Shock

Shock

a generalized, systemic response to decreased tissue perfusion and oxygenation leading to abnormal cellular metabolism

Absolute hypovolemia

hypovolemia where there is bleeding, excess urine/sweating, decrease in plasma volume

relative hypovolemia

hypovolemia related to systemic vasodilation or heart failure

1. hypovolemic

2. cardiogenic

3. neurogenic

4. anaphylactic

5. septic

five types of shock

1. compensatory (early)

2. progressive (intermediate)

3. irreversibe (late)

three phases of shock

After the initial event, there is hypovolemia and hypotension. Compensatory mechanisms to start in order to maintain BP and tissue perfusion

What happens during compensatory shock?

1. fluid shift

2. HPA activation

3. ADH release

4. activation of RAA

Compensatory mechanisms for hypovolemia [4]

intracellular dehydration because cells have shrunnk due to loss of water

1. poor skin turgor

2. dry mucous membranes

3. confusion

in early shock, get symptoms of what?

increase catecholamines / cortisol

HPA compensation in early shock:

– Restlessness/Agitation
– Tachycardia
– Diaphoresis
– Increased RR, shortness
of breath, dyspnea
– Pale, cool skin
– BP may be normal or
decreased
– Hyperglycemia

S+S associated with HPa in early shock

osoreceptors at hypothalamus stimulate posterior pituitary to release ADH. This increases permeability of renal tubule cells to increase water reabsorption.

Adh compensatory mechanism in early shock:

Progressive SNS activity and/or progressive S+S/problems related to hypoxia

If the initial event is not corrected and hypovolemia of early shock is not corrected, will get progressive what?

1. cardiogenic

2. hypovolemic

Cold shocks: [2]

1. neurogenic shock

2. anaphylactic shock

3. septic shock

warm shocks: [3]

Due to HPA compensation mechanism of vasoconstriction in early shock.

why are patient's cold in cold shock?

Cardiogenic shock

When there is a decreased circulating blood volume related to ventricular pump failure

relative hypovolemia

type of hypovolemia in cardiogenic shock

1. decreased BP

2. Cool pale skin, diaphoresis, oliguria

3. may not have tachycardia because ventricle not pumping

4. may have dysrhythmias

5. may have pulmonary edema due to CHF if ventricle not pumping

early signs and symptoms of cardiogenic shock

1. support myocardial perfusion as heart tries to recover

2. oxygen

3. reduce oxygen demand

4. supprt BP with fluids and vasopressors and inotropes

treatment of cardiogenic shock:

intraaortic balloon pump or ventricular assist device

how to support myocardial perfusion [2]

assess ABGs and serum lactate levels

what to assess related to oxygen and cardiogenic shock

hypovolemic shock

shock related to a decraese in intravascular volume

1. loss of whole blood (hemorrhage)

2. loss of plasma (burns )

3. loss of fluid

reasons for decrease in intravascular volume: [3]

• DKA – polyuria
• Excess emesis/diarrhea
• Excess diuresis
• Excess sweating
• Diabetes insipidus

reasons for loss of fluid [5]

1. an initiating event causing loss of circulatory volume

2. results in absolute hypovolemia

3. compensatory mechanisms kick in

4. get S+S

pathogenesis of hypovolemia: [4]

absolute hypovolemia

Type of hypovolemia in hypovolemic shock

low or normal BP

eary signs and symptoms of hypovolemic shock (before compensation kicks in)

cool pale skin, tachycardia,
diaphoresis, dyspnea,
agitation/confusion, oliguria

S+S of hypovolemic shock once compensation begins [6]

1. stop initiating event

2. fluid replacement

3. IV fluids or volume expanders or blood products

4. support BP with IV fluids/vasopressors

5. Oxygen (assess ABG, serum lactate)

treatment for hypovolemic shock: [5]

patient is warm because they experience vasodilation first before compensation mechanisms begin. There is a series of events causing warm skin before cool skin occurs.

why do patients feel warm in warm shock?

Neurogenic shock

shock caused by any factor that causes parasympathetic stimulation or inhibits sympathetic stimulation of vascular smooth muscle. Parasympathetic stimulation is greater than sympathetic stimulation.

