Briefs: C-spine radiography injury rules

Think about what you do in the ED? Do you recognize how the following studies have impacted your practice?

National Emergency X-Radiography Utilization Study

Multicenter, prospective, observational study of patients with blunt trauma for whom cervical spine X-rays were obtained.

Get C-spine films if:

  • Patients with abnormal neurologic examination
  • Distracting or painful injury (like a femur fracture)
  • Depressed or altered mental status
  • Intoxication
  • Midline cervical tenderness should get an X-Ray

Canadian C-spine rule

A prospective cohort study in Canada evaluating patients with head or neck trauma.

Radiography in high risk factors

  • Dangerous mechanism
  • Paresthesias

Assess range of motion in low-risk factors. If ANY of the following are present AND the patient can actively rotate 45 degrees to left and right, then C-spine films may not be needed.

  • Simple rear-end MVC
  • Sitting position in the ED
  • Ambulatory at any time since injury
  • Delayed onset neck pain
  • Absence of midline C-spine tenderness

Edit: Corrected Canadian C-spine rule to state if ANY of the above 5 items are present

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The Centor Criteria

Have you read my post on the exam based approach to the patient with a sore throat? Cool, you should also be using the Centor Criteria to help decide who needs to be tested for strep.

These criteria can be used to assess the likelihood of bacterial infection in patients with a sore throat. It was studied in adult patients, and assigns 1 point to each of 4 criteria:

  • History of fever
  • Tonsillar exudate
  • Tender anterior cervical adenopathy
  • Absence of cough

The modified Centor Criteria added age into the mix

  • <15 years add 1 point
  • >44 years subtract 1 point

The risk of Group A Streptococcal pharyngitis differs based on the number of “points”

  • <2 points: Risk of GAS infection <10% – no antibiotics or testing necessary
  • 2 points: Risk of strep 15%
  • 3 points: Risk of GAS 32%
  • >4 points: Risk of GAS 56% with a subsequent throat culture positive predictive value of 40-60%

If you have zero of the 4 original variables the negative predictive value is 80%. Though not implicitly stated in the criteria they can be extrapolated to help rule out strep throat and enable you to avoid swabbing for a rapid strep. Now, with any kid under 15 years of age you’ll always assign at least 1 point – thus, the above NPV doesn’t apply, but you still see the risk of strep at <10% if the child is afebrile, has a cough, and does not have tonsillar exudate or tender anterior cervical lymph nodes.

This is important if you don’t have rapid strep antigen testing available. If you do, then use it – the specificity is in the upper 90%s. So, it is great at “ruling in” strep. The sensitivity is 90-95%. So you could get 1/10 or 1/20 patients with a false negative result. You’ll probably send a backup culture – but do this with the knowledge that in the USA we’ll likely see 1-2 cases of acute rheumatic fever per state per year.

Overall the Centor Criteria are great, and important to teach, and especially to practice in a location where rapid strep testing is not available/feasible.

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The top ten articles in Pediatric Emergency Medicine (2014 edition)

Check out my live-tweet of the top ten Pediatric Emergency Medicine articles of the year presentation at the American Academy of Pediatrics National Conference & Exhibition in San Diego, CA on Saturday, October 11, 2014. I’ll be exploring these topics in a more in depth fashion soon and discussing how they wight impact your practice and teaching.

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Check out the newest edition of the PEM Currents podcast on topical anesthetics

PEM Currents returns with an examination of the different topical anesthetics used in Emergency Department. Specifically, by listening to this edition you’ll learn about LET, EMLA and LMX and how you can add them to your repertoire for pre-procedure anesthesia in the ED.

You can download it on iTunes

Or listen right here via the embedded media player

 

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Why we do what we do: Intravenous magnesium for asthma exacerbations

So you’ve thrown the kitchen sink at a child with a moderate to severe asthma exacerbation. And despite the large hematoma on their forehead from the concussive effect of the faucet ricocheting off their skull they’ve not improved. What’s a clinician to do? Give intravenous magnesium sulfate, that’s what you should do. Interestingly we learned that it was valuable when treating pregnant women with preeclampsia that also happened to have asthma (if that’s apocryphal let me know). If you want, you can also review stratification of asthma severity before moving on.

Let’s run down some of the evidence in chronological order (I won’t include every study – just some illustrative examples):

Skobeloff et al. JAMA, 1989

An early RCT, done in adults, that randomized 38 patients moderate to severe asthma exacerbations to get IV mag vs placebo. The authors noted that the Mag group had better improvement in peak flow and fewer Mag patients were admitted (7 for Mag vs 15 for placebo).

Green et al. Annals of Emerg Med, 1992

The authors randomized 120 consecutive patients in a block manner (alternating Mag vs placebo days) and failed to show a reduction in admission rate –  22% in Magnesium group (95%CI 13-32), 17% in control (95%CI 10-26), p = 0.523. I included this study because the physicians weren’t blinded to the randomization. Does this impact how you assess the validity of the study?

