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Here For The Summarized Version
Introduction:
Getting Put Under
Why Does One Need
Anesthesia?
How Does Anesthesia Work?
Your Choices In Anesthesia
Why
Shouldn't I Eat Before Surgery?
Well What Does It Feel Like?
Your Anesthesiologist
Recovery From Anesthesia
Risks,
Contraindications & Complications of Anesthesia
Medication and Supplement Contraindications Regarding
Anesthesia
In Conclusion
The Least You Need To Know
Online Anesthesia Textbooks
Related Links
Introduction:
Getting "Put Under"
The transition period both going under and coming out of it can be
frightening. Most patients report a preference for Light Sleep Sedation
(IV sedation) with such analgesic narcotics or benzodiazepines
such as versed, valium, or fentanyl. However, many do not know the
idfference, nor do they care. Although Light Sleep or Conscious Sedccation
may be a wonderful choice for
relatively quick procedures -- procedures which may last 3 hours or
more are usually performed under General anesthesia. We will discuss the what,
when and why in the following sections.
Why
Does One Need Anesthesia?
One would think that it is just to stop pain. Not only is it immobility of the
patient as well as pain relief it has to do with control. Control of
your body and its defense mechanisms having to do with pain. Although you
can tell the difference between a safe elected incision and an
accidental skin trauma like a cut or a stab wound. Your body, essentially, can not.
You see, as soon as your body is cut or manipulated -- your body goes to work.
Your heart rate quickens, your body starts to try and repair the injury with a vengeance.
Well, anesthesia blocks this reaction until after the surgery
is over and keeps your body from trying to overwork itself intra-operatively
(during surgery). It also helps you forget about your surgery. Surgery can be
very traumatic for some so why suffer? Healing is better and faster when
one does not realize or remembers pain.
How
Does Anesthesia Work?
There are hypotheses and then there are facts. The facts are anesthetics are
dependent upon your body fat, weight and the strengths or concentrations
themselves regarding duration and effectiveness.
Anesthesia works in 5 ways:
- analgesic (pain reliever)
- amnesiac (loss of memory)
- promotes unconsciousness
- immobility of the patient
- elimination (or reduction) of autonomic
responses such as tachycardia (increased heartbeat), increased
breathing, hypertension, lacrimation (tear production)
autonomic nervous system
(noun)
: a part of the vertebrate nervous system that innervates smooth
and cardiac muscle and glandular tissues and governs involuntary
actions (as secretion, vasoconstriction, or peristalsis) and that consists
of the sympathetic nervous system and the parasympathetic nervous system
(Merriam-Webster Medical)
The obstruction of sensory, reflex, mental and
motor functions are needed to safely and effectively operate on a
patient. There are gaseous and liquid General anesthetics or a combination
of both agents can be used. Ascertain that your anesthesiologist is fully
qualified and fully certified or at minimum, a CRNA, to safely administer
anesthesia to you. This is very important. However for some types of
anesthesia such as versed and fentanyl whereas light sedation is used, most
surgeons believe there is no need for an actual anesthesiologist -- just an OR
tech who repeatedly says your name over and over to make sure you are under
completely as well as monitors your heart rate, blood pressure, etc.
Everyone will have a different opinion about this so be sure to research and
determine what makes you feel safe. Ideally, a doctor of
anesthesiology might be considered safest, but there are no fool proof
scenarios.
These factors are what makes it possible for
anesthesia to work. This information has been provided for you so you
won't feel overwhelmed when you discuss anesthesia with your surgeon.
Your
Choices In Anesthesia
There are a few choices that you may have for anesthesia although not
all surgeons and their practices will offer every one.
The four main categories of anesthesia are:
- local anesthesia
- regional anesthesia
- sedation
- general anesthesia
Local anesthesia:
is what you have when you receive a shot to numb the immediate treatment area.
You most commonly receive local at the dentist's office but also receive it
during a rhinoplasty or other type of surgery in addition to Sedation.
The injection is most commonly of Lidocaine
(or Xylocaine, Marcaine), epinephrine (as a vasoconstrictor to
impede bleeding in the treatment area and absorption of the Lidocaine by the
patient) and sometimes sodium bicarbonate as a buffering agent. Injections
of anesthetic are thought to block nerve impulses by decreasing the permeability
(think of microscopic openings for the impulses to leak through) of nerve
membranes to sodium ions. There are many different local anesthetics that differ
in absorption, toxicity, and duration of action. There is a possibility of Lidocaine
Toxicity which we will discuss later on.
You can also obtain the benefits of local
anesthesia by using a topical agent, or ectatic mixture of local anesthetics
(EMLA) cream which contains lidocaine and prilocaine to numb the mucus membranes
or broken skin area before a procedure such as injectable fillers,
micropigmentation or other minimally invasive procedures. The white EMLA
cream is applied and covered and then an hour must go by before undergoing the
procedure for optimum anesthetic effects. For some procedures it is more
of a hassle to anesthetize with an EMLA than to stand the pain itself.
