Category: Trauma

I Choose You! Observation, I Hope.

We’re back with another patient-oriented clinical decision aid from the folks who brought you Chest Pain Choice – Pediatric Head CT Choice! In this episode, our noble heroes are out to educate parents regarding the risk of intracranial injury in children who are at “intermediate risk” for clinically-important traumatic brain injury by PECARN criteria.

In this multicenter, cluster-randomized, controlled-trial, these authors tested an information graphic and educational tool against usual care, with a primary outcome of parental knowledge. Additional measures of engagement in the decision-making processes, decisional conflict, and parental trust were measured as secondary outcomes related to the cognitive aspects, along with patient-oriented outcomes such as ciTBI and imaging utilization. They included 172 clinicians at 7 sites, and enrolled 971 patients, including 516 patients who consented for recording of their discussion regarding imaging. Follow-up by telephone was obtained in 890 (92%) of patients, with the remainder of outcomes assessment limited to electronic health record and vital records follow-up.

The results are mostly good news regarding the decision aid. Parents in the intervention arm could answer 6 of 10 questions about their choice correctly, compared with 5 of 10 receiving usual care. Secondary cognitive outcomes also favored the decision instrument, and physicians surveyed were generally in favor of the decision aid, as well. Imaging at the index visit was similar between the two groups, but downstream healthcare resource use and subsequent imaging was lower in the decision aid cohort.

There are findings here to critique, of course. There was only one ciTBI in the entire cohort, and they were imaged at the index visit. The expectation – and the tool – were constructed based on a 0.9% ciTBI rate, when the actual observed incidence was 0.1%. It is reasonable to consider the practical implementation of PECARN over-classifies patients into the “intermediate risk” cohort, placing additional children at risk for unneeded imaging – which, in turn, renders their “1 in 100” information graphic misleading. Then, clinicians spent an extra 2 minutes – 38% longer – with parents when using the decision aid. How much of the improved knowledge and trust stems from the decision aid, and how much from simply spending more time in the discussion? Finally, there are uncertain manifestations of the Hawthorne effect, particularly considering over half the encounters were recorded.

Overall, however, I have few quibbles with this decision aid. At the least, it is unlikely to exert a negative effect on parental knowledge or paradoxically increase unnecessary scanning.

“Effect of the Head Computed Tomography Choice Decision Aid in Parents of Children With Minor Head Trauma”
https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2703135

Clearing the Cervical Spine with Distracting Injuries

Ah, the “distracting” injury. An utterly subjective and modifiable component of cervical spine clearance in the NEXUS criteria. Is it an isolated finger dislocation? Is it a femur fracture? We’ve all seen patients writhing or stoic in the face of either. And, then, factor in any prehospital analgesia ….

This is a prospective, observational study coming out of the American Association for the Surgery of Trauma evaluating the effects of distracting injury on cervical spine clearance. For their purposes, the following injuries were considered “distracting”:

Skull fracture, >2 facial bone fractures, mandible fracture, intracranial hemorrhage (including subdural hematoma, epidural hematoma, subarachnoid hemorrhage, intraventricular hemorrhage, intraparenchymal hematoma), >2 rib fractures, clavicle fracture, sternal fracture, pelvic fracture, thoracolumbar spine fracture, intra-abdominal injury (including solid organ injury, hollow viscus injury, or diaphragmatic injury), femur fracture, tibia/fibula fracture, humerus fracture, radius/ulna fracture, and hip or shoulder dislocation.

The physical exam consisted of midline neck palpation and, absent any contraindication, active range of motion of the neck in flexion, extension and rotation. The cervical collar could be removed at the discretion of the treating team, but – in classic traumatology fashion – all patients underwent CT of the cervical spine, regardless of exam.

There were 2,929 blunt trauma patients with GCS ≥14, and 222 had cervical spine injuries identified on CT. Of these injuries, 25 were “missed” by the clinical exam. The “good news”: the rate of miss was “the same”, regardless of distracting injury – 0.7% vs. 1.3%. The bad news, of course, is that a normal physical examination missed 11% of cervical spine injuries. One patient whose injury would have otherwise been missed by a negative physical examination underwent operative intervention.

