Transcript 414e45535448455349412049

ANESTHESIA PART I
Anesthesia
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Types of
Concepts
Administration & Selection
Anesthesia
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Definition: “Lack of Sensation”
Describes a process that is used to
alleviate pain and suffering during a
surgical procedure
Optimal Anesthesia
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Achieved If All Of The Following Are
Met:
Hypnosis
Anesthesia
Amnesia
Muscle Relaxation
Optimal Positioning of Patient
Homeostasis of Vital Functions
Hypnosis
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Altered state of consciousness related
to how the patient perceives his or her
environment (surgical) and procedure
(surgical)
Induce sleep
Can be light to fully unconscious
Anesthesia
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Lack of sensation
Allows for “pain-free” surgery
Ranges from topical, local, regional and
general (systemic) agents
Amnesia
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Lack of recall of surgical events
Allows for more cooperative relaxed
patient
Muscle Relaxation
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Combined with inhalation (gases)
agents to produce muscle relaxation to
total paralysis
Allows for endotracheal intubation
Facilitates exposure of tissues and
organs as muscles are in a relaxed state
Patient Positioning
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Allows for surgical site exposure/access
Allows for monitoring of the surgical
patient
Allows/provides physiological
homeostasis
Homeostasis of Vital Functions
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Maintenance of the patient’s
physiological status until surgical
intervention is complete
Most dangerous part of surgery is
anesthesia
Are inducing a state close to death
without crossing that line
Methods of Administration
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Determining the Right Anesthetic
Patient’s age, weight, and build
Emotional, psychological and physical needs
Type of operation and duration of operation
Lab and X-ray findings
Pre-existing illnesses or diseases
Medications on
Allergies
History of drug or alcohol abuse
Time since last ingested food, particularly with
emergencies
American Society of
Anesthesiologists (ASA)
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Based on the evaluation/assessment
done preoperatively, the patient is
assigned a Class # 1 through #6. This
determines what kind of risk is involved
for the patient for the surgical
procedure about to be performed.
Class 1- Patient has no
previous/current physical or mental
medical history
Class 2- Mild to moderate disease
present (controlled HTN, asthma,
controlled diabetes, mildly obese,
anemic, tobacco use) that does not
interfere with ADLs
Age less than 1 year or greater
than 70 years old
Class 3- severe disease present
(controlled angina, has had a
myocardial infarction, HTN that is not
controlled, respiratory disease that is
causing difficulties presently, greatly
obese) that interfere with ADLs
Class 4- severe disease (s) present
that are life-threatening (unstable
angina, CHF, respiratory disease that is
debilitating, liver failure, kidney failure,
myocardial infarction in progress or in
the last 24 hours)
Class 5- Has little chance of survival,
but is operated on as a last ditch effort
or at the request of family members
Class 6- Is brain dead/life support is
being provided
This is an organ harvest or
procurement
(E) Emergency Modifier- an E is added
to the Class # in cases of emergency
surgery
Goal of Anesthesia
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Patient safety
Optimal results
Anesthetic Agents
2 types:
1. General
 Focus on altering state of
consciousness, awareness and pain
perception
2. Nerve Conduction Blockade
 Focus on preventing sensory nerve impulse
transmission
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General Anesthesia
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Combined to deliver “Balanced
Anesthesia”
Inhalation agents
Intravenous agents
Less Common:
Intramuscular agents
Instillation
Components of General
Anesthesia
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Amnesia
Analgesia
Anesthesia
Muscle Relaxation
Together provide “Balanced Anesthesia”
Stages of General Anesthesia
I. Amnesia stage is lightest stage that begins with administration of
agent ends with loss of consciousness
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Good stage for MAC
II. Excitement or Delirium stage from loss of consciousness to loss of
eyelid reflex and regular breathing
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Patient movements are uninhibited
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Might see vomiting, laryngospasm, hypertension, tachycardia
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Rarely seen except in children due to drugs that are available now
to carry patients straight to stage III
III. Surgical anesthesia stage from regular breathing and loss of eyelid
reflex to cessation of breathing
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Patient unresponsive and hearing is last to go
IV. Overdose stage dilated nonreactive pupils, cessation of breathing,
hypotension can quickly lead to circulatory arrest if uncorrected
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Autonomic response is totally blocked to all stimuli
Phases of Anesthesia
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Preinduction begins with premed administered
and ends when anesthesia induction begins in OR
Induction from consciousness to unconsciousness
Maintenance surgery takes place during this
