A randomised trial comparing intraoral ultrasound to landmark-based needle aspiration in patients with suspected peritonsillar abscess.

OBJECTIVES Traditionally, emergency physicians (EPs) have used anatomic landmark-based needle aspiration to drain peritonsillar abscesses (PTAs). If this failed, an imaging study and/or consultation with another service to perform the drainage is obtained. Recently, some EPs have used ultrasound (US) to guide PTA drainage. This study seeks to determine which initial approach leads to greater successful drainage. The primary objective of this study was to compare the diagnostic accuracy of EPs for detecting PTA or peritonsillar cellulitis (PTC) using either intraoral US or initial needle aspiration after visual inspection (the landmark technique [LM]). Secondary objectives included the successful aspiration of purulent material in those patients with a PTA in each arm, the use of computed tomography (CT) scanning in each arm, and the otolaryngology (ENT) consultation rate in each arm. METHODS This was a prospective, randomized, controlled clinical trial of a convenience sample of adult patients who presented to a single, large, urban university hospital. Patients were enrolled if they presented with a constellation of signs and symptoms that were judged to be a PTA. These patients were randomized to receive intraoral US or to undergo LM drainage. The US was performed using an 8-5 MHz intracavitary transducer immediately prior to the procedure. The probe was then withdrawn and the provider who did the US also performed the needle aspiration. The LM was performed using visual landmarks in a superior to inferior approach until pus was obtained or at least two sticks were performed. Anesthesia was standardized. Patients returned for follow-up in 2 days where a final diagnosis was rendered. RESULTS   There were 28 patients enrolled, with 14 in each arm. US established the correct diagnosis more often than LM [(100%, 95% confidence interval [CI] = 75% to 100% vs. 64%, 95% CI = 39% to 84%; p = 0.04)]. US also led to more successful aspiration of purulent material by the EP than LM in patients with PTA [(100%, 95% CI =63% to 100% vs. 50%, 95% CI = 24% to 76%; p = 0.04)]. The ENT consult rate was 7% (95% CI = 0% to 34%) for US versus 50% (95% CI = 27% to 73%) for LM (p = 0.03). The CT usage rate was 0% for US versus 35% for LM (p = 0.04). CONCLUSIONS   An initial intraoral US performed by EPs can reliably diagnose PTC and PTA. Additionally, using intraoral US to assist in the drainage of PTAs with needle aspiration leads to greater success compared to the traditional method of LM relying on physical exam alone.