Transcript Autonomic Nervous System

Autonomic Nervous System
Chapter 17,18, 19, 20
Central Nervous System or CNS
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Brain and spinal cord: receives and
processes incoming sensory information and
responds by sending out signals that initiate
or modify a process.
Peripheral Nervous System
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Includes all the neurons and ganglia found
outside the CNS
Includes the
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Sympathetic receptors (adrenergic)
Parasympathetic receptors (cholinergic)
Sympathetic Nervous System
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Helps the body cope with external stimuli and
functions during stress (triggers the flight or
fight response)
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Vasoconstriction – increase in blood pressure
Increased heart rate
Increased respiratory rate
Cold, sweaty palms
Pupil dilation
Sympathetic Nervous System
Parasympathetic Nervous System
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Works to save energy, aids in digestion, and
supports restorative, resting body functions.
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Decrease in heart rate
Increased gastro intestinal tract tone and
peristalsis
Urinary sphincter relaxation
Vasodilation – decrease in blood pressure
The Race Horse and the Cow
Sympathetic Nervous System
Norepinephrine and epinephrine
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Both always present in the blood.
Norepinephrine varies according to the
amount of stress present and will cause
transient changes in heart rate and systemic
arteries and veins.
Epinephrine is a constant in regulating heart
rate, vasoconstriction in systemic arteries and
veins and vasodilation of muscles and liver.
Adrenergic Receptors
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Norepinephrine produces its effects by
combining with adrenergic receptors
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Alpha
Beta
Adrenergic Receptors
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Found in:
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Cardiovascular
Endocrine
Gastrointestinal
Genitourinary
Respiratory
Ocular
Alpha Receptors
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Alpha 1: adrenergic receptors located on
postsynaptic effector cells.
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Smooth muscles of blood vessels: Constriction
Bladder sphincter
Penis
Uterus
Pupillary muscles of iris
Adrenergic Receptor
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Alpha 1
Therapeutic Uses
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Control topical superficial bleeding
Treat nasal congestion
Elevate blood pressure
Delay absorption of local anesthesia
Decrease intraocular pressure (pressure in eye)
Alpha 2
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Same as the Alpha 1 but are located in the
presynaptic nerve terminals.
Adrenergic Receptor
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Beta 1
Cardiovascular
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Cardiac muscle: increased contractility
Atrioventricular node (AV): increased heart rate
Sinoatrial node: increase (SA) in heart rate
Endocrine
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Pancreas (insulin)
Cardiac Conduction System
Beta 1 Drugs
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Predominately works on vascular smooth
muscle of the heart.
Adrenergic Receptor
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Beta 2
Cardiovascular
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Dilation of blood vessels
Endocrine
Uterine relaxation
Respiratory: dilation of bronchial muscles
Beta 2 Drugs
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Used in Asthma to relieve bronchocontriction.
Used to delay pre-term labor by relaxing the
uterus.
Dopamine
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Adrenergic neurotransmitter – essential for
normal brain function.
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Studies focus on connection between dopamine
malfunction in schizophrenia and Parkinson’s
Disease.
Role of dopamine: stimulants and depressants.
Body Responses – “fight or flight”
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Increase in blood pressure and cardiac
output.
Increase blood flow to brain, heart and
skeletal muscles.
Decrease blood flow to skin and organs not
needed for “fight”.
Increase in glycogen for energy, mental
activity, muscle strength, blood coagulation,
respiratory rate, pupil dilation to aid vision,
and increase in sweating.
Fight of Flight Response
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Can be a problem if the body stay in the “fight
or flight” mode.
Type A personalities?
High stress environment?
Medications may be needed reduce the
physiologic body responses.
Parasympathetic Nervous System
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Rest and Digest
Save energy
Decreased heart rate
Sympathetic Nervous System
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Protective mechanisms designed to help
person cope with the stress or get away from
it.
Body Responses – “rest and digest”
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Dilation of blood vessels in skin
Decrease heart rate
Increase secretion of digestive enzymes
Constriction of smooth muscle of bronchi
Increase in sweat glands - cooling
Contraction of smooth muscles of urinary
bladder
Contraction of smooth muscle of skeletal
system
Adrenergic Drugs
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What do they do?
Stimulation of the sympathetic nervous
system.
Indications
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Respiratory conditions
Topical nasal congestion
Ophthalmic conditions
Cardiovascular
Lungs
Asthma and COPD (Chronic Obstructive
Pulmonary Disease): Beta 2 drugs or
bronchodilators are used to relieve bronchoconstriction and broncho-spasm.
Action: dilation of bronchioles
Asthma
OTC Adrenergic Drugs
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Common cold: anti-histamines
Allergy: nasal or oral to relieve nasal
congestion
Heart
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Direct stimulation of receptors
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Alpha 1 –
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Vasoconstriction of blood vessels which increases blood
pressure
Pressor or vasopressor effect to maintain blood
pressure
Beta 1
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Increased force of myocardial contraction
Increased speed of electrical conduction in the heart.
