Transcript Principles of Anesthesia

Principles of Anesthesia
ST210
Concorde Career College
Objectives
• Assess the action, uses, and modes of
administration of drugs and anesthetic agents
used in the care of the surgical patient
• Recognize general terminology and
abbreviations associated with anesthesia
• Recognize the side effects and
contraindications for the use of various
anesthetic drugs
Objectives
• Interpret factors that influence anesthesia
selection for individual patients
• List the equipment used during anesthesia
administration
• Analyze how sterile technique is used in
relation to anesthesia procedures
• Compare and contrast the roles of the surgical
technologist and circulator during the
administration of anesthesia
Definitions
Anesthesia - From the Greek meaning lack of
sensation; particularly during surgical
intervention.
Definitions
• Review
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HYPNOSIS
ANESTHESIA
AMNESIA
MUSCLE RELAXATION
POSITIONING
HOMEOSTASIS
Anesthesia History Timeline
• 1500s: Coca leaves used as local
anesthetic during trephination of
the skull
• 1725: Ether was discovered by
Spanish chemist Raymundus
Lillius
• 1800s: Social use of ether - “ether
frolics”
• 1842: Crawford W. Long may
have been the first to use ether
for surgical pain control, but did
not publish his findings until 1848
Anesthesia History Timeline
• 1846: William T.G. Morton performed surgery at
Mass General Hospital in front of an audience
– First Surgical Use of Anesthetics – Click Here
– Ether Dome: Mass General Hospital
• 1905: Long Island Society Anesthetists (LISA) formed
• 1936: LISA changed name to ASA (American Society
of Anesthesiologists)
Anesthesia History Timeline
Anesthesia History Timeline
Anesthesia History Timeline
Anesthesia Administration
Two primary methods of anesthesia
administration:
1. Inhalation Agents
– Typically for General Anesthesia
2. Injectable Agents
– Typically for Nerve Conduction Blockade, or
– Regional Anesthesia
General Anesthesia
Alteration in the patient’s level of consciousness
(patient is “asleep”)
Accomplished by:
• Agent inhalation
• Agent injection
• Agent instillation
Nerve Conduction Blockade
Prevent initiation of conduction of nerve
impulses along a nerve pathway
(patient is “awake”)
Anesthesia Selection
Factors that affect selection of the type of anesthesia:
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Planned procedure and estimated duration
Patient position
Age, size, and weight of the patient
Patient status (emotional, mental, and physical)
General health of the patient (comorbid conditions)
Anesthesia Selection
Factors that affect selection of the type of anesthesia:
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Medication status
Allergy status
History of substance abuse
Emergency conditions
Preference (surgeon, anesthesia provider, patient)
ASA Risk Classification System
• Class 1 – No organic, physiological,
biochemical, or psychiatric disturbance
• Class 2 – Mild to moderate systemic disease or
disturbance (e.g., controlled hypertension or
diabetes, asthma, anemia, smoking, mild
obesity, age – less than 1 or greater than 70)
ASA Risk Classification System
• Class 3 – Severe systemic disease or disturbance
(e.g., stable angina, previous MI, poorly controlled
hypertension or diabetes, symptomatic respiratory
disease, massive obesity)
• Class 4 – Severe (life threatening) systemic disease or
disturbance (e.g., unstable angina, CHF, debilitating
respiratory disease, hepatorenal failure)
ASA Risk Classification System
Class 5 – Moribund
Class 6 – Brain dead
E – Emergency modifier
Roles of the Surgical Team
Members
(refer to the tables on pp. 257-261)
• Preoperative case management duties
• Intraoperative case management duties
• Postoperative case management duties
Anesthesia Evaluation &
Preparation
Preanesthetic evaluation and preparation
processes
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Preoperative routine
Preoperative education
Patient possessions
Preoperative procedures
Preoperative Routine
– Enema
– Nail polish and makeup
– Hygiene (shower and shave)
– Attire
– Sedation
– Call to the OR
– Family visit
– Identification, chart, consent, transportation,
transfer...