Believe it or not, sometimes brain surgery is performed under Local anesthesia
(to the scalp) so that the patient can be awake to assist the surgeon when a
specific cut or correction is made -- testing for the existence of senses after
a certain move, etc.
However, EMLA may now be moved aside as you can
now get Ela-Max. It is cheaper, available over the counter
(OTC), faster and doesn't have to be occluded (covered and packed against the
skin). Ela-Max contains 4% Lidocaine and is making it's way to a surgeon
near you.
Regional anesthesia:
was named such because a region of the body is anesthetized without
rendering the patient unconscious. For instance, spinal anesthesia
for childbirth. Do not get this confused with an epidural as they
are very similar in effects but a different locale is injected with the
anesthetic. In an epidural the injection is in the area outside the
spinal fluid called the epidural space, the catheter is placed inside
this area so that anesthetic injections may be given or can be tube-fed if
needed for longer periods of time (from hours to weeks). With spinal
anesthesia, the local anesthetic is injected into the spinal fluid that
causes a loss of sensation to the areas below the navel. Also, in spinal
anesthesia, such narcotics as morphine and fentanyl can be infused
in addition to or partially substituting the anesthesia. But since
regional blocks in plastic surgery do not often involve spinal anesthesia
(except in some tummy tucks and lower body liposuction), we won't be covering
this. Rather will will cover regional anesthesia of the face as some
facial surgeries can be and are routinely performed while under this type of
anesthesia. Such as brow lift touch ups, lip reduction and augmentation
surgeries, chemical peels, submental liposuction and more.
You may have also heard them referred to as nerve
blocks. A nerve block is considered regional as an anesthetic is injected
into a nerve cluster and it effects sensation in all areas which this cluster
controls. There are nerve clusters all of your body; for instance, under the
jaw, in the chin, and under the eye. They sometimes feel like little holes
in the bone where your nerves are clustered, then branch out to the
different areas of the face or anywhere on the body.
Sedation: can
be gas, oral or intra-venous (IV). Most common are liquids
such as versed. This is where a sedative such as Valium may
be given ahead of time as well as a liquid formulation for the main event -- a
catheter is inserted into the vein of the hand or arm and a mixture of saline
(as a carrier), Versed and DIPRIVAN or Ketamine and a few other
additives for a nice sedative cocktail. They can customize the
concoction specifically for the patient. You are usually given Sedation
with Local as well. The Sedation helps with the anesthetic properties -- ease of
mind, loss of memory, rendering unconscious, etc. with the benefits of Local for
pain relief after you awaken, lessening of autonomic functions and epinephrine
for impediment of bleeding (which can also lead to bruising) intra-operatively.
You may have had laughing gas (or
nitrous oxide) before for dental work or OBGYN matters. It is an
inhaled gas, actually low doses of the same type of gases for General
anesthesia, that incorporate the pain relief, the amnesiac properties as well as
the other 3 that are important in invasive surgery but are not as strong so a
sedative or local or even regional may be administered as well. The good
thing about nitrous oxide is when they take the mask off, you are back to normal a few minutes later but still with no pain if you had the
local anesthetic as well -- which is more probable than not.
A few liquid anesthetics like the Versed and
Ketamine can be taken orally, but some can be inserted via the rectum with a
small lubricated tube or even inhaled like a nasal spray.
General Anesthesia: General
can be given by an inhaled gas or by a liquid. General isn't fully understood,
yet. But they speculate that it works in several ways:
- neuromuscular blocking agents which effect the
spinal cord (resulting in immobility of the patient)
- "brain-stem reticular activating
system" (resulting in
unconsciousness)
- cerebral cortex (as seen as changes in
electrical activity on an electroencephalogram)
- Inhalational agents to control autonomic
responses and provide analgesia and amnesia
(or)
- Benzodiazepines
(such as Valium, my preference) for their anti-anxiety and amnesiac effects
- obstruction of nerve conduction
- interruption of synaptic transmission
(It is more difficult to explain synapses interruption, so take my word for
it - I don't even remotely understand it yet.)
Total Intravenous Anesthesia (or TIVA) is
intravenous sedation only, it's what I prefer with Light Sleep by Versed,
etc. This is done without a TCI pump and the anesthesiologist calculates the
needed dosage by skill and experience with the weight factors and also by
careful monitoring of the patient's vitals.
Gas
Or Liquid? Inhaled, Injected Or Swallowed?