Heart: SA Node
Ophthalmic Conditions
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Used to reduce intraocular pressure in
treatment of glaucoma.
Glaucoma
Contraindications
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Only contraindications to use of adrenergic
drugs are:
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Drug allergy
Severe hypertension
Adrenergic Drugs
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Epinephrine
Pseudoephedrine – Sudafed
Isoproterenol (Isuprel)
Phenylephrine (Neo-Synephrine)
Clonidine (antihypertensive)
pseudoephedrine
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Trade names: Sudafed, Afrin nose spray
Functional Classification: Adrenergic
Therapeutic classification: allergy, cold and
cough remedies, nasal drying agents /
decongestants
Action: stimulates alpha and beta adrenergic
receptors
Forms and Dosage
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How supplied: tabs, chew tabs, extended
release tabs, liquid or drops
Dosing: 30 to 60 mg / dose q 6-8 hours PO
Maximum dose 240 mg/24 hours
Sustained release: 120 mg PO q 12 hours
Contraindications
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Severe Hypertension
Severe coronary artery disease (CAD)
Use with caution in pregnancy, breast feeding
and renal failure
Side Effects
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Dizziness, nervousness, restlessness,
insomnia and arrhythmias
Seizures
Cardiovascular collapse
Additional Information
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Primarily excreted renally – adjust in patients
with renal impairment
May cause false-positive for amphetamines –
athletes
Currently need to ask pharmacist for Sudafed
– OTC has been limited due to abuse
Nursing Implications
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Assess for congestion
Monitor pulse and blood pressure before
beginning therapy
Assess lung sound for signs of bronchial
secretions
Allergies
Anaphylactic Shock
Epinephrine
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Epinephrine would be the drug of choice
Classification: Adrenergic
Action: affects both the beta 1 (cardiac) and
beta 2 (pulmonary) receptors
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produces bronchodilation
inhibits hypersensitivity reaction of mast cells.
Epinephrine
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Therapeutic Effects:
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Bronchodilation
Maintenance of heart rate and blood pressure
Adverse Side Effects:
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Nervousness, restlessness, tremors, angina,
arrhythmias, hypertension, tachycardia
How it is given?
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Sub-Q or IV or inhaled
Epi-pen is given to clients with severe allergy
reactions
Not given by mouth because drug is
inactivated by gastric juices
Can be inhaled in asthma attack
CAUTION!
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Check dose, concentration, and route of
administration
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fatalities have occurred from medication errors
use TB syringe for subcutaneous administration
Inhaled provided as metered dose inhaler
160 to 250 mcg – can have 3 treatments 5
minutes apart.
IV would be 0.1 to 0.25 mg (cardiopulmonary
resuscitation)
Calculation
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The order is for 0.25 mg of epinephrine.
How much would you need to draw up from
the vial:
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Epinephrine 1 mg / 1 ml
Precautions with Use
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Tachyarrhythmia's (fast irregular heart rate),
headache, nausea, and palpitations
Short acting so more definitive treatment
needs to be initiated
Need cardio-respiratory monitoring
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Pulse oximetry
Cardiac monitor
Vasopressive Drugs
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Pressor drugs or “pressors” or inotropes
Used to support the cardiovascular system
during cardiac failure or shock.
Common vasopressors:
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Dobutamine #1
Dopamine # 2
Nor-epinephrine (in addition to 1 & 2)
Dobutamine
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Functional classification: Adrenergic direct
acting B1 agonist, cardiac stimulant
Uses: management of heart failure caused by
depressed contractibility of the heart
Action: stimulates beta 1 (myocardial)
adrenergic receptors with relatively minor
effect on heart rate or peripheral blood
vessels.
Dopomine
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Functional Classification: adrenergic
Uses: to improve blood pressure, cardiac
output, urine output – treatment of shock
Action: stimulates Dopomine receptors and
beta 1 adrenergic receptors
Effect: increase BP, cardiac output and renal
blood flow
Adrenergic-blocking Drugs
Chapter 18
Antiadrenergic Drugs
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Blocks the effects of the sympathetic nerve
stimulation, endogenous catecholamine and
adrenergic drugs.
Mechanism of Action
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Act on alpha or beta receptors
Receptors are blocked by adrenergic
antagonists or pre-synaptic alpha 2 receptors
are stimulated.
When Used?
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To manage hypertension and a number of
cardiovascular disorders.
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Beta 1 blocking drugs: acute myocardial infarction
(heart attack) MI, angina (chest pain),
hypertension
Alpha1 blocking drugs: heart failure, angina,
hypertension
When Used?
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Urinary retention – to reduce smooth muscle
contraction of the bladder neck
Migraine headaches: ergotamines to dilate
blood vessels of the brain and carotid
arteries.
