Des was removed from our university hospital (where the inventor of Des is a Professor Emeritus), but we still have some vaporizers at the VA. The rationale was the GWP20 (global warming potential over 20 yrs, per mol) being so much higher than sevo. I have wondered, and I'd love some other opinions, whether sevo, run at the usual 2 l/min, ultimately puts more sevo molecules into the atmosphere compared to Des run at low-flow/closed-ish circuit, and whether this would offset the difference in GWP20. I mean, it's not like sevo's is zero, and if you're scavenging all that sevo out to the sky at higher flows, wouldn't this ultimately be worse than des?