While there is some obvious spectrum bias associated with any observational cohort enrolled at trauma centers, it is still a reasonable estimate of the sensitivity and specificity of the physical examination. Clearly, it’s not bulletproof in the context of multi-system trauma – but, depending on the pretest likelihood of a cervical spine injury based on other presenting features, a distracting injury need not disqualify a patient from clinical clearance.

“Clearing the Cervical Spine in Patients with Distracting Injuries: An AAST Multi-Institutional Trial”

https://journals.lww.com/jtrauma/Abstract/publishahead/Clearing_the_Cervical_Spine_in_Patients_with.98558.aspx

Adult Head CT Decision Instrument Showdown

Every country seems to have their own pediatric imaging rule for minor head trauma, featuring PECARN, CHALICE, and CATCH. Recently, a head-to-head-to-head comparison (no pun intended) found the clear winner was: clinical judgement in Australia and New Zealand. Adoption of any of the rules would not have reliably increased sensitivity, but all would dramatically increase imaging.

Now, what about adult head trauma? The same story of every-country-has-a-flavor seems to be the case, with the CT in Head Injury Patients rule, the New Orleans criteria, the Canadian CT Head rule, and the National Institute for Health and Care Excellence guideline. This time, we have the Dutch performing the comparison.

In this multicenter, observational study conducted in 2015 and 2016, the authors enrolled neurologically-intact patients aged greater than 16 years and presenting with blunt head trauma within 24 hours of injury. Clinical data with the elements necessary for each decision instrument were completed by treating clinicians and collected by study staff. Decisions to perform imaging were based on individual clinician discretion, but primarily based on the CHIP rule. Outcomes were ascertained by electronic record review.

There were 5,839 patients entered in their study database, 5,517 meeting eligibility criteria. At three centers, only patients undergoing CT were entered in the database, while the remaining six centers included a handful of patients who did not undergo CT. Obviously, this grossly limits the descriptive capacity of the study, as clearly a massive number of patients with minor head injury who did not undergo CT were not followed for outcomes.

Overall, 384 of the 3,742 patients undergoing CT had positive traumatic findings. Most were small skull fractures, but about half had intracranial bleeding of some variety or another, with a further 74 being judged potential neurosurgical lesions. The most sensitive of the decision instruments in this study was the New Orleans criteria, while NICE guidelines were the least. Of course, the New Orleans criteria also would have recommended CT in all but 189 patients, for a specificity of 4.2%.

Ultimately, there’s no clear “winner” in this study, and, unfortunately, there’s also no obvious superior “clinician judgement” comparison lurking. The underlying rate of imaging was effectively the same as CHIP, as this was the national guideline in the Netherlands at the time of the study. Whether this is the “best” depends on tolerance for risk and the reliability of their estimate of “potential neurosurgical lesion”. Then, regardless of the decision instrument chosen, each still recommends imaging in thousands of patients in order to pick up the few with positive findings. Considering data from children, it seems we ought to be able to do much better – but current practice does not appear to be moving in that direction.

“External validation of computed tomography decision rules for minor head injury: prospective, multicentre cohort study in the Netherlands”
https://www.bmj.com/content/362/bmj.k3527

Minor Head Injury and Anticoagulants

Guidelines advise performing imaging in those patients on anticoagulants who have suffered minor head injury. We virtually all dutifully obey, because, even though the incidence of intracranial hemorrhage is low – it’s still much higher than zero. But, how high, really? Particularly when they’re sitting there, looking normal, with a GCS of 15?

This systematic review and meta-analysis gathered together 5 studies comprising 4,080 anticoagulated patients with GCS 15 following a head injury. Three of the studies mandated imaging, while the others allowed physician discretion with observation, telephone, and chart-review follow-up to ascertain outcomes. The vast majority of patients were on Vitamin K antagonists, and most mechanisms of injury – where documented – were falls.

