SGEM#177: POCUS – A New Sensation for Diagnosing Pediatric Fractures

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Date: May 1st, 2017

Reference: Poonai et al. Point-of-care ultrasound for non-angulated distal forearm fractures in children: test performance characteristics and patient-centered outcomes. Acad Emerg Med May 2017.

Guest Skeptic: Dr. Corey Heitz is an emergency physician in Roanoke, Virginia. He is also the CME editor for Academic Emergency Medicine and the associate editor for emergency medicine simulation at the AAEM MedEdPORTAL

SGEM HOP: This is another SGEM Hot Off the Press with Academic Emergency Medicine. Here is a reminder of how this special edition of the SGEM works:

A paper that has been submitted, peer-reviewd, and accepted for publication in AEM is selected.
The SGEM puts its skeptical eye upon the
manuscript using the modified BEEM critical appraisal tool.
One of the authors is invited to discuss their work on the SGEM podcast.
A special SGEM Hot Off the Press blog is posted and the podcast is uploaded to iTunes the week the paper gets published.
SGEMers have one week to interact directly with the author via social media (SGEM blog, Twitter or Facebook) with the best feedback being published with a summary of the review in AEM.

Case: You are working in your community emergency department when an anxious father brings in his eight year old who was playing at the park, and tripped and fell onto his outstretched right hand. He has pain over the distal forearm with mild swelling and no deformity. You’ve gotten pretty good with point of care ultrasound, and are curious about how good it is to diagnose forearm fractures.

Background: Point of care ultrasound (POCUS) has become the stethoscope of the 21st century in emergency medicine. POCUS can be used for so many conditions and we have done a number of shows on the topic:

SGEM#41: Ultra Spinal Tap (Ultrasound Guided Lumbar Puncture)
SGEM#94: You Better Think Ultrasound for Acute Abdominal Aneurysm
SGEM#97: Hippy Hippy Shake – Ultrasound Vs. CT Scan for Diagnosing Renal Colic
SGEM#119: B-Lines (Diagnosing Acute Heart Failure with Ultrasound)
SGEM#124: Ultrasound for Skull Fractures – Little Bones
SGEM#153: Simulation for Ultrasound Education

Pediatric fractures are a common type of injury seen in the emergency department. The most common type of fractures seen in children are distal forearm fractures.

Fractures are a painful condition and appropriate analgesic should be provided to avoid oligoanalgesia. It has been shown that children represent one group known to be at risk for inadequate pain control (Brown et al, and Selbst and Clark).

We have covered the issue of pediatric pain control on SGEM#78. Pediatric EM Super Hero Dr. Anthony Crocco did a RANThony on pediatric pain on YouTube. In that 2015 rant he warned about using codeine for pain control in children.

Just last month the FDA put out a Drug Safety Communication stating that codeine is contraindicated in children younger than 12 years of age. This was due to the serious risks of using codeine in children, including death.

One aspect of pain management in pediatric patients with fractures is the discomfort caused in obtaining x-rays, even in non-displaced fractures.

Point of care ultrasound represents a possible solution. POCUS has been described as highly accurate for long bone and forearm fractures. However, many of these studies included patients with obvious angulations, potentially inflating the accuracy estimates.

Clinical Question: Is point of care ultrasound for non-angulated suspected forearm fractures in children just as accurate, faster and less painful than getting x-rays?

Reference: Poonai et al. Point-of-care ultrasound for non-angulated distal forearm fractures in children: test performance characteristics and patient-centered outcomes. Acad Emerg Med May 2017.

Population: Children age 4-17 years presenting to the emergency department with a suspected non-displaced distal forearm fracture less than 48 hours from injury from a fall on an outstretched hand
- Excluded: Children who received analgesia (pharmacologic or non-pharmacologic) prior to arrival, known metabolic bone disease, congenital malformation of distal radius, suspected open fracture, known radius or ulna fracture, signs and symptoms consistent with neurovascular compromise, distracting injuries, and gross angular deformity.
Intervention: Bedside Ultrasonography (POCUS)
Comparison: X-ray
Outcome:
- Primary Outcome: Sensitivity of POCUS as compared to x-ray
- Secondary Outcomes: Pain, caregiver satisfaction and procedure duration

Dr. Naveen Poonai

Dr. Naveen Poonai is a Paediatric Emergency Medicine physician at the Children’s Hospital, London Health Sciences Centre, Associate Professor of Paediatrics and Internal Medicine at Western University, Canadian Association of Paediatric Health Centres (CAPHC) project lead for Paediatric Pain Assessment, and Paediatric Section Lead for Best Evidence in Emergency Medicine (BEEM).

