All posts by TheTraumaPro

How To Remember Those “Classes of Hemorrhage”

The Advanced Trauma Life Support course lists “classes of hemorrhage”, and various other sources list a similar classification for shock. I’ve not been able to pinpoint where these concepts came from, exactly. But I am sure of one thing: you will be tested on it at some point in your lifetime.

Here’s the table used by the ATLS course:

classes_of_shock

The question you will always be asked is:

What class of hemorrhage (or what % of blood volume loss) is the first to demonstrate systolic hypotension?

This is important because prehospital providers and those in the ED typically rely on systolic blood pressure to figure out if their patient is in trouble.

The answer is Class III, or 30-40%. But how do you remember the damn percentages?

multiscore-maxi1

It’s easy! The numbers are all tennis scores. Here’s how to remember them:

Class I up to 15% Love – 15
Class II 15-30% 15 – 30
Class III 30-40 30 – 40
Class IV >40% Game (almost) over!

Bottom line: Never miss that question again!

Pan Scanning for Elderly Falls?

The last abstract for the Clinical Congress of the American College of Surgeons that I will review deals with doing a so-called “pan-scan” for ground level falls. Apparently, patients at this center have been pan-scanned for years, and they wanted to determine if it was appropriate.

This was a retrospective trauma registry review of 9 years worth of ground level falls. Patients were divided into young (18-54 years) and old (55+ years) groups. They were included in the study if they received a pan-scan.

Here are the factoids:

  • Hospital admission rates (95%) and ICU admission rates (48%) were the same for young and old
  • ISS was a little higher in the older group (9 vs 12)
  • Here are the incidence and type of injuries detected:
Young (n=328) Old (n=257)
TBI 35% 40%
C-spine 2% 2%
Blunt Cereb-vasc inj * 20% 31%
Pneumothorax 14% 15%
Abdominal injury 4% 2%
Mortality * 3% 11%

 * = statistically significant

Bottom line: There is an ongoing argument, still, regarding pan-scan vs selective scanning. The pan-scanners argue that the increased risk (much of which is delayed or intangible) is worth the extra information. This study shows that the authors did not find much difference in injury diagnosis in young vs elderly patients, with the exception of blunt cerebrovascular injury.

Most elderly patients who fall sustain injuries to the head, spine (all of it), extremities and hips. The torso is largely spared, with the exception of ribs. In my opinion, chest CT is only for identification of aortic injury, which just can’t happen from falling over. Or even down stairs. And solid organ injury is also rare in this group.

Although the future risk from radiation in an elderly patient is probably low, the risk from the IV contrast needed to see the aorta or solid organs is significant in this group. And keep in mind the dangers of screening for a low probability diagnosis. You may find something that prompts invasive and potentially more dangerous investigations of something that may never have caused a problem!

I recommend selective scanning of the head and cervical spine (if not clinically clearable), and selective conventional imaging of any other suspicious areas. If additional detail of the thoracic and/or lumbar spine are needed, specific spine CT imaging should be used without contrast.

Related posts:

Reference: Pan-scanning for ground level falls in the elderly: really? ACS Surgical Forum, trauma abstracts, 2016.

REBOA vs ED Thoracotomy: Which One Is Winning?

Many trauma centers are talking about REBOA (resuscitative endovascular balloon occlusion of the aorta), but only a few are actually doing it. And of those, only a handful are doing it regularly and closely studying how it’s working.

The RA Cowley Shock Trauma Center is one of those very few. They have integrated the preparation phase for REBOA (femoral art line insertion) into their initial resuscitation protocols. This allows them to actually perform the technique quickly in any patient who starts to go bad and meets criteria. This center has been using REBOA nearly exclusively since they began studying it  a few years ago. They have actually supplanted ED thoracotomy (EDT) with this technique, and are a leader in producing data and studies on its nuances.

They compared short term outcomes in patients suffering traumatic arrest undergoing REBOA  (2013-2015) to those in patients with EDT (2008-2013). This was a simple study, with easy to understand statistical analyses.

Here are the factoids:

  • 19 thoracotomies and 17 REBOA were performed during the study periods (this shows how uncommon these procedures are, even at a busy center)
  • Average ISS was about the same (31 vs 26). Median GCS was 3 in both groups.
  • Return of spontaneous circulation (ROSC) occurred in 7 EDT and 9 REBOA
  • 13 EDT and 9 REBOA patients survived long enough to get to the OR
  • Mean systolic BP after occlusion was higher after REBOA (80 vs 46 torr)
  • There was only one survivor of the 36, and they received REBOA. This patient actually discharged home. (!)

