LAUSR

To the Editor, The diagnostic utility of Point-of-Care Ultrasonography (POCUS) in nephrology is being increasingly recognized and some fellowship programs have formally integrated this skill into their training curricula [1]. In our program, we observed that checklists help novice users to systematically interpret the sonographic findings and reduce errors. In fact, the role of checklists in enhancing patient safety is well established in the context of bedside procedures [2]. Protocols such as 5Es for the interpretation of focused echocardiography and Pump-pipes-leaks approach for fluid status assessment are well known [3, 4]. Similarly, we devised SECONDS checklist for interpretation of nephrologist-performed renal ultrasound. S stands for size and constitutes renal length and parenchymal thickness. Decreased size may indicate chronic kidney disease (CKD) when interpreted in the appropriate clinical context. E indicates relative echogenicity, which means assessing how bright the renal cortex is compared to adjacent liver or spleen. Increased cortical echogenicity is non-specific and can be seen in both acute kidney injury (AKI) and CKD. However, in general, the likelihood of treatable pathology in small kidneys with increased cortical echogenicity is very low [5]. C designates collecting system, that is hydronephrosis. Indeed, exclusion of urinary tract obstruction as a cause for AKI is one of the commonest indications for renal POCUS. Hydronephrosis appears as an anechoic or black structure branching into the kidney. O stands for outline. As renal masses frequently interrupt the continuity of kidney outline and cortical architecture, it is important to make sure the outline is smooth and not significantly different when compared to the contralateral kidney. POCUS-performing nephrologist should be able to promptly identify any incidental masses and obtain further imaging or consultation when indicated. N signifies notable lesions, for example, cysts and stones. On greyscale ultrasound, stones appear as hyperechoic or bright structures with a posterior shadowing, whereas cysts appear as anechoic structures with an area of posterior brightness called acoustic enhancement. The nephrologist should be able to distinguish between benign lesions and those that require immediate intervention such as complex cysts with features suggestive of malignancy. D stands for Doppler. Color Doppler evaluation helps to identify structures with flow; for example, prominent hilar vessels and arteriovenous malformations can sometimes be confused with hydronephrosis as both blood and urine appear anechoic on greyscale images [6]. Similarly, renal infarcts may appear as areas devoid of blood flow on Doppler. In addition, users with training in advanced sonographic applications can perform spectral Doppler evaluation of the interlobar vessels to identify congestive nephropathy in cases of heart failure and fluid overload states [4]. The last S indicates surroundings and pertains to identification of peri-nephric collections especially when evaluating renal allografts. Some of these collections such as lymphocele and seromas can lead to hydronephrosis by exerting pressure on the collecting system. POCUSuser should also make a note of ascites or blood (hematomas) around the kidney depending on the clinical context. Figure 1 provides a pictographic summary of SECONDS checklist. I hope this serves as a teaching aid for nephrology programs newly incorporating POCUS training. The content has been presented at the American Society of Nephrology annual meeting 2021 by the author as an invited lecture.