The “headline” you’ll see from this article is that the Canadian Head CT Rule outperforms the New Orleans Criteria for radiographic imaging in minor head trauma. Specifically, it outperforms it in this prospective, observational cohort from several hospitals in Tunisia, consecutive patients with blunt trauma to the head and at least one symptom secondary to the head trauma.
The most striking thing about this article, however, remains the gruesome number of false positives generated by each of these head CT decision rules. While, obviously, the intent is to capture all the cases requiring neurosurgical intervention, the New Orleans Criteria could not rule out potential need for neurosurgical intervention in 1,180 out of 1,582. When the theoretical purpose of these rules is to prevent “scanning everyone”, we’re not getting much bang for our buck. The Canadian Head CT Rule was better – but still indicated a need for scan in 656 out of 1,582.
While the article focuses mostly on the need for neurosurgical intervention in GCS 15 patients, it’s interesting to see their “secondary outcomes” which did not need “intervention”. Only 34 total patients in their cohort required intervention – while they found 133 skull fractures, 41 subdurals, 45 epidurals, 69 subarachnoids/hemorrhagic contusions, and 1 case of pneumocephalus. The Canadian rule would have missed 11 of the 218 “clinically significant” findings, for a sensitivity of 95%. The article does not specific precisely which types of findings were missed, but, clearly, many of those may be argued to be not significant. Unfortunately, deriving a better rule based on a more liberal definition of “clinical significance” is likely to result in more missed interventions – but it’s still probably worth trying.
“Prediction Value of the Canadian CT Head Rule and the New Orleans Criteria for Positive Head CT Scan and Acute Neurosurgical Procedures in Minor Head Trauma: A Multicenter External Validation Study”
http://www.ncbi.nlm.nih.gov/pubmed/22251188
Category: Trauma
Platelet Transfusion & Intracerebral Hemorrhage
This systematic review is published in Annals of Emergency Medicine under the section heading of “Best Available Evidence”, which somehow to me seems to pleasantly understate the unfortunate lack of data on this topic.
Intracererbral hemorrhage in the setting of antiplatelet use unfortunately is one of those clinical situations where outcomes are so dire that the philosophy seems to be to throw the kitchen sink of potentially beneficial interventions at patients. Use of clopidogrel, and to a lesser extent aspirin, are associated with increased hematoma size and poorer outcomes. Platelet transfusions, using measures of platelet aggregation activity, are demonstrated to improve and reverse inhibition in approximately two-thirds of patients. Therefore, it follows that platelet transfusions would improve outcomes in intracranial hemorrhage.
Unfortunately, the “best” evidence – which is mostly retrospective data of small cohorts – fails to demonstrate any improvement in mortality or morbidity. It is not possible to say from the data whether the platelets do not show efficacy at treating the extension of the ICH, or whether the poor outcomes result from parallel transfusion-related complications. The article concludes that withholding platelet transfusion should be considered to be within the standard of care. I tend to agree that resource-intensive treatments should be required to demonstrate benefit before widespread adoption, and therefore agree with these authors.
The authors additionally note a prospective, multicenter trial is underway.
“Does Platelet Transfusion Improve Outcomes in Patients With Spontaneous or Traumatic Intracerebral Hemorrhage?”
It’s Nothing Like “ER”
This is a fun little article regarding the realism of the Emergency Medicine environment showcased on the popular U.S. television show “ER”. As the authors state in their introduction, the viewers of the show have been surveyed, and a significant portion of the viewers believe the content of the show to be valid clinical information. However, the televised outcomes are frequently unrealistic (CPR success rates, patients emerging from comas, etc.), and lead to inaccurate public perceptions.
This team of authors watched all 22 episodes from a single season of “ER” to evaluate the types of patient encounters depicted, and then compared their findings with representative data from the NHAMCS dataset. Overall, there were 192 patients during the 22 episodes, and they differed from the real-world by:
– Weighted heavily towards 25-44 years of age, rather than infants and elderly.
– More male and white, rather than black and female.
– Depictions of lower pain levels.
– Far more traumatic injuries.
And, this analysis only observed the patients – the responsibilities and skills of the treating medical students, residents, and attendings are also wildly dramatized, of course.
So, it’s nothing like “ER”. It’s really more like “Scrubs”….
“ER vs. ED: A comparison of televised and real-life emergency medicine.”
http://www.ncbi.nlm.nih.gov/pubmed/22766407
Xigris Isn’t Dead – Just Hibernating
Activated Protein C, also known as Xigris, which has had an infamous and circuitous career of sorts, is back.