Authors’ Conclusions: “We concluded that “POCUS assessment of distal forearm injuries in children is accurate, timely, and associated with low levels of pain and high caregiver satisfaction.“

Quality Checklist for A Diagnostic Study:

The clinical problem is well defined. YES
The study population represents the target population that would normally be tested for the condition (ie no spectrum bias). Yes
The study population included or focused on those in the emergency department. YES
The study patients were recruited consecutively (ie no selection bias). NO
The diagnostic evaluation was sufficiently comprehensive and applied equally to all patients (ie no evidence of verification bias). YES
All diagnostic criteria were explicit, valid and reproducible (ie no incorporation bias). YES
The reference standard was appropriate (i.e. no imperfect gold-standard bias). Unsure
All undiagnosed patients underwent sufficiently long and comprehensive follow-up (ie no double gold-standard bias). Unsure. No follow-up performed.
The likelihood ratio(s) of the test(s) in question is presented or can be calculated from the information provided. YES
The precision of the measure of diagnostic performance is satisfactory. Unsure

Key Results: There were 169 patients included in this study with 76 fractures identified. The mean age was 11 years of age with 52% being male. The majority of the fractures 61/76 (80.3%) were buckle fractures.

POCUS had a sensitivity of 94.7% (95% CI; 89.7% to 99.8%)

POCUS Test Characteristics:
- Specificity 93.5% (95% CI; 88.6 to 98.5%)
- PPV 92.3 % (95% CI; 86.4% to 98.2%)
- NPV 95.6% (95% CI; 91.4 to 99.8%)
- +LR 14.6
- -LR 0.6

There were four missed fractures, which included three ulnar styloid fractures and one distal radius buckle fracture.

Secondary Outcomes: Interrater agreement was 0.74. Pain scores were lower with POCUS, as was procedure duration. 90% of caregivers were “satisfied” or “very satisfied” with POCUS.

1) Convenience Sample: These were not consecutive patients presenting to the emergency department with suspected distal forearm fractures. Children were screened three days a week between 5-11pm when both the research assistant and the study physician trained in POCUS were available. Do you think this could have introduced some selection bias?

There absolutely remains the possibility of selection bias but unfortunately without moving out of my house and into the paeds ED for a year, this was the single best approach to recruitment. One factor mitigating against selection bias is that participants were recruited consecutively during availability of research personnel.

2) POCUS Experts: Ultrasound was done by one of four pediatric emergency physicians with a minimum of two years POCUS experience, have performed 25 satisfactory trainings scans and viewed a four-minute training video. Most community emergency physicians will not have this level of expertise. How do you think that may affect the results?

The short answer is that it limits our findings’ external generalizability to more experienced sonographers. What’s important to note however, is that many rural health care settings including disaster and conflict zones around the world may not have ready access to x-ray technology and POCUS is arguably one of the fastest growing skill sets that community physicians are acquiring. I think our findings provide a good rationale for emergency providers to acquire this skill set.
One physician performed about 50% of the scans. Do you think that too may have impacted the results?
- Definitely, and this too may have limited external generalizability to more experienced POCUS providers. But I would like to point out that there were no glaring differences in test performance characteristics between sonographers.

3) Analgesia, X-ray and then POCUS: Over half of patients received analgesia at triage with a median (IQR) until x-ray being 24 minutes while the median IQR to POCUS was 61 minutes. It is known to take about 30 minutes for acetaminophen and ibuprofen to provide effective analgesia. More than four out of five times the x-ray was done before the ultrasound. Could it be that there was just more time before the POCUS and that is why patients reported less pain?

This is definitely possible and in designing this study, we wrestled with how best we would account for this limitation. We couldn’t control for the timing of diagnostic imaging so we performed an exploratory analysis which showed that pain scores were unrelated to order of the imaging modality or provision of analgesia.

4) Outcomes: There were four missed fractures but are these clinically important misses (three styloids and one buckle)?

As far as clinical outcomes go, I would have to say no Ken. The missed fractures were all undisplaced. Our results are in line with what has been described as a lower diagnostic accuracy at the ends of long bones. And what this does teach us is that POCUS education programs should emphasize the importance of this region for novice ultrasonographers.
POCUS was associated with significantly lower median pain scores statistically but this was not considered clinically significant?
- That’s right, a clinically significant difference on the Faces Pain Scale – Revised, is one face. However, for both x-ray and POCUS, pain was largely in the mild range. One possible explanation is that non-angulated fractures, which made up our study sample, may be inherently less painful than angulated fractures during manipulation for x-rays. And what we have shown is that clinicians can confidently reassure patients that POCUS assessment of an injured limb is not painful.
It took less time to do the POCUS (30min) but is this clinically significant to the patients/caregivers and did it impact their overall length of stay significantly?
- That’s a good question and it’s one that we couldn’t answer easily because each participant served as their own control and got both POCUS and an x-ray. What we have shown is that POCUS is more than an order of magnitude faster than x-ray, which may or may not be important to patients, clinicians, and administrators.
The primary outcome (sensitivity) had wide confidence interval going down to 89.7%. Should we be concerned about that lack of precision?
- Yes and we tried to avoid that by performing a sample size calculation. Most clinicians are concerned about missing a fracture and so we should focus on the lower bound of the confidence interval for the sensitivity estimate, which is as you stated, 89.7%. To interpret this with some perspective however, we would ideally have liked to compare sensitivity of POCUS to the treating clinician’s interpretation of the x-ray. This wasn’t possible in this study but I suspect that sensitivity of the clinician’s interpretation may be similar.

5) X-Ray Gold Standard: While x-rays are the clinical standard used they are not perfect and fractures can be missed. Certainly we do not want to get CT scans on these children. How do we know all the negative x-rays were true negatives without follow-up performed on these patients?

Another good point. Truthfully, we don’t know because not all patients with non-displaced fractures receive follow-up x-rays. So the presence or absence of callus formation couldn’t be determined.

Is there anything else you would like the SGEMers to know about this study or how to interpret the results?

One of our key findings was a specificity of 94%. This suggests that if a fracture is identified using POCUS, an x-ray be unnecessary, depending of course on a reliable history and a cooperative patient.

Comment on authors’ conclusion compared to SGEM Conclusion: We agree with the author’s conclusions.

SGEM Bottom Line: Point of care ultrasound, performed by experienced ultrasonographers, has high diagnostic accuracy for distal forearm fractures, takes less time, and has low level of reported pain.

Case Resolution: You perform POCUS on your patient and diagnose a distal radius fracture without any need for manipulation. You offer the patient an x-ray, which confirms your diagnosis, and you splint the patient prior to discharge.

Dr. Corey Heitz

Clinical Application: POCUS can be used to confirm a distal forearm fracture, but misses a few minor fractures. X-ray should continue to be the clinical standard, but shared decision making may reduce the use of x-ray in some cases.

What do I tell my patient? The ultrasound shows your son broke their arm. We are going to confirm that with an x-ray. The nurse already gave him some acetaminophen for pain and he can take some more in about four hours. If it truly is broken it will be placed in a splint and we will refer him to the broken bone doctors called orthopaedic surgeons.

Keener Kontest: Last weeks’ winner was Natalie Cho from the University of Ottawa. They kne is the name of the imaginary equilateral triangle with the heart at its centre, formed by the axes of the three bipolar limb leads.

An update from the previous weeks’ keener question. An SGEMer named Mario, an EM physician from Lubbock, Texas sent me an email clarifying the issue about ASA and the bark of a willow tree. To be more accurate, the bark contains salicin, which is metabolized to salicylic acid. Modern chemists added the acetyl group making ASA to make it easier on the stomach. Thank you very much to Mario and it demonstrates why you need to be skeptical of anything you learn, even if you heard it on the SGEM. I will be sending Mario a extra special cool skeptical prize.

Listen to the SGEM podcast on iTunes to hear this weeks’ question. If you think you know the answer send an email to TheSGEM@gmail.com with “keener” in the subject line. The first correct answer will receive a cool skeptical prize.

Dr. Justin Morgenstern

Now it is your turn SGEMers. What do you think of this episode? Tweet your comments using #SGEMHOP. What questions do you have for Dr. Poonai and his team? Ask them on the SGEM blog. The best social media feedback will be published in AEM. This is a time limited offer and you need to get your responses in within one week of this episode.

CME Credits: Don’t forget that SGEMers can also get claim CME credits through this SGEMHOP episode from AEM. Follow the steps below:.