Are there different levels of conciousness? What are they?

Question

I once saw an old medical diagram relating different surgeries to the level of conciousness or unconcious needed to attain by anethesia for the patient not to be cognizant of it.

Answer 1

Anaesthesia can be dangerous. Sometimes even fatal. Therefore, it is usually a good idea to use as little of it as possible. There are a number of different effects that you might produce with anaesthesia. Some operations will require one, some a few, and some all of them. Because you want to use as little as possible, and because most operations do not require all possible effects of anaesthesia, it behooves those who use such drugs to know which to apply when.

Of the various things anaesthesia can do, the effects generally fall into just a few categories:
- preventing muscle movement
- blocking sensations of pain
- preventing the formation of memory
- producing total unconsciousness
Anaesthesia is further subdivided into how broad the effect is, whether it's local to a small area or general across the whole body.

Obviously, if you go back far enough they didn't have access to the suite of drugs we have available to us today, so the only question was dosage instead of all these other things. The first operation with ether was in 1842, so depending on how old your book is, that may be what you're looking at. Ether was largely replaced by choloform shortly thereafter, and since there were no trained anaesthesiologists at the time, lots of people died from it.

Answer 2

The "stages" of anesthesia first characterized by Guedel are still useful in judging anesthetic depth.
Stage I Amnesia/analgesia. Patients still respond to command but are analgesic (comfortable) with mildly painful stimuli. This is a commonly sought level for suturing and mild procedures on the skin and mouth. Muscle tone and airway reflexes remain mostly intact.
Stage II Delirium/excitement. This stage lasts from loss of consciousness to the start of rhythmic breathing. Uninhibited excitation may lead to serious consequences such as movement, laryngospasm, vomiting, and hypertension and tachycardia.
Stage III Surgical Anesthesia. From rhythmic breathing to complete respiratory arrest this stage progresses through four planes. 1-slight muscle relaxation ocular movement. 2-eyes are still and inspiration and expiration are separated with a slight pause. 3-our goal often for surgery. abdominal muscles relax and diaphragmatic breathing ensues. 4-irregular breathing and dilated pupils
Stage IV overdosage/apnea. Loss of most reflexes. progressive circulatory failure.

Answer 3

The three levels of consciousness according to this website (see link below) are:

1. Waking /Conscious
2. Dreaming / Unconscious
3. Deep Sleep / Subconscious