After a short life of use in severe sepsis, the continued investigations into its efficacy have finally been unable to establish its benefit. Although many expensive therapies without conclusive benefit are still in use in medicine, we’ll score this one (belatedly) for the good guys.
This early animal research, published as a letter in Nature Medicine, reports on interventions targeting the aPC pathway to prevent lethal radiation injury to hematopoietic cells. They say that starting infusions of aPC within 24 hours of lethal radiation exposure mitigated radiation mortality in mice. Probably quite a long way off for real-world usage, but any potential treatment is better than none.
“Pharmacological targeting of the thrombomodulin–activated protein C pathway mitigates radiation toxicity”
Impaled in a Rowing Accident
This article I dredged up from the archives is mostly of sentimental value – although, I could claim it’s related to Olympic sport-related trauma with the upcoming Games.
This is from the series “Case records of the Massachusetts General Hospital”, which run the gamut all the way out to some of the most esoteric diagnoses possible. This particular article describes the management and outcomes of a man impaled by a rowing shell while on the Charles River. Eight-person rowing shells are ~17 meters in length, have a crewed weight of nearly 1,000 kg, and travel fast enough that a water skier may be towed behind. There is a small rubber bumper affixed to the, otherwise sharp, wooden or carbon-fiber bow that is meant to reduce the potential for injury in event of a collision. In this incident, the momentum of a head-on impact dislodged the bow ball and resulted in the unfortunate impalement incident described. A fascinating little read.
Rowing collisions are uncommon, injuries are rare, and this is probably nearly unique.
“Case records of the Massachusetts General Hospital. Case 10-2007. A 55-year-old manimpaled in a rowing accident.”
www.ncbi.nlm.nih.gov/pubmed/17392306
How to Be Popular at the Beach
The summer is a great time for swimming – and, luckily, there’s an evidence-based systematic review of treatment of jellyfish stings available from Annals of Emergency Medicine. Unfortunately, it’s only the relatively benign and inconvenient species from North America, rather than the life-threatening species found more commonly in the southern hemisphere.
Literally, everything has been tried on jellyfish stings in an attempted in treatment, from vinegar, to ammonia, to ethanol, to meat tenderizer, to magnesium chloride, and the list goes on. Essentially, the attempted treatments fall into two camps – wash off the nematocysts without inducing discharge, or simply to treat the pain and tissue damage from the venom itself.
The American Red Cross First Aid consensus suggests the use of vinegar – which, according to this review, induces nematocyst discharge in everything but some Physalia species. The real answer is…no single agent reliably inactivates nematocysts from every organism. The authors recommend simply using readily available saltwater to wash the affected area. For post-envenomation pain, topical anesthetics such as lidocaine and hot water were found to be most reliably effective. Given the limited availability of anesthetics to laypersons, the best treatment is likely to be hot water submersion to help inactivate the toxins.
“Evidence-Based Treatment of Jellyfish Stings in North America and Hawaii”
www.ncbi.nlm.nih.gov/pubmed/22677532
Plain C-Spine Radiography in Children
In adults, the use of plain radiography has largely been replaced in the U.S. by computed tomography over concerns regarding missed injuries – and some literature even argues that, given the right clinical circumstances, even a normal CT scan is inadequate. But, in children, the harms of radiation exposure are greater, so pediatrics has been more hesitant to move to CT as the first imaging study of the cervical spine in blunt trauma.
Unfortunately, this retrospective PECARN study of children with cervical spine injuries isn’t as helpful as one would hope. The authors identified 204 children, 58 of whom were aged less than 7 years, who sustained a CSI and had plain radiographs of the cervical spine performed. Of these patients, 127 patients had a definite injury on plain radiography. 41 additional patients had “possible” abnormalities. Then, 20 films were judged to be inadequate by technique. And, finally, there were 18 adequate radiographs with normal findings who subsequently had a CSI identified. The overall sensitivity, then, was 90% (CI 85-94%) – which compares very similarly to the sensitivity in adults from the 34,000 patients in the NEXUS study.
The authors note that most missed injuries fell into two general categories: they were either subtle and non-morbid, or the patients were altered/intubated/focal neurologic findings. It is probably still reasonable to start with screening plain-film radiography and use clinical judgment to determine when CT may be necessary, but if you’re looking for airtight evidence to guide your decision-making, CSI in children is too rare to generate that sort of data.
