Background: Weaning from mechanical ventilation is a challenging step during recovery from critical illness. Weaning failure or early reintubation are associated with increased morbidity and mortality, exposing patients to life-threatening complications. Cardiac dysfunction represents the most common cause of weaning failure. We conducted a systematic review and meta-analysis to evaluate the association between transthoracic echocardiographic parameters and weaning failure. Methods: We performed a systematic search of MEDLINE and EMBASE screening for prospective studies providing echocardiographic data collected just before the beginning of spontaneous breathing trial and outcome of the weaning attempt. We primarily focused on parameters currently recommended for evaluation of left ventricular (LV) systolic or diastolic dysfunction. Results: We included 11 studies in our primary analysis, which included data on LV ejection fraction (LVEF, n¼10 studies) and parameters recommended for the assessment of LV diastolic function (E/e 0 ratio n¼10; E/A ratio n¼9; E wave n¼8; and e 0 wave n¼7). Weaning failure was significantly associated to a higher E/e 0 ratio (standardised mean difference [SMD]¼ 1.70, 95% confidence interval [CI; 0.78e2.62]; P<0.001), lower e 0 wave (SMD¼À1.22, 95% CI [À2.33 to À0.11]; P¼0.03), and higher E wave (SMD¼0.97, 95% CI [0.29e1.65]; P¼0.005). We found no association between weaning failure and LVEF (SMD¼À0.86, 95% CI [À1.92e0.20]; P¼0.11) and E/A ratio (SMD¼0.00, 95% CI [À0.30e0.31]; P¼0.98). Conclusions: Weaning failure is associated with parameters indicating worse LV diastolic function (E/e 0 , e 0 wave, E wave) and increased LV filling pressure (E/e 0 ratio). The association between weaning failure and LV systolic dysfunction as evaluated by LVEF is more unclear. More studies are needed to clarify this aspect and regarding the role of right ventricular function.

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