Chanel O’Brien, DO| EM PGY-3

The Article: Novice emergency physician ultrasonography of optic nerve sheath diameter compared to ophthalmologist fundoscopic evaluation for papilledema. Wilson et al. (2021), JACEP Open 2021;2:e12355.

The Idea: The purpose of this study was 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.

The Study: This was an observational study performed at a large, >100,000 annual volume, tertiary-care urban academic medical center which retrospectively analyzed results regarding ultrasound measured ONSD of emergency department (ED) patients. The study looked at patients over the age of 18 years that presented with primary vision complaints evaluated for papilledema both by an emergency physician-performed ultrasound and an ophthalmologist-performed fundoscopic examination. Operators were novice resident emergency physicians and had varying levels of POCUS experience. Images were collected on a Phillips Sparq or a Sonosite Xporte ultrasound machine using a high-frequency linear transducer with patients in an upright position. Optic-nerve sheath diameter was measured 3 mm posterior to the papilla with calipers placed at the interior border of the hypoechoic nerve, measured in two planes with the average of the measurements recorded. Patients were excluded if they did not receive both formal ophthalmology evaluation and bedside ocular ultrasound performed by an emergency physician. A retrospective chart review was conducted for adult patients that meet the study criteria above. All POCUS ocular examinations reviewed had been stored within the centralized image repository and were queried for concomitant ED visit ophthalmology consultation via electronic health record database query. As a second measure, the ultrasound images were also reviewed in QPath. During the chart review, the results of the ophthalmologist-performed fundoscopic examination including detection of papilledema and grading of the papilledema (if applicable) were recorded against the physician-measured ONSD. ONSD measurement greater than 5 mm on ocular ultrasound was diagnosed as papilledema.

The Findings: A total of 206 individuals (51% female, 49% male) were included in the analysis for a total of 212 considered encounters performed by 55 unique resident physician operators ranging from PGY1–PGY4. Of those 212 encounters included in the final analysis, 28 (13.2%) resulted in a diagnosis of papilledema by funduscopic examination for at least 1 eye. There was no significant difference in sex amoung the encounters (female: 53.3%, male: 46.7%), but there was a statistically significant difference in sex between encounters with (female: 78.6%; male: 21.4%) and without (female: 49.5%; male: 50.5%) papilledema. There was also a significant difference in age between individuals with (median: 37.0 years, interquartile range: 27.0-46.5 years) and without (median: 48.0 years, interquartile range: 33.0-60.0 years) fundoscopic- diagnosed papilledema. A total of 372 instances of ophthalmologist fundoscopy and emergency physician-performed ONSD measurement were used to calculate the sensitivity and specificity as well as positive and negative predictive value of the emergency physicians’ ocular ultrasound evaluation for papilledema. Sensitivity for the ocular ultrasound (cutoff = 5.0 mm) performed by emergency physicians to diagnose papilledema was calculated to be 46.9%, and specificity was 87.0%. The PPV was 35.4%, and the NPV was 91.5%.

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The Takeaway: Compared to the standard of care of formal ophthalmology evaluation via fundoscopy, the ocular ultrasound performed by novice emergency physicians has low sensitivity and high specificity, showing that although it may be a useful tool for ruling in a diagnosis of papilledema, it is not sufficiently sensitive to rule out papilledema. For now, ocular ultrasound cannot be used as a screening tool for evaluation of increased intracranial pressure in the emergency department, and if the physician is concerned for papilledema, the patient should undergo formal ophthalmology evaluation.

Danica Zold, DO MPH | EM/FM PGY4

Article:

Lahham S, Shniter I, Thompson M, et al. Point-of-Care Ultrasonography in the Diagnosis of Retinal Detachment, Vitreous Hemorrhage, and Vitreous Detachment in the Emergency Department. JAMA Network Open. Published online April 12, 20192(4):e192162. doi:10.1001/jamanetworkopen.2019.216

Objective:

To determine if Emergency medicine physicians can use POCUS for early and accurate identification of retinal detachment, vitreous hemorrhage, and vitreous detachment.

Importance:

Early detection and distinction among these 3 common ocular diagnoses, helps lead to proper disposition of patients, faster treatment and therefore prevention of potential permanent vision loss.

Study:

A prospective, observational, multicenter, diagnostic study was performed across 2 academic and 2 county EDs in southern CA from Feb 2016- April 2018. The study enrolled a total of 225 patients with ocular symptoms and concern for retinal detachment, vitreous detachment or vitreous hemorrhage (blurry vision, vision loss, flashers, floaters); 18 years or older, without concern for ocular trauma or globe rupture.

Ocular POCUS was performed by 75 Emergency medicine attendings, residents (PGY1-4) and PA’s of variable experience. They were given a 30 minute lecture and 30 minute hands on scanning lesson for the key US findings associated with each of the 3 diseases.

Both the POCUS scanners and ophthalmologists were blind to one another’s findings, however physicians were not blind to the patient, their histories or other evident physical exam findings. Patients underwent ocular POCUS evaluation followed by ophthalmologic evaluation. Diagnoses were compared, with the definitive correct diagnosis determined by ophthalmologist evaluation.

Findings:

Of the 4 sites involved in the study, the prevalence of ocular disease was found to 36%.
Of the 225 patients, ophthalmologists diagnosed 20.8% with retinal detachment. Ocular POCUS correctly diagnosed 46 of these 47 patients, resulting in 96.9% sensitivity. POCUS correctly ruled out retinal detachment in 156 of the 176 cases, resulting in 88.1% specificity.
Ophthalmologists diagnosed 24% of patients with vitreous hemorrhage. Ocular POCUS diagnosed 46 of these 54 patients correctly, resulting in 81.9% sensitivity and 82.3% specificity.
Ophthalmologists diagnosed 15% of the patients with vitreous detachment. Although ocular POCUS was only able to identify 19 of the 34 patients correctly, leading to a 42.5% sensitivity, POCUS was able to rule out vitreous detachment in 178 of the 190 negative cases, resulting in 96.0% specificity.
Overall, POCUS has a >90% negative predictive value for all 3 of these ocular diseases. It appears however, that emergency medicine providers are best at ocular POCUS when diagnosing retinal detachment, with a 99% NPV, 64.5% PPV, and 90.6% accuracy.

Take Home Points:

EM providers using ocular POCUS are better at successfully ruling in the disease then definitively ruling out.
Ocular POCUS should not replace the role of an ophthalmologist, however EM practitioners can use POCUS as an adjunct to help accurately and reliably identify retinal detachment, vitreous hemorrhage, and vitreous detachment with statistical significance, expediting care and treatment for ocular disease in the Emergency room.