Anesthesia in a gaseous state is
inhaled into the lungs; the blood that travels to the lungs for oxygenation is
then saturated by the oxygen and anesthetic gas absorbed by your aveoli
(the little spongy things in your lungs that grab oxygen out of the air)
which is then carried to the central nervous system (CSN). The effects of the
anesthesia and the rate at which they affect the patient are dependent upon
these factors:
- gas concentration
- rate of gas flow from the anesthesia machine
- rate/depth of breathing (that's why they say breathe deeply)
- amount of blood the patient's heart pumps each
minute
- solubility of the gas in the patient's blood
(some gases are more soluble than others)
Some inhalants are:
- Enflurane
- Halothane
- Isoflurane
- Sevoflurane
- Desflurane
Once the anesthesiologist turns off the
anesthetic gas and only delivers pure oxygen; or alternatively removes the mask
entirely (as in gaseous state Twilight, Laughing Gas), the blood
stream returns the gases to the lungs where it is then eliminated by exhalation.
However, the more soluble the gas is in blood, the longer it will take to
purge from the body. Nitrous oxide and desflurane are the shortest in
duration of the available anesthetic gases and soon after the gas concentration
is turned off -- viola! you wake up! Halothane or sevoflurane are stronger and work rather fast but they also take longer to expel
from the body. Usually these two are utilized first to render the patient
unconscious then the anesthesiologist changes over to the desflurane.
Regardless you will more than likely require a
urinary catheter to catch any accidental urinating. They usually
insert the catheter after you are already under. I had mine inserted without anything,
straight insertion for a kidney infection. You, thankfully, will be oblivious
of the whole event.
Anesthesia in a liquid,
injectable state is
administered by injection directly into the bloodstream, usually through an
intravenous catheter (IV). Some of these anesthetics include:
barbiturates
such as:
- Propofol: (DIPRIVAN®
Injectable Emulsion is one name brand -- which is what I prefer with Versed)
"Widely used anaesthetic induction agent with slightly slower onset
than thiopentone, a greater tendency to drop blood pressure. The rapid,
pleasant offset makes it suitable for monitored sedation, maintenance of
anaesthesia, and patient sedation in ICU. Pain on injection is probably pH
related and can be ameliorated by addition of plain lignocaine (2-5ml of 1%
to 20ml propofol works fine. New target controlled infusion (TCI) technique
makes continuous administration easier" (Virtual Anesthesia Textbook)
*please read
below!
- Ketamine:
"An intravenous NMDA-receptor antagonist anesthetic agent with
analgesic, intoxicating and dissociative hallucinatory properties.
Associated catecholamine output which masks cardiac depression. Potent
analgesic properties, mild respiratory depresion and some maintenance of
muscle tone. Can be used as a total intravenous anesthetic, particularly
useful for trauma or field situations. Recreationally abused (referred to as
"vitamin K") for intoxicating and hallucinatory effects. These
same effects are undesirable after anesthesia. Some interest in use of low
doses with general anesthesia to inhibit NMDA-receptor associated nocioceptive
'wind-up'. Limited cerebral protection." (Virtual Anesthesia
Textbook)
- Etomidate:
"An induction agent presented in propylene
glycol with less cardiovascular depression than thiopentone. Causes pain on
injection, occasional involutary movements, suppresses cortisol production.
Depresses cerebral metabolism but conflicting evidence for cerebral
protection. (Virtual Anesthesia Textbook)
- Pentothal (sodium
thiopental, thiopentone, aka sodium Pentothal): "...Main
advantage of thiopentone is rapid onset and lesser tendency than propofol to
drop blood pressure". (Virtual Anesthesia Textbook) This was
once very popular but is losing to Propofol.
Eventually there will be "Target Controlled
Infusion (TCI) machines in which a microprocessor-controlled syringe pump
automatically and variably controls the rate of infusion of a drug to attain a
user defined target level in an effect site in the patient (usually blood).
This
greatly simplifies maintenance of a steady blood level. At present commercial
TCI systems are only available for propofol." http://www.diprivan.com
analgesic narcotics (or opioids)
such as:
- Alfentanyl
- Anileridine
- Buprenorphine
- Butorphanol
- Codeine
- Dextromoramide
- Diamorphine
- fentanyl (most common)
- Hydrocodone
- Hydromorphone (rarely used! this is a
synthetic heroin, aka Dilaudid)
- Levorphanol
- Meperidine/Pethidine
- Methadone
- morphine
- Nalbuphine
- Nalmefene
- Naloxone
- Naltrexone
- Oxycodone
- Pentazocine
- Propoxyphene, Dextropropoxyphene
- Sufentanil
- Tramadol (weak opiod action but prevents
noradrenaline and serotonin reuptake (which is similar to a number of
antidepressant agents)
benzodiazepines
like:
- Valium
- Diazapam (which is a
generic version of valium)
- Versed is also considered in
this category
Flumazenil:
(used for reversal of anesthesia/reversal of conscious sedation) "Flumazenil
is a specific benzodiazepine antagonist which may be used to promptly reverse or
attenuate benzodiazepine-induced sedation or anesthesia, usually postoperatively
or in the intensive care unit. Flumazenil is also useful in the management of
the patient presenting a suspected benzodiazepine overdose, has had anecdotal
success in the treatment of hepatic encephalopathy, and can be used for
intra-operative "wake-up" testing (e.g., to test for neurological
intactness during back surgery)...Flumazenil does not antagonize the CNS
effects of opioids, ethanol, or, propofol" (D. John Doyle MD PhD FRCPC
Department of Anaesthesia, The Toronto Hospital)
Just like gases, the effects and
duration depend on a few factors such as the amount injected, the weight of the
patient, the fat-solubility of the drug and the fat percentage of the patient's
body as well as the patient's body and how it reacts to drugs. Pentothal (sodium
thiopental) is fat soluble and its effects are felt soon after injection.
