Category: Trauma

An Uninsightful Look at Traumatic ICH in Ground Level Falls

The ground is ubiquitous. There are many ways to injure oneself, but the typical readily available impact surface is the ground. The ground is particularly pernicious, it seems, in the elderly and those in assisted care facilities. Thus, we have a great number of patients for whom imaging decisions must be made in elderly patients who have fallen from, apparently, “ground-level”.

Many of these same elderly patients have multiple medical comorbidities, including those for whom antiplatelet or anticoagulant therapy is indicated. These patients are, then, at elevated risk for intracranial hemorrhage despite the apparent low mechanism of injury. Wouldn’t it be lovely if we had better descriptive data with which to estimate and determine those at greatest risk?

Unfortunately, this fundamentally flawed observational study design tells us quite little. These authors included every patient whose electronic health record included antiplatelet and anticoagulant medications, and subsequently had intracranial imaging ordered. The EHR, then, prospectively prompted clinicians to indicate “ground-level fall” as their mechanism of injury. Of 668 patients on antiplatelets, 29 (4.3%) demonstrated ICH on CT. Of 180 patients on anticoagulants, 3 (1.7%) suffered ICH. Another 91 were on some sort of combined treatment, and 1 (1.1%) suffered ICH.

And this tells us nothing, other than the risk of ICH is non-zero. Even from a simple frequentist statistical standpoint, the sample sizes are small enough the confidence intervals around these numbers are quite wide. Then, there is the problem of their screening methods – which starts after the decision has been made to perform CT. Unless it is specifically protocolized all patients with ground-level fall are mandated to perform CT, decisions to initiate imaging would depend on the selection bias of individual clinicians. Individual perceptions of the risk of ICH on antiplatelet and anticoagulant medications dramatically impact the rate of imaging – so this ultimately only tells us the risk for ICH in their uniquely selected population.  Additionally, without structured follow-up of those not imaged, neither the numerator nor the denominator are reliable in this estimate.

These patients fall out of all of our decision support instruments, and it would be lovely to have better information regarding their true risk and specific predisposing factors in order to be better stewards of imaging resources and costs. These data unfortunately do not add much to our decision-making substrate.

“Risk of Intracranial Hemorrhage in Ground Level Fall with Antiplatelet or Anticoagulant Agents”

http://onlinelibrary.wiley.com/doi/10.1111/acem.13217/abstract

PECARN, CATCH, CHALICE … or None of the Above?

The decision instrument used to determine the need for neuroimaging in minor head trauma essentially a question of location. If you’re in the U.S., the guidelines feature PECARN. In Canada, CATCH. In the U.K., CHALICE. But, there’s a whole big world out there – what ought they use?

This is a prospective observational study from two countries out in that big remainder of the world – Australia and New Zealand. Over approximately 3.5 years, these authors enrolled patients with non-trivial mild head injuries (GCS 13-15) and tabulated various rule criteria and outcomes. Each rule has slightly different entry criteria and purpose, but over the course of the study, 20,317 patients were gathered for their comparative analysis.

And, the winner … is Australian and New Zealand general practice. Of these 20,000 patients included, only 2,106 (10%) underwent CT. It is hard to read between the lines and determine how many of the injuries included in this analysis were missed on the initial presentation, but if rate of neuroimaging is the simplest criteria for winning, there’s no competition. Applying CHALICE to their analysis cohort would have increased their CT rate to approximately 22%, and CATCH would raise the rate to 30.2%. Application of PECARN would place 46% of the cohort into CT vs. observation – an uncertain range, but certainly higher than 10%.

Regardless, in their stated comparison, the true winner depends on the value-weighting of sensitivity and resource utilization. PECARN approached 100% or 99% sensitivity, missing only 1 patient with clinically important traumatic brain injury out of ~10,000. Contrawise, CATCH and CHALICE missed 13 and 12 out of ~13,000 and ~14,000, respectively. Most of these did not undergo neurosurgical intervention, but a couple missed by CHALICE and CATCH would. However, as noted above, PECARN is probably substantially less specific than both CATCH and CHALICE, which has relatively profound effect on utilization for a low-frequency outcome.

Ultimately, however, any of these decision instruments is usable – as a supplement to your clinical reasoning. Each of these rules simplifies a complex decision into one less so, with all its inherent weaknesses. Fewer than 1% of children with mild head injury need neurosurgical intervention and these are certainly rarely missed by any typical practice. In settings with high CT utilization rates, any one of these instruments will likely prove beneficial. In Australia and New Zealand – as well as many other places around the world – potentially not so much.  This is probably a fine example of the need to compare decision instruments to clinician gestalt.

