3.1 Metabolic acidosis
Studies have shown that hyper-lactic acidosis is an effective biomarker, and the severity of pre-ECMO arterial acidosis is related to outcomes[9]. In our study, 5 patients with lactic acid<10 mmol/L before ECMO were discharged, while in 18 neonates with lactic acid>10mmol/L, only 7 survived. This suggests that higher lactate levels before ECMO is an independent risk factor for poor outcomes. There was a significant difference in the highest lactate, the levels of ECMO 12h and 24h, the lactate clearance time between two groups (P =0.03, 0.005, 0.001, 0.036, respectively). The results are similar to those findings of the reports[10,11]. The Fux[12] team analyzed VA-ECMO patients and found that ischemic heart disease and arterial lactate were independent predictors of 90-day mortality; The 90-day survival rate of lactic acid>10 mmol/L was lower than patients with lactic acid<10 mmol/L before ECMO (13% and 55%, P <0.001). If the lactate remained at 3mmol/L after 48h, the 30-day mortality rate is 52%. Other papers[13,14] suggested that persistent metabolic acidosis after ECMO reflect the severity of ischemia and hypoxia and confirmed that the peak lactate level affects the survival rate. Therefore, early application to reverse poor perfusion and prevention high lactate are critical factors for successful outcomes following ECMO.