Chapter 11
General and Local Anesthetics
Copyright © 2014 by Mosby, an imprint of Elsevier Inc.
Anesthetics

Drugs that reduce or eliminate pain by
depressing nerve function in the central nervous
system (CNS) and peripheral nervous system
(PNS)
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Anesthesia


A state of depressed CNS activity
Two types



General anesthesia
Local anesthesia
Balanced anesthesia
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General Anesthetics

Drugs that induce a state in which the CNS is
altered to produce varying degrees of:

Pain relief
 Depression of consciousness
 Skeletal muscle relaxation
 Reflex reduction
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General Anesthetics (cont’d)

Inhalational anesthetics


Volatile liquids or gases that are vaporized in oxygen
and inhaled
Parenteral anesthetics

Administered intravenously
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Classroom Response Question
The nurse anesthetist is planning to use balanced
anesthesia during a surgical procedure. A characteristic of
this type of anesthesia is the
A. administration of minimal doses of multiple anesthetic
drugs.
B. administration of inhaled anesthetics.
C. IV administration of anesthetics.
D. administration of anesthetics to cause muscle
relaxation.
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Inhaled Anesthetics


Used to induce anesthesia
Inhaled gas


nitrous oxide (“laughing gas”)
Inhaled volatile liquids

enflurane (Ethrane)
 halothane (Fluothane)
 isoflurane (Forane)
 methoxyflurane (Penthrane)
 Others
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Parenteral Anesthetics

Used:



To induce or maintain general anesthesia
To induce amnesia
As an adjunct to inhalation-type anesthetics
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Parenteral Anesthetics (cont’d)





etomidate (Amidate)
ketamine (Ketalar)
methohexital (Brevital)
propofol (Diprivan)
thiopental (Pentothal)
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Adjunct Drugs

Sedative-hypnotics

Barbiturates (pentobarbital, secobarbital)
 Benzodiazepines (diazepam, midazolam)
 hydroxyzine
 promethazine

Opioid analgesics

fentanyl, sufentanil, meperidine, morphine
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Adjunct Drugs (cont’d)

Neuromuscular blocking drugs (NMBDs)



Depolarizing drugs (succinylcholine, d-tubocurarine)
Nondepolarizing drugs (pancuronium, vecuronium)
Anticholinergics

atropine, glycopyrrolate, scopolamine
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Mechanism of Action



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
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Classroom Response Question
When assessing a patient under general anesthesia, which
change to organ systems does the nurse expect?
A.
B.
C.
D.
Nystagmus
Skeletal muscle constriction
Hypertension
Decreased intracranial pressure
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Indications

General anesthetics are used during surgical
procedures to produce:

Unconsciousness
 Skeletal muscular relaxation
 Visceral smooth muscle relaxation


Rapid onset; quickly metabolized
Also used in electroconvulsive therapy
treatments for depression
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Adverse Effects


Vary according to dosage and drug used
Sites primarily affected


Heart, peripheral circulation, liver, kidneys, respiratory
tract
Myocardial depression is commonly seen
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Adverse Effects (cont’d)

Malignant hyperthermia





Occurs during or after general anesthesia or use of
the NMBD succinylcholine
Sudden elevation in body temperature (greater than
104° F)
Tachypnea, tachycardia, muscle rigidity
Life-threatening emergency
Treated with cardiorespiratory supportive care and
dantrolene (skeletal muscle relaxant)
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Classroom Response Question
During surgery, the anesthetist notes that the patient’s
heart rate is gradually increasing and becoming more
irregular, the patient’s blood pressure is becoming
unstable, and the patient is starting to sweat profusely.
What other assessment should the anesthetist note
immediately?
A.
B.
C.
D.
Pupillary reactions
Respiratory effort
Temperature
Urinary output
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Moderate Sedation




Also called conscious sedation and procedural
sedation
Combination of an IV benzodiazepine (e.g.,
midazolam) and an opiate analgesic (e.g.,
fentanyl or morphine)
Anxiety and sensitivity to pain are reduced, and
patient cannot recall the procedure
Preserves the patient’s ability to maintain own
airway and to respond to verbal commands
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Moderate Sedation (cont’d)


Used for diagnostic procedures and minor
surgical procedures that do not require deep
anesthesia
Rapid recovery time and greater safety profile
than general anesthesia
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Classroom Response Question
Which statement regarding conscious sedation does the
nurse identify as being accurate?
A. The intravenous route of drug administration is
commonly used in pediatric patients to provide
conscious sedation.
B. Mild amnesia is a common effect of midazolam.
C. Patients receiving conscious sedation must be
intubated with an endotracheal tube.
D. Effects of propofol include relief of anxiety and pain.
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Local Anesthetics




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
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Local Anesthetics (cont’d)

Topical



Applied directly to skin or mucous membranes
Creams, solutions, ointments, gels, ophthalmic drops,
powders, suppositories
Parenteral

Injected intravenously or into the CNS by various
spinal injection techniques
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Types of Local Anesthesia

Spinal or intraspinal





Intrathecal
Epidural
Infiltration
Nerve block
Topical
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Parenteral Anesthetics





lidocaine (Xylocaine)
mepivacaine (Carbocaine)
procaine (Novocain)
tetracaine (Pontocaine)
Others
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Drug Effects: Paralysis




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)
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Indications

Local anesthetics are used for:




