Use of combined cardiac and lung ultrasound to predict weaning failure in elderly, high-risk cardiac patients: a pilot study

Purpose Weaning failure from mechanical ventilation may be due to lung de-recruitment or weaning-induced pulmonary oedema (WIPO). Both can be diagnosed by lung ultrasound (LUS) and transthoracic echocardiography (TTE), respectively. We conducted a prospective observational study, combining TTE and LUS, to determine if LUS alone may identify elderly patients at high risk of weaning or extubation failure. Methods Before and at the end of spontaneous breathing trials (SBT) in 40 elderly patients, we prospectively performed LUS and TTE. Extubation was decided by an independent operator. LUS included global and anterolateral LUS score. TTE included measurement of E/A and E/Ea ratios to determine LV filling pressures. SBT LUS scores for prediction of weaning outcome and for the diagnosis of WIPO were studied. Results Weaning or extubation failure was observed in 45% (95% CI 28-61) of patients. ROC analysis for ability of global SBT LUS to predict weaning/extubation failure and extubation failure found AUC of 0.80 and 0.81, respectively. AUC for anterolateral SBT LUS to predict weaning/extubation failure and extubation failure was 0.79 and 0.81, respectively. Increased LV filling pressure during SBT was observed without increase of anterolateral LUS score. Inversely, increase of anterolateral LUS was observed without increased filling pressure and was associated with extubation failure. Global and anterolateral SBT LUS were not correlated to E/Ea. Conclusion In elderly patients, global and anterolateral LUS scores were associated with weaning and extubation failures while echocardiographic indices of filling pressures were not.