury to trauma professionals, so be selective and take precautions. Assign someone to run the chemical code while the surgeons open the chest. Watch out for broken ribs and scalpels gone wild!
I’ll post pictures and specific pointers over the next three days.