Knife and gun club

Every ER doc knows of the Saturday night knife and gun club. Stabbings and shootings are more common on the weekend. The ingestion of alcohol and other intoxicants makes an escalation of disputes to deadly outcomes, much more likely. The frequency of penetrating trauma is higher in inner cities but occurs in every community.

Trauma is roughly divided into blunt and penetrating. A baseball bat and a knife can both cause severe trauma but the mechanism and injuries are relatively specific. Sharp objects such as knives, swords, glass (broken bottle), even knitting needles can easily penetrate the skin and injure deeper structures. Blood vessels, nerves, muscles and tendons are easily damaged in the extremities.

Penetrating a major artery can cause death from blood loss in minutes. The neck and groin are especially vulnerable. Treatment at the scene is critical. An object that is still in place is never removed. The tamponading of the blood vessel by the penetrating object may be all that is preventing exsanguination. Firm pressure and rarely tourniquetting the bleeding vessel is standard care in the field. The ER doc and surgical team can glean helpful information from a description of the weapon and the depth of penetration.

When the neck or trunk are the site of penetration, specific organ injuries must be considered and assessed. The trachea, esophagous, major arteries and veins and crucial nerves course through the neck. These injuries may not be apparent at first but must be suspected and urgently evaluated. The neck is divided into three zones to highlight the most likely injuries from penetrating trauma.

The chest and abdomen contain organs that are easily injured with penetrating weapons. Blood vessels, lungs, solid organs such as the liver and spleen, hollow organs (stomach and intestines), and especially the heart are reachable only inches from the surface of the skin. A knowledge of anatomy and a forensic appreciation of the shape, length and depth of penetration can guide the trauma team.

Pneumothorax is the collapse of the lung. Like a deflated balloon, the lung collapses when the pleura is punctured. A chest tube is inserted into the chest cavity and drains the air and blood in the chest cavity from the injured lung. Bleeding can be severe from the aorta and its branches but also from the intercostal arteries just inside of the ribs. If the heart is penetrated death may be instantaneous. Injuries to the atria give some time for the trauma team to react and perform a thoracotomy. We have all been captivated by the brave ER doc on TV asking for a scalpel and rib spreader. The results on TV were usually successful, much less frequent survival occurs in the real ER.

Abdomenal injuries are often very complex. Bleeding, leakage of bile, gastric and intestinal contents and urine makes for a horrific mess. Infections are frequent and potentially life threatening. Early surgery is determined by imaging studies (CT and/or Ultrasound) and most importantly the patient's vital signs. Tubes are placed in any available opening. Naso-gastric suction and foley catheter (urinary drainage) are mandatory. Large IV's deliver fluids and blood products. Early intubation of the trachea is also practiced.

Energy equals mass times velocity squared. Einstein was not thinking of guns when he wrote E=MC2. Guns come in three basic forms: high velocity (rifles), low velocity (handguns) and pellets (shotguns). They all cause devastating injuries to the human body. 22, 38, and 45 refer to the caliber of a handgun. The caliber is the percentage of an inch that is the diameter of the bullet. A 45 is .45 inches in diameter. The metric measurement is more direct. A 9mm round is 9mm in diameter. A shotgun blast contains many small pellets of steel or lead. The distance from the end of the barrel to the victim helps to determine the extent of the injuries.

The velocity of the bullet is more important than the size. The energy imparted to the victim's body is the square of the velocity. Military and hunting rifles have very high muzzle velocities. These projectiles can easily penentrate the full thickness of the body. The speed of the bullet decreases with distance. This is more important with low velocity handguns than with high velocity rifles.

The bullet's shape and composition is also important to an understanding of the injuries they cause. Soft bullets or hollow point rounds tend to flatten or mushroom when the strike the body. The resulting shock wave is quite large and can tear vessels, and ruptures hollow organ far from the site of entry. Jacketed bullets have a hard outer coat and are more likely to enter and exit the body. There is a large shock wave along the track of the bullet. This often is visible as a small entry wound and a much larger exit wound.

Small bullets, or pellets from an airgun or shotgun can penetrate into a blood vessel and travel quite far from the entry site. When the pellet finally lodges in a small vessel, such as in the brain, the result would be a stroke. If the final resting place for the wandering pellet is in a limb, the trauma team will note a sudden loss of blood flow to that limb.

As a resident, I treated a gentleman for a boil on his buttocks. When I opened the abscess to promote drainage, I found a 22 caliber copper jacketed bullet. On further questioning, my patient related a story of a poker game gone bad some 7 years prior to our encounter. He felt some thing "bite my ass" as he exited the game after being accused of cheating. Small caliber + low velocity= bullet lodged in the buttocks.

I do not own a gun. I am not a hunter. I have fired handguns, rifles and shotguns. ER docs who see the devastation caused by guns are divided in their opinions concerning gun ownership. A recent episode in Massachusetts is instructive and troubling. An ER doc from Connecticut who is a gun owner, brought his 8 year old son to a gun show. His son was given a 9mm automatic weapon that can fire up to 200 rounds per minute. A 15 year old "instructor" was supervising the 8 year old. As the boy fired the weapon, the recoil caused the gun to elevate and the barrel to go towards the boy. He was killed with the very weapon he was firing. The NRA bumper sticker reads: "Guns don't kill people, people kill people". Discuss.