Abstract
BACKGROUND: To investigate the association of clinical and hematological parameters with return of spontaneous circulation (ROSC) in out-of-hospital cardiac arrest (OHCA). METHODS: Clinical data of successive non-traumatic adult OHCA patients with available laboratory data of complete blood count and peripheral blood smear at emergency department (ED) arrival were requested. Hematological parameters were collected and calculated, and logistic regression and survival analysis were performed for association of ROSC with the parameters. RESULTS: From December 2015 to December 2016, a total of 188 OHCA patients transported to our ED were enrolled. In ROSC group, neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) were signifi cantly higher and smudge cell count was signifi cantly lower when compared with non-ROSC group. In the univariate regression, NLR more than 2.0 (odds ratio [OR]: 2.40, 95% confi dence interval [CI]: 1.31-4.41; p = 0.004) and smudge cell count less than 0.45 °- 109/L (OR: 0.33, 95% CI: 0.15-0.71; p = 0.004) were signifi cantly associated with ROSC in OHCA. In logistic regression, bystander witnessed (OR: 3.15, 95% CI: 1.59-6.27; p = 0.001) and prehospital epinephrine use (OR: 2.15, 95% CI: 1.10-4.23; p = 0.026) were signifi cantly associated with ROSC in OHCA. NLR and smudge cell count were also seemingly related to ROSC in OHCA, but without statistical signifi cance. In survival analysis, neither NLR nor smudge cell count was associated with patient survival to discharge in OHCA. CONCLUSIONS: NLR and smudge cell count at ED arrival could be potential indicators of ROSC in OHCA.