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Three Part Question

In [a paediatric patient with blunt abdominal trauma] how [accurate is an ultrasound scan] at [identifying intra-abdominal injury]?

Clinical Scenario

An 8 year old boy is taken to the Emergency Department after falling out of a tree. He has no signs of injury apart from abrasions and tenderness across his upper abdomen; he is haemodynamically stable. He undergoes an abdominal ultrasound that is normal but you wonder how accurate this is at identifying intra-abdominal injury compared with the current gold-standard, abdominal CT.

Search Strategy

Medline 1966-12/00 using the OVID interface.
{[(exp child OR children.mp OR exp pediatrics OR pediatric.mp OR paediatric.mp) AND (exp abdominal injuries OR abdominal trauma.mp)] AND (exp tomography, x-ray computed OR CT.mp OR computerised tomography.mp OR exp ultrasonography OR ultrasonography.mp OR exp ultrasonics OR ultrasonics.mp OR ultrasound.mp)} LIMIT to human AND english.

Search Outcome

Altogether 511 papers were found of which 505 were irrelevant or of insufficient quality. The remaining six papers are shown in the table.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Krupnick AS et al, 1997, USA	32 children with blunt abdominal trauma and splenic injury diagnosed on abdominal CT with contrast. 32 control studies.	Diagnostic test study	Splenic injury detected by USS	Sensitivity 69% Specificity 100% NPV 76%	Ultrasound done on average within 5.5 days of CT and 6.5 days of the injury All data not given Specificity calculated from control group, none of whom had been victims of trauma No power study
Richardson MC et al, 1997, UK	26 children who had scans performed within 48 hours of blunt abdominal trauma. Abdominal CT with contrast as gold standard	Diagnostic test study	Intra-abdominal fluid or organ injury detected by USS	Sensitivity 87.5% Specificity 100% NPV 40%	Retrospective Only 2 patients had no intra-abdominal injury implying that this sample group may have been more severely injured than most children with blunt abdominal trauma.
Partrick DA et al, 1998, USA	100 children with blunt abdominal trauma who had abdominal ultrasound performed by an emergency physician. Abdominal CT as gold standard	Diagnostic test study	Intra-abdominal fluid or organ injury detected by USS	Sensitivity 42% Specificity 100% NPV 93%	Retrospective Sample group selective
Mutabagani KH et al, 1999, USA	46 children with suspected intra-abdominal injury undergoing focussed abdominal sonography for trauma (FAST) Abdominal CT as gold standard	Diagnostic test study	Intra-abdominal fluid or organ injury detected by FAST	Sensitivity 30% Specificity 100% NPV 71%	No power study
Coley BD et al, 2000, USA	107 children with blunt abdominal trauma undergoing focussed abdominal sonography for trauma (FAST)	Diagnostic test study	Intra-abdominal fluid or organ injury detected by FAST	Sensitivity 55% Specificity 18% NPV 50%
Benya EC et al, 2000, USA	51 children with blunt abdominal trauma Abdominal CT with contrast as gold standard	Diagnostic test study	Intra-abdominal fluid or organ injury detected by USS	Sensitivity 64.7-70.6% Specificity 70.6-79.4% NPV 81.8-82.6%	Interval between scans up to 24 hours with CT scan performed first All data not given No power study

Comment(s)

The evidence indicates a variability in the accuracy of ultrasound at identifying intra-abdominal injury in children. This is probably related to the skill of the ultrasonographer. Ultrasound can have a high diagnostic specificity and it may be useful as part of a rule-in strategy in these situations. Focused abdominal sonography for trauma (FAST) seems to be neither sensitive nor specific enough.

Clinical Bottom Line

Abdominal ultrasound can be used to rule in intra-abdominal fluid or organ damage in children. Negative ultrasound does not rule out intra-abdominal injury and, if clinical suspicion persists, abdominal computed tomography with contrast should be performed.

References

1. Krupnick AS, Teitelbaum DH, Geiger JD, et al. Use of abdominal ultrasonography to assess pediatric splenic trauma. Potential pitfalls in the diagnosis. Ann Surg 1997;225:408-14.
2. Richardson MC, Hollman AS, Davis CF. Comparison of computed tomography and ultrasonographic imaging in the assessment of blunt abdominal trauma in children. Br J Surg 1997;84:1144-6.
3. Partrick DA, Bensard DD, Moore EE, et al. Ultrasound is an effective triage tool to evaluate blunt abdominal trauma in the pediatric population. J Trauma 1998;45:57-63.
4. Mutabagani KH, Coley BD, Zumberge N, et al. Preliminary experience with focused abdominal sonography for trauma (FAST) in children: Is it useful? J Pediatr Surg 1999;34(1):48-52.
5. Coley BD, Mutabagani KH, Martin LC, et al. Focused abdominal sonography for trauma (FAST) in children with blunt abdominal trauma. J Trauma 2000;48:902-6.
6. Benya EC, Lim-Dunham JE, Landrum O, et al. Abdominal sonography in examination of children with blunt abdominal trauma. Am J Roenterol 2000;174(6):1613-6.