Category: Trauma

You Can Use Absorbable Sutures Anywhere

Although, can and should are entirely different interpretations of these data.

There have been many studies showing facial lacerations can be repaired with absorbable sutures with similar cosmetic and adverse outcomes compared with non-absorable sutures.  The same principles, presumably, hold for the trunk and extremities – although, there are significant differences in blood supply and healing time.

This study aimed to demonstrate the non-inferiority of absorbable sutures – specifically, Vicryl Rapide – compared with non-absorbable monofilament.  All lacerations were simple, superficial, and repaired using identical interrupted technique.  At plastic surgery 3-month follow-up, although the absorbable sutures were judged to have generated increased “train tracking” of wounds, cosmesis on the visual analog scale was identical.

However, of the 113 patients they enrolled, they lost 40 to follow-up at 3 months – 20 in each group.  There was no wound dehiscence in either group, but 4/35 developed wound infectious in the Vicryl cohort versus 1/38 in the Prolene cohort.  Given the small sample sizes, this did not reach statistical significance, but increased infection cannot be ruled out.

So – yes, you can use absorbable sutures anywhere.  However, given the attrition in this study and the confidence intervals around infection rates, this study does not represent strong evidence in support.

“A Comparison of Cosmetic Outcomes of Lacerations on the Extremities and Trunk Using Absorbable Versus Nonabsorbable Sutures”
http://onlinelibrary.wiley.com/doi/10.1111/acem.12387/abstract

A Prehospital Transfusion Confusion

Which is to say – endorsing conclusions founded on sparse data is worse than simply admitting the limitations of our knowledge.

Clearly, if a patient requires blood, the more, the sooner, the better with severe injury.  However, starting that transfusion outside a setting fully capable of assessing injury severity and physiology can mean wasted or inappropriate product use.

These authors attempt to show patients receiving blood in the pre-trauma center setting have markedly decreased mortality and traumatic coagulopathy.  However, they do so using a retrospective database of patients from 2003 to 2010, of which only 50 patients received pre-trauma center transfusion, compared with 1,365 who did not.  Additionally, there were diverse differences in ISS, base deficit, and total crystalloid and product transfusion.  They subsequently attempt to control for this using logistic regression and by deriving a propensity-matched cohort – which then compares 35 patients with pre-hospital transfusion with 78 patients without, but still has diverse significant differences in initial physiology and total product transfusion.

So, because of all these intrinsic differences, all their reported odds ratios are adjusted after “controlling for confounders”.  After all the statistical wrangling, “covariate-adjusted” 30 day survival was ~95% in the cohort with pre-trauma center transfusion, and ~88% in others.  The propensity-matched results showed similar odds ratios.  Unadjusted mortality in the cohorts is not presented.

Who knows what this really shows?  The data used is retrospective, heterogenous and collected over the course of 8 years, their sample of pre-trauma center transfusions is tiny, and all their reported odds ratios required huge statistical adjustments.  Pre-trauma center transfusions are probably helpful, if used judiciously, but this is not the study that shows it.

“Pretrauma Center Red Blood Cell Transfusion Is Associated With Reduced Mortality and Coagulopathy in Severely Injured Patients With Blunt Trauma”

Time is Brain, Perhaps – in Trauma

Or, at least, that’s what the adjusted analysis here wants to suggest – and, by implication, validate using aeromedical transport for patients with traumatic brain injury.

This is a retrospective evaluation of 209,529 TBI patients in the National Trauma Data Bank between 2009 and 2011, comparing ground-based transport to Level I and Level II centers with aeromedical transport to these same centers.  Patients flown to Level I and II trauma centers were far more likely to die – in the unadjusted analysis, owing to much higher injury severity scores.  Using two methods of adjustment, however, and incorporating propensity score matching, patients with TBI had odds ratios between 1.73 and 1.95 for survival (95% CI 1.55 to 2.10).  The adjusted absolute risk reductions for death ranged from 4.69% to 6.37% (95% CI 4.08% to 6.85%).