Overall, there were 209 (5%) patients with ICH after their fall, nearly all of which were diagnosed at the index visit. There was a wide range of findings, ranging from 4% in the largest studies to 22% in the smaller. However, the larger studies were the ones with the least-complete follow-up after the index event. Therefore, these authors’ random effects analysis and sensitivity analysis generated higher estimates of the incidence, up to 10.9%.

So, while yield is low, we’re still far from having a strategy to support selective scanning to improve value. While it is unlikely many of these would have neurosurgical intervention indicated, a substantial portion likely underwent anticoagulation reversal to prevent further morbidity or mortality. While resource stewardship is always an important consideration, it is unlikely we will anytime soon be altering our approach to minor head injury in the context of anticoagulation.

“Incidence of intracranial bleeding in anticoagulated patients with minor head injury: a systematic review and meta-analysis of prospective studies”

https://www.ncbi.nlm.nih.gov/pubmed/30028001

Magical Biomarkers in TBI

Decision instruments be damned. Clinical judgment be damned. We need a test! We need a biomarker test to tell us whether we should perform a CT in traumatic brain injury!

Thus enter ubiquitin C-terminal hydrolase-L1 (UCH-L1) and glial fibrillary acidic protein (GFAP), mated together in loving embrace by Banyan Biomarkers in a prospective, observational trial – ALERT-TBI. The aim of this study was to validate these biomarkers, each with their pre-set cut-off thresholds, as accurate predictors of intracranial injuries on CT. Specifically, as accurate predictors in a convenience sample of patients presenting to one of 22 investigational sites with a GCS between 9 and 15.

These trialists collected samples on 1,977 patients, 125 of whom were “CT-positive” – meaning intracranial blood, as typical, but also “bland sheer injury … brain oedema, brain herniation, non-haemorrhagic contusion, ventricular compression, ventricular trapping, cranial fractures, depressed skull fractures, facial fractures, scalp injury, or skull base fractures.”  Only 8 of these patients ultimately underwent neurosurgical intervention.

The good news: these assays were 100% sensitive for neurosurgical lesions. The bad news: the lower bound of the 95% confidence interval is 63%. The other bad news: the specificity of the test is only ~35%, meaning it recommends CTs in two-thirds of your TBI patients. And, also: median time from injury to blood draw was 3.2 hours, meaning we can’t actually generalize these findings to potential phlebotomy in the the acute peri-injury trauma evaluation. And, we could keep going on with the bad news, to be certain, but I think we’ll stop there.

The final point to make is to note this study concluded in 2014. It is now, of course, past the midpoint of 2018. It probably goes without saying study findings with obvious advantages to their funding sponsor are not neglected for several years, nor shuffled into Lancet Neurology absent any fanfare.

Chalk this study up as yet another failed dalliance into potential biomarker use for TBI.

“Serum GFAP and UCH-L1 for prediction of absence of intracranial injuries on head CT (ALERT-TBI): a multicentre observational study”

https://www.thelancet.com/journals/laneur/article/PIIS1474-4422(18)30231-X/fulltext

Anything But Crystalloid

The balanced transfusion ratio has been in vogue for many years in military settings (read: whole blood), but, until recently, less popular with civilians. There are probably still kinks to be worked out with respect to improving the value of resource consumption in massive transfusion, but, at the least, it appears roughly equivalent ratios of plasma to blood cells are beneficial.

So, given the opportunity, why not initiate this sort of balanced resuscitation in the prehospital setting?

This somewhat messy and heterogenous trial does precisely that – randomizing 523 unstable trauma patients to either standard resuscitation or transfusion of 2 units of FFP, followed by standard resuscitation. The randomization took place in clusters at the aeromedical transport base level, and included bases whose initial protocol included PRBC transfusions for eligible patients. In these instances, the FFP was transfused first, and then the PRBCs. Additionally, 111 of the enrolled aeromedical transports were transfers from an outlying hospital. This meant the pre-enrollment resuscitation could be virtually any permutation of potential volume replacement. While the two groups were roughly balanced as far as etiologies of trauma, injury severity, and other baseline features, the initiation of FFP prior to standard resuscitation did skew the numbers with respect towards prehospital PRBCs, as they had to wait until the intervention transfusion was complete.

