Transient creatine kinase-BB activity in serum or plasma after cardiac or respiratory arrest.

We studied the transient appearance of creatine kinase (EC 2.7.3.2) isoenzyme BB, as measured by electrophoresis, in serum or plasma from 19 patients who had just experienced cardiac or respiratory arrest. Creatine kinase BB activity was greatest 0.5 to 3 h after the arrest, with values (measured at 30 degrees C) ranging from 3 to 27 U/L (mean, 7.8 U/L) in 18 patients who were successfully resuscitated. Elimination time for the isoenzyme ranged from 8 to 48 h (mean, 20 h). Elimination t1/2 varied from 4.6 to 16 h for 13 patients from whom adequate serial blood specimens were obtained. We could find no correlation between peak BB activity and eventual case outcome. We attribute this to the near impossibility of drawing a blood specimen exactly when the isoenzyme activity peaks, the instability of creatine kinase BB activity at 37 degrees C, and the fact that nine of these patients died after second or multiple arrests.