Bloch et al. Chest 1995

Another adults only trial, this time involving 135 patients. They also noted a decreased risk of admission, 35.3% in the placebo group and 25.4% in the Mag group (p = 0.21). When they broke it down to moderate (FEV1 <75% predicted) and severe (FEV1 <25% predicted) they noted that only the severe group had significantly reduced admission rates. Specifically they stated that in the severe patients “admission rates were 78.6% (11/14) for the placebo-treated group and 33.3% (7/21) for the magnesium-treated group (p = 0.009). For the moderate patients, admission rates were 22.4% (11/49) for the placebo-treated group and 22.2% (10/25) for the magnesium-treated group (p = 0.98).” This study built upon Skobeloff by including more patients and stratifying severity.

Ciarrallo et al. J. Pediatr, 1996

A study on kids? Now you’re talking. This RCT of kids 6 to 18 years with peak flow rates <60% predicted following 3 nebulized treatments included 31 kids (15 Mag vs 16 placebo). The dose was 25mg/kg IV over 20 minutes – more on the dose in a little bit. The Mag group had higher serum Mag levels (only mean 1.3), and a better improvement in % increase in expected peak flow. They also noted that 27% of IV mag were discharged home vs 0% placebo; p = 0.03.

Ciarrallo et al. Arch Pediatr Adolescent Medicine

Ciarrallo followed up earlier work by going with a higher dose of IV Mag (40mg/kg) – more is better! This RCT involved 30 children age 6 to 18 that needed 3 back to back nebs (albuterol alone or combo of albuterol/ipratropium). They excluded febrile patients, as well as those with cardiac, renal or non-asthma pulmonary disease and theophylline use in the last week. Patients got IV Mag or placebo. The authors noted a reduced risk of admission 50% IV mag (8/16) vs 100% placebo (14/14); p=0.02, and improved respiratory scores at approximately one and a half hours (mean asthma score 1.4 for IV mag and 2.5 placebo; p<0.001). The small numbers limited the generalizability, but it was a start.


Let’s get meta

So, out of the 5 aforementioned studies, 4 showed a reduced risk of admission and improved pulmonary function or clinical asthma scores. Two are more germane to Pediatric Emergency Medicine as they included children. To better draw conclusions we’d need a meta analysis… And here you go, it’s from Rowe et al. in 2000. Overall the authors examined 7 studies with 665 patients and concluded the following:

  • The pooled results showed non-significant improvements in peak expiratory flow rates (weighted mean difference: 29.4 L/min; 95% confidence interval: -3.4 to 62)
  • In severe exacerbations alone peak expiratory flow rate improved by 52.3 L/min (95% CI: 27 to 77.5)and FEV1 improved by 9.8 % predicted (95% confidence interval: 3.8 to 15.8)
  • Admission to the hospital was not reduced overall – OR = 0.31 (95% CI: 0.09 to 1.02)
  • In severe patients those receiving Mag did see a reduced risk of admission (OR = 0.10, 95% CI: 0.04 to 0.27)
  • There were no worrisome or clinically relevant changes in vitals or adverse side effects

So what does this mean for me in the Emergency Department?

Well, if inhaled beta-agonists and iprotropium (remember, dounebs decrease the risk of admission) plus systemic glucocorticoids don’t help a child with a moderate to severe asthma exacerbation you should consider giving IV Magnesium. The best recommended dose is:

Magnesium sulfate 50 mg/kg IV over 20 minutes (max dose 2 grams)

Though the meta analyses failed to show problematic decreases in BP it is probably a good idea to give a 20 mL/kg NS bolus as well. Not only will this offset potential Mag induced peripheral vasodilation and resultant decrease in BP, but it will also augment cardiac preload, which can be negatively impacted by pulmonary hyperinflation and its effects on reducing venous return to the heart through the lungs.

Can I send a kid home after giving magnesium IV?

In short, yes you can – but this may not be the usual practice in your institution for a variety of reasons. You’ll want to make sure that the child is symptom free, not hypoxic, not expected to require albuterol more frequently than every four hours and have reliable transportation and primary care doctor follow up.


 

Want to learn more? Check out the following companion post:

Why we do what we do: Systemic corticosteroids in acute asthma exacerbations

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Take a break and bone up on injuries with Fracture Fridays

Did you know that there is a regular feature on PEMBlog called Fracture Fridays? Did you know that these posts are about fractures, and that they are released on Fridays? OK, so that last question was a bit pandering, of course you did. Well then, why don’t you check out a few of my favorite posts from the past couple of years and learn something about kids and their broken bones.

Boxers

HumerusJones

Triplane

 

 

 

 

ApophysisTibiaFingerFOOSH

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