Overall, 24-hour mortality was 22% in the “standard care” group and 14% in the plasma group. Only a handful of potentially transfusion-related adverse events occurred, and this early survival advantage proved durable through the length of follow-up. There is enough in the pre-specified subgroup analysis to fuel any number of editorials, other retrospective analyses, and homegrown inclusion or exclusion criteria for prehospital FFP – but, overall, this grossly consistent with our priors for a survival advantage associated with balanced transfusions.

Now, what we really need, is a plasma product with a better shelf-life ….

“Prehospital Plasma during Air Medical Transport in Trauma Patients at Risk for Hemorrhagic Shock”

Don’t Give NEXUS II Much Thought For Kids

Into the the world of PECARN, CHALICE, and CATCH, we add NEXUS II. Why? Good question.

This is a planned secondary analysis of the NEXUS Head CT decision instrument among enrolled patients less than 18 years of age. Like most decision instruments, this rule classifies patients into “high risk” or “low risk”, with “low risk” being free of any mandated imaging. Their rule, which I will not recount, was tested in 1,018 blunt head trauma patients, and their rule picked up all 27 of those who required neurosurgical intervention. Unfortunately, it also only classified 330 patients as “low-risk” – for an abysmal 33% specificity.

The authors state it may yet have value, despite this poor specificity, as a one-way decision rule. Unfortunately, one-way decision rules are fraught with peril, as the inability to classify a patient as “low risk” is difficult to ignore.  This leads clinicians to ultimately use the one-way instrument as a two-way, despite the bleak positive predictive value. This rule also missed one of 49 patients with “significant intracranial injuries”, meaning it is reasonable to expect it may not actually be 100% sensitive.  Considering clinical judgement is vastly superior to this product, and there are enough alternative options, it is reasonable not to give this product another thought.

“Validation of the Pediatric NEXUS II Head CT Decision Instrument for Selective Imaging of Pediatric Patients with Blunt Head Trauma”
https://www.ncbi.nlm.nih.gov/pubmed/29665151

The Elephant in the PECARN/CHALICE/CATCH Room

A few months ago, I wrote about the main publication from this study group – a publication in The Lancet detailing a robust performance comparison between the major pediatric head injury decision instruments. Reading between the lines, as I mentioned then, it seemed as though the important unaddressed result was how well physician judgment performed – only 8.3% of the entire cohort underwent CT.

This, then, is the follow-up publication in Annals of Emergency Medicine focusing on the superiority of physician judgment. Just to recap, this study assessed 18,913 patients assessed to have had a mild head injury. Of these, 160 had a clinically important traumatic brain injury and 24 underwent neurosurgery. The diagnostic performance of these decision instruments is better detailed in the other article but, briefly, for ciTBI:

  • PECARN – ~99% sensitive, 52 to 59.1% specific
  • CHALICE – 92.5% sensitive, 78.6% specific
  • CATCH – 92.5% sensitive, 70.4% specific

These rules, given their specificity, would commit patients to CT scan rates of 20-30% in the case of CHALICE and CATCH, and then an observation or CT rate of ~40% for PECARN. But how did physician judgment perform?

  • Physicians – 98.8% sensitive, 92.4% specific

Which is to say, physicians missed two injuries – each detected a week later in follow-up for persistent headaches – but only performed CTs in 8.3% of the population. As I highlighted in this past month’s ACEPNow, clinical decision instruments are frequently placed on a pedestal based on their own performance characteristics in a vacuum, and rarely compared with clinician judgment – and, frequently, clinician judgment is as good or better. It’s fair to say these head injury decision instruments, depending on the prevalence of injury and the background level of advance imaging, may actually be of little value.

“Accuracy of Clinician Practice Compared With Three Head Injury Decision Rules in Children: A Prospective Cohort Study”
http://www.annemergmed.com/article/S0196-0644(18)30028-3/fulltext

When Can You Clear the Intoxicated Cervical Spine?

The answer is: it depends – are we talking about the “real world”, or the world of evidence-based medicine?