requires maintenance of physiological function by
anesthetist
Emergence as surgery is completed (start to wake
up), restoration of gag reflex, extubation
Recovery time during when patient returns to full
consciousness begins in OR and carries into stay in
PACU and beginning healing stages
Advantages verses
Disadvantages
General Anesthesia
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Inhalation Agents:
Nitrous Oxide (N²O)
Ethrane (Enflurane)
Forane (Isoflurane)
Halothane (Fluothane)
Sevoflurane (Sevoflurane)
Suprane (Desflurane)
General Anesthesia
Intravenous Agents:
1. Barbiturates
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Short acting
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Anesthesia
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Not analgesic
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Pentothal (thiopental)
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Brevital (Methohexital)
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General Anesthesia
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Benzodiazepines
Sedative and amnesiac effects
Versed (Midazolam)
Valium (Diazepam)
Ativan (Lorazepam)
General Anesthesia
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Individual Agent
Propofol (Diprivan)
Sedative/Hypnotic
Anesthetic
Amnesiac
No Analgesia
No Muscle Relaxation
General Anesthesia
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Narcotics
Maintenance of general anesthesia
Anesthetic
Sublimaze (Fentanyl)
Alfenta (Alfentanil)
Sufenta (Sufentanil)
Morphine (Morphine Sulfate)
General Anesthesia
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Muscle Relaxants (neuromuscular blocking agents)
To receive endotracheal intubation, patient must be
paralyzed or have relaxed muscles
a. Depolarizing Agents: Initiate
contractions called fasciculation
example: Succinylcholine (Anectine)
b. Nondepolarizing Agents: Prevent
contractions
examples: Curare, Pavulon, Norcuron
Nerve Conduction Blockade
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Includes:
Topical anesthesia
Local anesthesia
Regional anesthesia
Spinal (intrathecal) block
Epidural block
Caudal block
Nerve plexus block
Topical Anesthesia
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Used on mucous membranes: upper
aerodigestive tract, urethra, rectum, and skin
Cryoanesthesia reduces nerve conduction by
localized freezing with a probe connected to a
cryoprecipitate unit that uses nitrogen
Cryoanesthesia can also be performed with
ice
Lidocaine jelly
Cocaine (topical only!) Most common use:
sinus surgery
Local Anesthetics
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Immediate surgical site anesthesia
Affects small circumscribed area
Can be injected or applied topically
Lidocaine (Xylocaine)
Bupivicaine (Marcaine, Sensorcaine)
Procaine (Novocain)
Tetracaine (Pontocaine)
Mepivacaine (Carbocaine)
Hyaluronidase (Wydase) facilitator/enhancer of above
medications’ effects
Epinephrine (Adrenalin) additive to above for vasoconstrictive
properties
Local Anesthesia with MAC
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Combination of nerve conduction
blockade on topical or local level with
supplementation by the anesthesia
provider with analgesics, sedativehypnotics, or amnestics
Regional Anesthetics
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Injected along a major nerve tract
Nerve Plexus Block or Field Block
Bier Block
Spinal
Epidural
Caudal Block
Nerve Plexus Block
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Anesthetic injected into major nerve
plexus or the base of a structure
Result is anesthesia of tissue innervated
by that plexus
Used in dental and extremities
Examples: axillary, wrist, ankle, cervical
plexus (CAE)
Bier Block
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Anesthetic injected to an extremity into a vein below
the level of a tourniquet
For arm/wrist/hand surgery that will last less than 1
hour
Blood exsanguinated from extremity with an esmark,
tourniquet is inflated, anesthetic given
Tourniquet prevents anesthetic agent from circulating
above it
Tourniquet will be released slowly to allow for gradual
circulation of the agent to prevent cardiovascular or
CNS effects
Spinal Block
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Injected into CSF in the subarachnoid space
between L-3 and L-5 vertebrae
For lower body procedures
Onset 3-5 minutes
Duration 1 ½ hours
Tetracaine most common agent used
Lidocaine and Procaine others used
Epinephrine can prolong effect
Never put patient in Trendelenburg position
with spinal anesthesia
Spinal Block
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Disadvantages:
Hypotension
Nausea and vomiting
One time dose means cannot adjust
Temporary or permanent paralysis
Spinal Block
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Advantages:
Conscious patient
No respiratory irritation
Bowel contraction enhances abdominal
visibility
Muscle relaxant effects allow easy
abdominal wall retraction
Epidural Block
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Injected outside of the dura in the epidural
space that contains the fatty tissue
Injected T-4 vertebral area and down
Lower limb & perineal surgeries and
obstetrics
Thoracic surgeries will be placed for post-op
pain management
Can be single dose or a catheter can be
inserted to allow for redosing
Caudal Block
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Type of Epidural being replaced by the
Epidural Block
Only difference is placement in the
epidural space of the sacral canal
Primarily seen with mothers in labor
Summary
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Anesthesia Types
Anesthesia Administration & Selection