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63 Cards in this Set

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Four components that need to be intact to maintain normal tissue perfusion
1. Intact vascular system
2. Adequate air exchange
3. Adequate volume of fluid
4. functioning pump
Formulas that describe the "steady state" of activity needed to maintain blood pressure (BP + cardiac output)
Blood Pressure = Cardiac Output x Peripheral Vascular Resistance
Cardiac Output = Heart Rate x Stroke Volume
4 basic rules of shock management
1. Maintain airway
2. Maintain oxygenation / ventilation
3. Control bleeding where possible
4. Maintain circulation - adequate HR and vascular volume
How positive pressure ventilations can have a negative effect on cardiac output
by decreasing the blood return to the heart
Description of shock
condition that occurs when the perfusion of the body's tissues with oxygen, electrolytes, glucose, and fluid becomes inadequate to meet the body's needs
the backup process of energy production the body uses when deprived of oxygen
anaerobic metabolism
by product of anaerobic metabolism that disrupts cellular activity
lactic acid
With inadequate oxygen to the body, the sympathetic nervous system increases release of what 2 circulating catecholamines? What are their effects?
epinephrine and norepinephrine. increase in heart rate and contractility and constriction of peripheral blood vessels
Response of the midbrain to hypoxia and acidosis
increases respiratory rate
Clinical manifestations of shock. When present, what do they imply?
pale, diaphoretic, tachycardic. Cells in vital organs are vulnerable and susceptible to severe and permanent damage. Multisystem organ failure can develop days after admission to ICU
hypotension is a late sign of the state of shock, how low can a blood pressure get and still maintain proper perfusion?
varies with each patient; elderly or patients with chronic hypertension can't tolerate hypotension as well as a healthy young patient
What type of shock is most often categorized into either compensated or decompensated?
hypovolemic shock
Shock state in which the body is able to employ regulatory mechanisms to maintain perfusion
compensated shock
signs and symptoms associated with compensated shock
Weakness, thirst, pallor, tachycardia, diaphoresis, tachypnea, decreased urinary output, weakened peripheral pulses
cause of pallor in hypovolemia
catecholamine-induced vasoconstriction and/or loss of circulating RBC's
cause of diaphoresis in hypovolemia
effect of catecholamines on sweat glands
cause of tachypnea in hypovolemia
combined effect of stress, catecholemines, acidosis, and hypoxia
cause of thready pulse in hypovolemia
arteries shrink in diameter as volume is lost
signs and symptoms of decompensated shock
Hypotension, altered LOC, cardiac arrest
causes of cardiac dysfunction in shock
hypoxia and acidosis
effects of acidosis on blood pressure
causes a loss of response to catecholamines, worsening the drop in BP; usually the point where compensating patient crashes
the pressure driving blood through the vascular system
pulse pressure
how to measure pulse pressure
subtract diastolic from systolic
Why is there almost always a narrowing in pulse pressure early in shock syndrome?
vasoconstriction causes initial rise in BP, raising diastolic more than systolic
the loss of approx. 15 - 25% of the blood volume stimulates slight to moderate compensation symptoms. pulse is fast
early shock
loss of approx. 30 - 45% of blood volume causes hypotension as body's ability to compensate has failed. patient is near death. pulse weak or absent
late shock
tip to estimating systolic BP in late shock
radial 80
femoral 70
carotid 60
What are the pros and cons of using capillary refill time as a diagnostic tool
pros: useful in evaluating small children in whom it is difficult to get an accurate BP.
