Anesthesia does three things:
With no anesthesia at all, the patient would scream, making the surgeon’s job impossible. However, there can arise the situation where the patient has been deliberately paralysed by the anesthetist, but not enough anaesthetic has been given to keep the patient unconscious.
Generally Anesthesia is safe, but there are some possibilities for the complications. Local anesthesia causes the lowest risk, and general anesthesia causes the highest risk. An allergic reaction to an anesthetic agent can be life threatening and can occur with any type of anesthesia. Drug allergies are unknown until the substance is ingested; so many people are unaware of them.
There are generally few adverse reactions to local anesthesia. Some patients experience nausea and vomiting. There may also be soreness at the injection site.
General anesthesia also carries the risk for serious complications. A number of more serious complications are associated with general anesthetics. These are rare: