Methemoglobin Levels In Patients Post Cardiopulmonary Resuscitation. A Retrospective Study

Objective:Our aim was to investigate the relationship between methemoglobin (MetHb) and severity and the early outcome in patients who return of spontaneous circulation (ROSC) after cardiopulmonary resuscitation (CPR).Methods:This was a retrospective and observational study that examined 66patients data from an intensive care unit (ICU) at the First Affiliated Hospital of Guangxi Medical University between August 2013 and March 2016.The inclusion criteria were patients after cardiac arrestand examination oflevels of MetHbafter ROSC.The acute physiology and chronic health evaluation Ⅱ (APACHE II) scores and sequential organ failure assessment (SOFA) scores were recorded. The primary endpoint was survival outcome at 7days.The patients were divided into survival group and non-survival group, according to the outcomes after 7 days.And then the clinical data of two groups were analyzed.Results:A total of 66 patients were included into the study.The mean MetHb levels(%) in all patients was 1.15±0.47.MetHb values measured in survivors and non-survivors were, respectively:0.94+0.26 vs 1.34±0.54 on admission (P< 0.01).MetHb levels on admission were significantly correlated with SOFA scores (r=0.449, P< 0.001), APACHE II scores (r= 0.264, P< 0.05), and lactate (r= 0.376, P< 0.001). MetHb levels were negatively correlated with PH(r=-0.540, P< 0.001), BE (r=-0.477, P< 0.01), and Hb (r=-0.495, P< 0.01). In the multivariate logistic regression model, BE (OR=1.175, P=0.035), lactate (OR=1.213, P=0.033), and MetHb on admission (OR=1.384, P=0.034) remained associated with an increased risk of early (D7) mortality.In addition, the areas under the receiver operating characteristic (ROC) curves of MetHb that discriminates survivors and non-survivors were:0.748 (0.632～0.865) at admission. The optimal cut-off value to predict post-CPR mortality was measured as> 1.25%, with a sensitivity of 44.1% and a specificity of 93.7%.Conclusion:Our study shows a correlation between elevated MetHb levels and unfavorable prognosis in patients post cardiopulmonary resuscitation. MetHb may be a useful tool for assessment of early prognostication.