Used in small doses most of these
can be used for Light Sleep Sedation.
Why
Shouldn't I Eat Before Surgery?
You are often told "don't eat past midnight
the night before your surgery" but perhaps only a few sips of water. To
better explain this to you, this is best said by the American Society of
Anesthesiologists Guidelines on Sedation and analgesia by Non-Anesthesiologists
Example of Fasting Protocol for
Sedation and Analgesia for Elective Procedures:
Gastric emptying may be influenced by many
factors, including anxiety, pain, abnormal autonomic function (e.g.,
diabetes), pregnancy, and mechanical obstruction. Therefore, the suggestions
listed do not guarantee that complete gastric emptying has occurred. Unless
contraindicated, pediatric patients should be offered clear liquids until 2 to
3
hours before sedation to minimize the risk of dehydration.
| age |
Solids and Nonclear Liquids* |
Clear Liquids |
| Adults |
6 to 8 h or none after midnight1 |
2 to 3 h |
| Children older than 36 months |
6 to 8 h |
2 to 3 h |
| Children aged 6 to 36 months |
6 h |
2 to 3 h |
| Children younger than 6 months |
4 to 6 h |
2 h |
* This includes milk,
formula, and breast milk (high fat content may delay gastric emptying).
1 There are no data to establish whether a 68 h fast is
equivalent to an overnight fast before sedation/analgesia. American Society
of Anesthesiologists Guidelines on Sedation and analgesia by
Non-Anesthesiologists, source: www.GasNet.org
Well,
What Does It Feel Like?
If you had been given an oral
sedative or valium prior you usually could care less what they are sticking in
you. Regardless if you have IV or gas they will more than likely insert an
IV for a saline drip to keep you hydrated and have a vascular doorway should the need arise. If you haven't been given a
sedative, it is more stressful for some patients. Having an IV inserted feels
sort of like blood being drawn, but for a shorter period of time. It's the
initial placement of the IV catheter that may sting a bit. After the
needle is injected into the vein it is pulled out and a little plastic tube is
left in your vein. This is called a catheter, which is taped
to your skin so it is not knocked out and is ready to be used as a sort of
entryway for anything they deem suitable for your body. This is usually
done before you get into the actual O.R. (by a nurse) and you have a saline bag
hooked up to you. The medications will be given with a drip system with
this saline. As I said, the saline will keep you hydrated both during and
post-operatively.
Some people get it in the
crook of the elbow, some the hand. I dislike the ones in the hand as it's
a nasty place for a bruise to be, at least with the arm you can hide it -- it
all depends upon your veins though. So if your veins are not very
prominent this can be a problem. Some patients even have to be
catheterized in the neck. You
are then brought to the O.R. if you aren't on the table yet.
If you have
chosen an IV Liquid Sedative,
they will insert a hypodermic into your tube that you are attached to or more
than likely they will attach a bag of anesthetic with a drip system to add a few
drops every few seconds or so. When they spring open the stopper and it
starts heading towards your body. The the effects of the anesthesia are
felt soon after injection or opening the stopper, a few seconds in fact. It
feels like heat going into you veins then creeping up your arm; then
it jumps from your shoulder to a metallic-like taste under your
tongue and then you are blissfully anesthetized. I have had several forms
of this and actually prefer it.
If you have
chosen Gaseous-state anesthesia (Twilight, Gaseous General) All
this entails is breathing through a mask. However this depends upon what
type. The newer intubation (LMA) is a lot like the older intubation for
General but there is a shorter tube and a little balloon the size of your two
thumbs holds your tongue out of the way so it does not obstruct your breathing.
With the older intubation you have the pleasure of having a tube down your
throat but you don't usually remember it going in. You may wake up with a
raw throat. You may wake up with a sore, dry throat regardless because canned or cylinder air (scubadiving tanks as well) is d-r-y.
There is no moisture in these tanks. It is your turbinate structure
(three little fleshy flaps in your sinuses) inside your nasal structure that
mostly warms and humidifies the air which you breathe. When you have to
humidify your air, your body needs more moisture. The saline drip will
assist in this as well.
This is also why
they Also be advised that if you have bronchospasm, asthma or other disorders
such as this, intubation is contraindicated. Please make sure you read the
risks
associated with Anesthesia, below.
Then again, Twilight
or Laughing Gas (basically a weak form of General) can be given via a mask as
well, with no intubation. I have had this as well and find it to be really
mild and fast acting. The good thing about this is that as soon as they
remove the mask you start waking up or coming to.
