All posts by TheTraumaPro

A New Proposed Practice Guideline For Cervical Spine Clearance

In my last post, I reviewed a very recent prospective study on using CT scan alone for  cervical spine clearance in intoxicated patients. I believe that this is the final piece in the spine clearance puzzle to allow us to perform this task intelligently.

We’ve been accumulating more and more data that supports the use of CT scan in patients who fail clinical clearance. This failure can be due to the patient being obtunded or intoxicated, bearing a “distracting” injury, or being just plain uncooperative. Because of this, and our fear of missing a potentially devastating injury (typically because of rare anecdotal cases or urban legends), we have resorted to a significant degree of overkill. This has included, over the years, prolonged immobilization in a rigid collar, flexion/extension imaging (plain x-ray or fluoro), and MRI.

I’ve synthesized the available literature, and have drafted a simple, one sheet practice guideline for discussion. In order to use it, you must have the following:

  • A decent CT scanner – minimum 64 slice
  • A well-defined scan setup protocol – 3mm collimation, skull base to T2, 2-D reconstruction in sagittal and coronal planes (get a copy of our protocol below)
  • A skilled radiologist – neuroradiologist required

An image of the protocol can be found at the bottom of this post. I’m interested in your comments, and your comfort or discomfort with adopting something like this. Please leave comments here or on twitter.

Links: 

Reference: Cervical spine evaluation and clearance in the intoxicated patient: A prospective Western Trauma Association Multi-Institutional Trial and Survey. J Trauma 83(6):1032-1040, 2017.

It’s Time To Simplify Cervical Spine Clearance!

Cervical spine clearance is another one of those tasks that everyone seems to do their own way. Most trauma centers have an algorithm for clearance, or even two, like my center. But anytime different clinicians or centers do the same thing in different ways, it means we don’t really know what we’re doing. 

It basically means that the hard data is not there to dictate what we truly should do. So there are two alternatives:

  1. Wait for good data to become available. Unfortunately, this can take forever.
  2. Extrapolate from any existing data, and fill in the gaps with our clinical experience to come up with something that works and causes no harm.

The protocols in use at Regions Hospital are based on #2, and have been in place for over a decade. But now, we have a good example of #1 to work with.

Fortunately for us, cervical spine clearance has been evolving for decades. And as technology has improved, so has our ability to miss fewer and fewer “significant” injuries. A multi-center trial published this month provides one of the final puzzle pieces to help us settle upon a uniform cervical spine clearance guideline. It was a prospective look at intoxicated patients after blunt trauma, who can’t always participate in the process of clinical cervical spine clearance.

This three year study took place at 17 centers and specifically looked at the combination of clinical and radiographic clearance in alcohol and drug intoxicated patients. Over 10,000 patients participated in the study. There are some limitations, of course, when so many centers participate. But the pros massively outweigh the cons.

Here are the factoids:

  • The overall incidence of cervical spine injury was 10.6% (!)
  • 30% of patients were intoxicated (19% etoh, 6% drugs, 5% both (also !)
  • Intoxicated patients had a significantly lower incidence of cervical injury (8% vs 12%). (Don’t get any ideas about the old adage about being relaxed when they crash. This probably represents lower speeds involved.)
  • For intoxicated patients, sensitivity of CT scan was 94%, specificity was 99.5%, and the negative predictive value (NPV) was 99.5%
  • The NPV for clinically significant injuries in intoxicated patients was 99.9%, and no unstable injuries were missed by CT  (100% NPV) (!!)
  • When CT was negative, being intoxicated led to longer time in a collar (8 hrs vs 2 hrs)

Bottom line: Fear of clearing the cervical spine without a clinical exam, or in obtunded or intoxicated patients, is primarily due to old anecdotal reports. And much of it is not first-hand experience, but rumors of others’. What is finally becoming clear is that it is okay to clear based upon radiographic findings alone. 

Tomorrow, I’ll provide my version of a new, unified clearance protocol based on this work.

Reference: Cervical spine evaluation and clearance in the intoxicated patient: A prospective Western Trauma Association Multi-Institutional Trial and Survey. J Trauma 83(6):1032-1040, 2017.

Deer Hunting and Tree Stand Injuries

Deer hunting season is upon us again in Minnesota and Wisconsin, so it’s time to plan to do it safely. Although many people think that hunting injuries are mostly accidental gunshot wounds, that is not the case. The most common hunting injury in deer season is a fall from a tree stand.

