The Basics

Definitions

  • Consciousness is being clearly aware of yourself and your environment.

  • Unconsciousness is when you are completely or partially unaware of yourself and your environment, or you don't respond to sensory stimuli.

  • Conscious sedation is caused when an anesthesiologist administers depressant drugs and/or analgesics in addition to anesthesia during surgery. Consciousness is depressed and you may fall asleep, but are not unconscious.

  • Sleep is a state of reduced consciousness, depressed metabolism, and little activity of the skeletal muscles. Strong stimuli such as loud noise, bright light or shaking can arouse the sleeper.
    • Anesthesia is divided into four basic categories:
    • general anesthesia
    • regional anesthesia
    • local anesthesia
    • sedation

    Each type of anesthesia has an effect on a part of the nervous system, which results in a depression or numbing of nerve pathways. General anesthesia affects the brain cells, which causes you to lose consciousness. Regional anesthesia has an effect on a large bundle of nerves to a particular area of the body, which results in losing sensation to that area without affecting your level of consciousness. Local anesthesia causes you to lose sensation in a very specific area.

    Some of the drugs that produce general anesthesia in large doses can be used to produce sedation, or "twilight sleep" in lower doses. Sedation can be given in many ways. A common example of an anesthetic gas that is used for sedation is nitrous oxide or laughing gas.

    If you are scheduled to have surgery, you may be told not to eat anything for eight hours. It is very important that you follow whatever instructions you are given for not eating or drinking anything prior to surgery. Why? Because when you are given anesthesia, you lose the ability to protect your lungs from inhaling something you're not supposed to inhale. When you are awake, you can usually swallow saliva and food without choking because part of the swallowing mechanism involves a reflex that results in covering the opening into the lungs. When you are anesthetized, you lose that reflex. So, if you have any solids or liquids in your stomach, they could come up into your mouth and be inhaled into your lungs. The result could be very serious lung damage.