Shock Flashcards
Define shock
Inadequate perfusion of tissue with 02 rich blood
Define perfusion
The circulation of blood through an organ or tissue in amounts adequate to meet the body’s demand
What is another name for shock?
Hypovolemic shock
Why hemoglobin important?
Hemoglobin carries 02 to your cells. Binds to oxygen that is absorbed in the lungs and transports it to the tissues
Components of perfusion?
The pump, the fluid, the container
The heart, the blood, blood vessels. They are essential for circulation of oxygenated blood throughout the body
Define stroke volume
The amount of blood ejected by the heart in 1 contraction
Define preload
Volume of blood delivered to the atria prior to ventricular diastole
Defined afterload
Tension developed by the heart during contraction.
Resistance against which the left ventricle must pump and how much effort the ventricle must put forth to force blood into the systemic circulation
Atrial kick
Atrial kick occurs at the end of diastole.
Define frank starling mechanism
Law that states that the stroke volume of the heart increases in response to an increase in the volume of blood filling the heart
Define cardiac output? Formula? Factors that affect output?
The volume of blood moved by the heart in 1 minute
Stoke volume x heart rate
Stoke volume and heart rate directly affect cardiac output
3 layers of an artery?
Tunica adventitia, tunica media, tunica intima
What does tunica advenitia do?
Allows the arteries to stretch to prevent over expansion due to the pressure that is exerted on the walls by blood flow
What does tunica media do?
Controls the lumen size
What is tunica intima?
It is in intimate contact with the blood in the lumen
What kind of event is shock?
Shock is a cellular event
Where are baroreceptors located?
In the arch of the aorta, the carotid artery, and the kidneys
What are baroreceptors?
They respond to stretching of the arterial wall and manipulates BP. They are most sensitive to changes in BP. Cause vasoconstriction
Baroreceptors send a message to the brain stem and do what?
A message is related to the adrenal glands to secret epinephrine and norepinephrine into the bloodstream.
What are epinephrine and norepinephrine also known as? Where are they secreted and what do they interact with?
They are also known as catecholamines and are directly secreted into the blood stream. Eli and norepinephrine interact with alpha 1 and 2 and beta 1 and 2 receptors
What is a beta 2 receptor and where is it located?
It causes bronchodilation and located in the lung
In decompensated shock what do the kidneys do?
Kidneys stimulates the release of ADH/aldosterone (antidiuretic hormone) and increases the release of renin.
What is rouleaux and what happens?
The stacking of RBCs in misshapen chains which cause microemboli
What is the clotting process?
Vascular phase (vasoconstriction), platelet phase (agglutination and aggregation), coagulation (release of fibrin, clotting/scab, and dissolution of the clot
What is a transverse wound?
Wound is a clean cut, vessels constrict and draw inward
What is a longitudinal wound?
Constriction of smooth muscle, which enlarges wound because there is no vessel constriction which causes increased in blood loss. Ex, crushing trauma
What happens with aggressive fluid therapy?
Increases bp and can dislodge the clots, fluid dilutes body’s natural clotting factors
Where do baroreceptors send in pluses to?
The medulla aka vasomotor center
What nerve controls PNS?
The vagus nerve
What is a mechanism of shock?
Uncontrolled vasodilation
Types of distributive shocks?
Neurogenic, anaphylatic and septic shock
What does renin do and what is it released by?
It is a protein released into the bloodstream by the kidneys and responds to changes in BP to main cardiac output
What does aldosterone do?
Regulates sodium and potassium levels in the body to control blood pressure and the Balance of fluids and electrolytes
How does aldosterone work on the kidneys?
Increases sodium reabsorption into the mood to maintain cardiac output. Enhances potassium elimination in the urine (retains sodium) to raise BP
What does the vasomotor center oversee?
Changes in the diameter for the blood vessels. They vasoconstrict
The combined effects of alpha and beta stimulation help the body increase its ______ supply by converting glycogen to glucose.
Energy
What type of metabolism is being used in compensated shock?
Cellular metabolism, aerobic
What is kerbs cycle?
Series of chemical reactions that release chemical energy in the form of ATP
As shock continues stimulus to what system increases?
The sympathetic nervous system
In decompensated shock, the kidneys kick into high gear and stimulate the release of what?
ADH/aldosterone
The kidneys also increase the release of what?
Renin
The release of ADH/aldosterone and renin causes increase vasoconstriction to support what?
