Feasibility and Accuracy of an Ultrasound Algorithm for Acute Dyspnea Diagnosis in the Emergency Department

• Duration of the ultrasound examination[ Time Frame: up to 30 minutes ]
  Duration of the ultrasound examination is defined by the delay between the first and last contact between the ultrasound probe and the patient
• Proportion of complete realization of the ultrasound algorithm[ Time Frame: up to 30 minutes ]
  Proportion of complete realization of the ultrasound algorithm through study completion
• Diagnosis given by the algorithm after core-lab reading of the blinded ultrasound compared to the diagnosis provided by the emergency physician based on the EMERALD algorithm in the emergency department[ Time Frame: At baseline ]
  Diagnosis given by the algorithm after core-lab reading of the blinded ultrasound compared to the diagnosis provided by the emergency physician based on the EMERALD algorithm in the emergency department
• Patient management time in the emergency department[ Time Frame: An average of 24 hours (Time between the time of entry to the emergency department and the time of discharge). ]
  Patient management time in the emergency department is defined by the time between the time of entry to the emergency department and the time of discharge specified in the patient's medical report.
• Brain Natriuretic Peptide (BNP) or N-terminal pro-brain natriuretic peptide concentration[ Time Frame: At admission in the emergency department ]
  Assess the association between the diagnosis obtained from the ultrasound algorithm (EMERALD-US) and the results of additional laboratory exams. NT pro BNP will be measured from the biobanking.
• C Reactive protein and procalcitonin concentration,[ Time Frame: At admission in the emergency department ]
  Assess the association between the diagnosis obtained from the ultrasound algorithm (EMERALD-US) and the results of additional local laboratory exams
• D-dimer concentration,[ Time Frame: At admission in the emergency department ]
  Assess the association between the diagnosis obtained from the ultrasound algorithm (EMERALD-US) and the results of additional local laboratory exams
• Radiological diagnosis (chest X-ray or chest CT).[ Time Frame: At admission in the emergency department ]
  Assess the association between the diagnosis obtained from the ultrasound algorithm (EMERALD-US) and the results of additional local radiological exams
• Main discharge diagnosis including combined diagnosis (e.g. heart failure and pneumonia) from initial hospitalization adjudicated by a college of 3 senior physicians[ Time Frame: An average of 2 weeks (from date of admission in the emergency department until the date of discharge) ]
  Main discharge diagnosis including combined diagnosis (e.g. heart failure and pneumonia) from initial hospitalization adjudicated by a college of 3 senior physicians
• All-cause mortality at D30.[ Time Frame: At Day 30 ]
  Assess the association between misdiagnosis (without using ultrasound) and survival at D30

The management of chest pain has revolutionized its prognosis, primarily by improving urgent diagnosis of myocardial infarction. Currently, acute dyspnea is twice as frequent as chest pain and its associated mortality is much higher (16% of acute dyspnea admitted to emergency departments (ED) ). Inappropriate treatment of acute dyspnea in the ED is frequent (30%) and is associated with a tripling of intra-hospital mortality after adjustment for confounding factors (2.83, IC 1.48 to 5.41, p=0.002). Other elements have also highlighted the importance of a quick and appropriate acute dyspnea diagnosis: - The 2015 European Guidelines on acute heart failure emphasize the need for appropriate treatment within 90 minutes after the first medical contact. - Inadequate treatment of chronic bronchitis decompensation is associated with a doubling of intra-hospital mortality. - An initiation of antibiotic treatment within 4 hours of admission for pneumonia is recommended. - 30% of pulmonary embolisms are not diagnosed during the initial emergency department visit, whereas their mortality in the absence of treatment is 25%. Lung, venous and (simplified) cardiac ultrasound is associated with improved diagnostic performance in ED. However, no ultrasound algorithm dedicated to emergency physicians has been formally validated. The Blue Protocol (Lichtenstein et al., Chest 2008) has been validated in intensive care patients with very different phenotypes than those admitted to the ED. Pivetta et al. (Chest 2015) proposed an algorithm focused solely for the diagnosis of heart failure, thus not providing a diagnosis for all the other causes of dyspnea in ED. Finally, Zanbonetti et al. (Chest 2017) proposed an "unguided" ultrasound use, notably integrating inferior vena cava evaluation. However, measuring the inferior vena cava is difficult at the start of ED management when patients are in acute respiratory distress.

• Procedure: Ultrasound algorithm (EMERALD-US)
  Ultrasound algorithm EMERALD-US is an dedicated to emergencies using lung, cardiac and vascular ultrasound for the 3 main dyspnea causes (heart failure, pneumonia and obstructive pulmonary disease exacerbation) in patients with acute non-traumatic dyspnea managed in the emergency department. The ultrasounds will be performed within first hour after first medical contact in emergency department by another emergency physician not in charge of the patient. The ultrasound results will be not shared with the emergency physician in charge of the patient.

• Other: Acute non-traumatic dyspnea patients
  Patients with acute non-traumatic dyspnea managed in the emergency department to assess the diagnostic accuracy of an ultrasound algorithm (EMERALD-US) dedicated to emergencies using lung, cardiac and vascular ultrasound for the 3 main dyspnea causes (heart failure, pneumonia and obstructive pulmonary disease exacerbation)