Heart and Blood Vessel Injuries in the Chest
The heart is relatively protected by the bones and muscles around the chest. Severe injury comes from penetrating trauma to the heart in most cases. Heart injuries account for about 10 percent of deaths due to gunshot wounds. This is a highly lethal injury. Most victims do not survive the trip to the hospital. Injury to the thorax is responsible for 25 percent and many of these deaths are due to blunt cardiac rupture.
Penetrating injury comes from gunshots and knife wounds. The right and left ventricles of the heart are at the greatest risk of injury. The overall mortality is 47 percent. In some cases, there can be foreign bodies inside the heart and pericardial sac, which can lead to infection or blood in the pericardial sac.
Blunt cardiac trauma comes from high energy car accidents. Cardiac rupture can result from overaggressive CPR. The majority of blunt trauma to the heart come from motor vehicle accidents, pedestrian injuries, crush injuries, falls from a height, blast injuries, assaults, rib fractures, or recreational events, such as rodeo or baseball injuries. The heart can rupture through the pericardium, ending up in the abdomen or chest cavity. This can result from a strangulated heart that does not function very well.
Injuries to the heart can be caused by the treatment itself. This can include injuries from catheterizing the heart, insertions of central venous catheters or pericardiocentesis. These procedures need to be done very carefully in order to avoid injuring the heart.Clinical Presentation
Wounds involving the top of the abdomen or in front of the chest should increase the suspicion of a heart injury. The patient can have normal vital signs or can be in complete cardiac arrest. Up to 80 percent of stab wounds that injure the heart cause blood to collect between the heart and its covering—the pericardial sac. This can easily lead to heart failure. As little as 60-100 cc of blood in the pericardial sac can cause problems with heart functioning.
Blunt cardiac injury includes rupture of the ventricles of the heart, ruptures of the walls within the heart, problems with the heart valves, and injury to blood vessels supplying the heart. Many blunt heart injuries show up as having heart arrhythmias, especially premature ventricular contractions. These symptoms usually show up about 24-36 hours after the injury.
Injury to the pericardial sac is rare and most of these patients do not survive the trip to the hospital because of other injuries. Those who make it to the hospital still die at a rate of 64 percent.Evaluation of Heart Injuries
If the chest is injured, there should be a high index of suspicion of a heart injury. Tests used to evaluate the heart include blood tests for enzymes released by the damaged heart. Focused assessment with ultrasound or FAST procedure can be done to see if there is a heart injury or blood in the pericardial sac. Echocardiography can be used to find cardiac injury and to assess the function of the heart. A small window can be used to look inside the pericardial sac and to drain blood if it is found.Treating Heart Injuries
Few people survive to the emergency room to be treated for heart injuries. Treatment involves opening up the chest and fixing the areas of hemorrhage. The heart can be sutured with staples or with sutures. These can all be done on the beating heart without the need for bypassing the heart with machines.
If the heart is just bruised, this can be watched to make sure no heart damage has been incurred. Most of these patients have normal blood pressures and normal EKG readings. The overall survival rate for penetrating injuries of those that make it to the hospital is 30-90 percent. The survival rate for stab wounds to the heart is 70-90 percent. Survival after gunshot wounds is between 30 and 40 percent. Cardiac rupture has the worst prognosis at 20 percent survival rate.Thoracic Great Vessel Injury
This includes injuries to the main artery coming out of the heart—the aorta as well as its branches. The pulmonary arteries and veins can be injured as well as the inferior vena cava in the chest cavity. Due to advances in medicine, some of these injuries are survivable.
More than 90 percent of injuries to the great vessels are due to penetrating injuries. Some are due to accidental injuries during the placement of various tubes and catheters into the vessels near the heart. Aortic injuries can happen and can cause mortality in motor vehicle accidents and account for up to 15 percent of deaths in motor vehicle accidents. It can happen because of shear forces to the great vessels or because the aorta was crushed between two bones. It can also be caused by a sudden increase in blood pressure inside the vessels during a crush injury.
Most patients with great vessel injuries die of extreme blood loss within 0-2 hours after the injury. Those who die within 2-4 hours of injury usually die of multisystem trauma. Some are found to have injuries to the great vessels but die of other injuries, like head injuries, instead.
If there is a lot of bleeding inside the chest cavity, foreign bodies near where the great vessels are, or a missing bullet in the chest cavity, this represents the possibility that a great vessel injury has taken place. An emergency thoracotomy in which the chest wall is opened can be done in a patient with signs of life with some of these patient’s surviving. This is especially true if a chest tube is placed a very large quantity of blood is immediately returned from the chest tube. This is a sign that surgery must be done to repair the great vessels.
A dye study of the great vessels can be done in a stable patient to find out where there is a rupture of a great vessel. It helps plan the type of incision made for getting at the area of the hemorrhaging.
Treating these wounds do not require immediate surgery if there is already the following situations:
- Severe head injury
- Risk of infection
- Severe multisystem trauma
When repair is done, an endograft repair can be done on the inside of the great vessel wall. This is usually done on the descending part of the aorta, where a graft can be easily placed through the femoral artery and passed up into the aorta. Sometimes the vessels leading to the aorta are too small to accommodate the graft.
In many cases, surgery is done to repair the great vessels, knowing that things like stroke and infection can occur as a result of these injuries. People with ascending aorta injuries rarely survive to make it to the hospital. Those that do survive require a Dacron graft to repair the injury. Descending thoracic aortic injuries are also rarely survivable with mortality of 85 percent before arriving to the hospital. Those that do survive need immediate surgery to correct the tear in the aorta.
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