How to succeed on your next Lumbar Puncture

This is a post written by Bryce Carter, resident from Cincinnati Children’s Hospital Medical Center. It is focused on tips for success in lumbar puncture in children. Enjoy!

You are in the ED and have just finished draining that notorious ‘spider bite/abscess’ when a fussy 17 day old infant comes through triage with a fever to 38.9 C. We all know what is coming… SBI work up including lumbar puncture time… but the last thing a resident or any provider wants to do is be unsuccessful with tap leading to prolonged hospitalizations and antibiotic exposure. Here we will discuss not only how to better one’s chances of success but why.

In 2006 Baxter et al. published their findings of a prospective observational study in PEDIATRICS. They reviewed 428 of 594 LPs performed, 377 of which were done by trainees. Seventy-four percent (279/377) of the trainee LPs were successful. Amongst other factors local anesthesia was used for 280 (74%), and 225 (60%) were performed with early stylet removal. They found the following;

  • LPs were more likely to be successful in infants >12 weeks of age – OR=3.1 (95% CI 1.2-8.5)
  • Local anesthetic use showed increased odds of success OR=2.2 (95% CI 1.04-4.6)
  • In infants ≤12 weeks of age, early stylet removal improved success rates – OR=2.4 (95% CI 1.1-5.2)
  • Position (upright vs side-lying), drape use, and year of training were not significant predictors of success

Of note, of the anesthesia users in this study, only 4% used injected lidocaine and the rest used EMLA LMX.

In 2007 Nigrovic et al., in their prospective cohort of 1,474 lumbar punctures, looked at risk factors for traumatic or unsuccessful lumbar punctures in the first attempt.  Of the 1,474 lumbar punctures, 513 (35%) were traumatic or unsuccessful after the first attempt due to 1. Lack of physician experience (OR 1.08; 95% confidence interval [CI] 1.01 to 1.15), lack of local anesthetic use (adjusted odds ratio 1.6; 95% CI 1.1 to 2.2), advancement of the spinal needle with stylet in place versus stylet removed (adjusted odds ratio 1.3; 95% CI 1.04 to 1.7), and increased patient movement (adjusted odds ratio 2.1; 95% CI 1.6 to 2.6). They also found that age of <3 months increased likelihood of being unsuccessful.

Interestingly:

  • The presence of a family member(s) was not associated with an increased risk of traumatic or unobtainable lumbar puncture, nor was it associated with more attempts at the procedure as seen in a study also by Nigrovic et al (3).
  • The viewing of an educational video prior to performing an Lumbar Puncture by a study Srivastava et al. in 2012 showed that viewing the video helps with provider comfort in performing the procedure, but it does not help in actually being successful (4).

Boiled down, here are the results

What improves success

  • Experienced holder –Can’t be stressed enough! If you can’t keep patients safely in proper position, consider procedural sedation
  • Age > 12 weeks – spinal canal larger, dural pop more pronounced
  • Anesthesia use (topical and injectable) – the better pain is controlled = less wiggle
  • Oral Sucrose – safe, easy to administer but insufficient alone
  • Early stylet removal – able to appreciate CSF flash when in spinal canal

What does not improve success:

  • Position (upright vs side lying)
  • Drape use
  • Conflicting between the studies: Year of training.  Although significant but with only a slight increase in OR in Nigrovic et al. study (2), no difference in the Baxter et al.
  • Video Viewing of Procedure

Keep these tips handy as you perform your next lumbar puncture. Happy CSF collecting!

References

  1. Baxter AL, Fisher RG, Burke BL, et al. Local anesthetic and stylet styles: factors associated with resident lumbar puncture success. Pediatrics 2006; 117:876.
  2. Nigrovic LE, Kuppermann N, Neuman MI. Risk factors for traumatic or unsuccessful lumbar punctures in children. Ann Emerg Med 2007; 49:762.
  3. Nigrovic, L. E., A. A. Mcqueen, and M. I. Neuman. “Lumbar Puncture Success Rate Is Not Influenced by Family-Member Presence.” Pediatrics 120.4 (2007): n. pag. Web.
  4. Srivastava, Geetanjali, Mark Roddy, Daniel Langsam, and Dewesh Agrawal. “An Educational Video Improves Technique in Performance of Pediatric Lumbar Punctures.” Pediatric Emergency Care 28.1 (2012): 12-16. Web.

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Summer Reading List: Kocher Criteria

You could go ahead and pick out a good book this summer. But why waste time on formulaic plots and slapdash characterizations when you could be reading great articles relevant to the Pediatric Emergency Department. Here’s another paper from the PEMBlog Summer Reading List!

Kocher et al.
J Bone Joint Surg Am. 1999 Dec;81(12):1662-70.

What this article is about?

This is a retrospective review of children with an acutely painful hip designed to help develop prediction rule for septic arthritis. Both univariate analysis and multiple logistic regression analysis were used to compare groups. This was the derivation study, and it was later validated in 2004.

Why is it important?

This article is the backbone of how we differentiate septic hip versus transient synovitis. Per Dr. Kocher himself, “Patients often presented similarly with atraumatic hip pain, limp, and fever. However, the differentiation is essential since septic arthritis is a surgical emergency with the potential for a poor outcome such as septic necrosis of the hip, whereas transient synovitis is treated with observation and has a generally benign outcome. The goal of the prediction rule was to make the diagnosis in a more accurate, reliable, and timely manner.” The authors noted the following four factors were important in the differentiation of septic hip versus transient synovitis;

  • Fever
  • Elevated WBC (>12,000)
  • Elevated ESR >40
  • Inability to bear weight

The combination of different features is spelled out in the paper – which you should read since it guides our practice – but in summary the likelihood of septic arthritis based on number of predictors was:

  • 0  –  <0.2%
  • 1  –  3%
  • 2  –  40%
  • 3  –  93.1%
  • 4  –  99.6%

How you can use it in your practice

 

In a child with an acutely painful hip that you are concerned could be septic arthritis obtain a CBC and ESR. In addition you will likely benefit from getting a blood culture and plain radiographs of the hip as well. In addition ultrasounds of the hip can help identify effusion.