This is a qualitative survey and prospective, multi-center observational study of the cervical spine clearance practices following major trauma. Performed at 17 centers, these authors collected data on definitions of evaluability, length of time in cervical-spine immobilization, and the diagnostic characteristics of CT in the context of the intoxicated trauma patient.

These authors analyzed 10,191 patients, approximately 3,000 of whom were intoxicated with alcohol, drugs, or both. The median injury severity score was ~10, with about a quarter of the cohort having “severe injury” or ISS >15. Incidence of any identified cervical spine injury was 7.6%, or overall 1.4% clinically significant CSI. In this intoxicated cohort, the sensitivity and specificity of the CT was 98% and 93%, respectively. A long questionnaire regarding real-world practice is presented, and the responses are very interesting – most surveyed indicated they would not clear the patient until they were clinically sober for a reliable examination, and patients stayed in their cervical collars for up to 8 hours as a result. On the other hand, despite their practice to the contrary, a small majority of respondents indicated they believed it was safe and reasonable to clear the cervical spine following a CT.

The takeaway for us in the Emergency Department, however, is that it is definitely safe to do so. Absent the multi-system trauma and mechanisms involved in this study, our typical otherwise-uninjured intoxicated patient has a vanishingly small chance of significant injury missed on CT. The risks and costs of staying in the collar – including those of follow-up MRI – exceed the potential harms of a missed injury. If these authors, in the Journal of Trauma – despite their spectrum bias – ultimately conclude it is safe to remove the c-collar based on the NPV in their sample, it is even moreso for our less severely-injured general ED population.

“Cervical spine evaluation and clearance in the intoxicated patient: a prospective western trauma association multi-institutional trial and survey”
https://www.ncbi.nlm.nih.gov/pubmed/28723840

The FAST Is Wrong, Bob

What happens when you routinely do an unnecessary test that rarely changes management? Essentially, nothing.

So, here is a randomized, controlled trial demonstrating precisely that.

This trial looks at the Focused Assessment with Sonography in Trauma exam, as performed in pediatric blunt trauma patients. The FAST, if you recall, is generally indicated primarily for hypotensive blunt trauma patients – that is, it has supplanted diagnostic peritoneal lavage as a non-invasive alternative. It does not routinely provide a diagnosis, but it helps guide initial management and may triage a patient to emergency laparotomy rather than resuscitation and further testing.  Therefore, in a stable pediatric trauma patient, the pretest likelihood of a significant finding – free fluid relating to hemorrhage from trauma – is quite low. Furthermore, because many significant intra-abdominal injuries to solid and hollow organs are missed by ultrasound, a negative FAST has poor negative likelihood ratios and should not substantial affect decisions for advanced imaging as otherwise clinically indicated.

So, then, this trial is a bit of an odd duck with respect to any expected difference observed – and that’s precisely what they found in their “coprimary outcomes”. Among the 925 patients randomized to trauma team assessment alone or trauma team assessment supplemented by Emergency Physician FAST, there was no significant difference in imaging, Emergency Department length of stay, missed intra-abdominal injuries, or total hospital charges. The authors hypothesized, based on adult data, there might be savings at least in ED LOS – though, I might rather suggest adding in one more non-diagnostic test to the acute evaluation is more likely to mildly prolong LOS.

There are also issues generalizing this study setting, where ~53% of patients in each cohort received CTs, to other institutions. Interestingly, mean time to CT was over 2 1/2 hours, suggesting a great deal of observation and reassessment drove imaging decisions rather than the initial evaluation. Then, after expert review, EPs incorrectly identified a positive FAST in 10 out of 23 cases – and missed 11 true positives, as well.  The FAST, even at this academic medical center where it is done as routine, cannot be relied upon.

The sum of this evidence is: no change in practice. A stable patient is, by definition, stable for imaging as indicated – and the FAST is an unnecessary part of the initial clinical evaluation.

“Effect of Abdominal Ultrasound on Clinical Care, Outcomes, and Resource Use Among Children With Blunt Torso Trauma”

http://jamanetwork.com/journals/jama/article-abstract/2631528