Tag Archives: pediatric

Abstracts

EAST 2018 #5: Predicting Absence Of Pediatric Abdominal Injury

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More on prediction systems today! The authors of this abstract used good old mathematics, albeit very fancy math, instead of a machine learning algorithm. The specifics of this tool were described in an article published in JACS earlier this year (see reference).

The authors were interested in finding a way to decrease the use of CT scan for evaluating blunt abdominal trauma in children. After developing the model using prospectively collected data from 14 Level I pediatric trauma centers, they sought to validate it using a public dataset from the Pediatric Emergency Care Applied Research Network (PECARN). This dataset contained more than 2,400 records, and included 10% of patients who had an intra-abdominal injury (IAI), and 2.5% with an IAI that required intervention (IAI-I).

Here are the factoids:

  • There were five prediction rule variables: complaint of abdominal pain, tenderness / distension / or contusion on exam, abnormal chest x-ray, AST > 200, elevated pancreatic enzymes)
  • Prediction rule sensitivity was 98% and specificity was 37% for IAI, and 100% / 35% for IAI-I
  • The negative predictive value for finding any abdominal injury was 99.3%, and for injury requiring intervention was 100%
  • Unfortunately, nearly half of the very low risk children underwent CT scanning anyway!

Bottom line: This is a nice validation study for a well-designed prediction tool. It builds on previous work published earlier this year. The variables make clinical sense. Although the number of patients with injury were relatively small, I believe these results should be considered for incorporation in our blunt pediatric trauma evaluation protocols now!

Here are some questions for the authors to consider before their presentation:

  • The liver function and pancreatic enzyme tests results take some time to perform. How much do they contribute to the negative predictive value, since they are relatively uncommon injuries?
  • What are considered abnormal chest x-ray findings?
  • How do you recommend incorporating this into the care of trauma activation patients? Wait for 30 minutes in the trauma bay for the lab tests to come back? Evaluation in patients undergoing a more routine evaluation for abdominal trauma would not be unduly delayed.
  • Be prepared to explain how you derived the decision rule in very simple language.

References:

  • EAST 2018 Podium paper #7.
  • Identifying Children at Very Low Risk for Blunt Intra-Abdominal Injury in Whom CT of the Abdomen Can Be Avoided Safely. JACS 224(4):449-458.
Abstracts

EAST 2018 #1: Plasma Over-Resuscitation And Mortality In Pediatric TBI

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The first EAST abstract I will discuss is the very first to be presented at the annual meeting. This is a prospective, observational studied that was carried out at the University of Pittsburgh. It looked at the association between repeated rapid thromboelastography (rTEG) results in pediatric patients and their death and disability after plasma administration. They specifically looked at the degree of fibrinolysis 30 minutes after maximum clot amplitude and tried to correlate this to mortality.

For those of you who need a refresher on TEG, the funny sunfish shape above shows the clot amplitude as it increases from nothing at the end of R, hits its maximum at TMA, then begins to lyse. The percent that has lysed at 30 mins (LY30%) gives an indication if the clot is dissolving too quickly (LY30% > 3%) or too slowly (LY30% < 0.8%).

The authors selected pediatric patients with TBI and performed an initial rTEG, then one every day afterward. They looked at correlations with transfusion of blood, plasma, and platelets.

Here are the factoids:

  • A total of 101 patients under age 18 were studied, with a median age of 8, median ISS of 25, and 47% with severe TBI (head AIS > 3)
  • Overall mortality was 16%, with 45% having discharge disability
  • On initial analysis, it appeared that transfusion of any product impeded fibrinolysis, but when controlling for the head injury, only plasma infusion correlated with this
  • Increasing plasma infusion was associated with increasing shutdown of fibrinolysis
  • The combination of severe TBI and plasma transfusion showed sustained fibrinolysis shutdown, and was associated with 75% mortality and 100% disability in the remaining survivors
  • The authors conclude that transfusing plasma in pediatric patients with severe TBI may lead to poor outcomes, and that TEG should be used for guidance rather than INR values.

