All posts by TheTraumaPro

Best Of: How To Read A Stab Wound

Most emergency departments do not see much penetrating trauma. But it is helpful to be able to learn as much as possible from the appearance of these piercing injuries when you do see them. This post will describe the basics of reading stab wounds.

ImportantThis information will allow some basic interpretation of wounds. It will not qualify you as a forensics expert by any means. I do not recommend that you document any of this information in the medical record unless you have specific forensic training. You should only write things like “a wound was noted in the midepigastrium that is 2 cm in length.” Your note can and will be used in a court of law, and if you are wrong there can be significant consequences for the plaintiff or the defendant. This information is for your edification only.

1. What is the length of the wound? This does not necessarily correspond to the width of the blade. Skin stretches as it is cut, so the wound will usually retract to a length that is shorter than the full width of the blade.

2. Is the item sharp on one side or both? This can usually be determined by the appearance of the wound. A linear wound with two sharp ends is generally a two sided knife. A wound with one flat end and one sharp end is usually from a one-sided weapon. The picture below shows a knife wound with one sharp side.

Single edge knife wound

3. Is there a hilt mark? This can usually be detected by looking for bruising around the wound. The picture below shows a knife wound with a hilt mark.

Knife wound with hilt mark

4. What is the angle? If both edges are symmetric, the knife went straight in. If one surface has a tangential appearance, then the knife was angled toward that side. You can approximate the direction of entry by looking at the tangential surface of the wound edge. In this example, the blade is angling upward toward the right.

Angled knife entry

5. How deep did it go? You have no way of knowing unless you have the blood stained blade in your possession. And yes, it is possible for the wound to go deeper than the length of the knife, since the abdominal wall or other soft tissues can be pushed inwards during the stab.

Tips For Surgeons: Abdominal Packing

One of the tenets of trauma surgery, handed down for generations, is that we should pack the abdomen to help manage major abdominal hemorrhage. “All four quadrants were packed” reads the typical operative note. But how exactly do you do that? Sounds easy, right?

Well, there are nuances not found in the surgery textbooks. Here are some practical tips for the trauma surgeon:

  • Prepare. Have your scrub nurse fluff up about 20 laparotomy pads in advance. The point of packing is two-fold: soak up blood and stop bleeding. Fluffed up pads work better than the flat, rolled up pads shown above. And you will need them fast, so have a supply ready.
  • Do you really need to pack? Your patient is hypotensive, and you are convinced the abdomen is the source. You run to the OR, open it and… no blood. So don’t pack. It won’t slow down the (lack of) bleeding, but it is possible to cause serosal tears or worse. Just figure out where the bleeding is really coming from.
  • Be careful. Don’t just jam them in there. Carefully place pads over and under the liver. Carefully place a hand on the spleen and push toward the hilum so you can place pads between spleen and body wall. Try not to cause more damage than is already there.
  • Penetrating trauma: Pack where you know (or think) the penetrations are first. Basically, if it’s not bleeding there, don’t pack there.
  • Blunt trauma: Pack the upper quadrants first. This is where the money is, because the liver and spleen are the top culprits. Then pack the lower quadrants to soak up shed blood.
  • Once packed, check for successful control. If bleeding has stopped (or at least decreased significantly) stop and wait for anesthesia to catch up and continue your massive transfusion protocol. If bleeding continues, remove packs from the offending area and try to obtain definitive control. This is now the patient’s only chance, since you can’t stop the bleeding with packing.
  • Remove packs in the proper order. In blunt trauma, remove the lower quadrant packs first. They’re not doing anything and just take up valuable space. In penetrating trauma remove the packs in the area of the injury first. 
  • Get an xray to confirm that all packs are out at the end of the case. Self explanatory. It’s easy to lose a few in the heat of the moment. I’ve seen two bundles (10 pads) left over the liver in one case decades ago!

Enoxaparin And Pregnancy

Lovenox

Pregnant women get seriously injured, too. And pregnancy is an independent risk factor for deep venous thrombosis. We reflexively start at-risk patients on prophylactic agents for DVT, the most common being enoxaparin. But is it safe to give enoxaparin during pregnancy?

Studies have looked at drug levels in cord blood when the mother is receiving enoxaparin, and none has been found. No specific bleeding complications have been identified, either. So from the baby’s standpoint, administration is probably safe.