Anesthesia Equipment
Equipment and techniques used to monitor the patient
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Blood pressure
O2 Sat
Temperature
I&O
Heart
BIS
• Respiration
– SARA
• Doppler
• Peripheral Nerve
Stimulator
• ABG
Anesthesia Equipment
Equipment and techniques used to monitor the patient
Blood Pressure
Sphygmomanometer
(with stethoscope)
Anesthesia Equipment
Equipment and techniques used to monitor the patient
O2 Sat
Pulse Oximeter
Anesthesia Equipment
Equipment and techniques used to monitor the patient
Temperature
Thermometer
Esophageal Stethoscope
with temperature
probe
Anesthesia Equipment
Equipment and techniques used to monitor the patient
I&O
Intake and Output
Anesthesia Equipment
Equipment and techniques used to monitor the patient
Heart
Apical Stethoscope
Earpiece
Anesthesia Equipment
Equipment and techniques used to monitor the patient
Heart
Electrocardiogram
Electrodes
Anesthesia Equipment
Equipment and techniques used to monitor the patient
Heart
Electrocardiogram
Leads
Anesthesia Equipment
Equipment and techniques used to monitor the patient
Heart
Electrocardiogram
(ECG)
Anesthesia Equipment
Equipment and techniques used to monitor the patient
BIS Monitor
(Bispectral Index)
Anesthesia Equipment
Equipment and techniques used to monitor the patient
Respiration
SARA
(System for Anesthetic
and Respiratory
Analysis)
Anesthesia Equipment
SARA is capable of several functions including:
• Capnography
• Spirometry
• Oxygen analysis
Anesthesia Equipment
Equipment and techniques used to monitor the patient
Doppler
Anesthesia Equipment
Equipment and techniques used to monitor the patient
Peripheral Nerve
Stimulator
Anesthesia Equipment
Equipment and techniques used to monitor the patient
ABG
(Arterial Blood Gas)
Methods of Anesthetic
Administration
• General
– Balanced
– Neuroleptanalgesia
• Nerve Conduction Blockade
– Regional
– Local
– Topical
Common Anesthetic Agents
• Inhalation Agents
– Oxygen
– Nitrous oxide
– Waste gases
Common Anesthetic Agents
Oxygen
• Inhalation agent
• Not anesthetic agent
• Necessary for life
Common Anesthetic Agents
Nitrous Oxide
• Produces analgesia
and amnesia
• Produces little muscle
relaxation
• Decreases myocardial
contractility and
respiratory function
Common Anesthetic Agents
Waste gas scavenger
system
Common Anesthetic Agents
Volatile Agents
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Liquids with potent evaporative vapors
CNS depression produces general anesthesia
Myocardial and respiratory depression
Decrease muscle tone
Volatile Agents
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Halothane (Fluothane)
Enflurane (Ethrane)
Isoflurane (Forane)
Desflurane (Suprane)
Sevoflurane (Ultane)
Halothane
• Rapid acting
• Sweet odor
• Nonirritating to the
respiratory tree
• Used for induction
and maintenance
Enflurane
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Halogenated
Sweet odor
Rapid induction
Rapid recovery
Hypotension (when not
surgically stimulated)
• Potentiates
nondepolarizing NMB
Isoflurane
• Rapid induction and
recovery
• Musty smelling
• Profound respiratory
depression and
hypotension
• Markedly potentiates
NMB
• Increases ICP
Desflurane
• Halogenated
• Requires heated
vaporizer
• Pungent aroma
• Not biotransformed in
the liver
Sevoflurane
• Odorless
• No irritation to
respiratory tree
• Causes bradycardia,
hypotension,
dysrhythmias,
decreases cardiac
output
Intravenous Agents
• Permit rapid pleasant transition from consciousness
to unconsciousness
• Produce marked sedation and amnesia
• Produce hypotension and respiratory depression
• Some induction agents may also be used for
maintenance
Intravenous Agents for Induction
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Propofol (Diprivan)
Etomidate (Amidate)
Thiopental sodium (Pentothal Sodium)
Methohexital sodium (Brevital)
Propofol
• Sedative hypnotic
• Soy oil in water emulsion
(inhibits microbial growth)
• Induction or conscious
sedation
• Alkaline – irritating to the
vein
• Causes increased ICP and
hypotension
Propofol
• Formulations of intravenous anesthetic propofol emulsions
are provided which contain sufficiently low concentrations of
soybean oil to produce a stable emulsion and simultaneously
provide reduced nutrients, which inhibit microbial growth
thereby providing protection against accidental microbial
contamination during long-term IV infusions. In addition to
the inhibition of microbial growth due to a reduction of
nutrients, the formulation exhibits unanticipated additional
microbial inhibition due to an increased availability of
propofol. The low concentration of soybean oil also provides a
formulation that reduces the chances of fat overload when
administered over an extended period of time to chronically ill
patients.
