Is Iso passé?

I'm 42 tomorrow. A number which Douglas Adams said was the answer to something. Not that old, I think, but old enough to be seen as an old dog with old tricks. In the teaching hospitals I am often quizzed by trainees as to why I am using thiopentone (see a previous blog fro one expanation) or isoflurane. (Not that I use them all the time!) Isoflurane used to be kept in directors' offices, only to be used for special indication. Now its going the way of halothane. The flight of time! But it's such a nice drug: no metabolites or fluoride, no compound A, no arrythmias. I revisted comparative pharmacology today when I provided anaesthesia for free flap surgery. The literature indicates that isoflurane leads to better graft survival than sevoflurane and the older agents, probably because it is a better vasodilator without causing too much cardiac depression. So there is more to volatile agent choice than the faster offset that the drug companies emphasise. One difference that is not well known is the greater bleeding with sevoflurane compared to isoflurane. Workers from the Department of Anesthesia, Kitano Hospital, Osaka, Japan have produce several papers which conclude that sevoflurane has a significant bleeding tendency effect, most likely by inhibition of platelet aggregation. So in addition to old fashioned thipentone induction for the bleeding patient (so to avoid excessive hypotension of propofol), isoflurane should be used for maintenance (so to avoid the anti-platelet action of sevoflurane). And perhaps it should remain the agent of choice for surgery with a tendency to bleeding, such as cesarean section?