These are fairly substantial improvements in a reasonably important patient-oriented outcome (mortality).  There are, of course, serious limitations in doing this sort of retrospective analysis, making these statistical adjustments, and extrapolating this association out to the presumed benefit of the intervention – that a reduction in trauma response and transport time confers the survival advantage.

This study provides a very low level of evidence moving the needle in favor of aeromedical transport.  It’s reasonably clear there are patients that benefit from aeromedical transport – but at $10,000+ per transport, and field over-triage already a problem, this study alone should not inform any change in practice.

“Prehospital Helicopter Transport and Survival of Patients With Traumatic Brain Injury”
http://www.ncbi.nlm.nih.gov/pubmed/24743624

Predicting Past Massive Transfusion Practices

Traumatic resuscitation is evolving – and reasonably so – to an aggressive, early-intervention strategy.  The current evidence seems to suggest patients benefit from early, whole blood volume replacement in the setting of hemorrhage.

But, in order to aggressively intervene early, it’s necessary to predict such need equally early in the initial trauma assessment process.  Therefore, a variety of prediction decision-instruments have been derived, such as this one from Japan.  These authors looked retrospectively at 119 severely injured trauma patients, developed odds ratios for massive transfusion via logistic regression, and then created a scoring system with a cut-off predicting massive transfusion.  They then subsequently validated this score on another retrospective cohort of 113 patients from the same institution.  Their score contains, essentially, the expected elements – age, lactic acid level, systolic blood pressure, FAST exam findings, and pelvic fracture type – and a score of 15 or higher was 97.4% sensitive and 96.2% specific for massive transfusion.

However, what this rule predicts is not the population that needs massive transfusion – but, because both steps were performed retrospectively, it simply describes the consistency in the authors’ general practice at this single institution.  At the authors’ institution, the patients that looked like the ones described by the rule – elderly, hypotensive, positive FAST, etc. – are the ones that received massive transfusion.  Therefore, when they look back to derive a decision instrument – they’ll find it simply reflects their general practice.  Subsequently, to validate the instrument – again, if their practices haven’t changed, the decision rule will simply accurately reflect the continued practice pattern from which it was derived.  The authors do not mention whether they had a formal early massive transfusion protocol or practice in place, but, if so, this would further skew the decision instrument to reflect the guidelines guiding practice, rather than actual patient need.  Finally, for one last hit to external generalizability, a “massive transfusion” was defined as 10 units of PRBCs – which, in Japan, are about 1/3rd the volume of those in the United States.

Despite its reportedly excellent performance, this rule cannot be relied upon until prospective, external study validates its use.

“Predicting the need for massive transfusion in trauma patients: The Traumatic Bleeding Severity Score”
http://www.ncbi.nlm.nih.gov/pubmed/24747455

Grilling Injuries on Memorial Day

If life were a generic action movie, otherwise idyllic backyard food preparation activity would be interrupted by nonsensical brawling.  And, invariably, the injuries occurring would probably include those suffered from direct contact – in effect, to grill the villainy out of the antagonist.

Reality is rather less sensationalist.  Indeed, apparently, the grilling injury of note is rather from the wire bristles on the grill cleaning implement.  These wire bristles become inadvertently detached, embedded in the culinary creations, and ultimately ingested.  As this CDC Morbidity and Mortality Weekly Report report on a small case series of grilling injuries states:

“The severity of injury ranged from puncture of the soft tissues of the neck, causing severe pain on swallowing, to perforation of the gastrointestinal tract requiring emergent surgery.”

Yet another hidden danger in the home!

“Injuries from ingestion of wire bristles from grill-cleaning brushes – Providence, Rhode Island, March 2011-June 2012.”
http://www.ncbi.nlm.nih.gov/pubmed/22763887

Head Injury Showdown: PECARN Wins!

