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The following is a summary of “Prevalence and implications of perinephric fluid on renal point-of-care ultrasound in the emergency department,” published in the December 2023 issue of Emergency Medicine by Cannata, et al.

Point-of-care ultrasound (PoCUS) is commonly used in diagnosing renal colic, but perinephric fluid, a potential sign of ureteral obstruction, may be overlooked. For a study, researchers sought to determine the prevalence of perinephric fluid on emergency physician-performed PoCUS and its association with stone size and urologic intervention.

A 12-month cross-sectional study was conducted at an academic emergency department from January 1, 2022, to December 31, 2022. Adult patients (≥18 years) who underwent renal PoCUS were included. Missing or inadequate PoCUS images led to exclusion. Blinded investigators performed chart reviews for demographic data and outcome variables, while separate blinded investigators reviewed PoCUS images for perinephric fluid and hydronephrosis. The chi-square analysis determined associations between perinephric fluid and outcome variables (stone size, urologic intervention).

Of 442 screened patients, 18 were excluded for inadequate images, leaving 420 analyzed. Perinephric fluid prevalence was 6.2% (n = 26), with most (23/26) having ureterolithiasis. Hydronephrosis was present in 27.4% (115/420), with 19.1% (22/115) showing perinephric fluid, significantly associated with needing urologic intervention (OR 10.38, 95% CI 2.70–39.85, P < 0.01). Among 67 patients with confirmed ureterolithiasis, perinephric fluid was associated with stone size ≥5 mm (OR 4.00, 95% CI 1.01–15.85, P = 0.04).

Perinephric fluid prevalence in emergency physician-performed renal PoCUS was 6.2% overall and 19.1% in hydronephrosis cases. In ureterolithiasis, perinephric fluid was linked to larger stone size and a need for urologic intervention.

Reference: sciencedirect.com/science/article/abs/pii/S0735675723004916