Surgical, dental, and diagnostic procedures
Treatment of certain types of chronic pain
Spinal anesthesia: to control pain during surgical
procedures and childbirth
Local anesthetics are given by:


Infiltration anesthesia
Nerve block anesthesia
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Indications (cont’d)

Infiltration anesthesia



Minor surgical and dental procedures
Injection of the anesthetic solution intradermally,
subcutaneously, submucosally, or intramuscularly
across the path of nerves supplying target area
May be given in a circular pattern around operative
area
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Indications (cont’d)

Infiltration anesthesia and epinephrine

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
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Indications (cont’d)

Nerve block anesthesia



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
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Adverse Effects


Usually limited
Adverse effects result if:

Inadvertent intravascular injection
 Excessive dose or rate of injection
 Slow metabolic breakdown
 Injection into highly vascular tissue

“Spinal headache”
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Classroom Response Question
When teaching a patient about spinal headaches, which
statement will the nurse include?
A. Spinal headaches can be prevented with bed rest after
the epidural procedure.
B. Patients who have a spinal headache should have very
limited fluid intake.
C. A graft of skin from the patient’s hand can be used to
seal the leaking area causing the headache.
D. High Fowler’s positioning should be used for patients
who have a spinal headache.
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Neuromuscular Blocking Drugs



Also known as NMBDs
Prevent nerve transmission in certain muscles,
resulting in muscle paralysis
Used with anesthetics during surgery
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Neuromuscular
Blocking Drugs (cont’d)

When used during surgery, artificial mechanical
ventilation is required

These drugs paralyze respiratory and skeletal
muscles
 Patient cannot breathe on his or her own
 Do not cause sedation or pain relief
 Patient may be paralyzed yet conscious
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Neuromuscular
Blocking Drugs (cont’d)


Depolarizing drugs
Nondepolarizing drugs

Short-acting
 Intermediate-acting
 Long-acting
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NMBDs: Depolarizing Drugs

Succinylcholine



Works similarly to neurotransmitter acetylcholine
(ACh), causing depolarization
Metabolism is slower than ACh, so as long as
succinylcholine is present, repolarization cannot occur
Result: flaccid muscle paralysis
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NMBDs: Nondepolarizing Drugs

Short-acting


mivacurium (Mivacron)
Intermediate-acting

atracurium (Tracrium)
 vecuronium (Norcuron)
 rocuronium (Zemuron)

Long-acting


pancuronium (Pavulon)
doxacurium (Nuromax)
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NMBDs: Nondepolarizing Drugs
(cont’d)



Prevent ACh from acting at neuromuscular
junctions
Nerve cell membrane is not depolarized; muscle
fibers are not stimulated
Skeletal muscle contraction does not occur
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Neuromuscular Blocking Drugs





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, resulting in cessation of respirations
Recovery of muscular activity usually occurs in
reverse order
Transient muscle fasciculations may result in
later muscle soreness
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NMBDs: Indications





Main use: facilitating controlled ventilation during
surgical procedures
Endotracheal intubation (short-acting)
To reduce muscle contraction in an area that
needs surgery
Diagnostic drugs for myasthenia gravis
Other uses
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NMBDs: Adverse Effects


Few when used appropriately
May cause:

Hypotension (blockade of autonomic ganglia)
 Tachycardia (blockade of muscarinic receptors)
 Hypotension (release of histamine)

Effects vary according to site
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NMBDs: Safety


Respiratory muscle paralysis occurs with these
drugs
Emergency ventilation equipment must be
immediately available
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Classroom Response Question
A patient is to receive a neuromuscular blocking
drug while on mechanical ventilation. While the
patient is receiving this medication, the nurse
should expect the patient to be:
A. sedated.
B. resisting the ventilator.
C. awake but unable to move.
D. pain free.
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NMBDs: Overdose



Overdose causes prolonged paralysis requiring
prolonged mechanical ventilation
Cardiovascular collapse may occur
Several conditions may increase sensitivity to
NMBDs
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Nursing Implications



Always assess past history of surgeries and
response to anesthesia
Assess past history, allergies, medications
Assess use of alcohol, illicit drugs, opioids
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Nursing Implications (cont’d)

Assessment is vital during preoperative,
intraoperative, and postoperative phases

Vital signs
 Baseline lab work, ECG
 Oxygen saturation
 ABCs (airway, breathing, circulation)
 Monitor all body systems
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Nursing Implications (cont’d)


Each perioperative phase has its own complex
and very specific nursing actions
Provide preoperative teaching about the surgical
procedure and anesthesia
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Nursing Implications (cont’d)



Perform close and frequent observation of the
patient and all body systems
During a procedure, monitor vital signs, ABCs
Watch for sudden elevations in body
temperature, which may indicate malignant
hyperthermia
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Classroom Response Question
A patient in the intensive care unit will be receiving
a neuromuscular blocking drug. Which piece of
equipment is essential to have nearby when the
nurse initiates this therapy?
A.
B.
C.
D.
Defibrillator
Sphygmomanometer
Mechanical ventilator
Oxygen source
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Nursing Implications (cont’d)


During recovery, monitor for cardiovascular
depression, respiratory depression, and
complications of anesthesia
Implement safety measures during recovery,
especially if motor or sensory loss occurs
because of local anesthesia
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Nursing Implications (cont’d)


Reorient patient to his or her surroundings
Teach the patient about postoperative turning,
coughing, deep breathing
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