General anesthesia
Overview
Modern anesthesia began to find its way as a
medical subject in the 1840's when Ether and nitrous oxide (or: dioxide
nitrogen oxide, also known as "laughing gas" - Nitrous Oxide) began
to be used in the United States of America for the purpose of anesthesia during
surgical procedures. Throughout human history, there have been many attempts to
relieve pain through the use of some plants (such as opium) or some chemicals
(such as alcohol). These methods were not sufficient to overcome the severe
pain during the complex surgeries that caused the patients great suffering.
Since the second half of the nineteenth century, until the present day, the
need for anesthesia and its use has increased and expanded. The development
achieved in the field of new methods and drugs in the field of anesthesia, in
addition to the development in the theory of contamination, in the 19th
century, constituted one of the most important foundations in modern surgery
Definition of
General
anesthesia is a combination of medications that put you in a sleep-like state
before a surgery or other medical procedure. Under general anesthesia, you
don't feel pain because you're completely unconscious. General anesthesia
usually uses a combination of intravenous drugs and inhaled gasses
(anesthetics).
General
anesthesia is more than just being asleep, though it will likely feel that way
to you. But the anesthetized brain doesn't respond to pain signals or reflexes.
An
anesthesiologist is a specially trained doctor who specializes in anesthesia.
While you're under anesthesia, the anesthesiologist monitors your body's vital
functions and manages your breathing.
In many
hospitals, an anesthesiologist and a certified registered nurse anesthetist
(CRNA) work together during your procedure.
Why it's done
Your
anesthesiologist or nurse anesthetist, along with your doctor, will recommend
the best anesthesia option for you based on the type of surgery you are having,
your overall health and your individual preferences. For certain procedures,
your team may recommend general anesthesia. These include procedures that may:
·
Take a long time
·
Result in significant
blood loss
·
Expose you to a cold
environment
·
Affect your breathing
(particularly chest or upper abdominal surgery)
Other
forms of anesthesia, such as light sedation combined with local anesthesia (for
a small area) or regional anesthesia (for a larger part of your body), may not
be appropriate for more involved procedures.
Risks
General
anesthesia is overall very safe; most people, even those with significant
health conditions, are able to undergo general anesthesia itself without
serious problems.
In
fact, your risk of complications is more closely related to the type of
procedure you're undergoing and your general physical health, rather than to
the type of anesthesia.
Older
adults, or those with serious medical problems, particularly those undergoing
more extensive procedures, may be at increased risk of postoperative confusion,
pneumonia, or even stroke and heart attack. Specific conditions that can
increase your risk of complications during surgery include:
·
Smoking
·
Seizures
·
Obstructive sleep apnea
·
Obesity
·
High blood pressure
·
Diabetes
·
Stroke
·
Other medical conditions
involving your heart, lungs or kidneys
·
Medications, such as
aspirin, that can increase bleeding
·
History of heavy alcohol
use
·
Drug allergies
·
History of adverse
reactions to anesthesia
These
risks are more generally related to the surgery itself rather than the
anesthesia.
Anesthesia awareness
Estimates
vary, but about 1 or 2 people in every 1,000 may be partially awake during
general anesthesia and experience what is called unintended intraoperative
awareness. It is even rarer to experience pain, but this can occur as well.
Because
of the muscle relaxants given before surgery, people are unable to move or
speak to let doctors know that they are awake or experiencing pain. For some
patients, this may cause long-term psychological problems, similar to
post-traumatic stress disorder.
This
phenomenon is so rare that it's difficult to make clear connections. Some factors
that may be involved include:
·
Emergency surgery
·
Cesarean delivery
·
Depression
·
Use of certain
medications
·
Heart or lung problems
·
Daily alcohol use
·
Lower anesthesia doses
than are necessary used during procedure
·
Errors by the
anesthesiologist, such as not monitoring the patient or not measuring the
amount of anesthesia in the patient's system throughout the procedure
How you prepare
General
anesthesia relaxes the muscles in your digestive tract and airway that keep
food and acid from passing from your stomach into your lungs. Always follow
your doctor's instructions about avoiding food and drink before surgery.
Fasting
is usually necessary starting about six hours before your surgery. You may be
able to drink clear fluids until a few hours prior.
Your
doctor may tell you to take some of your regular medications with a small sip
of water during your fasting time. Discuss your medications with your doctor.
You may
need to avoid some medications, such as aspirin and some other over-the-counter
blood thinners, for at least a week before your procedure. These medications
may cause complications during surgery.
Some
vitamins and herbal remedies, such as ginseng, garlic, Ginkgo biloba, St.
John's wort, kava and others, may cause complications during surgery. Discuss
the types of dietary supplements you take with your doctor before your surgery.
If you
have diabetes, talk with your doctor about any changes to your medications
during the fasting period. Usually you won't take oral diabetes medication the
morning of your surgery. If you take insulin, your doctor may recommend a
reduced dose.
If you
have sleep apnea, discuss your condition with your doctor. The anesthesiologist
or anesthetist will need to carefully monitor your breathing during and after
your surgery.
What you can expect
Before the procedure
Before
you undergo general anesthesia, your anesthesiologist will talk with you and
may ask questions about:
·
Your health history
·
Your prescription
medications, over-the-counter medications and herbal supplements
·
Allergies
·
Your past experiences
with anesthesia
This
will help your anesthesiologist choose the medications that will be the safest
for you.
During the procedure
Your
anesthesiologist usually delivers the anesthesia medications through an
intravenous line in your arm. Sometimes you may be given a gas that you breathe
from a mask. Children may prefer to go to sleep with a mask.
Once
you're asleep, the anesthesiologist may insert a tube into your mouth and down
your windpipe. The tube ensures that you get enough oxygen and protects your
lungs from blood or other fluids, such as stomach fluids. You'll be given
muscle relaxants before doctors insert the tube to relax the muscles in your
windpipe.
Your
doctor may use other options, such as a laryngeal airway mask, to help manage
your breathing during surgery.
Someone
from the anesthesia care team monitors you continuously while you sleep. He or
she will adjust your medications, breathing, temperature, fluids and blood
pressure as needed. Any issues that occur during the surgery are corrected with
additional medications, fluids and, sometimes, blood transfusions.
After the procedure
When
the surgery is complete, the anesthesiologist reverses the medications to wake
you up. You'll slowly wake either in the operating room or the recovery room.
You'll probably feel groggy and a little confused when you first wake. You may
experience common side effects such as:
·
Nausea
·
Vomiting
·
Dry mouth
·
Sore throat
·
Muscle aches
·
Itching
·
Shivering
·
Sleepiness
·
Mild hoarseness
You may also experience
other side effects after you awaken from anesthesia, such as pain. Your
anesthesia care team will ask you about your pain and other side effects. Side
effects depend on your individual condition and the type of surgery. Your
doctor may give you medications after your procedure to reduce pain and nausea.