This rule is for the hip and is not validated for use in other joints like the knee. You can extrapolate the results to the knee – but know where the evidence ends and your suppositions begin.

It is also important to note that the original prediction rule utilized ESR. CRP was not widely available yet. It does rise quicker, and ultimately a CRP >2.0 mg/dL could replace ESR in the prediction rule. Overall the performance between the two is similar.

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Summer Reading List: Ipratropium in asthma exacerbations

You could go ahead and pick out a good book this summer. But why waste time on formulaic plots and slapdash characterizations when you could be reading great articles relevant to the Pediatric Emergency Department. Here’s another paper from the PEMBlog Summer Reading List!

Quareshi et al.
NEJM. 1998 Oct 8;339(15):1030-5.

What this article is about?

This is a randomized controlled trial 434 children with moderate to severe asthma exacerbations treated in the emergency department. Here is how it was designed from the patient perspective;

  • All patients received one nebulized albuterol (2.5 or 5 mg per dose, depending on body weight) every 20 minutes for three doses
  • A corticosteroid (2 mg/kg prednisone or prednisolone) was given orally with the second dose of albuterol
  • Children in the treatment group received 500 μg (2.5 ml) of ipratropium bromide with the second and third doses of albuterol
  • Children in the control group received 2.5 ml of normal saline with the second and third doses of albuterol

Why is it important?

This article is one of the main reasons why you give duonebs (albuterol/ipratropium) in the Emergency Department in patients with asthma exacerbations. It was an example of a RCT that altered how we practice. Note that this was written A. in the era when we gave 2 mg/kg prednisone (now we only give 1 mg/kg/day or dexamethasone) and B. when I was in college. Overall the authors noted that:

  • The rate of hospitalization was lower in the ipratropium group (59/215 = 27.4%) vs the control group (80/219 =36.5%, P=0.05)
  • In moderate asthma (Peak Flow 50-70% expected or asthma score 8-11/15) hospitalization rates were similar in the two groups – ipratropium: 8/79=10.1%; control: 9/84=10.7%
  • In severe asthma (Peak Flow <50% expected or asthma score 12-15) ipratropium significantly reduced the need for hospitalization (51/136=37.5% vs 71/135=52.6%; P=0.02

How you can use it in your practice

So interestingly some institutions give 3 back to back duonebs as opposed to Albuterol then Duoneb x2. There are reasons for this, many related to the electronic medical record. In my mind, iprotropium has a long enough half-life, and the cost difference is negligible that this is OK. But yes, the “pure” version from the RCT is different than practice. So, from this article you can intone that a reaonsable approach to asthma in the ED would be:

  1. Assess asthma severity
  2. For moderate to severe patients give an albuterol treatment (or duoneb)
    1. If the patient normalizes stop there
    2. If they have not improved give two more duonebs and an oral steroid

You can also use this article as a great way to teach how to critically appraise an RCT. It is a relatable example, and it makes the EBM math very easy.

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Summer Reading List: UTI Practice Guideline in febrile children 2-24 months

You could go ahead and pick out a good book this summer. But why waste time on formulaic plots and slapdash characterizations when you could be reading great articles relevant to the Pediatric Emergency Department. Here’s another paper from the PEMBlog Summer Reading List!

American Academy of Pediatrics Clinical Practice Guideline
PEDIATRICS Volume 128, Number 3, September 2011

What this article is about?

Obviously this is an updated guideline for diagnosis and management of UTI in infants and toddlers. Questions that it may help you answer include;

  • On which patients should I obtain urinalysis and culture?
  • What is the best empiric treatment for suspected UTI?

I won’t address VCUG, prophylaxis or other issues not directly related to the Emergency Department, but know that this CPG does include information on post UTI imaging and more.

Why is it important?

Febrile infants between two and twenty-four months have an overall prevalence of UTI as high as 5%. Some children have higher risks than others, as detailed in Figure 2. These risks should be kept in mind when deciding who to test and empirically treat.

UTI Figure 2

How you can use it in your practice

When it comes to testing first determine the pre-test probability for UTI in the febrile patient you are evaluating:

  • The overall prevalence is 5%, but girls have 2x the prevalence of boys. This is partly due to the shorter urethra that allows passage of bacteria into the bladder in girls
  • Uncircumcised boys have a rate between 4 and 20 times that of circumcised boys, whose rate of UTI in fever without a source is only 0.2-0.4%
  • Another clinically obvious infection reduces the risk of UTI by at least 50% – sometimes more, like in bronchiolitis where the risk is only 1/33
  • The factors in Figure 2 above have a sensitivity of 88% and a specificity of 30%

When you do test be aware of the characteristics of urinalysis, but know that culture is the gold standard – >50,000 CFU/mL:

UA test Characteristics

Treatment depends on age and overall appearance:

  • Infants under 2-3 months basically have pyelonephritis and should be admitted. IV ceftriaxone is a great option. Note that the concomitant risk of meningitis is low in well-appearing infants with UTI. See this great synopsis from Best Bets for more.
  • There is limited evidence on treatment length. Overall 7, 10 and 14 days were studied. We do know that outcomes of short (1-3day) courses are inferior for 2-24 month olds.

Antibiotic options are varied, see the following tables for more:

UTI IV treatment

UTI Oral Treatment

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