Regardless of the type, you
basically are told to count down from 100, and see how far you can make it --
usually 97 or 96. After the gas hits the aveoli in your lungs, your
blood is saturated by the anesthesia gases where they are carried to your
central nervous system (CNS) where you are in all actuality, knocked out.
Your
Anesthesiologist
If you are going under General deep sedation, it is
best to choose a surgeon who will have a separate anesthesiologist -- this is
important. The anesthesiologist basically must know for your weight and
body fat percentage what will work best for you and in what amounts plus they
monitor your heart rate, breathing rate, your blood pressure, etc. and stand
there and say your name over and over so that if you answer or your vitals
change during the course of the surgery, or even if you stir, they know you
aren't getting enough anesthesia.
If you are going under light sleep
(IV or Gas) a separate anesthesiologist may not be present in some O.R'.s.
Some use CRNA's, in others the surgeon may be in charge of it. The amount
of anesthetic is determined per your individual body weight with anesthetic to
body-ounce formulations and fed via a drip system mixed with your IV saline.
Personal tolerances are also taken into account. However, any reactions by
the body while under anesthesia should be monitored closely by a highly
qualified individual.
To become an anesthesiologist, a
person must complete:
Recovery
From Anesthesia
This is very important. Many things can go
wrong during initial recovery. The shivering and feeling cold is the least of
your worries. Please read the below information and discuss the regarding your
surgeon's anesthesia protocol.
- "Patients must be monitored during
recovery to ensure that any adverse events are rapidly recognized and
treated.
- Vital signs should be recorded at regular
intervals and pulse oximetry should be continued until the patient is no
longer at risk of hypoxemia.
- Monitoring should include observation by a
person trained in recognition of post-procedure/post-sedation complications.
- Appropriate discharge criteria should be met
prior to discharge.
Example
of Recovery and Discharge Criteria after Sedation and Analgesia:
Each patient care facility in which sedation/analgesia is
administered should develop recovery and discharge criteria that are
suitable for its specific patients and procedures. Some of the basic
principles that might be incorporated in these criteria are
enumerated.
General
Principles
1. All patients receiving
sedation/analgesia should be monitored until appropriate discharge
criteria are satisfied. The duration of monitoring must be
individualized depending on the level of sedation achieved, overall
condition of the patient, and nature of the intervention for which
sedation/analgesia was administered.
2. The recovery are
should be equipped with with appropriate monitoring and
resuscitation equipment.
3. A nurse or other
trained individual should be in attendance until discharge criteria
are fulfilled. An individual capable of establishing a patient
airway and providing positive pressure ventilation should be
immediately available.
4. Level of
consciousness and vital signs (including frequency and depth of
respiration in the absence of stimulation) should be recorded at
regular intervals during recovery. The responsible practitioner
should be notified if vital signs fall outside of the limits
previously established for each patient.
Guidelines for
Discharge
1. Patients should be
alert and oriented; infants and patients whose mental status was
initially abnormal should have returned to their baseline.
Practitioners must be aware that pediatric patients are at risk for
airway obstruction should the head fall forward while the child is
secured in a car seat.
2. Vital signs should
be stable and within acceptable limits.
3. Sufficient time
(up to 2 h) should have elapsed after last administration of
reversal agents (naloxone, flumazeil) to ensure that patients do not
become resedated after reversal effects have abated.
4. Outpatients should
be discharged in the presence of a responsible adult who will
accompany them home and be able to report any post-procedure
complications.
5. Outpatients should
be provided with written instructions regarding post-procedure diet,
medications, and activities, and a phone number to use in case of
emergency."
|
Recovery Care - Adapted from the American
Society of Anesthesiologists Guidelines on Sedation and analgesia by
Non-Anesthesiologists, source: www.GasNet.org
Risks,
Contraindications & Complications of Anesthesia
Causes of anesthesia-related death are
usually linked to the respiratory system. These include insufficient intubation
or proper ventilation which results in hypoxia:
hypoxia
hyp*ox*ia (noun)
[New Latin] First appeared 1941
: a deficiency of oxygen reaching the tissues of the body
-- hyp*ox*ic (adjective)
(Meriam-Webster)
But this was usually
because the older monitors were not very good. Medical Science has progressed
very much in that respect.
Complications are
mostly related to General Gaseous-state anesthesia and may include:
-
laryngospasm:
la*ryn*go*spasm (noun) : spasmodic closure of
the larynx
-
bronchospasm: bron*cho*spasm
(noun) : constriction of the air passages of the lung (as in asthma) by
spasmodic contraction of the bronchial muscles
-
aspiration:
as*pi*ra*tion (noun) 3 : the
taking of foreign matter into the lungs with the respiratory current
-
intubation injury: The
teeth, lips, pharynx, esophagus, larynx and trachea may be injured by
the tube which is placed down your throat.