Most are familiar with the Pediatric Emergency Care Applied Research Network (PECARN) decision instrument for children with mild traumatic brain injury.  While they enrolled the largest number of patients in their derivation, they’re not alone:  the Canadian Assessment of Tomography for Childhood Head Injury (CATCH) and Children’s Head Injury Algorithm for the Prediction of Important Clinical Events (CHALICE) address similar clinical questions.

And, now that you know about them, you might as well forget about them.

This is a prospective validation of each of the three decision instruments at Denver Health, enrolling 1,009 children with blunt head injury and GCS 13 or greater.  52 patients had head injuries on CT, 21 of which were judged clinically significant, and 4 required neurosurgical intervention.  Based on the 90% of their cohort for whom they had complete outcome data, the PECARN rule was 100% sensitive and 62% specific, CATCH was 91% sensitive and 44% specific, and CHALICE was 84% sensitive and 85% specific.  Therefore it is most defensible to use the PECARN decision instrument in a setting concerned with maximal sensitivity.

However, what’s most interesting in this study – only 188 children underwent CT, and physician practice had 100% sensitivity.  All told, the PECARN instrument classified 47 as “high risk” and 335 as “intermediate risk”.  The original derivation publication states this intermediate cohort may be eligible for observation vs. CT, depending on provider comfort level.  Ultimately, the management of “intermediate risk” is the key to this instrument’s role in reducing resource utilization.  In many settings, such as this one, if the “intermediate risk” group predominantly undergoes CT rather than observation, resource utilization will increase, rather than decrease.

However, the Denver Health expertise is not generalizable to most institutions – but provides an interesting perspective on the performance of PECARN to expert clinical judgment.

“Comparison of PECARN, CATCH, and CHALICE Rules for Children With Minor Head Injury: A Prospective Cohort Study”
http://www.ncbi.nlm.nih.gov/pubmed/24635987

Splicing Up PECARN

The PECARN study is the largest of the prospective evaluations of children with minor head injury for clinically important traumatic brain injury.  The derived prediction instruments, for children aged <2 years of age and for children aged 2 to 18 years, generate “very low risk” cohorts whose incidence of important injury is negligible.  However, the overall incidence of cTBI was quite low in the entire study – meaning each positive predictor still only raises the risk of cTBI from negligible to tiny.

One of the predictors, vomiting, is an element in the decision instrument for children aged 2 to 18 years.  The management recommendation for patients with vomiting, then, defaults to “do as is your wont” – and studies suggest most folks are going ahead with CT, rather than using the “observation” option.

This study goes back and looks specifically at the vomiting component – and tries to tease out whether “isolated” or “non-isolated” prior to enrollment provided additional information.  Of the 5,392 enrolled patients with complete data, 815 had a single episode of vomiting – with 0.2% having cTBI.  The remaining 4,577 with non-isolated vomiting had a 2.5% incidence of cTBI.  The article goes further into the details of the data set, noting patients with vomiting who received CT were more likely to have cTBI – but also had other concomitant comorbid injury.

This is, unfortunately, not terribly profound – and of debatable utility.  The joy – what there is – of PECARN is its use as a decision-instrument with which to simplify medical decsion-making.  Mining the details of individual +LR and -LR provides more patient-specific information, but increases the complexity of knowledge translation – and ultimately decreases the contextual acceptability of the product.  The cTBI is heterogeneously distributed throughout the PECARN set – but the existing rule cannot be improved upon until better tools emerge to offload the cognitive demand required for for precision medicine-type applications.

“Association of Traumatic Brain Injuries With Vomiting in Children With Blunt Head Trauma”
http://www.ncbi.nlm.nih.gov/pubmed/24559605

Still Muddling Through Massive Hemorrhage

The last few years have given way to a paradigm shift in the resuscitation of traumatic hemorrhage.  Using observational data from military settings, resuscitation strategies utilizing reactive correction of coagulopathy have given way to strategies mimicking whole blood transfusion.  Limited evidence suggests PRBC:FFP:Platelet ratios nearing 1:1:1 may be beneficial in resuscitation from traumatic hemorrhage.

