Lung ultrasound and chest x-ray for detecting pneumonia in an acute geriatric ward

Our aim was to compare the accuracy of lung ultrasound (LUS) and standard chest x-ray (CXR) for diagnosing pneumonia in older patients with acute respiratory symptoms (dyspnea, cough, hemoptysis, and atypical chest pain) admitted to an acute-care geriatric ward.

We enrolled 169 (80 M, 89 F) multimorbid patients aged 83.0 ± 9.2 years from January 1 to October 31, 2015. Each participant underwent CXR and bedside LUS within 6 hours from ward admission. LUS was performed by skilled clinicians, blinded to CXR results and clinical history. The final diagnosis (pneumonia vs no-pneumonia) was established by another clinician reviewing clinical and laboratory data independent of LUS results and possibly prescribing chest contrast-enhanced CT. Diagnostic parameters of CXR and LUS were compared with McNemar test on the whole cohort and after stratification for Rockwood Clinical Frailty Scale.

Diagnostic accuracy for pneumonia (96 patients) was significantly higher in LUS (0.90, 95% confidence interval [CI] 0.83-0.96) compared with CXR (0.67, 95%CI 0.60-0.74, P < 0.001). LUS had a better sensitivity (0.92, 95%CI 0.86-0.97 vs 0.47, 95%CI 0.37-0.57) and negative predictive value (0.95, 95% CI 0.83-0.96 vs 0.57, 95%CI 0.48-0.56). In those patients with frailty (n = 87 with Rockwood Clinical Frailty Scale ≥5), LUS maintained a high diagnostic accuracy, but CXR did not (P = 0.0003). Interobserver agreement for LUS, calculated in a subsample of 29 patients, was high (k = 0.90).

In multimorbid patients admitted to an acute geriatric ward, LUS was more accurate than CXR for the diagnosis of pneumonia, particularly in those with frailty. A wider use of LUS should be implemented in this setting.