cons: associated with late shock, associated with both false-positives and false-negatives, affected by cold, low blood volume, and vasoconstriction
earliest reliable sign of shock
tachycardia - anyone sustaining HR over 100 must be suspected of having occult hemorrhage until proven otherwise; over 120 is red flag
Factors that could prevent tachycardia in hypovolemia
- 20% of abdomen bleeding victims don't develop tachycardia
- medications: beta-blockers, calcium channel blockers
capnography findings that can indicate circulatory collapse and worsening shock
falling much under 35, especially into the 20's or below
3 major classifications (types) of shock
Low volume (absolute hypovolemia)
High space (relative hypovolemia)
Mechanical (cardiogenic or obstructive)
Examples of low-volume shock
- hemorrhage, diarrhea, vomiting
- third spacing from burns, peritonitis, etc
Examples of high-space shock
- spinal injury, vasovagal syncope, sepsis, OD of vasodilators
Examples of mechanical shock
- damage to heart (contusion or MI), cardiac tamponade, tension pneumothorax, pulmonary embolism (obstructs pulmonary blood flow)
number one cause of preventable death from injury
hemorrhagic shock
term that describes the shock that develops from loss of fluid volume only
absolute hypovolemic shock
another term for high-space shock
relative
blood volume an adult vascular system could conceivably hold if arterioles were fully dilated. What prevents this
25 L
steady-state action of the sympathetic nervous system
spinal shock
neurogenic shock
causes/types of high-space shock
neurogenic shock (only traumatic cause), OD, sepsis
in neurogenic shock, the brain's sympathetic signals cannot be sent because the pathway is disrupted; what physiological factor may allow the body to maintain BP for a short time in this case?
circulating catecholamines already present in the bloodstream
presentation of neurogenic shock
skin is warm, dry, and pink (no catecholamine production)
hypotensive, HR is normal or slow
may have paralysis or deficit
diaphragmatic breathing
priapism
what is observed with diaphragmatic breathing
abdomen protrudes with inspiration; often only observed when patient is asked to consciously take a deep breath
average cardiac output for adult
5 L / min
type of shock caused by a traumatic or medical condition that slows or prevents normal blood flow
mechanical shock (cardiogenic or obstructive)
causes of mechanical shock
tension pneumothorax, cardiac tamponade, cardiac contusion
physiology of tension pneumothorax effect on blood flow
developing high positive pressure in the pleural space collapses the low pressure superior and inferior vena cava, preventing blood return to the heart, thus lowering cardiac output (this is why JVD may be present)
physiology of pericardial tamponade (cardiac tamponade)
blood fills potential space between heart and pericardium, squeezing the heart and preventing it from filling; lowers cardiac output. (JVD may be present)
name given to three major signs of cardiac tamponade
Beck's triad
3 major signs of pericardial tamponade
JVD, muffled heart tones, pulsus paradoxus
a drop of >10mmHg in systolic BP during inspiration (may lose radial pulse during inspiration and regain during expiration)
pulsus paradoxus
tx of cardiac tamponade
surgical care for pericardial decompression
IV fluids only under medical direction (could increase filling pressure, but also increase bleeding)
physiology of cardiac contusion
heart loses pumping strength due to direct injury to the heart muscle and/or disrhythmias that may result.
difficult to differentiate from cardiac tamponade in the field
effect of taking the time to immobilize a patient with penetrating injury to the trunk
doubles the death rate
signs of mechanical shock
JVD
cyanosis - extremely late sign from lung hypoperfusion
tachycardia
O2 administration for shock
give high-flow to all patients at risk for shock. (don't forget to put on capnography, too)
steps to control bleeding
direct pressure in most cases
otherwise quickly apply tourniquet
body position to transport trauma patient
horizontal
IV gauge for trauma patient
large bore (16 g or more)
IO if you can't get quick IV access
fluid administration for external controlled bleeding
20 mL / kg IV rapidly then repeat Ongoing exam. if signs of shock persist, continue to administer fluid in boluses and reassess
fluid administration for external uncontrolled bleeding or internal bleeding
give only enough to maintain a BP high enough for adequate peripheral perfusion.
measured with radial pulses and LOC (brain perfusion)
higher BP may be required for head injured patient or patient with hx of htn
recommended BP in hemorrhagic shock with head injury
120 systolic to maintain 60 mmHg cerebral perfusion pressure