Short communicationImmature/total granulocyte ratio: A promising tool to assess the severity and the outcome of post-cardiac arrest syndrome

BackgroundThe immature/total granulocyte (I/T-G) ratio increases during severe systemic inflammatory response syndrome. This study evaluated the I/T-G ratio as a predictor of poor outcome after out-of-hospital cardiac arrest (OHCA).MethodsWe conducted a pilot prospective cohort study of patients who were admitted in our intensive care unit (ICU) during a one-year period after post-OHCA resuscitation. I/T-G ratio measurements were obtained from blood samples collected on admission using flow cytometry and the outcomes were ICU mortality and post-cardiac arrest syndrome.ResultsAmong the 130 patients (76% male, median age 54 [46-67] years), the median I/T-G ratio was 0.85 [0.42-1.98]%. The I/T-G ratio was poorly correlated with the SOFA score and lactate level on day 1 (r = 0.25, p = 0.005 and r = 0.5, p < 0.001, respectively). Patients with high I/T-G ratios were more likely to develop post-resuscitation shock (37% vs. 58%, p = 0.02). Patients dying from post-resuscitation shock had a higher I/T-G ratio than patients dying from neurological causes (2 [1-4]% vs. 1.2 [0.6-1.2]%, p = 0.02). The area under the ROC curve based on the I/T-G ratio was 0.82 for predicting ICU mortality.ConclusionThe I/T-G ratio appears to be an accurate predictor of poor outcome. However, the added clinical value of this marker and the possible involvement of immature granulocytes in the pathophysiology of post-cardiac arrest syndrome remain to be investigated.