Evaluation of a short formation on the performance of point-of-care renal ultrasound performed by physicians without previous ultrasound skills: prospective observational study.

Background: Point-of-Care Ultrasound (PoCUS) is recommended by emergency medicine societies for the detection of hydronephrosis. Training of certified Emergency Physicians (EP) without prior ultrasound experience remains debated. We investigate performance of a brief training session for the detection of hydronephrosis with PoCUS performed by EP without previous ultrasound experience.

Patients and methods: This was a prospective observational study of a convenience sample of patients older than 18 years with presumed renal colic, acute pyelonephritis or documented acute renal failure. Exclusion criteria were pregnancy and documented end of life.After inclusion and informed consent, a PoCUS was performed. A radiologist's renal ultrasound (RRUS) was then conducted, the radiologist being blind to PoCUS result.The objective was to determine the diagnostic performance of PoCUS performed by EP for the detection of hydronephrosis using RRUS as gold standard.

Results: Six EP participated in this study. 55 patients were included, five secondary excluded for lack of RRUS. Age was 47 ± 22 years, sex ratio 1. Hydronephrosis prevalence was 38% (CI 95% [26-52%]). Sensitivity of PoCUS was 100% (CI 95% [82-100%]) while its specificity was 71% (CI 95% [52-86%]) with a NPV of 100% (CI 95% [85-100%]) and a 68% (CI 95% [48-84%]) PPV. Kappa coefficient was 0.65 (CI 95% [0.45-0.85]).

Discussion: We demonstrated that a short training program enables EP without previous ultrasound skills to rule out hydronephrosis with satisfactory performances. The main limitation was the absence of collection of the number of PoCUS by EP. After this didactic course, an experiential phase must be carried out.