Chapter 12- General and Local Anesthetics

Question 1

Anesthetics

Answer 1

Drugs that depress the central nervous system (CNS)

• depression of consciousness
• loss of responsiveness to sensory stimulation (including pain)
• muscle relaxation

Question 2

Anesthesia

Answer 2

A state of depressed CNS activity

Question 3

Two types of anesthesia

Answer 3

• General anesthesia

* Local anesthesia

Question 4

General Anesthetics

Answer 4

• Drugs that induce a state in which the CNS is altered to produce verying degress of:
• analgesia
• depression of consciousness
• skeletal muscle relaxation
• reflex reduction

Question 5

General Anesthetics: Inhaled anesthetics

Answer 5

Volatile liquids or gases that are vaporized/mixed in oxygen and inhaled

Question 6

General Anesthetics: Parenteral anesthetics

Answer 6

Administered intravenously

Question 7

Inhaled Anesthetics

Answer 7

Inhaled gas:

-nitrous oxide

Question 8

Inhaled volatile liquids:

Answer 8

• desflurane
• enflurane (Ethrane)
• halothane (Fluothane)
• isoflurane (Forane)
• methoxyflurane (Penthrane)
• sevoflurane

Question 9

Injectable Anesthetics- Used:

Answer 9

• To induce or maintain general anesthesia
• To induce amnesia
• As an adjunct to inhalation-type anesthetics

Question 10

Injectable Anesthetics:

Answer 10

• etomidate (Amidate)
• ketamine (Ketalar)
• methohexital (Brevital)
• propofol (Diprivan)
• thiamylal (Surital)
• thiopental (Pentothal)

Question 11

Sedative-hypnotics

Answer 11

• Barbiturates (pentobarbital, secobarbital)
• Benzodiazepines (diazepam, midazolam)
• hydroxyzine
• promethazine

Question 12

Opioid Analgesics

Answer 12

fentanyl, sufentanil, meperedine, morphine

Question 13

Neuromuscular blocking drugs (NMBDs)

Answer 13

• depolarizing drugs (succinylcholine)

- nondepolarizing drugs (pancuronium, d-tubocurarine, vecuronium)

Question 14

Anticholinergics:

Answer 14

atropine, glycopyrrolate, scopolamine

Question 15

Mechanism of Action

Answer 15

• Varies according to drug
• Overton-Meyer theory
• Overall effect
• orderly and systematic reduction of sensory and motor CNS functions
• progressive depression of cerebral and spinal cord functions

Question 16

Indications

Answer 16

• General anesthetics used during surgical procedures to produce:
• unconsciousness
• skeletal muscular relaxation
• Rapid onset; quickly metabolized
• Also used in electroconvulsive therapy treatments for depression

Question 17

Adverse Effects

Answer 17

• Vary according to dosage and drug used
• Sites primarily affected
• heart, peripheral circulation, liver, kidneys, respiratory tract
• Myocardial depression is commonly seen

Question 18

Adverse Effects: Malignant Hyperthermia

Answer 18

• occurs during or after general anesthesia or use of the NMBD succinylcholine
• sudden elevation in body temperature (greater that 104)
• tachypnea, tachycardia, muscle rigidity
• life threatening emergency
• treated with dantrolene (skeletal muscle relaxant)

Question 19

Moderate Sedation

Answer 19

• Also called conscious sedation, procedural sedation
• combination of an IV benzodiazepine and an opiate analgesic
• anxiety and sensitivity to pain are reduced, and patient cannot recall the procedure
• preserves the patients ability to maintain own airway and to respond to verbal commands

Question 20

Moderate Sedation also used for:

Answer 20

• diagnostic procedures and minor surgical procedures that do not require deep anesthesia
• topical anesthetic may be applied also
• Rapid recovery time and greater safety profile than general anesthesia

Question 21

Local Anesthetics

Answer 21

• Also called regional anesthetics
• used to render a specific portion of the body insensitive to pain
• interfere with nerve impulse transmission to specific areas of the body
• do not cause loss of consciousness