Uterine contractions: ocytocics used to
control post-partum bleeding
Patient Teaching
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Teach about therapeutic and adverse effects.
Take medications as prescribed and do not
abruptly stop do not take more or less.
Avoid caffeine and other CNS stimulants.
Change positions slowly to avoid dizziness or
syncope
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Hypotension
Postural hypotension or orthostatic hypotension
Patient Education
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Avoid alcohol
Hot tubs and saunas
Report constipation and urinary retention
Report to health care providers:
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Confusion
Depression
Hallucinations
Nightmares
Palpitations
Dizziness
Orthostatic Hypotension
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Abnormally low blood pressure that occurs
when a person assumes a standing position
from a sitting or lying position.
Cholinergic Drugs: Chapter 19
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Cholinergic drugs stimulate the
parasympathetic nervous system.
Mechanism of Action
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Direct acting cholinergic drugs are synthetic
derivative of choline.
Effects of drug
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Decrease heart rate, vasodilation, and changes in
BP
Increase tone and contractibility of smooth muscle
Increase tone and contractibility of bronchial
smooth muscles
Increased respiratory secretions
Indications for Use
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Urinary retention without obstruction
Postoperative abdominal distention due to
paralytic ileus
Myasthenia gravis – muscle weakness
During surgery to reverse the effects of
muscle relaxants used during surgery
bethanechol
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Trade name: Urecholine
Functional classification: urinary tract
stimulant
Chemical classification: cholinergic
Uses: postoperative urinary retention
Action: stimulates cholinergic receptors
Nursing Assessment: urine retention
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Urinary retention
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Bladder distention
Difficulty voiding
How do you know drug is working?
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Fluid intake equal to urine output
Patient has voided within the last 8 hours
Nursing Assessment: paralytic ileus
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Paralytic ileus
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Hypo-peristalsis
Decreased bowel sounds
No gas or bowel movement
How do you know drug is working?
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Bowel sounds heart in all four quadrants
Client states has passes gas
Client states has had a bowel movement
Myasthenia Gravis
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Signs and symptoms: muscle weakness,
ptosis (droopy eye lid), diplopia (double
vision), difficulty chewing and swallowing,
decreased activity intolerance.
pyridostigmine
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Trade name: Mestinon and Antillrium
Functional classification: antimyasthemics
Chemical classification: cholinergics
Indications: used to increase muscle strength
in the symptomatic treatment of myasthenia
gravis
Evaluation of drug effectiveness
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How do you know medication is working?
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Increased muscle tone
No droopy eye lid or double vision
Increased activity tolerance.
Alzheimer
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Signs and symptoms: loss of memory,
cognitive function and decreased self-care
Clinical trials with Razadyne (drug is in test
stage and there is not enough evidence to
show that is works)
Evaluation of medication effectiveness:
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Increase memory and cognitive function
Increase interest in activities of daily living.
Cholinergic-Blocking Drugs
Chapter 20
Colinergic-Blocking Drugs
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Anticholinergics are a class of medications
that inhibit parasympathetic nerve impulses
by selectively blocking the binding of the
neurotransmitter acetylcholine to its receptor
in nerve cells.
Mechanism of Action
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Drugs act by occupying receptor sites on
target organs innervated by parasympathetic
nervous system leaving fewer receptor sites
free to respond to acetylcholine.
Parasympathetic response is absent or
decreased depending on number of receptors
blocked.
Effects of Anticholinergic Drugs
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CNS stimulation followed by depression
Decreased cardiovascular response to
parasympathetic (vagal) stimulation that
slows heart rate.
Bronchodilation and decrease respiratory
secretions
Antispasmodic effects in GI system
Change in intra-ocular pressure in patients
with glaucoma
Uses
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GI disorders – peptic ulcer disease, gastritis,
increased gastric acid secretion – relax gastric
smooth muscle (replaced by newer drugs)
Genitourinary – anti-spasmodic – urgency
Excessive secretions
Ophthalmology – relax eye for exam
Respiratory disorder – asthma or bronchitis –
inhaled form only
Cardiac disorders – bradycardia or heart block
Parkinson’s disease
Side Effects
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Hyperthermia, hot, dry flushed skin, dry
mouth, tachycardia, delirium, paralytic ileus
and urinary retention
Atropine
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Chemical classification: anticholinergic
Functional classification: antiarrhythmic
Action: Inhibits the action of acetylcholine at
postganglionic sites located in the smooth
muscle, secretory glands, CNS. Low doses
decrease: sweating, salivation and
respiratory secretions.
Atropine
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Therapeutic effects:
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Increased heart rate
Decreased GI and respiratory secretions
May have spasmodic action on the biliary and
genitourinary tracts.
Atropine
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Side effects:
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Drowsiness
Blurred vision
Tachycardia
Dry mouth
Urinary hesitancy