Before going under the knife for some type of surgery, anesthesia is generally the treatment recommended for the patient not to feel pain. The medicine given to the patient intravenously or inhaled would make the patient sleep and feel no pain. It does this by cutting out the nerve signals, effectively preventing the brain from experiencing or processing pain. This is administered just before the surgery.
Until very recently, little was known about how anesthesia works, but that has changed now that science is able to study the effect of the medicine on specific molecules within cells. The medicine works by altering the activity of the membranes.
What are the stages of anesthesia?
There are four basic stages in anesthesia according to Guedel’s classification:
- Analgesia Stage: introduction of anesthesia into the bloodstream leads to patient’s gradual loss of consciousness, followed by the gradual loss of awareness of pain. The patient moves to a state of amnesia.
- Delirium Stage: After slipping into unconsciousness, the patient moves to a state of delirium characterized by irregular breathing and involuntary movement of the body. The Nurse helps to adjust the moving part of the body of the patient to ensure that the patient does not injure self or the team. Some patient might also experience nausea. This is kept under control by administering sodium pentothal into the patient’s bloodstream. The patient is not left in this stage for long.
- Surgical Anesthesia: This is the third stage in anesthesia. At this stage, the involuntary body movement stops, the patient is no longer experiencing nausea. The breathing becomes normal, the muscles are no longer tense and the patient becomes fully unconscious. The nurse anesthetist evaluates the depth of the anesthesia. This is the desired state to keep the patient throughout the duration of the surgery.
- Respiratory Arrest: The fourth stage of anesthesia is experienced by some patient. It is a critical stage that may lead to loss of patient if not quickly reversed. At this stage, there is an overdose of anesthesia in the bloodstream leading to medullary suppression. The cardiovascular collapse that may follow could lead to death. At this point, the Nurse Anesthetist must take the patient back to stage three.
Once the procedure is completed, the anesthetist gradually brings the patient back to consciousness.