However, there are two other issues to consider. In a study looking at the use of enoxaparin for prophylaxis in women with a mechanical heart valve, 2 of 8 women (and their babies) died. Both suffered from clots that developed and blocked the valves. Most likely, the standard dose of enoxaparin was insufficient, so monitoring of anti-Factor Xa levels must be done.

The other problem lies in the multi-dose vial of Lovenox (Sanofi-Aventis). Each 100mg vial contains 45mg of benzyl alcohol, which has been associated with a fatal “gasping syndrome” in premature infants. The individual dose syringes do not have this preservative.

Bottom line: It is probably safe to give enoxaparin to pregnant women after trauma. However, it is unclear if the dose needs to be increased to achieve adequate prophylaxis. Only consider using this medication after consultation with the patient’s obstetrician, and use only the individual dose syringes. Otherwise fall back to standard subcutaneous non-fractionated heparin (even though it is a Category C drug by FDA; it is still considered the anticoagulant of choice during pregnancy).

How I Keep Up With The Trauma Literature

Medicine advances quickly. How can one keep up with new developments in their field? Well, there’s an app for that! You can also do it without a handheld device, but it’s not quite as convenient. Let me show you how I do it.

Most regularly updated online content is syndicated for RSS (Rich Site Summary). You know, those cute little  icons on web pages. There are loads of RSS readers available, both online and for handheld devices, that allow you to organize and browse content from RSS feeds. I use Google Reader on desktops or laptops, and the River of News app on my iPad.

I visited the home page of each of the journals I was interested in “following” and snagged the RSS web address from each. I then added it to my Google Reader collection of feeds. Now, at some point every day I can quickly browse through new abstracts in each journal. For most journals, abstracts are released once a month. A few publish early release abstracts more regularly.

When you click an abstract of interest, a web page opens that shows the full abstract. If it looks interesting, I save it using Instapaper, a clipping service that helps you organize web pages of interest. I just click a link at the top of the browser and the page is instantly saved for later reference.

As you probably already know, much of what is published is junk. Class III or worse data. Concluding that “additional research is necessary.” So why didn’t you do the study right in the first place? Therefore, it is vitally important that you read the whole article for the abstracts that you have saved. For this, you need access to a biomedical library, either online or brick and mortar. If you’re not lucky enough to have this, you’ll need to rely on others who do. I just run through my list of saved pages on Instapaper and pull up the full article via an online library connection through work.

Here’s a screen shot of my River of News app. I currently monitor 18 journals that publish trauma articles to a greater or lesser degree. I’m also a firm believer that some of the best ideas come from cross-pollinating your own field with ideas from others. To that end, I also scan another 22 feeds in technology, publishing, cooking, aviation and many others. I’m interested in hearing how others do this as well. Please feel free to comment below.

Related links:

Who Travels By Air?

Getting seriously injured trauma patients to a trauma center quickly is generally believed to be a good thing. And helicopters are usually faster than ground ambulances. So sending severely injured patients by air is a good thing, right?

Not quite so fast, there. There are other concerns as well. Helicopter transport is significantly more expensive. Quarters are very cramped, and you can’t just pull off to the side of the road if major patient or equipment problems arise. And has anybody really shown a survival benefit?

Although there is a (relatively) standard national trauma triage protocol from the CDC that indicates which patients should be transported to a trauma center, there is no standard protocol for who should be transported by air. The University of Rochester School of Medicine looked at 2007 transport data from the National Trauma Databank and tried to determine if the CDC protocol could be adapted to air transport as well.

Over 250,000 patient records were included in the study. As would be expected, patients flown by helicopter tended to be more severely injured, needed intubation more often, and were admitted to an ICU and stayed in the hospital longer. Average transport time for the helicopter was longer (60 mins vs 43 mins), implying longer distance traveled. Using a regression analysis, the authors found that the following subsets of patients had better survival with helicopter transport:

  • Penetrating injury
  • GCS < 14
  • Resp rate <10 or >29
  • Age >55
  • Any one physiologic criterion and any one anatomic criterion from the CDC protocol

Bottom line: A more standardized set of air transport criteria is needed. Some studies have found that as many as 50% of patients in some communities are flown who do not meet local air transport rules. Time and distance also need to be taken into account, since these will vary widely between rural and less rural areas. This study begins to lay an objective framework of criteria that can be incorporated into a more uniform set of guidelines.

Related posts:

Reference: The National Trauma Triage Protocol: Can this tool predict which patients with trauma will benefit from helicopter transport? J Trauma 73(2):319–325, 2012.