Thrombin-antithrombin appearance in out-of-hospital cardiac arrest

Objective. Intravascular thrombosis induced during out-of-hospital cardiac arrest (OOHCA) may contribute to the pathophysiology of cardiac arrest and complicate resuscitation. We characterized the prevalence of thrombogenesis during OOHCA by measuring plasma levels of thrombin-antithrombin complexes (TAT). Methods. An observational cohort study of medical OOHCA patients in an urban emergency medical services (EMS) system. Subjects were patients >= 18 years suffering medical OOHCA. Citrated blood samples were drawn in the prehospital setting either directly from venous blood or during the placement of a central venous catheter and frozen (-70 degrees C). The EMS physician documented age, gender, time intervals, return of spontaneous circulation (ROSC), therapies administered and time of blood draw. TAT assays were performed by commercial ELISA. Results. Eighty-eight patients (58% male) aged 63.4 +/- 15.9 years were enrolled in the study. Median [interquartile range IQR] TAT values in 80 samples (8 samples were grossly clotted and excluded) were 159.2 [38.2, 522.8] and ranged from 0.79 to 1,343.9. Patients transported to the hospital had lower TAT levels than those pronounced in the field (p = 0.014). Of four EMS-witnessed arrests, three had return of pulses with TAT values of 0.79, 6.8, and 17.9. The fourth had a TAT over 525 after a long unsuccessful resuscitation. For subjects with TAT below 50 (n = 23), all but three were witnessed arrests or received bystander CPR. Conclusions. Except for a single case witnessed by EMS and immediately defibrillated into a perfusing rhythm, all cases of OOHCA exhibited increased thrombotic state. Intravascular thrombosis may represent a global barrier to resuscitation and ultimately, end-organ perfusion.