Personally I'd get it removed. Anesthesia protocols are extremely safe these days. Ask them what their protocols are; do they give a pre-med (a mild sedative and pain reliever), then an induction, and are they then maintained on gas anesthesia. This three tiered protocol is called "balanced anesthesia" and it is extremely safe. The sedative allows the doctor to not have to give as much of an induction, and in turn they will not need to use as much gas anesthesia. Also some tranquillizers have a reversal agent. Ask questions, if you don't feel comfortable with what they tell you, go get a second opinion from a different vet. Not all clinics do things the same and have the same level of care.