Post-operatively, each patient was transferred and cared for in the intensive care unit during the entire duration of the microdialysis sampling period. Dialysate samples were obtained from 5 patients, with sampling obtained for approximately 72 h from catheter insertion. Drug administration and monitoring while in the ICU included regadenoson administration by the trial-associated cardiologist. Each patient received temozolomide 150 mg/m2 daily for 2 days and on day 2 was administered regadenoson by the cardiologist; who noted expected regadenoson side effects of transient tachycardia, elevated blood pressure and flushing. Only two patients experienced grade 1 headaches, (patient 2 and 4) which resolved within 30 min from regadenoson administration. No subjects required aminophylline as a reversal agent to regadenoson. No unanticipated adverse events were noted from temozolomide, regadenoson drug administrations, or microdialysis catheter sample collections.