Contribution of lung ultrasound in diagnosis of community-acquired pneumonia in the emergency department: a prospective multicentre study

Lung ultrasound (LUS) can help clinicians make a timely diagnosis of community-acquired pneumonia (CAP). Objectives To assess if LUS can improve diagnosis and antibiotic initiation in emergency department (ED) patients with suspected CAP. Design A prospective observational study. Settings Four EDs. Participants The study included 150 patients older than 18 years with a clinical suspicion of CAP, of which 2 were subsequently excluded (incorrect identification), leaving 148 patients (70 women and 78 men, average age 72 +/- 18 years). Exclusion criteria included a life-threatening condition with do-not-resuscitate-order or patient requiring immediate intensive care. Interventions After routine diagnostic procedure (clinical, radiological and laboratory tests), the attending emergency physician established a clinical CAP probability according to a four-level Likert scale (definite, probable, possible and excluded). An LUS was then performed, and another CAP probability was established based on the ultrasound result. An adjudication committee composed of three independent experts established the final CAP probability at hospital discharge. Primary and secondary outcome measures Primary objective was to assess concordance rate of CAP diagnostic probabilities between routine diagnosis procedure or LUS and the final probability of the adjudication committee. Secondary objectives were to assess changes in CAP probability induced by LUS, and changes in antibiotic treatment initiation. Results Overall, 27% (95% CI 20 to 35) of the routine procedure CAP classifications and 77% (95% CI 71 to 84) of the LUS CAP classifications were concordant with the adjudication committee classifications. Cohen's kappa coefficients between routine diagnosis procedure and LUS, according to adjudication committee, were 0.07 (95% CI 0.04 to 0.11) and 0.61 (95% CI 0.55 to 0.66), respectively. The modified probabilities for the diagnosis of CAP after LUS resulted in changes in antibiotic prescriptions in 32% (95% CI 25 to 40) of the cases. Conclusion In our study, LUS was a powerful tool to improve CAP diagnosis in the ED, reducing diagnostic uncertainty from 73% to 14%.