Etomidate
• Non-barbiturate
hypnotic
• Produces minimal
cardiovascular system
effects
• Causes nausea,
vomiting, and adrenal
suppression
Thiopental Sodium
• Potent barbiturate
• Short acting
• Alkaline – irritating to
the vein
• Less expensive than
propofol
Methohexital Sodium
• Similar in action to
propofol and thiopental
sodium
• Ultrashort onset and
duration of action
• Ideal agent for short term
loss of consciousness
during nerve conduction
blockade
Dissociative Agents
• Interrupt the associative pathways of the brain
(patient appears awake, but is unaware of
surroundings
• Produce amnesia and profound analgesia
Dissociative Agents
Ketamine Hydrochloride (Ketalar)
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Most commonly used
IM or IV administration
Rapid induction of dissociative state
Potentiated by other agents (narcotics/barbiturates)
Increases muscle tone
Increases ICP and IOP
Opiate/Opioids
• Narcotic (Class II) analgesics
(decrease pain impulse transmission from CNS and
spinal cord receptors)
• Also produce sedation
• Produce euphoria and decrease anxiety
• High doses lead to unconsciousness and respiratory
depression
Opiate/Opioids
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Morphine sulfate
Meperidine (Demerol)
Fentanyl citrate (Sublimaze)
Sufentanil citrate (Sufenta)
Alfentanil hydrochloride (Alfenta)
Remifentanil hydrochloride (Ultiva)
Narcotic Antagonists
• Antagonize or reverse narcotic effects
• Increased level of consciousness seen in 1-2
minutes
• Naloxone hydrochloride (Narcan)
Benzodiazepines
• Sedative tranquilizers
• Reduce anxiety/apprehension
• Adjunct to general anesthesia (reduce amount
and concentration of other agents)
• Do not produce analgesia
Benzodiazepines
• Diazepam (Valium)
• Midazolam (Versed)
• Droperidol (Inapsine)
Benzodiazepine Antagonist
• Flumazenil (Mazicon)
– Reverses the sedative effects, but may not reverse
the amnesia effects
– May cause convulsions
– Rebound sedation and respiratory depression may
occur
Neuromuscular Junction
Neuromuscular Junction Review
• http://www.wisconline.com/objects/ViewObject.aspx?ID=AP28
04
Neuromuscular Junction
Neuromuscular Blockers (NMBs)
• Skeletal muscle relaxants (cause weakness –
paralysis)
• Interfere with passage of impulses from motor
nerves to skeletal muscles
• May use only one dose or re-administer throughout
procedure
Neuromuscular Blockers (NMBs)
• Used to relax the jaw for ease of endotracheal
intubation
• Muscles of respiration are affected (mechanical
ventilation required)
• Surgical site relaxation to allow for tissue retraction
Neuromuscular Blockers (NMBs)
Depolarizing Agents
• Mimic release of acetylcholine across the
neuromuscular junction
• Causes muscle contraction (fasciculation) followed by
a period of muscle fatigue
• Patient may experience postprocedure muscle ache
Neuromuscular Blockers (NMBs)
Depolarizing Agents
• Metabolized by plasma cholinesterase in the
synapse reversing the effect of the agent
• NO pharmacologic antagonist
Neuromuscular Blockers (NMBs)
Depolarizing Agents
• Succinylcholine (Anectine)
– Most commonly used
– Short acting
– Known triggering agent for MH
• Decamethonium (Syncurine)
Neuromuscular Blockers (NMBs)
Nondepolarizing Agents
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Compete for post synaptic receptors
Prevents stimulation of muscle contraction
Duration (short, intermediate, long)
Spontaneous recovery may occur
Pharmacologic antagonist available
– Edrophonium chloride (Tensilon)
– Neostigmine (Prostigmin)
Neuromuscular Blockers (NMBs)
Nondepolarizing Agents
Short Acting
• Mivacurium chloride (Mivacron)
• Vecuronium bromide (Norcuron)
• Rocuronium bromide (Zemuron)
Neuromuscular Blockers (NMBs)
Nondepolarizing Agents
Intermediate Acting
• Atracurium Besylate (Tracrium)
• Cisatracurium besylate (Nimbex)
Neuromuscular Blockers (NMBs)
Nondepolarizing Agents
Long Acting
• Tubocurarine chloride (Curare)
• Pancuronium bromide (Pavulon)
• Metocurine iodide (Metubine)
Antimuscarinic (Anticholinergic)
• Used to limit salivation and bradycardia
• Two commonly used agents
– Atropine sulfate