Tree stands typically allow a hunter to perch 10 to 30 feet above the ground and wait for game to wander by. They are more frequently used in the South and Midwest, usually for deer hunting. A recent study by the Ohio State University Medical Center looked at hunting related injury patterns at two trauma centers.

Half of the patients with hunting-related injuries fell, and 92% of these were tree stand falls. Only 29% were gunshots. And unfortunately, alcohol increases the fall risk, so drink responsibly!

Most newer commercial tree stands are equipped with a safety harness. The problem is that many hunters do not use it. And don’t look for comparative statistics anytime soon. There are no national reporting standards. No matter how experienced you are, always clip in to avoid a nasty fall!

The image on top is a commercial tree stand. The image below is a do-it-yourself tree stand (not recommended). Remember: gravity always wins!

Serial Lab Testing: Worthwhile or Worthless?: Final Answer

In my last two posts, I detailed the serum sodium measurements in a hypothetical patient two ways. The first was a listing of daily values, and the second provided values obtained every six hours or so. It also showed the sodium supplementation that was ordered based on those values. (I’ve included the table at the bottom of this post)

What did you think? Did the extra determinations help you decide what, if any, treatment was needed? Did the therapies ordered help?

Here are my thoughts:

  • Overall, there was not a huge or rapid decline in sodium values. Given the initial values, I would not have started a saline infusion on day 1, just watched a few daily values and the patients physical exam. The infusion only provided 3gm of salt per day, and the serum Na remained fairly stable for the first 3 days.
  • There was a significant amount of intra-day variation seen on the six hour table. You need to know the normal “within-person ” variation for any lab test you order. If two assays on specimens drawn at the same time can vary by 5%, you must factor this in to your decision making. If the value is 3% lower than the previous draw, the difference could represent normal variation. Obtaining more frequent assays exacerbates the amount of variation you see and my be confusing.
  • From day 5 to 6, the sodium appeared to be rising without any salt supplementation! But then a higher dose was given, and one of the intra-day values dropped to 124. What’s up with that? More variation?!
  • Is the morbidity of frequent blood draws worth it if there is no clinical change in the patient’s exam? What morbidity, you ask? Sleep disturbances, with all the cascading problems like delirium, sundowning, administration of additional meds to compensate, and on and on. Unnecessary medication or interventions. Plus it does not promote patient or family satisfaction at all.

Bottom line: Unless your patient has a clinical problem that may deteriorate rapidly, serial lab determinations are probably not of much value. The example patient was many days out from a TBI with some extra-axial blood. So yes, he could develop hyponatremia, but it would have probably surfaced earlier. Know your within-person  variability, which for sodium is roughly +2 meq. Is your new value within that limit? Then it is statistically the same as the first value unless you see a trend over several measurements. And as always, if you note a marked change in just one value, repeat it immediately before beginning any more drastic interventions.

Reference: Biological variation of laboratory analytes based on the 1999-2002 national health and nutrition examination survey. Natl Health Statistic Reports 21:March 1, 2010.

Day/Time Na Treatment NaCl per day
Day 1 18:30 131
Day 1 22:54 132 0.9% NS @ 125/hr 3G
Day 2 05:59 133 continues 3G
Day 2 12:19 129 continues
Day 2 17:50 129 continues
Day 3 07:18 127 continues
Day 3 12:09 127 continues
Day 3 17:58 126 continues
Day 3 23:53 126 continues
Day 4 07:45 125 continues
Day 4 11:38 122 2% NS @ 25/hr 6G
Day 4 15:25 125 continues
Day 4 19:31 125 continues
Day 5 00:06 122 continues 6G
Day 5 04:04 126 continues
Day 5 08:01 122 continues
Day 5 11:50 132 stop
Day 5 16:14 126
Day 5 19:26 127
Day 6 00:20 129 9.2G
Day 6 04:42 127 2% NS @ 40/hr
Day 6 08:30 124 continues
Day 6 12:29 127 stop
Day 6 16:16 127 Salt tabs 2G tid
Day 6 20:28 132 continues
Day 7 05:22 134 Salt tabs 2G qid 8G
Day 7 12:33 135 continues
Day 8 07:02 131 stop None
Day 8 13:33 136