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 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: Inhalation Agents Typically for General Anesthesia Injectable Agents Typically for Nerve Conduction Blockade, or Regional Anesthesia

Alteration in the patient’s level of consciousness 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”)

Factors that affect selection of the type of anesthesia: 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)

Factors that affect selection of the type of anesthesia: (continued) 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 Equipment Equipment 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

Esophageal Stethoscope with temperature probe 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

Apical Stethoscope Earpiece 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)

(System for Anesthetic and Respiratory Analysis) 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

Peripheral Nerve Stimulator 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

Ketamine Hydrochloride (Ketalar) 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)

Nonsteroidal Anti-Inflammatory Agents 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 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

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)

(Monitored Anesthesia Care) 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