-
pulmonary
edema: pul*mon*ary
e*dem*a (noun) : abnormal accumulation of fluid in the lungs
-
respiratory
arrest: (noun)
Cessation of breathing. the condition of being stopped
Cardiovascular
complications:
-
myocardial
ischemia/infarction,: of
or relating to the myocardium: myo*car*di*um plural -dia (noun): the
middle muscular layer of the heart wall
-
myocardial
ischemia (noun) : localized tissue anemia due to
obstruction of the inflow of arterial blood (as by the narrowing of
arteries by spasm or disease)
-
myocardial
infarction (noun) : infarction of the myocardium that
results typically from coronary occlusion
-
cardiac
failure: *see
heart failure: (noun) 1 : a condition in which the heart is unable to pump
blood at an adequate rate or in adequate volume
-
cardiac
arrest: (noun)
: temporary or permanent cessation of the heartbeat which may be secondary
to an underlying respiratory problem.
-
emboli:
em*bo*lus (plural -li) (noun) : an abnormal
particle (as an air bubble) circulating in the blood
-
possible
causes:
-
clots
-
air
bubbles
-
orthopedic
stimuli
-
hypotension:
hy*po*ten*sion (noun) 1 : abnormally low
pressure of the blood -- called also low blood pressure...
-
possible causes:
-
hypovolemia:
(noun) : decrease in the volume of the
circulating blood
-
massive
hemorrhage: massive bleeding
-
anaphylaxis:
(noun) 1 : hypersensitivity (as to foreign proteins or drugs)
resulting from sensitization following prior contact with the
causative agent. Also affects the pulmonary system (lungs)
-
drug
overdose
-
malignant
hyperthermia: (noun) : a rare inherited condition characterized by a
rapid, extreme, and often fatal rise in body temperature following the
administration of general anesthesia
-
machine
malfunction
-
liver or
kidney injury
-
stroke:
(noun) : sudden diminution or loss of
consciousness, sensation, and voluntary motion caused by rupture or
obstruction (as by a clot) of an artery of the brain
- ventricular tachycardia
(rapid heartbeat of 100-200 bpm)
- possible causes:
- hypoxia:
(noun) : a deficiency of oxygen
reaching the tissues of the body
- Increased CO2:
increased carbon dioxide
- Decreased K+
(vitamin K): (noun) 1 :
either of two naturally occurring fat-soluble vitamins that are
essential for the clotting of blood because of their role in the
production of prothrombin in the liver and that are used in
preventing and treating hypoprothrombinemia and hemorrhage:
- Digitalis toxicity
- Acid-base
imbalance (see Acidosis): (noun)
: a condition of decreased alkalinity of the blood and tissues
marked by sickly sweet breath, headache, nausea and vomiting, and
visual disturbances and usu. a result of excessive acid production
- electromechanical
dissociation (EMD) ("Clinically, a description of EMD covers
a spectrum of bradycardic (relatively slow heart action whether
physiological or pathological), to tachycardic (relatively rapid
heart action whether physiological (as after exercise) or pathological),
arrhythmias associated with pulselessness (excluding V-Tach or V-Fib).
*According to new AHA guidelines, EMD is now known as PEA (Pulseless
Electrical Activity" J Bergsbaken, University of Wisconsin).
- possible causes:
- Hypovolemia
- Hypoxia:
(noun) : a deficiency of oxygen
reaching the tissues of the body
- Cardiac
tamponade: (noun) :
mechanical compression of the heart by large amounts of fluid or
blood within the pericardial space that limits the normal range of
motion and function of the heart
- Tension
pneumothorax: (noun):
pneumothorax resulting from a wound in the chest wall which acts as
a valve that permits air to enter the pleural cavity but prevents
its escape
- Pulmonary embolus: a
clot that reaches and affects the lungs (plural: pulmonary emboli)
- Acidosis:
(noun) : a condition of decreased
alkalinity of the blood and tissues marked by sickly sweet breath,
headache, nausea and vomiting, and visual disturbances and usu. a
result of excessive acid production
- Hyperkalemia:
(noun) : the presence of an abnormally
high concentration of potassium in the blood -- called also hyperpotassemia
- Hypothermia: (noun) :
subnormal temperature of the body. *some surgeons automatically wrap
you in thermal or thermal-compression blankets to keep your blood
circulating well and your body warm)
Lidocaine Toxicity:
Lidocaine toxicity is something that can occur with
way too many injections of Lidocaine. A common procedure requiring vast amounts
of Lidocaine is Tumescent and Super-Wet Technique Liposuction.
"Maximum dose of plain lidocaine is 5mg/kg
(7mg/kg max dose for lidocaine with epinephrine). So for a 30-kg patient
the maximum is 150 mg total. A concentration of 1% means 1 gm lidocaine
per 100cc which equals 10mg/cc. Total volume which can be injected is
therefore: 15cc.
