You likely will be given
anesthesia by an
anesthesia specialist. Final preparations before your
surgery may include:
instruments to check your breathing, oxygen
level, heart rate, blood pressure, and other body
- Positioning your body for surgery. You will be placed in
a position that allows your surgeon access to the appropriate body area and
avoids unnecessary pressure on any parts of your body.
The three main phases of anesthesia are induction, maintenance, and
The first phase of anesthesia, when you first begin receiving an
anesthetic, is called induction.
local anesthesia and many types of
regional anesthesia, induction occurs when a local
anesthetic is injected into the part of your body that needs to be
anesthetized. Local and regional anesthesia often are given with other
medicines that make you relaxed or sleepy (sedatives) or relieve pain
(analgesics). These medicines are often given through a vein (intravenously, IV) before the local anesthetic is
epidural and spinal anesthesia may require the
insertion of a needle into the space around the spinal nerves in the lower
back. You will receive an injection of local anesthetic to reduce discomfort
before the needle is inserted.
General anesthesia is often induced with
IV anesthetics, but
inhalation anesthetics also may be used.
- Because they enter directly into the
bloodstream, intravenous anesthetics usually cause unconsciousness in less than
- Inhalation anesthetics also act quickly, but you must
inhale them for a short time before they cause unconsciousness. Inhalation
anesthetics are usually given through a mask that covers your nose and mouth.
Induction with inhalation agents is mainly used for small children and adults
who do not yet have an IV catheter.
Maintenance and monitoring
The second phase of anesthesia is called maintenance. During
maintenance, the anesthesia specialist keeps a balance of medicines while
carefully watching your breathing, heart rate, blood pressure, and other
vital functions. Anesthesia is adjusted based on your responses during the
With local anesthesia and regional nerve blocks, maintenance
frequently requires additional injections of sedatives to prolong the effects
for more lengthy procedures.
For general anesthesia, after you are unconscious, anesthesia may
be maintained with an inhalation anesthetic alone, with intravenous
anesthetics, or most commonly with a combination of the two. Very often,
inhalation anesthetics are given through an
endotracheal (ET) tube or a laryngeal mask airway
(LMA), which is an airway placed at the back of your throat but not in your
windpipe like an ET tube. The airway is inserted after you become
It also is common during general anesthesia for you to be given
other medicines intravenously to maintain stable vital functions and to help
prevent or decrease pain or nausea after the procedure.
The final phase of anesthesia is called emergence. When your
procedure is completed, the anesthesia specialist will stop giving the
anesthetic. As your body clears the anesthetic medicines from your system, the
effects begin to wear off, and your body functions begin to return. How quickly
you emerge from anesthesia depends on the anesthetics and other medicines used
and on your response to the medicines.
With local and regional anesthesia, emergence occurs as the
effect of the injected anesthetic wears off and sensation returns. How long it
takes for sensation to return depends on the type of anesthetic used, how much
you were given, and the area of your body that was affected. Local anesthesia
and some regional nerve blocks may wear off within 1 to 2 hours. Emergence from
epidural or spinal blocks may take longer.
Emergence from general anesthesia begins when the intravenous or
inhalation anesthetic is stopped. It may take a short time before your body
clears the anesthetic from your system. You will be closely watched during
emergence to make sure that you are breathing well on your own; your heartbeat,
blood pressure, and other vital functions stay at normal levels; and your
muscle control has returned. If an endotracheal tube or laryngeal mask
airway was used, it will be removed as soon as you are breathing on your
In some cases, to help speed emergence,
reversal agents are used to counteract, or reverse,
the effects of certain anesthetics. These agents may help reduce the time it
takes for you to recover from anesthesia.
Emergence does not mean you will have completely recovered from
all the effects of anesthesia. Some effects may persist for many hours after
anesthesia has ended. For example, you may have some numbness or reduced
sensation in the part of your body that was anesthetized until the anesthetic
wears off completely. Even if you feel alert and normal, your judgment and
reflexes may still be affected for some time after your procedure, especially
if you continue to take medicines, such as those to control pain or nausea. If you have numbness or reduced sensation longer than expected, contact
your anesthesia specialist or doctor.