Bottom line: There is a lot that is not explained well in this abstract. It looks like an attempt at justification for using TEG in place of chasing INR in pediatric TBI patients. This may be a legitimate thing, but I can’t really come to any conclusions based on what has been printed in this abstract so far.

Here are some questions for the authors to consider before their presentation:

  • There seem to be a lot of typos, especially with < and > signs in the methods.
  • Disability is a vague term. What was it exactly? Was it related to TBI or the other injuries as well?
  • These children also appear to have had other injuries, otherwise why would they need what looks like massive transfusion activation? Why did they need so much blood? Could that be the reason for their fibrinolysis changes and poor outcomes?
  • I can see the value of the initial rTEG, and maybe one the next day. But why daily? What did you learn from the extra days of measurements? Would a pre- and post-resuscitation pair have been sufficient?
  • Plasma is the focus of this abstract, but it does not describe how much plasma was given, or whether there was any departure from the usual acceptable ratios of PRBC to plasma administration.
  • Big picture questions: Most importantly, why would you think that poor outcomes, which are the focus of this paper, are related to plasma administration? Why haven’t we noticed this correlation before? And how does daily TEG testing help you identify and/or avoid this? What questions raised here are you going to pursue?

Reference: EAST 2018 Podium paper #1.

Imaging

ACS Trauma Abstracts #5: Pan-scan vs Selective CT For Pediatric Patients

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In major adult blunt trauma, there are still two factions: those who pan-scan for diagnosis, and those who use CT selectively. The pan-scan proponents argue that they find everything, including things that would have been missed with selective scanning. The selective scanners argue that those things are typically not clinically significant, and radiation exposure is reduced.

Who is right? We’re still not sure. But when it comes to children, most believe that less radiation is always better. The group at USC decided to look at their experience with pan-scan vs selective imaging in blunt pediatric trauma patients, defined as those < 16 years of age. They reviewed their experience over a three year period, excluding those who had low blood pressure (<90). A total of 648 children met these criteria, and an array of variables were analyzed to try to determine “superiority.”

Here are the factoids:

  • 88% of these patients had low injury severity (ISS < 15), 567 patients
  • The low severity group who were selectively scanned had a half-day decrease in length of stay*, a quarter-day decrease in ventilator days, lower morbidity (15% vs 24%)*, and radiation exposure (8 vs 18 mSv)*, with the asterisked variables being “statistically significant”
  • The high severity also showed positive differences in decreased ICU length of stay, ventilator days, morbidity*, and radiation exposure*
  • For both pan- and selective-scanning, additional imaging led to no additional interventions in 95% of cases

Bottom line: Ugh! This is not a good abstract. It shows association, but not causation with anything but the radiation exposure calculations. Yes, if you scan less in the selective arm, there better be less exposure. But the other variables are either not clinically significant, or not defined well (i.e. morbidity).

The authors conclude that selective scanning is the way to go based on this (extremely weak) data. This is why I always recommend that you read the whole paper, not just the abstract, or in this case the whole abstract and not just the conclusion. The data, as presented in this abstract, do not support this at all.

The authors don’t say how many of these patients were very young, and how many of them actually received pan-scans. But any pediatric trauma surgeon would cringe if they read this  article. Although you may be a big believer in pan-scanning, reserve it for adults only until we have some better data. Don’t irradiate kids unnecessarily!

Reference: Selective CT imaging is superior to liberal CT imaging in the hemodynamically normal pediatric blunt trauma patient. JACS 225(4S1):562, 2017.

Imaging

Are You Overusing Chest CT In Kids?

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Many centers have developed guidelines for ordering various imaging studies, mostly in adults. These frequently dictate indications for head, cervical spine, and abdominal CT. The use of chest CT guidelines are far less common. And for the most part, such guidelines are significantly lacking for pediatric trauma evaluation.

Oregon Health Sciences University published a study detailing the use and utility of chest CT in pediatric patients, which they defined as age less than or equal to 18. They also looked at the impact of implementation of imaging guidelines for chest CT. They pooled data on blunt injuries from two Portland children’s hospitals. They collected a historical cohort over 8 years ending in 2015. One hospital had implemented region-specific imaging guidelines in 2010, and the impact of this was observed. They pooled data from both centers to identify mechanisms predictive of significant thoracic injury.

