principles of anesthesia st210 concorde career college
TRANSCRIPT
Principles of Anesthesia
ST210Concorde 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• 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 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:
• 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: (continued)
• 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
• 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 EquipmentEquipment and techniques used to monitor the patient
• 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
ThermometerEsophageal 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
ElectrocardiogramElectrodes
Anesthesia Equipment Equipment and techniques used to monitor the patient
Heart
ElectrocardiogramLeads
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
• Liquids with potent evaporative vapors• CNS depression produces general anesthesia• Myocardial and respiratory depression• Decrease muscle tone
Volatile Agents
• 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
• 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
• 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)
• 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
• 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.wisc-online.com/objects/ViewObject.aspx?ID=AP2804
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
• 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• Agents
– 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
• 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
Anesthesia Circuit
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
• 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
• 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
• 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:– 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:
– 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
• Patient is awake• May be used to avoid
undesirable cardiac and respiratory side effects
• Recovery time from anesthesia is decreased
Disadvantages
• 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
• Induced Hypothermia• Induced Hypotension• Neuroleptanalgesia• Neuroleptanesthesia
Alternative (Nontraditional) Anesthesia Treatments
• Hypnoanesthesia
• Acupuncture