Lidocaine freely crosses the blood-brain
barrier. Early symptoms are CNS-related including headache, tinnitus,
restlessness, facial twitching, lightheadedness, metallic taste, numbness of
the lips and tongue. At higher dose levels, one may see: seizures, loss
of consciousness, apnea, and CV collapse. CV manifestations are rarer;
these are related to direct myocardial depression through depression of
vascular smooth muscle and conducting system. At very high doses, one
will see: hypotension, labile heart rate, and v-fib arrest.
Treatment for seizures: hyperventilate with
100% O2, diazepam (thiopental if symptoms persist). Treat low
blood pressure with fluids, trendelenberg, and pressors if required.
Arrhythmia may be refractory (inadvertant IV marcaine) and require prolonged
rescuscitation.
Mechanism of local anesthetics is by blocking
nerve conduction. Anesthetic diffuses passively through cell membrane,
becomes charged, blocks Na+ channel, and prevents action
potential." Yale Medical University Core Curriculum
Major Organ Systems
"- Pre-existing cardiac or pulmonary
disease may require reduced dosage because sedative and analgesic medications
tend to cause cardiovascular and respiratory depression.
- Hepatic and renal abnormalities may impair
drug metabolism and excretion resulting in longer duration of drug
action." Adapted from the American Society of Anesthesiologists
Guidelines on Sedation and analgesia by Non-Anesthesiologists, source: www.GasNet.org
Smoking Tobacco & Illegal
Substances
"- Smoking increases risk of airway
irritability, bronchospasm, or cough during sedation. "Adapted
from the American Society of Anesthesiologists
Guidelines on Sedation and analgesia by Non-Anesthesiologists, source: www.GasNet.org
Physical Disorders or
Attributes
"- Previous problems with anesthesia or
sedation
- Stridor, snoring, or sleep apnea
- Dysmorphic facial features (e.g. Pierre-Robin
syndrome, trisomy 21)
- Advanced rheumatoid arthritis
- Habitus (extreme obesity)
- Small opening (<3 cm in an
adult); edentulous [toothless], protruding incisors; loose or capped teeth;
high arched palate; macroglossia; [enlarged tongue] tonsillar
hypertrophy [enlarged tonsils]; nonvisible uvula [: the pendent fleshy
lobe in the middle of the posterior border of the soft palate; or in English:
the little thing that hangs in the back of your mouth]
- Micrognathia
[: abnormal smallness of one or both jaw], retrognathism
[: a condition characterized by recession of one or both
of the jaws], trismus
[: spasm of the muscles of mastication
(chewing) resulting from any of various abnormal conditions or diseases (as
tetanus) ], significant malocclusion
[: improper occlusion (bringing together); esp :
abnormality in the coming together of teeth]"
Adapted from the American Society of
Anesthesiologists Guidelines on Sedation and analgesia by
Non-Anesthesiologists, source: www.GasNet.org
Medication
and Supplement Contraindications Regarding Anesthesia
There are some medications and
supplements that you simply should not be consuming before and after going under
anesthesia, although this is a partial list PLEASE talk this over with your
surgeon!!!
- Ginseng may cause rapid
heartbeat/and or high blood pressure in some individuals.
- St. John's Wort,
Yohimbe, ("The
natural Viagra®")
and Licorice root
have a mild monoamine oxidase (MAO)
inhibitory effect and may intensify the effects of anesthesia. (*note
some well known and popular anti-depressants are MAO inhibitors, disclose
any and all medications you are taking - your life may depend on it!)
- Melatonin decreases the
amount of anesthesia needed for surgery.
- Echinacea may
have a severe impact on the liver when general anesthesia is used. Please
advise your surgeon of all medications and supplements and alert him to the
possible effects of herbal supplements and remedies, he may not be aware of
the contraindications.
Special
Medication Alerts
If you are on
Anti-depressants, please advise your doctor. Some monoamine oxidase (MAO)
inhibitors (also known as MAOI) intensify the effects of the anesthesia -
especially General. This could be quite dangerous in the operating room if your
doctor is unaware of your medication usage. If you advise your doctor he or she
can make adjustments for your anesthesia or at least will watch for the slightest
decrease in heart or breathing rate.
These medications
may include: Isocarboxazid, Marplan, phenelzine (Nardil, Nardelzine)
tranylcypromine (Parnate, Sicoton), Deprenyl, selegiline hydrochloride, They are
used for the treatment of depression, obsessive-compulsive disorder, eating
disorders, essential hypertension (pargyline), chronic pain syndromes, and
migraine headaches. They work by inhibiting nerve transmissions in brain that
may cause depression. Tranylcypromine and phenelzine account for over 90% of all
MAO inhibitors currently prescribed.
It is reported that
drug interactions can occur even weeks after discontinued use of an MAOI.
Therefore, in patients undergoing General anesthesia, cessation of usage is
normally instructed several weeks prior to surgery to avoid possible
cardiovascular effects. Although, I know of several patients who never were
instructed to cease their medications and were perfectly fine.