Question 22

Local Anesthetics: Topical

Answer 22

• Applied directly to skin or mucous membranes

- creams, solutions, ointments, gels, ophthalmic drops, lozenges, suppositores

Question 23

Local Anesthetics: Parenteral

Answer 23

-injected parenterally or into the CNS by various spinal injection techniques

Question 24

Types of Local Anesthesia

Answer 24

• Spinal or intraspinal
• Intrathecal
• Epidural
• Infiltration
• Nerve block
• Topical

Question 25

Parenteral Anesthetics

Answer 25

* procaine (Novocain) * tetracaine (Pontocaine) * lidocaine (Xylocaine) * mepivacaine (Carbocaine) * bupivacaine

Question 26

Drug Effects: Paralysis

Answer 26

* First, autonomic activity is lost * Then pain and other sensory functions are lost * Last, motor activity is lost * As local drugs wear off, recovery occurs in reverse order (motor, sensory, then autonomic activity are restored)

Question 27

Indications: Local anesthetics are used for-

Answer 27

* Surgical, dental, and diagnostic procedures * Treatment of certain types of chronic pain * Spinal anesthesia: to control pain during surgical procedures and childbirth

Question 28

Local anesthetics are given by:

Answer 28

- Infiltration anesthesia | - Nerve block anesthesia

Question 29

Infilitration anesthesia

Answer 29

- Minor surgical and dental procedures - injection of the anesthetic solution intradermally, subcutaneously, or submucosally across the path of nerves supplying the target area - May be given in a circular pattern around the operative area

Question 30

Infilitration anesthesia and epinephrine

Answer 30

* Some local anesthetics used for infiltration or nerve block are combined with vasoconstrictors - to prevent systemic absorption of anesthetic - to help confine local anesthetic to injected area - to reduce local blood loss during procedure - epinephrine, phenylephrine, norepinephrine

Question 31

Nerve block anesthesia

Answer 31

* Used for surgical, dental, and diagnostic procedures - also used for therapeutic management of pain - the anesthetic drug is injected directly into or around the nerve trunks or nerve ganglia that supply the area to be numbed

Question 32

Adverse Effects:

Answer 32

* usually limited * adverse effects result if: - inadvertent intravascular injection occurs - excessive dose or rate of injection is given - slow metabolic breakdown occurs - "spinal headache," treated with an epidural blood patch

Question 33

Neuromuscular Blocking Drugs:

Answer 33

- Also known as NMBDs - Prevent nerve transmission in certain muscles, resulting in muscle paralysis - Used with anesthetics during surgery

Question 34

Neuromuscular Blocking Drugs: When used during surgery

Answer 34

``` Artificial mechanical ventilation is required -these drugs paralyze respiratory and skeletal muscles -patient cannot breathe on is or her own -do not cause sedation or pain relief -patient may be paralyzed yet conscious -depolarizing drugs -Nondepolarizing drugs short acting intermediate acting long acting ```

Question 35

NMBAs: depolarizing drug

Answer 35

Succinylcholine - works similarly to neurotransmitter acetylcholine (Ach), causing depolarization - metabolism is slower than Ach, so as long as succinylcholine is present, repolarizing cannot occur * Result: flaccid muscle paralysis

Question 36

NMBAs: nondepolarizing drugs

Answer 36

* Short acting - mivacurium (Mivacron) * Intermediate acting - atracurium (Tracrium), vecuronium (Norcuron) - rocuronium (Zemuron) * Long acting - pancuronium (Pavulon), doxacurium (Nuromax) - d-tubocurarine

Question 37

Nodepolarizing NMBAs

Answer 37

- prevent Ach from acting at neuromuscular junctions - muscle fibers are not stimulated - skeletal muscle contraction does not occur

Question 38

Neuromuscular Blocking Drugs

Answer 38

- first sensation is muscle weakness - followed by total flaccid paralysis - Small, rapidly moving muscles affected first (fingers, eyes) then limbs, neck, trunk - finally, intercostal muscles and diaphragm affected,