“Accuracy of PECARN, CATCH, and CHALICE head injury decision rules in children: a prospective cohort study”

http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(17)30555-X/abstract

Leave the Blood at Home?

In severely injured multi-system trauma patients, the gold standard for volume replacement is blood – in a relatively balanced ratio between PRBCs, plasma, and platelets. Match this need for blood with the conceptual “golden hour” for acute resuscitation, and it is reasonable to hypothesize there might be added benefit to providing blood products as early as feasible – including during emergency transport. Many of the most critically injured patients with time delays to a trauma center require aeromedical evacuation, so blood products on the helicopter may be ideal.

Sounds good, but the outcomes here are unfortunately not.

This is an observational report from nine trauma systems utilizing aeromedical transport, five of whose helicopters carried blood products and four whose carried only crystalloid. There were 25,118 patients during the study period, 2,341 of whom were transported by helicopter, and 1,058 of whom met “high risk” criteria. Approximately half of these were transported with blood products available, and 142 (24%) of those received transfusion.

Unfortunately, there were vast differences and great heterogeneity between the groups with and without blood products available, including GCS, ISS, and “prehospital lifesaving interventions”. There were similarly profound differences between those receiving blood and those not. The unadjusted mortality outcomes generally followed lower GCS and worse ISS, as one would expect. The authors then attempted a propensity-match analysis to dredge some signal from their data, but only 10% of their cohort could be parsed by their matching algorithm. Owing to only this small sample and the statistical techniques, no reliable difference in outcomes can be demonstrated.

The authors ultimately suggest a multicenter randomized trial will be required to adequately test whether the availability of blood has any mortality benefit. This is clearly the best strategy to improve our answer to this question, although it is prudent to recall non-obvious effect sizes in observational data potentially suggest only a very small magnitude of beneficial effect, if any. This must then be weighed against the important wastage of limited transfusion resources, which would require a non-trivial improvement in outcomes.

“Multicenter Observational Prehospital Resuscitation on Helicopter Study (PROHS)”

https://www.ncbi.nlm.nih.gov/pubmed/28383476

Does FEIBA Work for NOACs?

“Maybe”?

The novel oral anticoagulants – dabigatran, rivaroxaban, apixaban, edoxaban – have spread in use quite rapidly. There is weak evidence supporting the use of idarucizumab for emergency reversal of dabigatran, and even weaker evidence regarding the use of adenxanet alfa. Prothrombin concentrate complexes seem to be efficacious for the Factor Xa inhibitors – but what about factor eight inhibitor bypassing agent?

This small case series from Pittsburgh addresses this question in the least helpful fashion: 11 patients and no comparison group. These 11 patients, most of whom were on rivaroxaban, received 20mg/kg of FEIBA for emergency reversal of anticoagulation in the setting of traumatic intracranial hemorrhage. The authors report 6 of these 11 had stable ICH on repeat CT following initial diagnosis, and, therefore, FEIBA is a potentially safe reversal option.

Of course, the full accounting requires us to mention the remainder of patients had radiographic progression of their injuries despite FEIBA. Most injuries were minor and not expected to have elevated 30-day mortality – and, unsurprisingly then, most survived. In the patients demonstrating substantial derangement of laboratory measures of coagulation, most showed profound improvement of the PT following FEIBA administration. Two patients also suffered subsequent thromboembolic events.

So, yes, FEIBA may be a treatment option for the Factor Xa inhibitors – but this hardly supports routine use outside a study setting as these authors seem to be doing.

“Factor Eight Inhibitor Bypassing Agent (FEIBA) for Reversal of Target-Specific Oral Anticoagulants in Life-Threatening Intracranial Bleeding”

https://www.ncbi.nlm.nih.gov/pubmed/28007364

Opiates Versus NSAIDs, the Battle Continues

HealthDay says: “Opioids No Better Than Ibuprofen for Pain After Car Crash: Study”, leading with an assertion that prescription painkillers are no more effective than non-steroidal anti-inflammatory drugs. This was also picked up by the daily American College of Emergency Physicians e-mail newsletter.

So – no?

Despite the best of intentions, there is simply no reliable conclusion to be drawn from the cited publication. In the citation, the authors perform a propensity score-matching secondary analysis of prospectively collected observational data on patients discharged from the Emergency Department following a motor vehicle collision. There were 948 patients in their initial study cohort, with approximately half receiving a prescription at ED discharge. Propensity score matching then further excluded approximately 100 more, and finally patients lost to follow-up reduce their ultimate sample to 284. Their primary outcome was the presence of persistent self-reported moderate to severe pain six weeks after their MVC.

Unsurprisingly, with the wide confidence intervals mandated by their small sample, there was some overlap between the number in each group having persistent pain at six weeks. Thus, this leads the authors to make a guarded, but clearly anti-opiate, conclusion the evidence does not exist to recommend opiate therapy at ED discharge.

