Central venous oxygen saturation/lactate ratio: a novel predictor of outcome following emergency open laparotomy

Introduction: Emergency laparotomy is associated with high rates of morbidity and mortality. The need for highly sensitive readily prognostic biomarkers is necessary to improve the outcome. We investigated the usefulness of post-operative arterial lactate and ScvO2/lactate ratio as predictors of outcome after post-operative emergency open laparotomy. To the best of our knowledge, the novel ScvO2/lactate ratio was not investigated before in emergency open laparotomy patients. Methods: It is a prospective observational cohort study. We investigated the usefulness of post-operative arterial lactate and ScvO2/lactate ratio as predictors of early mortality in 40 patients following emergency open laparotomy admitted to the ICU. Results: Admission and 24 h lactate levels were predictor of mortality with cut-off point > 3.95 mmol/L, sensitivity 100%, and specificity 93.3%, and cut-off > 3.5 mmol/L, sensitivity 100%, and specificity 96.7%, respectively. In this study, ScvO2/lactate ratio on admission was predictor of at day 7 with cut-off point < 13.95, sensitivity 100%, and specificity 96.7% p < 0.0001. Lactate at 12 and 24 h was also predictor of survival p < 0.0001. Serial arterial lactate was highly correlated to ICU length of stay; admission APACHE II and day 1; and 2 MODS and SOFA scores (p < 0.001). Conclusion: Serial blood lactate as well as the novel ScvO2/lactate ratio can be useful for early predictors of mortality at 7 days. Serial lactate levels correlate to admission ICU scores APACHE II; MODS and SOFA in post-operative emergency open laparotomy patients.