Category: Trauma

When Is Blunt Chest Trauma Low-Risk?

According to this study, always – but rarely.

This is a prospective 3-center trauma study attempting to discern clinical variables that predicted the absence of serious traumatic chest injury in the setting of blunt trauma.  2,628 subjects enrolled, with 271 of them diagnosed with a serious injury – pneumothorax, hemothorax, great vessel injury, multiple rib fractures, sternal fracture, pulmonary contusion, and diaphragmatic rupture.  They do a recursive partitioning analysis and identify a combination of seven clinical findings that had a 99.3% (97.4 – 99.8) sensitivity for serious traumatic injuries.

But, I might be missing the point of this instrument a little bit.  Only 10% of their cohort had a traumatic injury – yet out of the remaining 90% without serious traumatic injury, their rule could only carve out 14% as low risk.  These low risk patients, the authors then propose, obviates any chest imaging at all.  While I am all for reducing unnecessary testing, this seems like an awfully low yield decision rule.  Yes, this study identifies young patients who are perfectly fine after a low-risk blunt trauma and do not need even an x-ray – but I’d really rather see more work preventing some of the 584 chest CTs performed in this cohort.  Additionally, their criterion standard for negative imaging is inadequate – most received CXR alone and there’s no follow-up protocol to test for possible missed injuries, whether clinically significant or not.

Considering the criteria they identified, it seems they could almost get equal or greater reduction in imaging if the clinicians were simply a little more thoughtful with respect to knee-jerk imaging in trauma.

“Derivation of a Decision Instrument for Selective Chest Radiography in Blunt Trauma.”
www.ncbi.nlm.nih.gov/pubmed/21045745

Tranexamic Acid – Critique of CRASH-2

These authors review the literature regarding TXA and it’s cost/risk/benefit for hemostatic control of injured trauma patients.  Of course, this specifically means they review the single significant piece of literature for TXA – the CRASH-2 trial published in the Lancet.

I’m not sure I entirely agree with their premise that TXA is safer because it is just an antifibrinolytic rather than an activator of clotting/platelet aggregation – clot formation and breakdown is a dynamic process and any interference in that system carries a risk.  But, they do a fairly detailed look at TXA and the CRASH-2 trial, and I think they make a fair and defensible point that, while the NNT is pretty high, it is a fairly low cost intervention with a relevant outcome variable of overall mortality.

While a study with 20,000 patients is a nice start, I’d still like to see at least one other prospective study replicating similar results with an appropriate safety analysis.

“Tranexamic Acid for Trauma Patients: A Critical Review of the Literature”
www.ncbi.nlm.nih.gov/pubmed/21795884

CT Is No Longer Adequate To Clear C-Spine

The insanity never stops.  It’s a good thing MRI is becoming increasingly available, because the more papers like this are published in major journals, the more we’re going to be stuck following every possible outcome to it’s bitterest end with the strongest microscope we have.

There a lots of problems with using this paper to change practice – of their 9152 patients undergoing CT for trauma, 741 had persistent midline tenderness leading towards MRI.  Of those 741, only 174 were enrolled for a variety of reasons.  And this study doesn’t tell us enough useful information to help distinguish the characteristics of the 78 patients in whom an injury was detected to help us differentiate them from the patients in whom no injury was detected.

But the fact remains, they identified serious injuries on MRI in patients who had negative CTs – and not just obtunded, intubated, polytrauma patients like in the other studies.

Just one more thing to worry about.

“Cervical Spine Magnetic Resonance Imaging in Alert, Neurologically Intact Trauma Patients With Persistent Midline Tenderness and Negative Computed Tomography Results”
http://www.ncbi.nlm.nih.gov/pubmed/21820209

Kids Are Too Fat For The Broselow Tape Now

Now that increasing numbers of children are overweight and obese (up to 36% of 10 to 17 year olds now), 53% of this pediatric sample from West Virginia fell out of the Broselow tape estimate based on height.  Of these, 77.1% of the incorrect weights were greater than that predicted by the Broselow.

It is West Virginia – not the healthiest state in the U.S. – but any hospital that serves a predominantly disadvantaged population may have similar results, and should realize that they may be under dosing their medications.  The authors suggest only a couple alternative strategies, but I think we’re probably just best off using clinical judgement as to whether the tape is accurate in each individual clinical situation.

