All posts by TheTraumaPro

Prehospital Lactate: Ready For Prime Time?

A few months ago, I started to notice a new piece of information coming across on my trauma activation pages: point of care lactate level. I had heard nothing about this prior to these pages, and was curious to know whether this was a new policy/practice, or some study that was in progress. So, of course, I had to do a little bit of reading to find out what was up with that. I’ll share that with you today.

Serum lactate has been used since forever in the inpatient setting, especially in the ICU. It is used as a surrogate for tissue hypoxia and/or metabolic acidosis. A number of studies have found that hypoperfusion is frequently underappreciated, since we tend to use crude vital signs (BP and pulse) which may look normal in early hypovolemia. Serum lactate guided therapy has been shown to improve survival in some studies, and can indicate that resuscitation is proceeding appropriately. Patients who do not show early improvement in their lactate levels are more likely to be refractory to resuscitation, and have higher mortality.

So it would make sense that if prehospital trauma professionals could identify occult tissue hypoperfusion in the field, appropriate resuscitation could start earlier. And nowadays, one can find a point of care device to measure just about anything. Thus, the extra tidbit of information on my trauma pages.

But remember, just because something makes sense doesn’t mean that it actually works. Thus, a group at the University of Birmingham (in the UK) did a systematic review of the literature through 2015, looking specifically at lactate levels obtained in the prehospital setting.

Here are the factoids:

  • Of the 2,415 articles screened, only 7 were suitable for analysis
  • These studies were judged to be of “low” or “very low” quality
  • The methods by which the lactate level were obtained (venous vs capillary), timing, and documentation were highly variable
  • The authors concluded that there is not yet enough data to support point of care lactate in the field

Bottom line: Point of care lactate drawn in the field would seem to be a good idea. Unfortunately, there aren’t any studies yet that are good enough to make this a standard practice. As with any new technique, if there’s no data then you MUST participate in a well designed study so it can be shown, yea or nay, that the practice is a good one. So join up!

Reference: Prehospital point-of-care lactate following trauma: a systematic review. J Trauma 81(4):748-755, 2016.

EMS: How Soon To Extricate The Pinned Patient?

This post was requested by one of my EMS colleagues who is the medical director of a rural EMS agency.

Maybe you watched the movie “Signs” by M. Night Shyamalan, starring Mel Gibson.  Gibson is a preacher whose wife was killed in a tragic accident. She was running and was pinned against a tree by a pickup truck. She is so badly injured that only the pressure of the truck against her is keeping her alive (and together, apparently). Gibson gets to have a few final words before being extricated (and killed).

Could this really happen? Shouldn’t entrapped people be extricated immediately, or do our prehospital providers need to wait until more advanced medical care is present at the scene?

Here’s the movie clip, if you are interested:

Obviously, you will find NO research on anything like this. The real question is, should EMS first responders (if not medically equipped and able) completely extricate an entrapped patient before paramedics or other trauma professionals with advanced skills are present? In other words, can you die just from being unentangled from the wreckage, like Mel Gibson’s wife?

The answer is, possibly. But it might not be for the reasons you think. Remember, this is Hollywood.

There are two killers upon release from entrapment. First, the mechanism by which the patient is pinned may be holding pressure on things that are or want to bleed. These include the pelvic bones, injuries to the torso, groins, and proximal extremities, and possibly even intra-abdominal hemorrhage sources. I’m discounting the chest because if there is enough pressure to tamponade bleeding, it will probably critically impair hemodynamics and ventilation to the point of killing your patient prior to extrication anyway.

The second factor is a crush injury, with release of a bolus of acidic, potassium laden blood from the crushed extremity upon release. This is probably quite rare, since it takes a significant amount of time for the un- or under-perfused extremity to build up enough of these substances to pose a threat. If the patient has been entrapped for less than 30-60 minutes, there is probably little danger to releasing them.

Bottom line: It is probably best to wait for ALS providers to arrive so IVs can be established and post-extrication resuscitation can be planned. This includes having fluid and/or blood products available in case critical bleeding starts once the pressure has been released. And don’t worry about reperfusion injury unless your patient has been trapped for quite a while.

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A Sample Final Damage Control X-ray

Yesterday, I wrote about ways to reduce and hopefully eliminate retained foreign bodies (instruments, sponges) during damage control surgery. Today, I’ll provide a sample x-ray and some tips on how to use this tool most effectively.

Here is an abdominal x-ray obtained just prior to closure of a patient who underwent damage control laparotomy. The OR record and surgeon from the initial operation documented that four sponges had been left in place for hemostasis.

dc-closure

Nothing retained, right?

Wrong! This image is not complete. This patient is larger than the x-ray plate used. The area under the diaphragms, the pelvis, and the entire left side of the peritoneal cavity have not been visualized.

Tips for imaging for damage control closure:

  • Always make sure the patient is on an x-ray OR table. It is so annoying (and potentially a sterility problem) to have to slide the plate under the patient!
  • Help the radiology tech to locate the desired imaging field using folds in the towels covering the body region. For example place the confluence of folds in the center of the towel in the exact place you want the center of the x-ray to be.
  • Remove all radiopaque objects from the x-ray field to reduce confusion when interpreting the image
  • Make sure the entire body cavity has been imaged! This may mean bracketing the area with several shots.
  • Read the image yourself! But if in doubt, or in patients with drains or other odd objects, call the radiologist to help you out.

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