Bottom line: Shock Trauma is a very busy center, and as you can see, even their REBOA numbers are low. This is why it is so critically important that all REBOA patients be part of a study. We really need to know how well it works, who it works best in, and what the downsides are. In this study, ROSC and survival to OR were statistically identical, but blood pressure was higher with REBOA compared to cross-clamping. Survival was also the same (abysmal), with one excellent outcome in the REBOA group.

The authors believe that REBOA and EDT are equivalent in terms of the variables they looked at. But remember, there are many other factors we need to look at, including things like resource utilization and healthcare worker safety. I strongly urge every center that is performing or considering REBOA to join a multi-center trial and/or report the the REBOA registry to hasten our understanding of this procedure.

Related posts:

Reference: Paradigm shift in hemorrhagic traumaic arrest: REBOA is at least as effective as resuscitative thoracotomy with aortic crossclamping. ACS Scientific Forum, trauma abstracts, 2016.

CT Crystal Ball – Part 3

And yet another one of these crystal ball abstracts, all presented at the same meeting of the American College of Surgeons Clinical Congress!

This one postulates that more injuries seen on CT scan might predict mortality in “older” trauma patients. Hmmm. The authors pulled info  on head CT findings, GCS, AIS Head, lengths of stay, death, functional scores, and discharge disposition. And the age had to be >45 years. Older? Hmmm.

A scoring tool was designed that gave 1 point each for subdural, epidural, subarachnoid, or intraparenchymal blood, cerebral contusion, skull fracture, brain edema/herniation, midline shift, and external trauma to the head/face. The score range was 0-8, even though there were 10 factors.

Lets look at the factoids:

  • Nearly 10 years of data were analyzed
  • 620 patients meeting criteria were identified
  • The scoring system positively correlated with all of the outcome measures
  • Independent predictors of mortality included GCS, AIS Head, and the CT score (odds ratio 1.3)
  • The CT test also “predicted” (author’s word) neursurgical intervention (odds ratio 1.2)

Bottom line: Oh boy, here we go again. Another correlation study, and a weak one at that. So if someone told you that an “older” patient (beginning after age 45) would do worse clinically the more injuries were seen in and around their head, what would you say? And why did it take 10 years of data to accumulate data on 620 patients in this age range (62 per year)? And why not test your scoring system prospectively? And run some really good statistics on the new data?  Sadly, I feel this is another run to submit an abstract and present at a meeting. But thankfully, I don’t think it will ever see the light of print.

Related posts:

Reference: Prognostication of traumatic brain injury outcomes in older trauma patients: a novel risk assessment tool based on initial cranial CT findings. ACS Scientific Forum, trauma abstracts, 2016.

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The CT Crystal Ball – Part 2

Yesterday, I wrote about a study that looked at a CT scan-derived index that promised to predict complications and mortality based on the waist-hip ratio. It was actually a very good one. But there is another abstract being presented at the American College of Surgeons Clinical Congress this week that promises miracles from the CT scanner as well.

This next abstract looks at muscle mass in trauma patients, as measured by CT scan. Specifically, the authors measured the density of the psoas muscle by determining its cross-sectional area and its density in Hounsfeld units. They then looked at the relationship between this and 90 day mortality, complications, and disposition location.

Really? Well, here are the factoids:

  • The study involved only 152 patients age 45+ from the year 2008
  • Median ISS was only 9
  • Patients with the lowest psoas cross-sectional area had an associated significantly higher death rate
  • Those with lowest psoas density had an associated increase in complications, dependency on discharge, and mortality
  • The authors suggest that these measurements could aid in patients who would benefit from aggressive nutritional support and physical therapy, and could aid in discharge planning

Bottom line: Very different from yesterday’s abstract. This one has no grounding in prior research. It appears to be one that was just dreamed up from nowhere. And it is truly an association study. No causality can or should be inferred.

There were only 152 patients studied. From 2008. Why? Why didn’t the authors use a more contemporary dataset? There is something weird going on behind the scenes. Is this an old study that was forgotten, and is just now being conveniently dusted off for analysis and submission? A power analysis to find out how many patients should be reviewed is not possible, so it is important to err on the high side. Not just 152 patients.

If you were to just read the abstract and especially the conclusions, you really might get the wrong idea. This is a study that will not see it’s day in any journal. Read and learn from it. But don’t duplicate it!

Related post:

Reference: Computed tomography-measured psoas density predicts complications, discharge location, and mortality in trauma patients. ACS Scientific Forum, trauma abstracts, 2016.