The Accuracy of Point of Care Ultrasound Performed by Emergency Physicians in Detecting Hydronephrosis in Patients with Renal Colic

Abstract

Objectives: to determine the accuracy of renal point of care ultrasound (POCUS) performed by emergency physicians in detecting hydronephrosis in patients with renal colic. Methods: We conducted a prospective cross-sectional diagnostic study at Sultan Qaboos University Hospital, emergency department (ED), from February 2017 to October 2018. All adult patients with suspected renal colic and who can give informed consent were included. The emergency physicians perform POCUS on both kidneys and graded hydronephrosis as none, mild, moderate, or severe cases. We compared POCUS grade to non-contrast computed tomography (NCCT) grade. Results: Three hundred and three participants were enrolled in the analysis. Most of the study population are adult males, 247 (81.5%), and the mean age is 39 years. Among the samples, 71.2% of patients had a degree of hydronephrosis based on CT findings. Ultrasound performed by emergency physicians had a sensitivity of 75.8% (95% CI: 69.5‒81.4), the specificity of 55.2% (95% CI: 44.1‒65.8), the positive likelihood ratio of 1.69 (95% CI: 1.32‒2.16), and negative likelihood ratio 0.43 (95% CI: 0.32‒0.59) for hydronephrosis using CT as the criterion standard. Conclusions: When evaluating patients with suspected renal colic, a bedside renal POCUS performed by emergency physicians (EP) has a moderate sensitivity to detect hydronephrosis and grade its severity. It should be utilized in the ED to screen patients for hydronephrosis. More training is required to improve the test's accuracy, as this might help as a screening tool in ED.Keywords: Hematuria; Hydronephrosis; Nephrolithiasis; Point-of-care testing; Renal colic; Ultrasonography.