Title: Evidence-Based Medicine Improves the Emergent Management of Peritonsillar Abscesses Using Point-of-Care Ultrasound. J Emerg Med. 2020 Nov;59(5):693-698. doi: 10.1016/j.jemermed.2020.06.030. Epub 2020 Aug 19.

1. What is already known about this topic?
   1. Ultrasound is an accepted modality for detecting peritonsillar abscess (PTA). There are two described approaches transcutaneous with linear transducer and intraoral with an endocavitary probe with sensitivity up to 80% and 90% respectively. Compared to physical exam has a sensitivity of 78% and a specificity of 50%, and computed tomography (CT) scan with sensitivity is 100%, but specificity is 75%.
   2. The referenced study by Costantino et al. compared endocavitary approach to landmark approach for drainage showed improved sensitivity and specificity, more successful aspiration and reduced otolaryngology (ENT) consultation.
2. What is the PICO question?
   1. Population: adult patients diagnosed with PTA who presented to the ED between January 2007-December 2008 and January 2013-December 2014, before and after the initial study Costantino et al.
   2. Intervention: diagnosis and management included POCUS
   3. Comparison: diagnosis and management included no ultrasound (NUS)
   4. Outcome: primary endpoint was POCUS utilization, and the secondary endpoints included: successful aspiration, ENT consultation, CT imaging, unscheduled return visits, and length of stay (LOS).
   5. Study design: Retrospective cohort study
3. What are the main findings?
   1. Primary: 
   2. Twelve patients in cohort 1 had a POCUS (25%) vs. 89 in cohort 2 (78%)
      1. p < 0.0001; odds ratio [OR] 0.09 (95% confidence interval [CI] 0.04–0.20)
   3. Secondary:
   4. Emergency physician (EP) successful aspiration: 
      1. 89.1% POCUS vs. 24.5% NUS (p < 0.0001; OR 25 [95% CI 10-59])
   5. Combined EP/ENT successful aspiration: 
      1. 99.0% POCUS vs. 80.3% NUS (p < 0.0001; OR 24 [95% CI 3-193])
   6. ENT consultation: 
      1. 12.9% POCUS vs. 65.6% NUS (p < 0.0001; OR 0.07 [95% CI 0.03-0.17])
   7. CT usage: 
      1. 23.8% POCUS vs. 37.7% NUS (p = 0.07; OR 0.51 [95% CI 0.25-1.02])
   8. Return visits: 
      1. 3.96% POCUS vs. 18.0% NUS (p = 0.004; OR 0.18 [95% CI 0.05-0.61]).
4. What are its limitations?
   1. Ideally each secondary endpoint could be the primary endpoint in individual studies. 
   2. A single-center, retrospective study and convenience sampling has innate limitations and less robust than other prospective studies, which results in risk for selection bias. 
5. How will this article change practice?
   1. Point of care ultrasound (POCUS) provides safer, more accurate, and more efficient patient care for the diagnosis and management of peritonsillar abscess (PTA)
   2. Some technique tips: 
      1. Be sure to assess for compressibility and swirl. 
      2. You can also utilize a dynamic ultrasound assisted approach to aspiration and drainage. 
      3. Fan the probe, apply color doppler 
      4. Compare to the opposite (hopefully normal) side 

Written by: Taylor Brittan, MD

Costantino TG, Satz WA, Dehnkamp W, Goett H. Randomized trial comparing intraoral ultrasound to landmark-based needle aspiration in patients with suspected peritonsillar abscess. Acad Emerg Med. 2012 Jun;19(6):626-31. doi: 10.1111/j.1553-2712.2012.01380.x. PMID: 22687177.