The bias in any underpowered study is to commit Type II error, which, as a reminder, is to retain the false null hypothesis in failing to detect an effect. Furthermore, as the authors note in their extensive methods section, in non-randomized studies, the measured and unmeasured confounders ultimately guide group assignment, which can bias the downstream results. The adjustments of propensity matching attempt to control for these, but tend to depend on large sample sizes and robust feature sets to reduce the magnitude of systematic bias – neither of which are present here. The need to impute missing data further reduces the reliability of under foundational data. Lastly, is their primary outcome relevant and related to the interventions examined? I am doubtful that six week persistent pain accurately reflects the scope of benefit (or lack thereof) relating to analgesic pharmacotherapy following MVC.

Avoiding the adverse effect of opiates is certainly important. However, this article should add little to the discussion – despite its lay medical press coverage.

“Persistent pain after motor vehicle collision: comparative effectiveness of opioids versus non-steroidal anti-inflammatory drugs prescribed from the emergency department—a propensity matched analysis”
http://journals.lww.com/pain/Abstract/publishahead/Persistent_pain_after_motor_vehicle_collision__.99393.aspx

When Is An Extremity CTA Necessary?

Here’s another piece regarding low-value testing in trauma, focusing on another topic: the use of CT angiograms for evaluation of extremity vascular injury.

This single-center, retrospective series looks at use of the extremity computed tomography angiogram in the setting of orthopedic and multi-system trauma. For what it’s worth, at least, there were only 275 scans identified during their 10-year study period. However, the bad news, of course: only 16 (6%) of those scans identified an injury requiring treatment.

Of greatest interest to those trying to eradicate low-value care comes the entirely unsurprising observation that 109 (40%) of patients received CTAs despite the absence of hard or soft signs of vascular injury – and all were normal. Additionally, all 16 cases requiring treatment had diminished or absent distal pulses on presentation.

I do anedcotally see the clinical examination being devalued, especially in trauma – it shouldn’t be!

“When are CT angiograms indicated for patients with lower extremity fractures? A review of 275 extremities”
http://journals.lww.com/jtrauma/Abstract/publishahead/When_are_CT_angiograms_indicated_for_patients_with.99386.aspx

From Way Too Many CTs to Many CTs

I am always keen to hear reports of successful imaging reduction interventions – and, even moreso, in trauma. The typical, modern, approach to trauma involves liberal use of advanced imaging – almost to the point of it being a punch line.

This single-center before-and-after report details their experiences between 2006 and 2013. Before 2010, there was no specific protocol regarding CT in trauma – leading to institutional self-examination in the setting of rampant overuse. After 2010, the following protocol was in effect:

trauma algorithm

There isn’t much besides good news presented here. Their primary imaging use outcome, abdominopelvic CT, decreased from 76.7% to 44.6% of all presentations. This was related to an increase in mean ISS for those undergoing CT. When free fluid from non-traumatic causes was individually accounted for, the rate of positivity of these CT rose from 12.3% to 17.5%. Finally, mortality was unchanged – 3.1% vs. 2.7%.

No doubt, any reduction in imaging will miss some important findings. The net counterbalancing effect, however, is likely a massive reduction in costs and harms from further evaluation of false-positives, renal contrast injury, and radiation. And, after all, they’re still performing CTs on nearly half their patients!

“Effect of an Institutional Triaging Algorithm on the Use of Multidetector CT for Patients with Blunt Abdominopelvic Trauma over an 8-year Period”

http://pubs.rsna.org/doi/abs/10.1148/radiol.2016152021

The Extra Head CTs in Trauma, Estimated

In the world of academia and residency training, the spirited debate in trauma is usually regarding the merits of the “pan-scan” – and whether we can all agree it is probably safe to reduce costs and resource utilization by selective scanning. In community practice, it’s about picking up the needle in a haystack – and, hence, preventing the innumerable unnecessary CTs.

This is a retrospective review using electronic health record data to estimate the number of potentially unnecessary head CTs in the setting of trauma. These authors pulled records for all patients for whom a head CT was obtained, and for whom recorded EHR values suggested an encounter for trauma. This cohort was then evaluated for appropriateness of a CT by retrospectively determining the presence of high-risk or exclusion criteria for the Canadian CT Head Rule.

Among 27,240 patients extracted, 11,432 (42.0%) were “discordant” with the CCHR by structured EHR content. However, upon manual review of the chart narrative, the structured EHR content misclassified the CCHR recommendation 12.2% (95% CI 5.6-18.8%) of the time. Thus, the authors then estimate approximately 36.8% (95% CI 34.1-39.6%) of CT head for trauma in a community setting is inappropriate.

