The value of oxygen challenge test in predicting the effect of fluid resuscitation in patients with septic shock

You Yong; Liu Ning; Guo Xiao-fang; Gu Qin

doi:10.3969/j.issn.1002-1949.2017.12.006

Abstract：Objective To evaluate the clinical value of oxygen challenge test (OCT) in predicting the effect of fluid resuscitation in patients with septic shock.Methods A prospective observational study was conducted.54 patients with septic shock admitted to intensive care unit (ICU) of Affiliated Hospital of Nanjing University Medical School from January 2015 to June 2016 were enrolled and given the standard treatment in accordance with the 2014 Chinese severe sepsis/septic shock treatment guidelines.OCT,transcutaneous oxygen pressure (PtcO2),mean arterial pressure (MAP),arterial blood lactic acid (Lac),central venous oxygen saturation (ScvO2) and other hemodynamic monitoring before and 6 h after fluid resuscitation were recorded,and the 6 h lactate clearance rate (LRC) was calculated.The patients were divided into high clearance group (n =32) with 6 h LRC ≥ 10％ and low clearance group (n =22) with 6 h LRC ＜ 10％.OCT,PtcO2 and ScvO2 after resuscitation were compared between 2 groups.The receiver-operating characteristics (ROC) analysis was performed to predict the effect of fluid resuscitation of the variables OCT,PtcO2 and ScvO2 after resuscitation.Results Before resuscitation,the hemodynamic parameters,tissue oxygen metabolism parameters had no significant differences in both groups.Six hours after resuscitation,arterial blood lactic acid is lower in the low clearance group [(3.3 ± 3.2) mmol/L vs.(7.3 ±4.1) mmol/L,P =0.010] than the high clearance group,PtcO2 and OCT was higher in the low clearance group [PtcO2:(88.2 ± 29.2) mm Hg vs.(54.0 ±25.9) mmol/L,P=0.004;OCT:(90.9±57.5) mmHgvs.(40.0±19.8) mmHg,P=0.010],ScvO2 of 6 h after resuscitation in the 2 groups had no significant difference [(76.6％ ±6.5) ％ vs.(77.7％ ± 7.5) ％,P =0.686)].OCT was significantly negatively correlated with Lac of the same period before and after resuscitation.OCT after 6 h resuscitation and 6 h LRC was significantly and positively correlated,and no correlation between ScvO2 and LRC after resuscitation.The AUC of 6 h OCT (0.836) was greater than 6 h PtcO2 (0.768),while the AUC of 6 h ScvO2 was the smallest (0.416).The best cutoff value of 6 h OCT for the predicting of 6 h LRC ≥ 10％ was 61 mm Hg,with the sensitivity 71.9％ and the specificity 90.9％.Conclusion OCT is well correlated with arterial blood lactate and lactate clearance rate in septic shock before and after fluid resuscitation,and can be used to evaluate the effect of fluid resuscitation in patients with septic shock.