Preload and stroke volume
Which hormone conserves sodium in the kidneys to conserve body water?
Aldosterone
Aldosterone helps to support what?
Preload and stroke volume to help cardiac output
In decompensated shock, cells and tissues become subject to increasing?
Hypoxemia
In decompensated shock, the body has transitioned into what type of metabolism?
Anaerobic
Define anaerobic metabolism
Massive amounts of waste products are produced and less ATP if created. Metabolic acids build in the body
As metabolic acids build up in the resp system, attempts to compensate by doing what to the resp?
Increasing rate and depth of ventilation
Shock continues by increasing vasoconstriction and it constricts the pre capillary sphincters which do what?
Shunts blood to your vital organs but traps remaining blood in capillary beds
What happens to O2 stores in increasing shock and what happens to wastes?
O2 stores are rapidly depleted and waste products quickly build
How does cellular damage occur in irreversible shock?
Continued buildup of metabolic acids and worsening pH
What happens to remaining circulating blood in irreversible shock?
Blood becomes toxic to surrounding cells
What happens to cell membranes in irreversible shock, what do they release, where does the fluid leak? What is the medical term for this process?
Cell membranes break down releasing lysosomal enzymes. The fluid leaks into interstitial space and causes microcirculation
Once the capillary sphincters become ineffective what does this process lead to?
Capillary washout. It’s the release of highly toxic capillary blood into the already acidic circulation
Define blood
A slurry of cells, protein, water and suspended elements
Renin is released into the blood stream by what?
The kidneys
What does renin respond to?
Changes to BP
Renin stimulates the release of what?
Aldosterone from adrenal cortex
What does aldosterone do?
Helps regulate sodium and potassium levels in the blood
How does aldosterone work on the kidneys?
Increases sodium reabsorption into the blood to maintain cardiac output. It enhances potassium elimination in the urine
What is the first and most common sign of shock?
Tachycardia
How does a patient present in compensated shock?
Anxious, agitated and combative
What happens to BP and RR in compensated shock?
Narrowing pulse pressure and increase in resp
How does a patient present in decompensated shock?
Confused, disorientated, sense of impending doom
What happens to BP and HR in decompensated shock?
BP drops precipitously >90 torr. HR decreases and it’s difficult to palpate
How does a patient present in irreversible shock?
Unresponsive
How does BP, HR and RR present in irreversible shock?
BP and HR disappear. RR are agonal, gasping and eventually cease.
Define hypoxia at cellular level
Further buildup of metabolic acids and other wastes caused by anaerobic metabolism and systemic acidosis
What causes hypovolemic shock and what’s the common cause?
Fluid loss due to blood, plasma and body water. Trauma is the most common cause
Unexplained shock is best attributed to what kind of trauma?
Abdominal
Define distributive shock
Widespread dilation of the resistance vessels, capacitance vessels or both
Define neurogenic shock
Inhibition of the sympathetic nervous system. Loss of sympathetic tone. The parasympathetic continues without balance.
How will BP and HR present in neurogenic shock?
BP and pulse will be slow
Define anaphylatic shock
A person reacts violently to a substance in which they have been sensitized.
What does the release of histamine cause?
Severe systemic vasodilation, swelling, flushing, urticaria can airway edema and swelling
Define septic shock
Caused by massive infection. Toxins interfere with the vascular system ability to control and distribute blood. Vasodilation and vasopermeability
How does BP present in septic shock?
Early BP there is an increase is cardiac output. Loss of peripheral vascular resistance. Late -hypotension, precipitous fall in BP.
What can cardiogenic shock cause?
Pulmonary edema
Define cardiogenic shock
Abnormal heart function due to failure of heart muscle, AMI, vascular insufficiency and rhythm disturbances.
what percentage of damage is done to the left ventricle in cardiogenic shock?
40%
What are some causes of obstructive shock?
Tension pneumo, cardiac tamponade, pulmonary edema, cardiac contusion and possible aortic dissection
What does MODS stand for?
Multiple organ dysfunction syndrome.
What is mods?
When enough cells die that the organs fail. Progressive impairment of 2 or more organ systems due to uncontrolled inflammatory response.
What are the two most common causes of mods?
Septic shock and sepsis
What is the pathophysiology of mods?
Microvascular thrombus form leading to tissue ischemia and the organ ultimately dies.
How do patients with mods present?
Cannot maintain BP, fever, tachycardia, dyspnea, necrosis of kidneys and liver