“Utility of Plain Radiographs in Detecting Traumatic Injuries of the Cervical Spine in Children”
Most Severe Mechanism Children Don’t Need Head CTs
The PECARN group has published a set of criteria that identify children at very low risk for significant traumatic injury. This is publicly available and an excellent decision instrument to enhance your clinical judgement. But, the problem is, with excellent sensitivity, the specificity is weak – such that a great number of patients who fail to meet low-risk criteria will still have good outcomes.
So, this is a follow-on study attempting to determine whether the severe mechanism portion of the decision instrument was predictive of significant TBI, or whether scans could be avoided if mechanism was the only positive feature in their decision instrument. And, yes, a severe injury mechanism in isolation – at least in the 35% of their cohort who received a head CT – had only a 0.3% chance of significant injury in age <2 years and 0.6% chance of significant injury in age >2 years. Severe injury mechanisms associated with additional PECARN criteria, however, had 4% and 6% incidence of TBI, depending on age.
Probably the most important aspect of these numbers is they allow for a better discussion of risks with parents and families. While 1 in 150 or 1 in 300 sound like pretty good odds, when you practice long enough, those odds will catch up with you. Even with severe mechanism and additional features, 19 of 20 CTs will be negative – you can still make a reasonable case for observation rather than knee-jerk scanning.
“Prevalence of Clinically Important Traumatic Brain Injuries in Children With Minor Blunt Head Trauma and Isolated Severe Injury Mechanisms”
Pan-Scan & Zero-Miss
In an interesting contrast to a prior article regarding over-scanning in trauma, this article takes a different perspective. While the authors do note that there is controversy regarding the impact of “pan scan” on survival, they are rather focused on the sensitivity/specificity of the “pan scan,” rather than the appropriateness.
This is a review of 982 consecutive patients undergoing “pan scan” in Germany. The indications for scanning were a set of “red flag” criteria, which included impaired patients, patients with obvious injuries, “suspicion of severe trauma” or “high risk mechanism”. The diagnostic reference standard was chart review by two reviewers of the electronic notes for any injuries missed on the initial scan.
The results are rather interesting in a couple ways: the prevalence of injuries per organ system is not terribly high, and the sensitivity of scanning was rather low. The highest prevalence of injuries for an organ system was 37%, for chest, followed by head and neck at 34%. However, the sensitivities range from a high of only 86.7% for chest down to a low of 79.6% for face – likely because dedicated fine cuts of the face were not part of their protocol. Regardless, with sensitivities in the mid-80s meant they missed almost one seventh of the total number of injuries. Of these 70 missed injuries, almost half required surgery or a critical intervention as treatment.
So, pan-scanning: expensive, low yield, yet still misses important injuries. The authors do not try to fully address whether their yield is reasonable or not, and wisely simply state further research is needed regarding triaging patients into groups likely to benefit from scanning.
“Accuracy of single-pass whole-body computed tomography for detection of injuries in patients with major blunt trauma.”
http://www.ncbi.nlm.nih.gov/pubmed/22392949
One-Man Crusade For Steroids In Spinal Trauma
The Cochrane Review regarding the efficacy of steroids in acute spinal cord injury, first published in 2002, has been updated for 2012. The author’s conclusions: “Methylprednisolone sodium succinate has been shown to enhance sustained neurologic recovery in a phase three randomized trial, and to have been replicated in a second trial.”
This is an interesting conclusion to draw from an analysis of, essentially, only negative studies. NASCIS 1 (1984) was statistically negative – but was discounted because the dosing was possibly too low. NASCIS 2 (1990) was also statistically negative, except for pinprick and light touch at six months, which disappeared at one year. The supposed positive outcome comes from a post-hoc analysis in which the patients who received their steroids between 3 and 8 hours after injury shook out to have a statistically significant improvements in motor score at six months and one year. However, post-hoc subgroup analysis cannot be considered practice-changing evidence until confirmed in subsequent studies. Otani (1994) was statistically negative for the primary outcome, but post-hoc analysis identified greater sensory improvement in the steroid group – which therefore implies greater motor improvement in the control group, as the overall combined neurologic scores were not different. NASCIS 3 is not placebo-controlled.
There is also no mention in the Cochrane Review of adverse events – the only mention of the safety profile of high-dose steroids in the discussion section references a systematic review of high-dose steroids given to general surgical patients, both elective and trauma. This is rigorously invalid, as the correct assessment of the safety profile of an intervention should be derived from the safety outcomes of the studies included in the analysis – nearly all of which had consistent, non-significant (underpowered) trends towards increased infectious complications.
Would it surprise you to discover that the author of the 2000, 2002 and 2012 Cochrane Review articles is the same first author of NASCIS 1, 2, and 3?
“Steroids for acute spinal cord injury.”