Transcript Drugs for treating shock - Suny-perfusion

Drugs for treating shock
Shock
• shock: a syndrome characterized by
collapse of the circulatory system
• vital tissues do not receive enough blood
to function properly
• cells cannot carry on normal metabolism
Symptoms of shock
• shock is a collection of signs and
symptoms, many nonspecific:
• skin: pale, cool, or clammy
• respiratory: breathing rapid and shallow
• CV: low b.p., low cardiac output, weak
pulse
• neurologic: restlessness, anxiety, lethargy,
confusion
Classification of shock
• 1. cardiogenic
• failure of the heart to pump sufficient blood
to tissues
• due to: left heart failure, ischemia, MI,
arrhythmias, pulmonary embolism,
myocardial/pericardial infection
• 2. hypovolemic
• loss of blood volume
• due to: hemorrhage, burns, profuse
sweating, excessive urination, vomiting,
diarrhea
• 3. septic
• multiple organ dysfunction as a result of
pathogenic organisms in the blood
• due to: widespread inflammatory response
to bacterial, fungal or parasitic infections
• 4. anaphylactic
• acute allergic reaction
• due to: severe reaction to allergens
(penicillin, nuts, shellfish, animal proteins)
Treatment of shock
• initial treatment includes basic life support
while identifying the underlying cause
• maintain ABC of life support: airway,
breathing, circulation
• administer fluids/electrolytes and blood
products if patient has lost a significant
amount of blood
Drug categories in treating shock
• There are 3 categories of drugs that play a
role in treating shock:
• vasoconstrictors
• cardiotonic drugs
• fluid replacement agents
Vasoconstrictors used to treat
shock
• early stages of shock: body compensates
for initial fall in b.p. by ↑ activity of
sympathetic nervous system
• this sympathetic activity results in
vasoconstriction which:
• ↑ b.p.
• ↑ heart rate and force of myocardial
contractions
• Purpose: maintain blood flow to vital
organs (heart, brain) and ↓ blood flow to
other organs (kidneys, liver)
• Body’s ability to compensate is limited
• Severe hypotension may develop
• vasoconstrictors are used to maintain b. p.
• given IV they immediately raise b. p.
• patients monitored continuously during
infusion to avoid HT due to overtreatment
Specific Vasoconstrictors used to
treat shock
• 1. epinephrine: a nonselective adrenergic
agent
• b.p. rises due to stimulation of alpha1
receptors in smooth muscle of blood
vessels
• cardiac output increases due to stimulation
of beta1 receptors in heart
• airway opens due to stimulation of beta2
receptors in the bronchi
• 2. norepinephrine (Levarterenol,
Levophed) has both alpha and beta1
activity
• 3. methoxamine hydrochloride (Vasoxyl)
selective to alpha receptors
Cardiotonic drugs used to treat
shock
• aka inotropic agents
• as cardiogenic shock progresses, the
heart begins to fail:
• cardiac output ↓, lowering amount of blood
reaching vital tissues and worsening shock
• cardiotonic drugs are used in the
treatment of shock to ↑ the force of
contraction and increase cardiac output
Specific Cardiotonic drugs used to
treat shock
• 1. digoxin (Lanoxin)
• 2. dobutamine (Dobutrex): a beta1
adrenergic agent that is often drug of
choice for short term (1/2 life of only 2
min.) treatment of shock
• has the ability to cause heart to beat more
forcefully without significantly increasing
heart rate
• increase in cardiac output assists in
maintaining blood flow to vital organs
• 3. dopamine (Dopastat, Intropin)
• mechanism of action is dependent on
dose
• low doses: selectively stimulates beta1
receptors in kidneys that cause
vasodilation and an ↑ blood flow to kidneys
(used in treating hypovolemic and
cardiogenic shock)
• moderate doses: stimulates beta1
receptors, causing heart to beat with more
force and increasing cardiac output
• higher doses: stimulates alpha receptors
causing vasoconstriction and raising b.p.
Fluid replacement agents used to
treat shock
• Used to replace blood or other fluids lost
during hypovolemic shock
• Fluid replacement agents are generally
placed into the following 3 categories:
• blood, colloids, crystalloids
Blood
• Whole blood indicated for treatment of
acute, massive blood loss when there is a
need to replace plasma volume and
supply RBC’s
Colloids
• Used when up to 1/3 of adult blood volume
is lost
• colloids are proteins that stay suspended
in the blood for a long period and draw
water from the body’s cells and tissues
into the blood vessels
• colloids include: normal serum albumin,
plasma protein fractions, dextran and
hetastarch
Crystalloids
• IV solutions that contain electrolytes in
amounts resembling those of natural
plasma
• Unlike colloids, crystalloid solutions leave
the blood and enter cells
• used to replace fluids lost, and to increase
urine output
• include: normal saline, lactated Ringer’s,
hyperotonic saline, 5% dextrose in water