[Predictive value of lactate concentration combined with lactate clearance rate in the prognosis of neonatal septic shock].

Objective: To investigate the predictive value of lactate concentration within 1 h after admission combined with lactate clearance rate (LC) at 6 h after fluid resuscitation in prognosis of neonatal septic shock. Methods: In this retrospective study, 58 newborns with septic shock admitted to the Neonatal Intensive Care Unit of Xi'an Children's Hospital,Xi'an Jiao Tong University from June 2016 to March 2020 were enrolled. According to the mortality within 60 days after admission,which was also set as the end point, the patients were divided into death group and survival group. The general demographic data and clinical variables including blood cell counts, procalcitonin, C-reactive protein, D-dimer, serum creatinine, and lactate concentration within 1 h after admission (Lac1) and at 6 h after fluid resuscitation (Lac2) were collected. The differences in the clinical variables between the survival and death group were compared by independent sample t test or Rank-Sum test, and the risk factors of poor prognosis were analyzed by binary Logistic regression. The predictive values of these risk factors were tested by receiver operating characteristic (ROC) curve. Furthermore, the cut-off of the risk factors were used to analyze the accumulative survival rate by Kaplan-Meier curve. Results: A total of 58 neonates were enrolled, among whom 24 survived and 34 died within 60 days after admission. The rate of premature rupture of membranes in the death group was higher than that in the survival group (41% (14/34) vs.13%(3/24), P=0.021). There were also significant differences in infection site, pathogenic characteristics, total fluid volume of resuscitation, vasoactive drug index, rate and complications of mechanical ventilation between the two groups (all P<0.05). The levels of Lac1, Lac2, procalcitonin, D-dimer and serum creatinine in the death group were higher than those in the survival group ((12±6) vs. (7±4) mmol/L, (14±6) vs. (4±2) mmol/L, (59±23) vs.(24±14) ng/L, (24±11) vs.(11±6) mg/L, (167±31) vs.(92±23) μmol/L, t=3.549, 3.112, 3.859, 4.499, 3.288, all P<0.05). While the blood pressure and LC at 6 h after fluid resuscitation were lower than those in the survival group ((41±12) vs. (52±5) mmHg (1 mmHg=0.133 kPa), t =4.230;-16 (-40, 20) % vs. 40 (18, 70) %, Z= 3.558, all P<0.05). Binary Logistic regression analysis showed that LC was negatively associated with the risk of death in neonates with septic shock (odds ratio (OR) and 95% confidence interval (CI): 0.679 (0.662-0.999), P<0.05), while Lac1 was the risk factor and positively associated with the risk of death (OR and 95% CI: 1.203 (0.965-1.500), P<0.05). Furthermore, the predictive values of LC, Lac1 and the combination of these two variables in the prognosis of neonatal septic shock were analyzed by ROC curve analysis, and the area under the curve (AUC) were 0.699, 0.875, 0.965, respectively, with the sensitivity of 83.32%, 89.65% and 94.31%, and the specificity of 72.52%, 77.18% and 88.76%, respectively. According to the cut-off value of Lac1, the newborns with Lac1>4 mmol/L had significantly lower accumulative survival rate than those with Lac1≤4 mmol/L by Kaplan-Meier analysis (21% (8/38) vs. 80% (16/20), χ²=54.520, P<0.05). According to the cut-off value of LC, the newborns with LC ≤ 10% had significantly lower accumulative survival rate than those with LC>10% by Kaplan-Meier analysis (19% (6/32) vs. 69% (18/26), χ²=14.140, P<0.05). Conclusion: The combination of lactate concentration and lactate clearance rate have an optimal predictive value in the prognosis of neonatal septic shock.