Here are the factoids:

  • Nearly 3000 patients were reviewed for thoracic CT use across the study period.
  • 1451 had chest x-ray only, 933 had chest CT only, and 567 had both
  • Although CT use in other body regions significantly declined across the study period, thoracic CT did not.
  • Chest CT changed management on only 17 of 1500 patients (1%).  There were 2 operations, 1 stent placement, 1 medical management, and 13 changes I consider rather weak (chest tube insertion, negative workup)
  • All clinically significant findings were predicted by an abnormal chest x-ray and motor vehicle mechanism

Bottom line: Chest CT continues to be overused in pediatric blunt trauma (and adults too!). This is especially unsettling due to it’s low yield and the unclear future danger of high dose radiation received during childhood. The major issue with this study is that it mixes adults and children and calls them all children. Specifically, most patients age 13-14 or above act anatomically and physiologically more like adults. It would have been nice to separate out the lower age group, but this typically results in very low numbers for analysis. In this case, it should have been possible because the median age was 13.

I recommend that all centers adopt some kind of blunt imaging guidelines to reduce clinician variability and unneeded radiation exposure. This is particularly true for children, since they are more sensitive to it and will live long enough to potentially experience the adverse effects from it. 

For both children and adults, chest CT should be reserved for evaluation of potential aortic injury, and nothing else. Rib fractures, hemothorax, and pneumothorax are best evaluated by traditional chest x-ray, and therapeutic decisions based on this alone. Abnormal chest x-ray findings, coupled with a high-energy mechanism (MVC, crush, pedestrian struck, and fall from a real height (3+ storys) should drive the decision to obtain a chest CT.

Related posts:

Reference: Limiting thoracic CT: a rule for use during initial pediatric trauma evaluation. J Ped Surg, In press, Aug 28, 2017.

General

Delayed Diagnoses In Children Revisited

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A couple of years ago I wrote about a paper that examined patterns in delayed diagnoses in injured children. It was a single-hospital study of children treated at a Level II pediatric trauma center. In that study, the overall rate of delayed diagnosis was 4%. The orthopedic component looked high but was not really broken down in detail.

A soon-to-be-published study looked at more recent experience with this issue, specifically in pediatric patients with orthopedic injury. They specifically evaluated all pediatric patients with bone, joint, peripheral nerve, and tendon injuries treated at their Level I pediatric trauma center over a nearly 6 year period. Orthopedic surgery consults were obtained at the discretion of the trauma or primary service.

How good was their discretion? Here are the factoids:

  • 1009 trauma activations were reviewed, of which 196 (19%) were eventually diagnosed with an orthopedic injury
  • There were 18 children (9%) with a delayed diagnosis, defined as one discovered 12 hours or longer after admission. Most were missed on initial exam or imaging
  • The injuries were literally all over the place. There was no obvious pattern.
  • Six of these were detected on tertiary survey
  • Average time to discovery was 3 days, and the average age of these children was 11 years
  • Children with a delayed diagnosis tended to be much more seriously hurt (ISS 21 vs 9), and more likely to have a significant head injury (GCS 12 vs 14)
  • One child required surgery for the delayed diagnosis, the rest were managed with splinting/casting or observation

Bottom line: Delayed diagnoses happen in children, too. And typically, they are due to a failure in the physical exam. Sometimes there is nothing to discover on the exam. But often times, if the mechanism is fully taken into account and a really good  exam is performed, these injuries may be found early.

I don’t consider an injury found on tertiary exam to be a delayed diagnosis, as long as it is performed within a reasonable time frame (24-48 hours max). It’s a well established fact that some injuries will not manifest as pain or bruising until the next day, or longer. So pick a maximum time interval (but don’t make it too early either) and do a tertiary survey on all children who are trauma activations, have multiple injuries, or have a significant mechanism. 

Related posts:

Reference: Incidence of delayed diagnosis of orthopaedic injury in pediatric trauma patients. J Ortho Trauma epub ahead of print, April 29, 2017.