"Anesthetic Requirements: Anesthetic requirements are increased,
reflecting accumulation of norepinephrine in the CNS." Ref: Stoelting,
R.K, Pharmacology & Physiology in Anesthetic Practice, pp. 378-381.
In
Conclusion
The above information is not meant to scare you but rather to inform you so that
you are able to make a well-educated decision regarding your anesthesia choice.
Remember, thousands of people undergo anesthesia safely every day. Please don't
let anesthesia be the straw that broke the camel's back, just know that these
complications are possible.
The
Least You Need To Know
-
As soon as your
body is cut or manipulated, your body goes to work. Your heart rate
quickens, your body starts to try and repair the injury with a vengeance.
Well, anesthesia blocks this reaction until after the surgery is over
and keeps your body from trying to overwork itself intra-operatively (during
surgery).
-
Anesthesia
also helps you forget about your surgery. Surgery can be very traumatic for
some so why suffer, right? Healing is better and faster when one does not
realize or remembers pain.
-
Anesthesia works
in 5 ways:
- analgesic
(pain reliever)
- amnesiac
(loss of memory)
- promotes
unconsciousness
- immobility of the
patient
- elimination (or
reduction) of autonomic responses such as tachycardia
(increased heartbeat), increased breathing, hypertension, lacrimation
(tear production)
-
The obstruction of sensory,
reflex, mental and motor functions are needed to safely and effectively
operate on a patient.
-
There are a few choices that you
may have for anesthesia although not all surgeons and their practices will
offer every one.
-
The four main categories of anesthesia are:
- local anesthesia
- regional anesthesia
- sedation
- general anesthesia
-
General
Anesthesia can be given by an inhaled gas or by a liquid.
-
Liquid Sedation
can be given by injection or some even my oral medication.
-
Choose a certified
Anesthesiologist, especially when going under General. This may cost more
to have a separate anesthesiologist but it is worth your life.
-
To become an anesthesiologist, a
person must complete:
-
There are some medications and
supplements that you simply should not be consuming before and after going
under anesthesia, although the above list may be a
partial list PLEASE talk this over with your surgeon.
-
KNOW
THE RISKS
-
Do realize that
thousands of patients safely go under every day and that these
risks, although possible, are rare.
Online
Anesthesia Textbooks
Anesthesiology
Textbook - Yale
GASNet - An Online Anesthesia
Network
Virtual
Anaesthesia Textbook Home Page
Related
Links (all
links leading out of the site launch a new window)
American
Board of Anesthesiology
American
Association of Nurse Anesthetists
Anaesthesia On-Line
- UK
Anesthesia
Patient Safety
General
Anesthesia in Plastic Surgery - Emedicine
Anesthesia:
Local with Sedation - Emedicine
References:
Yale Medical Core
Curriculum - Yale Medical University
Ovassapian A, Schrader SG. Fiberoptic-aided bronchial intubation. Sem
Anesth 6:133-142, 1987.
Stoelting, R.K, Pharmacology & Physiology in Anesthetic Practice, pp.
378-381.
Merriam-Webster Medical Dictionary
J Bergsbaken, University of Wisconsin, Pulseless
Electrical Activity"
Virtual Anesthesia Textbook
D. John Doyle MD PhD FRCPC Department of Anaesthesia,
The Toronto Hospital
Diagrams, Henry Gray - Anatomy of the Human Body
American Academy of Pediatrics, The Transfer of Drugs and Other Chemicals
Into Human Milk (RE9403) Pediatrics - Volume 93, Number 1 January, 1994, p
137-150
*drug
interactions: "Induction dose requirements of DIPRIVAN may be
reduced in patients with IM or IV premedication, particularly with narcotics (eg,
morphine, meperidine, and fentanyl, etc) and combinations of opioids and
sedatives (eg, benzodiazepines, barbiturates, chloral hydrate, droperidol, etc).
These agents may increase the anesthetic effect of DIPRIVAN Injectable Emulsion
and may also result in more pronounced decreases in systolic, diastolic, and
mean arterial pressures and cardiac output. During maintenance, the rate of
DIPRIVAN administration should be adjusted to the desired level of anesthesia
and may be reduced in the presence of supplemental analgesic agents (eg, nitrous
oxide or opioids). The concurrent administration of potent inhalational agents (eg,
isoflurane, enflurane, and halothane) during maintenance with DIPRIVAN has not
been extensively evaluated. These inhalational agents can also be expected to
increase the anesthetic and cardiorespiratory effects of DIPRIVAN. DIPRIVAN does
not cause a clinically significant change in onset, intensity, or duration of
action of the commonly used neuromuscular blocking agents (eg, succinylcholine
and nondepolarizing muscle relaxants). No significant adverse interactions with
commonly used premedications or drugs used during anesthesia (including a range
of muscle relaxants, inhalational agents, analgesic agents, and local anesthetic
agents) have been observed when used in recommended dosages". http://www.diprivan.com
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