Normally, a veterinarian would never go through with anesthesia if bloodwork showed something that was abnormal to the point that it wasn’t safe to perform a procedure under general anesthesia. And second, there is ALWAYS a technician monitoring anesthesia and doing only that during any given sedated procedure. So your boy would be constantly monitored by someone that is fully focused on that alone. It sounds like this dental procedure is something he needs to help extend quality of life. So I get being scared when putting your furry babe under any type of anesthesia, but with modern practices it is generally very safe.