Effect of a point-of-care ultrasound-driven diagnostic pathway on diagnostic certainty in emergency department patients with dyspnea: a randomized controlled substudy.

Abstract

Background and importance: In emergency department (ED) patients with dyspnea, diagnostic uncertainty has been linked to poorer outcomes. Point-of-care ultrasound (POCUS) may help reduce this uncertainty.

Objective: To explore how POCUS influences ED physicians' diagnostic thinking and perceived uncertainty.

Design, settings, and participants: This preplanned substudy of a randomized controlled trial across 10 Danish EDs compared diagnostic pathways with vs. without focused lung and cardiac ultrasound.

Outcomes measure and analysis: Paired physician surveys and electronic health record data were used to evaluate predefined outcomes: (a) physicians' experienced benefit of diagnostic tests; (b) the number of differential diagnoses; (c) posttest probability estimates; (d) concurrent treatment; and (e) concordance between tentative diagnoses. The primary outcome of the parent trial was discharge alive within 24 h; this substudy focused on early diagnostic reasoning and certainty.

Main results: Between 25 January 2023 and 23 August 2024, 40 physicians enrolled 674 patients. The median number of differential diagnoses was similar between groups [intervention: 3 (interquartile range - IQR: 2-4); control: 3 (IQR: 2-4)]. The proportion of patients with a reduced differential count was 65.3 vs. 72.9% [risk difference: -7.6, 95% confidence interval (CI): -14.9 to -0.3]. The median estimated probability of the leading diagnosis was higher with POCUS (80 vs. 73%). Concordance between initial and revised physician diagnoses was also higher (70.6 vs. 63.1%; risk difference: 7.5, 95% CI: 0.1-15.0), while concordance with final hospital diagnoses was similar (35.9 vs. 38.9%, risk difference: -3.0, 95% CI: -10.4 to 4.4).

Conclusion: A POCUS-driven diagnostic pathway increased early diagnostic certainty, but not diagnostic certainty at the time of patient disposition. This was reflected in a higher initial diagnostic probability for the primary diagnosis and greater concordance between the primary tentative diagnoses recorded in the paired surveys.