- the abnormal physiologic state that is the first phase of the body's alarm reaction to an insult or injury.
- - progresses to multiple system organ failure
When does shock occur?
CV system fails to perfuse tissues adequately
What happens if shock is left untreated?
progressive circulatory collapse occurs, compensatory mechanisms unable to adjust, death results.
What are the three classifications of shock?
- 1. Hypovolemic shock: decreased intravascular volume
- 2. Cardiogenic shock: pump failure
- 3. Distributive shock "vasogenic shock" : includes neurogenic, anaphylactic (hypersensitivity), and septic (infection) - alterations in smooth muscle tone.
Define hypovolemic shock.
occurs when there is a 15-20% loss of the blood volume.
What is the most common cause of hypovolemic shock?
- excessive blood loss through trauma of major blood vessel or organ- spleen, liver, kidney
- - hemorrhage
- -severe burn
- -overuse of diuretics
- -third spacing (ascites)
The severity of hypovolemic shock relies on ...
amount and rate of blood loss.
When is hypovolemic shock irreversible?
If volume loss is not replaced quickly and the aortic pressure is low for longer than 60 minutes.
What are common clinical manifestations of hypovolemic shock?
- Low: CO, CVP, PAP, BP, UO, pulse, pH (acidosis), O2 (hypoxemia)
- High: SVR, HR, RR,
- -Cold, clammy skin, Confusion, Restless, Pallor
In hypovolemic shock three main compensatory mechanisms are activated:
- 1. Vasoconstrictor
- 2. Shift fluid from interstitial to intravascular compartment
- 3. Increased pumping efficiency of the heart
What is the treatment for hypovolemic shock?
- 1. Treat the cause
- 2. Volume replacement
- 3. O2
- 4. Monitor: EKG, Hemodynamic status, UO
- 5. Vasopressors (not effective until volume is replaced)
Define Cardiogenic shock.
heart fails to maintain an adequate CO to meet the body's metabolic needs.
What is the most common cause of Cardiogenic shock?
- Acute MI: most common cause
- - heart failure, post open heart surgery, cardiomyopathy, valvular heart disease, arrhythmias, mechanical defects-VSD, myocardial infections, drug toxicity
Clinical manifestations of Cardiogenic shock.
- impaired thinking
- Low: BP, hypoxemia, pH (acidosis), SOB, UO to oliguria, CO
- High: HR, preload, pulmonary edema
- - Pallor to cyanosis
What is the treatment for cardiogenic shock?
1. Regulation of fluid volume: frank-starling mechanism without pulmonary congestion done through hemodynamic monitoring
2. Promote pumping ability of heart (CO): inotropic drugs like dopamine and dobutamine, control arrhythmias, afterload reduction through NTG, and Nitropusside IABP
3. Increase blood flow: regulation of bp via fluid replacement or dopamine
4. Neutralize the effects of tissue hypoxia through bicarb
Define distributive shock
normal pump, normal volume but intravascular volume is mal-distributed within circulatory system.
When does distributive shock occur?
when there is a loss of blood vessel tone
Which types of shock fall under the classification of distributive shock?
- 1. Neurogenic Shock
- 2. Anaphylactic Shock
- 3. Septic Shock
Define neurogenic shock
results from an imbalance between parasympathetic and sympathetic NS - due to decreased sympathetic control of blood vessel tone.
What causes neurogenic shock?
- -brain injury
Define anaphylactic shock
"distributive shock" - result of widespread hypersensitivity reaction
Define septic shock
- type of distributive shock
- - develops because of body's immune and inflammatory responses to endotoxins released when gram negative bacteria is destroyed
Which type of distributive shock is most common?
Septic shock is marked by altered _______, decreased _____ ______, and the loss of ______ _______.
- altered hemodynamics
- decreased tissue perfusion
- loss of cellular energy
the over-response in severe septic shock disrupts homeostasis through ....
- an uncontrolled cascade:
- -impaired fibrinolysis
The increasing severity and mortality of sepsis is illustrated by a contiuum of events:
- -Severe sepsis
- -Septic Shock
- -Multiple organ dysfunction (MOD), which often leads to death
Manifestations of SIRS includes the presence of more than one of the following:
- Temp >100.4 or <96.8
- HR > 90 bpm
- RR > 20 or hyperventilation PaCO2<32
- WBC >12,000 or < 4,000
Who is at risk of developing severe sepsis?
- -chronic health issue
- -bladder infection
- -defects in skin integrity
- -untreated GI
What are some common complications of shock?
What are the three stages of clinical manifestations in septic shock?
1. Hyperdynamic: confused, flushed & warm skin, bounding pulse, increased HR & CO, normal BP, decreased SVR
2. Normodynamic: short hard to recognize
3. Hypodynamic: cold and clammy skin, hypotension, weak thready pulse, hypoxia, acidosis, decreased UO, high PAP and CVP pressure, respiratory failure
What is the treatment of septic shock?
antimicrobial, remove infection source, fluid, activated protein C