As part of a thorough history and physical on any trauma patient, we typically ask “How big was the knife you were stabbed with?” and “How deep did it go?”
Unfortunately, the answers you typically will get are “This big!” while they hold their hands at least 3 feet apart, and “All the way, doc!”
These answers are not very helpful, so it is not really of much use to ask the questions. The “how big” question is not helpful at all, because a long knife may barely penetrate, and a paring knife can make it all the way into the heart.
This leaves the “how deep” question. There are two ways to determine the answer. If the paramedics or police bring the weapon in, you can carefully examine it (taking proper care to preserve forensic evidence) and see if there is a blood line extending from the tip. This will show the maximum depth of penetration.
The second way is to examine the wound, either by local wound exploration or using CT.
Helpful hint: You can’t tell how large (wide) the blade is by looking at the wound. The elastic nature of the skin causes it to stretch as it is being cut during the stab. When the knife is removed, the resulting laceration will always be less wide than the blade.
There is considerable variability in the way that penetrating wounds are approached. Some are located over areas of lesser importance (distal extremities) or are so superficial that they obviously don’t fully penetrate the skin.
Unfortunately, some involve high-value structures (much of the neck and torso), or are too small to tell if they penetrate (ice pick injury). How should these injuries be approached?
Too often, someone just probes the wound and makes a pronouncement based on that assessment. Unfortunately, there are major problems with this technique:
- The tract may be too small to appreciate with a finger or even a cotton-tip swab
- The tract may be oriented in an unexpected direction, or the soft tissues may have moved after the penetration occurred. In this case, the examiner may not appreciate any significant depth to the wound.
- Inserting an object may violate a structure that you wish it hadn’t (resulting in a hissing sound after probing a chest wound, or a column of blood after probing the neck)
A better way to approach these wounds is as follows:
- Is the patient unstable? If so, you know the penetration caused the problem and the patient belongs in the OR.
- Is there other evidence of deep injury, such as peritonitis with a penetrating abdominal wound? If so, the patient still needs to go to the OR.
- Do a legitimate local wound exploration. This entails making the hole bigger with a knife, and using surgical instruments and your eyes to find the bottom of the tract. Obviously, there are some parts of the body where this cannot be done, such as the face, but they probably don’t need this kind of workup anyway.
As one of my mentors, John Weigelt, used to say, “Doctor, do you have an eye on the end of your finger?” In general, don’t use anything that doesn’t involve an eyeball in your local wound explorations!
Foley catheters are a mainstay of medical care in patients who need control or measurement of urine output. Leave it to trauma surgeons to find warped, new ways to use them!
Use of these catheters to tamponade penetrating cardiac injuries has been recognized for decades (see picture, 2 holes!). Less well appreciated is their use to stop bleeding from other penetrating wounds.
Foley catheters can be inserted into just about any small penetrating wound with bleeding that does not respond to direct pressure. (Remember, direct pressure is applied by one or two fingers only, with no flat dressings underneath to diffuse the pressure). Arterial bleeding, venous bleeding or both can be controlled with this technique.
In general, the largest catheter with the largest possible balloon should be selected. It is then inserted directly into the wound until the entire balloon is inside the body. Inflate the balloon using saline until firm resistance is encounted, and the bleeding hopefully stops. Important: be sure to clamp the end of the catheter so the bleeding doesn’t find the easy way out!
Use of catheter tamponade buys some time, but these patients need to be in the OR. In general, once other life threatening issues are dealt with in the resuscitation room, the patient should be moved directly to the operating room. In rare cases, an angiogram may be needed to help determine the type of repair. However, in the vast majority of cases, the surgeon will know exactly where the injury is and further study is not needed. The catheter is then prepped along with most of the patient so that the operative repair can be completed.
Simple penetrating injuries to the arms and legs are often over-treated with invasive testing and admission for observation. Frequently, these injuries can be rapidly evaluated and disposed of using physical examination skills alone.
Stabs and low velocity gunshots (no rifles or shotguns, please) should be thoroughly examined. This includes an examination of the entire, unclothed body. If this is not carried out, there is a risk that additional penetrating injuries may be missed.
For gunshots, look at the wounds and the estimated trajectory to try to demonstrate that the object stayed clear of neurovascular structures. This exam is imprecise, and must be accompanied by a full neurovascular exam and evaluation of the bones and joints. If there is any doubt regarding bony involvement, plain radiographs with entry markers should be performed. Any abnormal findings will require more in-depth evaluation and inpatient admission.
If the exam is negative but the trajectory is “in proximity” to a major vessel, an arterial pressure index (API) should be measured. This test involves the calculation of the ratio of the systolic pressure in the injured extremity to the contralateral uninjured extremity. It should not be confused with the ankle brachial index (ABI) which compares the systolic pressure in the ipsilateral uninjured arm or leg.
The magic ratio is 0.9. If the API is less than this, there is some likelihood that a vascular injury is present. If the API is higher, there is virtually no chance of injury.
The final test that must be performed before discharge is a function test. If the injured extremity is too painful to use or walk on, the patient may need to be admitted for pain management and therapy. Patients managed in this way can avoid arteriography, CT angiography or admission and save thousands of dollars in hospital charges.
Reference: Journal Am Coll Surgeons 2009;209:740-5.
Earlier this month I looked at outcome differences in insured and uninsured patients at an urban Level I trauma center. A study published last month looked at a similar type of trauma center but focused only on penetrating trauma. Guess what? Same result.
This study was a lengthy (10 year) retrospective look at only patients who sustained gunshot wounds. Only one fourth of the patients had insurance. The in-hospital mortality was 50% higher for uninsured vs insured patients (9% vs 6%). There was no difference in injury severity, and the mortality difference persisted after controlling for age, gender, race and injury severity.
Interestingly, in this study there was no difference in imaging or operative intervention like there was in the LA study.
Once again, it looks like insurance status does make a difference. There are three possible factors: differences in access to care, physiologic differences, and differences in socioeconomic backgrounds. Access in this case was equal regardless of insurance status, and physiologic differences were minimal. That leaves us with socioeconomic differences. These social factors can lead to baseline differences in health which may have an impact on outcome.
The results of this study and the one I previously commented on will become even more interesting as healthcare coverage legislation is phased in over the next few years. The hope is that mortality rates for insured and uninsured will begin to equalize over the following years. The reality may be that it will take longer than we expect due to the time and effort needed to change basic human behavior.