Lactate and Echocardiography Before Veno-Venous Extracorporeal Membrane Oxygenation Support.

BACKGROUND: Lactate has been recognised as a prognostic factor in several critical conditions. Veno-Venous Extracorporeal Membrane Oxygenation (VV-ECMO) is a well-established therapy in patients with Acute Respiratory Disease Syndrome (ARDS) unresponsive to conventional therapy and echocardiography pre ECMO initiation has been recently reported to help in risk stratifying these patients.

METHODS: We assessed whether the detection of hyperlactataemia could be associated with the presence of left ventricle (LV) or right ventricle (RV) dysfunction in 121 consecutive patients with refractory ARDS.

RESULTS: The mortality rate was 42.9% (52/121). Higher dosages of norepinephrine and dobutamine were administered to non survivors (p=0.023 and p=0.047, respectively) who showed significantly higher levels of lactate (p=0.002). At echocardiography, non survivors showed higher values of systolic pulmonary artery pressure (sPAP) (p=0.05) and a higher incidence of RV dysfunction (as indicated by lower Tricuspid Annular Plane Excursion (TAPSE)) and RV dilatation (p=0.001). At multivariate logistic regression analysis, the following variables were independent predictors of death: body mass index (BMI) (OR: 0.914, 95%CI 0.857-0.975, p=0.006), RV dilatation (OR: 0.239, 95%CI 0.101-0.561, p=0.001) and lactate (OR: 1.292, 95%CI 1.015-1.645, p=0.038). Lactate values were directly correlated with the simplified acute physiology score (SAPS) II (r=0.38, p<0.001), while they showed an indirect correlation with left ventricular ejection fraction (LVEF) (r=-0.24, p=0.009) and TAPSE (r=-0.21, p=0.024).

CONCLUSIONS: In refractory ARDS, hyperlactataemia before VVV-ECMO identified a subset of patients at higher risk of death, being an independent predictor of in-Intensive Care Unit (ICU) mortality. Lactate values are mainly related to disease severity (as indicated by SAPS II) and haemodynamic impairment (as inferred by LVEF) and RV failure, as (indicated by TAPSE).