“Is the Broselow tape a reliable indicator for use in all pediatric trauma patients?”
http://www.ncbi.nlm.nih.gov/pubmed/21629149

Significant Populations Have No Timely Access to Stroke, Pediatric Trauma Care

These are a couple studies from a family of publications that use population data, GIS mapping tools, and travel times by air and ground to estimate what percentage of the population has access to a certain healthcare resource.  In these two papers, the resources in question are Primary Stroke Centers and Pediatric Trauma Centers.  They estimate that 71% of the pediatric population is within 60 minutes of a pediatric trauma center by ground or air – which is appropriate, because trauma systems are set up to use aeromedical transport.  However – and, depending on what direction the TPA pendulum swings – only 55.4% of the population has access to a stroke center within 60 minutes – by ground, which is typical.  They say this could be increased to 79% within 60 minutes if aeromedical resources were involved, but I think we should wait to establish a greater treatment effect for acute stroke treatment before we go nuts with air travel.

I like maps; I worked with one of the authors (Dr. Branas) on previous iterations of descriptive articles similar to these.  The problem with these articles is the statistic they describe – timeliness of care – may or may not have significant effects on patient outcomes.  And, in theory, the solutions – moving trauma center designations, establishing new stroke centers, increasing aeromedical use, etc., have significant costs and unintended consequences.

http://www.ncbi.nlm.nih.gov/pubmed/20937948
http://www.ncbi.nlm.nih.gov/pubmed/19487606

rFactor VII Is Not Safe (Despite Their Conclusions)

When NovoNordisk writes an article analyzing safety data from the CONTROL trial, you get a skewed perspective on the data.  Specifically, if you only read the abstract, you’re going to think that it’s safer in some ways(ARDS was less), and there was no difference in adverse events (except for all that investigator-reported AMI/NSTEMI).  So, that sounds favorable.

But, the real reason there’s no significant differences in outcomes – and the reason why they terminated the trial early – is because the interim data is underpowered to detect a difference.  As you see, the 30-day mortality is 12% vs 11% in favor of placebo – and that wasn’t helping NovoNordisk, so they quit before they could reach sufficient statistical power to prove their product was unhelpful.  However, they can now benefit from that same lack of power to detect differences by applying it to the safety aspect, and trumpeting its equivalency in terms of AEs.

When taken in the context of the original trial, this is just a flawed piece of pharmaceutical propaganda to try and prevent the building crackdown on off-label Factor VII use.

http://www.ncbi.nlm.nih.gov/pubmed/21610529

Comparison of Adult Head CT Rules in Pediatrics

Interesting – if limited in prospective use – retrospective comparison of the New Orleans, Canadian, and NEXUS II instruments for risk stratifying adults suffering minor head trauma.  Busy, urban children’s ED went through 8 years of data to find over 6000 patients with minor head trauma.

Unfortunately, they only looked at the 2,101 that received a head CT, so we lose a huge chunk of our population to “clinical judgement” that could have profoundly affected the specificity of the rules and perhaps had small effects on their sensitivity.

Full of interesting tidbits – 25% of their study population was under 2 years old, but 41% of their injuries were detected in the under 2 population.  Sensitivity and specificity essentially rose and fell with the percentage of the cohort scanned – the New Orleans rule would have scanned 89% of their cohort…that had an incidence of 4.4% of intracranial injury.  That made the sensitivity 96%, but the specificity 11% – and I hate to think what the specificity would have been if the other 4000 patients had been included.  The Canadian Rule scanned the least, missed the most at 65% sensitivity, but achieved a 36% specificity.

But the real question is – what’s the point?  The PECARN criteria get you up to ~96% sensitivity with a specificity of 53-58%.  Kids aren’t small adults – especially infants, and especially in trauma.  Don’t apply adult criteria in kids.

http://www.ncbi.nlm.nih.gov/pubmed/21465153

Early Recognition of Massive Transfusion

From trauma resuscitation, a Chinese study trying to predict who will need massive transfusion after trauma.  They have a 7-item scoring system retrospectively derived…and it’s probably not terribly helpful.

It’s a nice idea, considering there’s only so much blood readily available in the bank, and a lot of massive transfusion protocols are 1:1 with FFP and sometimes platelets, so advance warning based on the initial clinical evaluation would definitely be helpful.  There are some interesting pieces of information in the paper, although, I wish they had all their OR listed for massive transfusion, as opposed to just the ones that shook out from their stepwise regression.  Their highest predictor for massive transfusion – a hemoglobin < 7 g/dL with an OR 45.7.  SBP < 90 and positive CT or FAST were also predictors with useful OR.  Their rule is a little unusual for a theoretically beneficial intervention (massive transfusion), as they focus on specificity rather than sensitivity – probably due to a need to conserve blood component products.

In the end, though, I think most folks with a hypotensive trauma patient whose FAST is positive and a Hgb < 7 could clinically predict massive transfusion as well as this rule does.

http://www.ncbi.nlm.nih.gov/pubmed/21458905