– Glycopyrrolate (Robinul)
NSAIDs
Nonsteroidal Anti-Inflammatory Agents
• Aid in pain management
• Main agent
– Ketoralac (Toradol) – May be given IM
intraoperatively to aid in emergence and recovery
pain management
Gastric Acid Management
• Used to alter the pH of gastric secretions and reduce
gastric acid volume
• Reduce the risk of stress ulcer
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Oral agent citric acid (Bicitra)
IV agent cimetidine (Tagamet)
IV agent ranitidine (Zantac)
Metoclopramide (Reglan) – promotes pyloric emptying
Antiemetic
• Used to prevent or alleviate nausea
• Agents
– Droperidol (Inapsine)
– Metoclopramide (Reglan)
Administration Devices
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Anesthesia Machine
Vaporizer
Anesthesia Circuit
Airway Delivery/Maintenance Devices
Hypo/Hyperthermia Devices
Administration Devices
Anesthesia Machine
Administration Devices
Anesthesia Cart
Administration Devices
Vaporizer
Administration Devices
Vaporizer
Administration Devices
Anesthesia Circuit
Administration Devices
Administration Devices
Soda lime
(calcium hydroxide)
• Chemically removes
carbon dioxide from
the breathing circuit
with the aid of
activators such as
sodium, potassium,
and barium hydroxide
Administration Devices
Airway
Delivery/Maintenance
Devices
Face Mask
Administration Devices
Airway
Delivery/Maintenance
Devices
Oxygen Mask
Administration Devices
Airway
Delivery/Maintenance
Devices
Nasal Cannula
Administration Devices
Airway
Delivery/Maintenance
Devices
Endotracheal Tube
Administration Devices
Airway
Delivery/Maintenance
Devices
Laryngoscope
Administration Devices
Positioning of
Laryngoscope
Administration Devices
Cuffed ET Tube in
Position
Administration Devices
Airway
Delivery/Maintenance
Devices
McGill Forceps
Administration Devices
Airway
Delivery/Maintenance
Devices
Oral Airway
Administration Devices
Airway
Delivery/Maintenance
Devices
Nasal Airway (Trumpet)
Administration Devices
Airway
Delivery/Maintenance
Devices
Nasal Airway (Trumpet)
Administration Devices
Airway
Delivery/Maintenance
Devices
Tracheotomy Tube
Administration Devices
Airway
Delivery/Maintenance
Devices
Tracheotomy Tube
Administration Devices
Airway
Delivery/Maintenance
Devices
Laryngeal Mask Airway
(LMA)
Administration Devices
Airway
Delivery/Maintenance
Devices
Laryngeal Mask Airway
(LMA)
Administration Devices
Ambu Bag
Administration Devices
Laryngeal Tracheal
Anesthesia (LTA) Kit
Hyper/Hypothermia Devices
• Bair Hugger
• Heating/Cooling Unit
• Heat Lamp
Hypo/Hyperthermia Devices
Bair Hugger
Hyper/Hypothermia Devices
Heating/Cooling Unit
(Blanket)
Hyper/Hypothermia Devices
Heat Lamp
Positioning for Anesthesia
• Supine
• Lateral
• Sitting
General Anesthesia
• Alteration in the patient’s level of
consciousness
• Accomplished by agent inhalation, injection,
or instillation
General Anesthesia
Goals of General Anesthesia
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Lack of sensation
Lack of movement
Muscle relaxation
Autonomic control (homeostasis)
General Anesthesia
(Four Stages – Depth)
• Stage I – Amnesia
• Stage II – Excitement
• Stage III – Surgical Intervention (4 planes)
• Stage IV – Overdose
General Anesthesia
(Four Phases)
• Induction
• Maintenance
• Emergence
• Recovery
General Anesthesia
Advantages
Disadvantages
Cricoid Pressure (Sellick’s Maneuver)
Purpose – To minimize the risk of aspiration
• Apply external pressure to the cricoid cartilage using the
thumb and first finger to form a “V”
• Pressure occludes the esophagus between the cricoid ring and
the body of the 6th vertebral body
• Must apply prior to induction and maintain until patient is
intubated
• Do NOT release pressure without permission from the
anesthesia provider
Cricoid Pressure (Sellick’s Maneuver)
Indications
• Emergency surgery shortly after eating
• NPO status cannot be verified
• GI bleeding
• Basic life support, if needed
Nerve Conduction Blockade
• Anesthetic agent is used to prevent initiation
and/or transmission of impulses along an
individual nerve pathway or at a nerve plexus
to provide anesthesia to tissues adjacent or
distal to the site.
