The effect of soft-tissue ultrasound on the management of cellulitis in the emergency department.

OBJECTIVES To evaluate the effect of diagnostic soft-tissue ultrasound (US) on management of emergency department (ED) patients with clinical cellulitis. METHODS This was a prospective observational study in an urban ED of adult patients with clinical soft-tissue infection without obvious abscess. The treating physician's pretest opinions regarding the need for further drainage procedures and the probability of subcutaneous fluid collection were determined. Emergency sonologists then performed US of the infected area, and the effect on management plan was recorded. RESULTS Ultrasound changed the management of patients with cellulitis in 71/126 (56%) of cases. In the pretest group that was believed not to need further drainage, US changed the management in 39/82 (48%), with 33 receiving drainage and 6 receiving further diagnostics or consultation. In the pretest group in which further drainage was believed to be needed, US changed the management in 32/44 (73%), including 16 in whom drainage was eliminated and 16 who had further diagnostic interventions. US had a management effect in all pretest probabilities for fluid from 10% to 90%. CONCLUSIONS Soft-tissue US changes physician management in approximately half of patients in the ED with clinical cellulitis. US may guide management of cellulitis by detection of occult abscess, prevention of invasive procedures, and guidance for further imaging or consultation.