Effect of Shenfu Injection (参附注射液) on Lactate and Lactate Clearance in Patients with Post-cardiac Arrest Syndrome: A Post Hoc Analysis of a Multicenter Randomized Controlled Trial

OBJECTIVE To assess the effects of Shenfu Injection (, SFI) on blood lactate, and secondarily its effect on the lactate clearance (LC) in patients with post cardiac arrest syndrome (PCAS). METHODS The present study is a post hoc study of a randomized, assessor-blinded, controlled trial. Patients experienced in-hospital cardiac arrest between 2012 and 2015 were included in the predefined post hoc analyses. Of 1,022 patients enrolled, a total of 978 patients were allocated to the control group (486 cases) and SFI (492 cases) group, receiving standardized post-resuscitation care bundle (PRCB) treatment or PRCB combined with SFI (100 mL/d), respectively. Patients' serum lactate was measured simultaneously with artery blood gas, lactate clearance (LC) was calculated on days 1, 3, and 7 after admission and compared between groups. Lactate and LC were also compared between the survivors and non-survivors according to the 28-d mortality, as well as the survivors and non-survivors subgroups both in the SFI and control groups. RESULTS In both groups, compared with pre-treatment levels, mean arterial pressure (MAP) and PaO2 were significantly improved on 1, 3, 7 d after treatment (P<0.05), while heart rate (HR) and blood glucose levels were significantly decreased on 1, 3 and 7 d after treatment (P<0.05). compared with control group, SFI treatment improved the values of MAP and PaO2 (P<0.05), and significantly decreased the levels of HR and the blood glucose level on 3 and 7 d after treatment (P<0.05). Compared with the control group, lactate levels decreased faster in the SFI group versus the control group on 3 and 7 d (P<0.05). From initiation of treatment and the following 3 and 7 d, SFI treatment greatly increased the LC compared with that in the control group (P<0.05). Compared with survivors, non-survivors had higher admission lactate levels (7.3 ±1.1 mmol/L vs. 5.5 ±2.3 mmol/L; P<0.01), higher lactate levels on days 1, 3 and 7 (P<0.05), and LC were decreased significantly on 3 and 7 d after treatment (P<0.05). Similar results were also found both in the SFI and control groups between survivors and non-survivors subgroups. CONCLUSION SFI in combination with PRCB treatment is effective at lowering lactate level and resulted in increasing LC in a targeted population of PCAS patients.