General Anaesthesia


General anesthesia is, essentially, a medically induced coma, not sleep. Drugs render a patient unresponsive and unconscious. They are normally administered intravenously (IV) or inhaled. Under general anesthesia, the patient is unable to feel pain and may also have amnesia.

Side effects

There are a number of potential side effects of anesthesia.

Some individuals may experience none, others a few. None of the side effects are particularly long-lasting and tend to occur straight after the anesthesia.

Side effects of general anesthesia include:

  • temporary confusion and memory loss, although this is more common in the elderly
  • dizziness
  • difficulty passing urine
  • bruising or soreness from the IV drip
  • nausea and vomiting
  • shivering and feeling cold
  • sore throat, due to the breathing tube

However, older adults and those undergoing lengthy procedures are most at risk of negative outcomes. These outcomes can include postoperative confusion, heart attack, pneumonia and stroke. Some specific conditions increase the risk to the patient undergoing general anesthetic, such as:

  • obstructive sleep apnea, a condition where individuals stop breathing while asleep
  • seizures
  • existing heart, kidney or lung conditions
  • high blood pressure
  • alcoholism
  • smoking
  • history of reactions to anesthesia
  • medications that can increase bleeding – aspirin, for example
  • drug allergies
  • diabetes
  • obesity or overweight

Unintended intraoperative awareness

Patients that experience unintended intraoperative awareness can suffer long-term psychological problems. Most often, the awareness is short-lived and of sounds only, and occurs prior to the procedure. Because unintended intraoperative awareness is so infrequent, it is not clear exactly why it occurs.

The following are considered to be potential risk factors:

  • heart or lung problems
  • daily alcohol use
  • emergency surgery
  • cesarean section
  • anesthesiologist error
  • use of some additional medications
  • depression


There are three main types of anesthetic:

Local anesthesia is another option. It is given before minor surgeries, such as removal of a toenail. This reduces pain sensations in a small, focused areas of the body, but the person receiving the treatment remains conscious.

Regional anesthesia is another type. This numbs an entire portion of the body – the lower half, for example, during childbirth. There are two main forms of regional anesthesia: Spinal anesthetic and epidural anesthetic.

Spinal anesthetic is used for surgeries of the lower limbs and abdomen. This is injected into the lower back and numbs the lower body. Epidural anesthesia is often used to reduce the pain of childbirth and lower limb surgery. This is administered to the area around the spinal cord through a small catheter instead of a needle injection.

The main reasons for opting for general anesthetic are:

  • The procedure is likely to take a long time.
  • There is a likelihood of significant blood loss.
  • Breathing may be affected, such as during a chest operation.
  • The procedure will make the patient feel uncomfortable.
  • The patient may be young, and they may have difficulty remaining still.

The purpose of general anesthetic is to induce:

  • analgesia, or removing the natural response to pain
  • amnesia, or memory loss
  • immobility, or the removal of motor reflexes
  • unconsciousness
  • skeletal muscle relaxation