In patients presenting to the emergency department with skin and soft tissue infections what is the diagnostic accuracy of point-of-care ultrasonography for the diagnosis of abscess compared to the current standard of care? A systematic review and meta-analysis

OBJECTIVES: The primary objective of this systematic review was to determine the accuracy of point-of-care ultrasonography (POCUS) in diagnosing abscess in emergency department (ED) patients with skin and soft tissue infections (SSTI). The secondary objective was the accuracy of POCUS in the paediatric population subgroup. SETTING: Prospective studies set in emergency departments. PARTICIPANTS: Emergency department patients (adult and paediatric) presenting with SSTI and suspected abscess. PRIMARY AND SECONDARY OUTCOME MEASURES: This systematic review was conducted according to Cochrane Handbook guidelines, and the following databases were searched: PubMed, MEDLINE, EMBASE and the Cochrane database of systematic reviews (1946–2015). We included prospective cohort and case–control studies investigating ED patients with SSTI and abscess or cellulitis, a defined POCUS protocol, a clearly defined gold standard for abscess and a contingency table describing sensitivity and specificity. Two reviewers independently ascertained all potentially relevant citations for methodologic quality according to QUADAS-2 criteria. The primary outcome measure was the sensitivity and specificity of POCUS for abscess. A preplanned subgroup (secondary) analysis examined the effects in paediatric populations, and changes in management were explored post hoc. RESULTS: Of 3028 articles, 8 were identified meeting inclusion criteria; all were rated as good to excellent according to QUADAS-2 criteria. Combined test characteristics of POCUS on the ED diagnosis of abscess for patients with SSTI were as follows: sensitivity 96.2% (95% CI 91.1% to 98.4%), specificity 82.9% (95% CI 60.4% to 93.9%), positive likelihood ratio 5.63 (95% CI 2.2 to 14.6) and negative likelihood ratio 0.05 (95% CI 0.01 to 0.11). CONCLUSIONS: A total of 8 studies of good-to-excellent quality were included in this review. The use of POCUS helps differentiate abscess from cellulitis in ED patients with SSTI. TRIAL REGISTRATION NUMBER: CRD42015017115.