Nerve Conduction Blockade
• Two types of agents used to accomplish nerve
conduction blockade
– Amino amide group
• Metabolized in the liver
• Excreted by the kidneys
– Amino ester group
• Biotransformed by pseudocholinesterase in the plasma
Nerve Conduction Blockade
• Amino amide group
– Lidocaine hydrochloride (Xylocaine, Lignocaine)
– Mepivacaine hydrochloride (Carbocaine)
– Bupivacaine hydrochloride (Marcaine,
Sensorcaine)
– Etidocaine hydrochloride (Duranest)
Lidocaine Hydrochloride
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Rapid onset
Moderate duration
Topical, local, regional
Available with or
without epinephrine
• Has properties that
affect the heart
Mepivacaine Hydrochloride
• Action similar to
lidocaine
• Longer action than
lidocaine
• Does not produce
significant cardiac
effects
Bupivacaine Hydrochloride
• Four times as potent
as lidocaine
• Longer onset of action
than lidocaine
• Longer duration of
effect than lidocaine
• Available with or
without epinephrine
Etidocaine Hydrochloride
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Prolonged onset
Long duration
Highly toxic
Contraindicated in
children
Nerve Conduction Blockade
• Amino ester group
– Cocaine hydrochloride
– Procaine hydrochloride (Novocain)
– Tetracaine hydrochloride (Cetacaine, Pontocaine)
Cocaine Hydrochloride
• CNS stimulant
• Controlled substance
• Topical application
only
• Produces anesthesia
and vasoconstriction
causing shrinkage of
mucous membranes
Procaine Hydrochloride
• Similar properties to
cocaine
• Less toxic than
cocaine
• SC, IM, or intrathecal
Tetracaine Hydrochloride
• Slow onset
• Prolonged duration
• Primarily used as a
topical agent
Nerve Conduction Blockade
Adjunctive Agents
• Influence onset and duration of action
• Two common agents
– Hyaluronidase (Wydase)
– Epinephrine (Adrenalin)
MAC
(Monitored Anesthesia Care)
• Provides monitoring, sedation, analgesia, and
amnesia
• Used in conjunction with nerve conduction
blockade
Nerve Conduction Blockade
Types of Nerve Conduction Blockade
• Topical
• Local
• Regional
Topical Anesthesia
• Placement of a nerve conduction blocking agent onto
a tissue layer (skin or mucous membrane)
• Anesthesia is limited to the area in contact with the
anesthetic agent
• In addition to pharmaceutical agents, cryoanesthesia
is another example of topical anesthesia
Local Anesthesia
• Placement of a nerve conduction blocking
agent onto a tissue layer
• Only the nerve or nerves that supply that
limited (localized) area are affected
Regional Anesthesia
• Nerve conduction blocking agent is injected along a
major nerve pathway blocking conduction of
impulses from all tissue (the entire region) distal to
the injection site
• Examples of regional anesthesia include:
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Bier Block
Nerve Plexus Block
Spinal
Epidural
Caudal
Bier Block
• Provides anesthesia to the distal portion of an extremity
• Used on procedures expected to last one hour or less
• Procedure is as follows:
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IV catheter is inserted
Double cuffed tourniquet is applied
Exsanguination is achieved with the use of an Esmarch bandage
Proximal cuff of tourniquet is inflated
Nerve conduction blocking agent is injected intravenously distal to the
tourniquet
– Distal cuff of tourniquet may be inflated and then the proximal cuff
may be deflated
Nerve Plexus Block
• Anesthetic solution is injected at a major
nerve plexus – usually located at the base of a
structure. For example the brachial plexus is
at the base of the arm.
Spinal (Intrathecal) Block
• Anesthetic solution is injected into the
subarachnoid space (into the CSF)
• Provides loss of sensation below the
diaphragm (patient should be able to breathe
independently)
Epidural Block
• Anesthetic solution is injected in the epidural
(outside the dura) space and is absorbed into
the CSF through the dura
• Provides loss of sensation below the
diaphragm (patient should be able to breathe
independently)
Caudal Block
• Type of epidural that is administered with the
patient in the lithotomy position.
• Agent is injected into the epidural space of the
sacral canal
• Used primarily in obstetrics
Nerve Conduction Blockade
Advantages
Disadvantages
• Patient is awake
• May be used to avoid
undesirable cardiac and
respiratory side effects
• Recovery time from
anesthesia is decreased
• Patient is awake
• Patient maintains
sensory awareness
• Patient retains ability to
move
• Positioning may be
difficult to maintain
Postanesthesia Care (Recovery)
• May occur in the PACU or the ICU
• Duration approximately 1 hour or longer, if necessary
– Patient is transferred or discharged when ready
• Patient is monitored
• Ventilatory support is provided, as needed
• Medications (e.g., analgesic, antibiotic) and fluids
(e.g., blood) are provided as needed
• Dressings are maintained
• Emotional support provided, as needed
Adjunctive Anesthesia Treatments
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Induced Hypothermia
Induced Hypotension
Neuroleptanalgesia
Neuroleptanesthesia
Alternative (Nontraditional)
Anesthesia Treatments
• Hypnoanesthesia
• Acupuncture