Novice emergency physician ultrasonography of optic nerve sheath diameter compared to ophthalmologist fundoscopic evaluation for papilledema

Objectives: The purpose of this study is to determine the sensitivity and specificity of novice emergency physician-performed point-of-care ultrasound diagnosis of papilledema using optic nerve sheath diameter (ONSD) against ophthalmologist-performed dilated fundoscopy. This observational study retrospectively analyzed results of ultrasound-measured ONSD of emergency department (ED) patients with suspected intracranial hypertension from a period spanning June 2014 to October 2017. Methods: This study concerns a population of ED patients at a large, tertiary-care urban academic medical center from June 2014 to October 2017 over the age of 18 years with primary vision complaints evaluated for papilledema both by an emergency physician-performed ultrasound and an ophthalmologist-performed fundoscopic examination during their ED stay. Sensitivity and specificity of emergency physician-performed ultrasound measurement of optic nerve sheath diameter in the diagnosis of papilledema were primary outcomes for this study. Results: A total of 206 individual patients (male 49%, female 51%; median age 45 years) were included in the study with a total of 212 patient encounters. Calculated sensitivity for the ocular ultrasound examination performed by emergency physicians to diagnose papilledema was 46.9% (95% confidence interval [CI], 32.5% to 61.7%), and specificity was 87.0% (95% CI, 82.8% to 90.5%). Positive predictive value and negative predictive value were calculated to be 35.4% (95% CI, 23.9% to 48.2%) and 91.5% (95% CI, 87.8% to 94.4%), respectively. Conclusions: Sonographic measurement of ONSD by emergency physicians has low sensitivity but high specificity for detection of papilledema compared to ophthalmologist-conducted fundoscopy.