Does physician experience influence the interpretability of focused echocardiography images performed by a pocket device?

Introduction: The use of focused cardiac ultrasound (FoCUS) in a prehospital setting is recommended. Pocket ultrasound devices (PUDs) appear to be well suited to prehospital FoCUS. The main aim of our study was to evaluate the interpretability of echocardiography performed in a prehospital setting using a PUD based on the experience of the emergency physician (EP).

Methods: This was a monocentric prospective observational study. We defined experienced emergency physicians (EEPs) and novice emergency physicians (NEPs) as echocardiographers if they had performed 50 echocardiographies since their initial university training (theoretical training and at least 25 echocardiographies performed with a mentor). Each patient undergoing prehospital echocardiography with a PUD was included. Four diagnostic items based on FoCUS were analyzed: pericardial effusions (PE), right ventricular dilation (RVD), qualitative left ventricular function assessment (LVEF), and inferior vena cava compliance (IVCC). Two independent experts blindly evaluated the interpretability of each item by examining recorded video loops. If their opinions were divided, then a third expert concluded.

Results: Fourteen EPs participated: eight (57 %) EEPs and six (43 %) NEPs. Eighty-five patients were included: 34 (40 %) had an echocardiography by an NEP and 51 (60 %) by an EEP. The mean number of interpretable items by echocardiography was three [1; 4]; one [0; 2.25] in the NEP group, four [3; 4] in EEP (p < .01). The patient position was also associated with interpretable items: supine three [2; 4], "45°" three [1; 4], sitting two [1; 4] (p = .02). In multivariate analysis, only EP experience was associated with the number of interpretable items (p = .02). Interpretability by NEPs and EEPs was: 56 % vs. 96 % for LVF, 29 % vs. 98 % for PE, 26 % vs. 92 % for RVD, and 21 % vs. 67 % for IVCC (p < .01 for all).

Conclusion: FoCUS with PUD in prehospital conditions was possible for EEPs, It is difficult and the diagnostic yield is poor for NEPs.