This observational study of trauma patients followed lactate levels and measures of coagulopathy during the acute resuscitative phase from major trauma.  106 patients with median Injury Severity Score of 34 received a median of 8 units of PRBCs, 6 units of FFP, and a smattering of platelets and cryoprecipitate transfusions.  Lactate levels, as compared by median and IQR, did not significantly normalize following the initial transfusion, requiring a full day of therapeutic intervention to improve.  Likewise, measures of coagulopathy did not reflect improvement in the acute phase, tending to normalize only after a full day.  It did not matter whether patients received a small, moderate, or large amount of resuscitation.

This study only comments on surrogate outcomes – serum lactate, markers of coagulopathy – and not patient-oriented outcomes, but it serves as a reminder the science is clearly not settled regarding the optimal, cost-effective fashion to resuscitate patients from traumatic hemorrhage.  While many centers have fully adopted whole blood-style resuscitation strategies, it would be incorrect to conclude we have any sort of certainty in the matter.

“Hemostatic resuscitation is neither hemostatic nor resuscitative in trauma hemorrhage”
http://www.ncbi.nlm.nih.gov/pubmed/24553520

The “Padding” on Obese Patients is not Protective in Blunt Trauma

Everyone has an anecdotal tale of a morbidly obese patient who suffered penetrating injury that transversed only adipose tissue, leaving the small person living beneath unharmed.  However, these isolated incidents do not appear to apply to blunt trauma.

This study is a retrospective analysis of the National Trauma Data Bank, evaluating 32,780 morbidly obese (BMI >40) and non-obese patients matched 1:1 on age, sex, ISS, GCS, and blood pressure on arrival.  Baseline characteristics – as much as could be gleaned retrospectively – showed no substantial imbalance between the two cohorts.  And, by nearly every measure, patients with morbid obesity suffered poorer outcomes.  ARDS, decubitus ulcers, infectious complications, and thromboembolic complications were all significantly more frequent in this population.  These carried forward with increased hospital LOS and increased mortality – 3% vs. 2.2%

Unsurprising, and yet another manner in which obesity shortens lifespan and degrades quality of life.

“Morbid obesity predisposes trauma patients to worse outcomes: A National Trauma Data Bank analysis”
http://www.ncbi.nlm.nih.gov/pubmed/24368375

Uninjured Children are Uninjured, and Other Tautologies

In America’s culture wars (e.g., War on Drugs, War on Women, War on Christmas, etc.), few rise to the magnitude of the Emergency Physician vs. the consultant surgeon.  The disagreement in necessity of CT radiography for minor trauma is well-documented, and even surgeons themselves admit to possibly overdoing it in their valorous quest for zero-miss.

This study has the conclusion we’d like to see – but not the evidence needed to fully support it.  These authors from Denver performed a retrospective review of 174 pediatric trauma team activations, specifically evaluating the incidence of CT-identified injuries for four categories of patients.  The cohort these authors focus on for their conclusions are those with no apparent injury and no abnormal vital signs, but were imaged (presumably, considering this is retrospective) based on “mechanism of injury”.  Of the 66 patients who received any kind of CT imaging in the absence of objective indications, zero serious injuries were identified.

However, this MOI-indicated CT group was not exactly uninjured – over a third had a long bone fracture, and 9% had a skull fracture.  In a group of children whose average age is 7, of whom half have a significant injury, it is hard to quibble retrospectively with the indications for each CT individually – even if all were ultimately negative.  There is an obvious hint of truth that, yes, if MOI is the overriding justification for CT, it will result in an embarrassingly low incidence of true injury.  In the end, this study only shows us we need to continue advancing our development of clinical evaluation instruments to improve yield and cost-effective care.

“Mechanism of injury alone is not justified as the sole indication for computed tomographic imaging in blunt pediatric trauma”