This is probably a reasonable research strategy, warts and all. Due to EHR limitations, they actually only filtered for 3 of the 5 high-risk criteria – basilar skull fracture and open skull fracture are such rare findings in their cohort the impact on overall results would be negligible. Then, Kaiser is probably more aggressive at minimizing CT use than the general community ED population, as routine quality improvement monitors individual and group rates of CT usage.

Bottom line: at least a third of head CTs for trauma in the community can probably be obviated by use of validated criteria.

“Computed Tomography Use for Adults with Head Injury: Describing Likely Avoidable ED Imaging based on the Canadian CT Head Rule”

http://www.ncbi.nlm.nih.gov/pubmed/27473552

Pan-Scans Don’t Save Lives

Humans are fallible.  We don’t always make good choices, and our patients – bless their hearts – can sometimes be time bombs wrapped in meat.  Logically, then, as many trauma services have concluded, the solution is to eliminate the weak link: don’t let the human chose which parts of the body to scan – just scan it all.

This is REACT-2, a randomised [sic] trial evaluating precisely the limits to human judgment in a resource-utilization versus immediacy context.  In this multi-center trial, adult trauma patients wth suspected serious injury were randomized to either imaging guided by clinical evaluation or total-body CT.  The primary outcome was in-hospital mortality, with secondary outcomes relating to timeliness of diagnosis, to mortality in other time frames, morbidity, and costs.

This was a massive undertaking, with 1,403 patients randomly assigned to one of the arms, with ~540 in each arm successfully allocated and included in their primary analysis.  Each cohort was well-matched on baseline characteristics, including all physiologic markers, although the Triage Revised Trauma Score was slightly lower (worse) for the total-body CT group.  The results, in most concise form, weakly favor selective scanning.  There was no difference in mortality nor complications nor length-of-stay nor virtually any reliable secondary outcome.  Costs, as measured in European terms, were no different, despite the few scans obviated.  Time-to-diagnosis was slightly faster in the total-body CT group, owing to skipping initial conventional radiography, while radiation exposure was slightly lower in the selective scanning group.

In some respects, it is not surprising there were no differences found – as CT was still frequently utilized in the selective CT cohort, including nearly half that ultimately underwent total-body CT.  There were some differences noted in in-hospital Injury Severity Score between groups, and I agree with Rory Spiegel’s assertion this is probably an artifact of the routine total-body CT.  This study can be used to justify either strategy, however – with selective CT proponents focusing on the lack of differences in patient-oriented outcomes, and total-body CT proponents noting minimal resource and radiation savings at the expense of timeliness.

“Immediate total-body CT scanning versus conventional imaging and selective CT scanning in patients with severe trauma (REACT-2): a randomised controlled trial”
http://www.ncbi.nlm.nih.gov/pubmed/27371185

Trauma is Still Trauma the Next Day

Acute closed head trauma is easy enough – and challenging enough.  There are validated decision instruments and guidelines, yet still plenty of CTs performed absent sound indications.  However, the question this study addresses is slightly different: what to do with those who present in a delayed fashion following minor head trauma?

The authors probably sum it up best in a reasonably concise fashion:

“Patients presenting after 24h of injury are a potentially distinct subpopulation. They could be at lower risk, as there is evidence that patients with mild/minor head injury who have injuries requiring neurosurgery will deteriorate within 24h. Alternatively, they could be a self-selecting higher-risk group attending due to the worsening or persistence of symptoms.”

These authors reviewed 2,240 patient encounters resulting in a CT scan of the head, with a goal of winnowing it down to just those performed for a traumatic indication.  Of those, 549 were performed within 24 hours of injury and 101 were delayed presentations.  There were 46 (8.4%) CTs positive for traumatic injury in the acute presentations and 10 (9.9%) in delayed, while 5 and 3 patients each underwent neurosurgical intervention, respectively.  So, the answer to their research question, at least in pragmatic terms, may be that the two forces balance each other out.

These authors also present “sensitivity” statistics regarding the utility of guidelines at predicting the presence of an important TBI, and quote a sensitivity of 70% based on chart review.  The denominator for sensitivity would more appropriately the entire population of presentations for trauma, not simply those who underwent CT scanning.  It is also probably more likely, given these patients had important TBI on CT, there may have been undocumented, guideline-compliant, indications not abstracted by chart review.

While our decision instruments for closed head injury were derived in typically an acute population, I would not yet draw any conclusions refuting their generalizability to delayed presentations.

“CT head imaging in patients with head injury who present after 24 h of injury: a retrospective cohort study”
https://www.ncbi.nlm.nih.gov/pubmed/27076439