I was involved with my first ASA 6 case the other day, a younger male who suffered a SAH secondary to aneurysm rupture. PMH of only HTN and not compliant at all with blood pressure medication, hence the aneurysm. Just prior to surgery patient was previously on vaso but that had since been turned off more than an hour ago. Standard drips: D5 .45NS 20K at 100/hr, levothyroxine, and some mag sulfate had just finished before we picked him up in the ICU. Patient temp was 35.5.

Case starts and I'm keeping MAP 65 or >, titrating systemic BP with Iso. What was interesting was that this patient's response to Iso was VERY quick, much quicker than I would expect and even more so than Des. Both increases and decreases in agent provided an immediate response in the appropriate direction. My question is, is there something about ASA 6 patients that allows for this faster response to an agent like Iso? Or was it just a patient-specific anomaly that likely would have happened regardless of brain function and ASA classification? I've thought about this and what physiological principles might be at work here and have also researched info and found nothing. What do you all think?