1. trauma to spinal cord/medulla

2. anaesthetic drugs

Causes f neurogenic shock (2 examples)

1. there is a neurologic insult with unopposed parasympathetic stimulation

2. parasympathetic is greater than sympathetic

3. loss of vasomotor tone

4. leads to peripheral vasodilation

5. get relative hypovolemia

6. some compensatory mechanisms kick in

pathogenesis of neurogenic shock [6]

relative hypovolemia

type of hypovolemia in neurogenic shock

1. warm flushed skin (vasodilation)

2. edema due to hydrostatic pressure

3. low BP due to vasodilation and bradycardia

early signs and symptoms of nuerogenic shock before compensation begins: [3]

get oliguria and concentrated urine. SKin becomes pale and cool due to hypoxia when patient progresses to second stage of shock

S+S of neurogenic shock once compensation mechanisms kick in

1. stop neurological insult (reverse aaesthetic or stabilize spine)

2. support bP with fluids and vasopressors

3. give oxygen

neurogenic shock treatment:

Anaphylactic shock

severe allergic reaction to an antigen causing excessive release of histamine from mast cells and basocphils

1. drugs (penicillin)

2. food allergies

3. latex

Most common allergies {3}

before compensation mechanisms for hypovolemia, skin is flushed due to vasodilation from histamine release.

Why is anaphylactic shock a warm shock?

Low blood pressure from vasodilation due to histamine release

How to patients in anaphylactic shock get relative hypovolemia?

1. warm flushed skin, edema, bronchospasm

2. low BP due to vasodilation and increased vascular permeability

early signs of anaphylactic shock before compensation kciks in:

tachycardia, dyspnea, diaphoresis, oliguria,
agitation, confusion,but with systemic edema
and bronchospasm

S+S of anaphylaxis once compensation bgins: [8]

• Remove Ag causing reaction
• Epinephrine IM/IV
• Airway management
• IV Fluids
• Oxygen (assess ABGs, serum lactate level)
• Support BP with IV fluids and vasopressors
• Antihistamines
• Corticosteroids
• Bronchodilators

anaphylactic shock treatments: [9]

septic shock

complex syndrome associated with a severe overwhelming infection, predeced by bacteremia and sepsis

bacterial toxin (e.g., Pseudomonas aeruginosa, Staphylococcus aureus
– toxic shock, Escherichia coli)

septic shock is frequently caused by what?

relative hypovolemia from vasodilation from chemical mediators

type of hypovolemia in septic shock:

tachycardic, dyspnea, diaphoretic, oliguria,
agitation, confusion, but with edema and
fever also
• Skin becomes pale and cool due to
hypoxia when patient progresses to
second stage of shock

s+s of septic shock once compensation kcisk in

– Warm flushed skin, edema, fever
– Low BP due to vasodilation (low PVR)

Early signs of septic shock before compensation [2]

– Remove source of infection
– Oxygen (assess ABGs, serum lactate level)
– Antibiotics
– Antipyretics (while treating underlying cause)
– Support BP with IV fluids and vasopressors

treatment fro septic shock: [5]

S&S of hypovolemia (low BP)
and cool skin

first presentation of cold shock:

flushed, warm skin secondary to peripheral vasodilation

First presentation of warm shock:

increased RR,

pale cool skin,

diaphoresis,

oliguria

classic shock symptoms: [4]

when there is inadequate tissue perfusion, progressive hypoxia, and metabolic acidosis

second stage of shock:

multiple organ/sstems failure (MODS). It is irreversible (death)

what happens in third stage shi

persistent hypovolemia/hypotension leading increased SNS activity, vasocnstriction, and leads to tissue hypoxia and metabolic acidosis

what happens during stage 2 of cold shock?

serum lactate levels and ABGs consistent with metabolic acdosis

what lab values are expected for second stage shock?

there is persistent hypovolemia. The body attempts to vasoconstrict but is unable to due to blood stuck in the periphery. INcreased tissue hypoxia and metabolic acidosis.

how doe warm shock lead to metabolic acidosis?

1. low BP

2. LOC

signs and symptoms of progressive shock:

Neurogenic shock. You don’t see vasoconstriction in anaphylactic or septic shock.

you don’t see HPA side effect in progressive ___ shock

Cold shock

which progressive shock sees increased vasoconstriction?

they try to help but actually leads to acidosis

How do compensatory mechanisms worsen hypoxia?

1. IV fluids

2. oxygen

3. medications to support BP

4. treat the cause

5. treat acidosis

Treatment for progressive shock:

persistent tissue hypoxia causes metabolic acidosis to worsen. There is altered heart contractility and the sodium/potassium pump malfunctions. Leads to decreased cardiac output, cerebral ischemia, and cardiorespiratory arrest.

Pathogenesis of irreversible shock: