Why are you monitored during a colonoscopy?

I presume when you say "Anastasia," you mean Anesthesia. (But, maybe you've got a Russian girl who holds your hand at your clinic; I don't know.) You ARE sedated, and you MAY be anesthetized, depending on the doctor, your physical condition, and other factors. You are monitored on an EKG machine, also your blood pressure and pulse are monitored. You will continue to be monitored until you have recovered sufficiently to leave the hospital or clinic.