Shock Flashcards
Shock is a pathophysiologic state with reduced systemic _______ causing tissue hypoxia
tissue perfusion
shock results in what 5 things?
- Compromised function (e.g., CNS, renal)
- Acidemia
- Inflammation
- Coagulopathy
- Cellular injury (reversible or irreversible):
Endothelial injury / dysfunction (enhanced coagulation)
Leakage of intracellular contents (e.g., LDH, ALT, AST – lab tests)
Four primary causes of shock
- Hypovolemic: intravascular volume loss
- Cardiogenic: pump failure
- Distributive: vasodilation (“hyperdynamic” shock)
- Obstructive: blood vessels and heart
Reversal of the cause of shock can reverse the ______ effects on tissues if it is recognized and treat quickly
hypoxic
Systemic tissue perfusion is KEY (think ABC – A_____, B_____, C_____)
Airway, Breathing, Circulation
Perfusion is determined by what 2 things?
- Cardiac output (CO) = heart rate (HR) x stroke volume (SV)
- Systemic vascular resistance (SVR)
Systemic vascular resistance (SVR) is affected by what 3 things?
Vessel length (e.g., obesity) Vessel diameter (constriction vs dilation) Blood viscosity (e.g., hemoconcentration)
Stroke Volume is affected by what 3 things?
preload (volume remaining in ventricle), afterload (resistance to ejection), and myocardial contractility (affected by cardiomyopathy)
shock is caused by decreased __ or decreased ___.
Caused by decreased CO or decreased SVR
Changes in CO or SVR will result in a compensatory change in the other factor, attempting to maintain _________ (e.g., decreased CO will result in an increase in SVR)
tissue perfusion
______ results when the compensation is unable to maintain tissue perfusion at an adequate level
Shock
reduction in perfusion due to vasodilation (e.g., decreased SVR due to anaphylaxis) may not be fully compensated for by increased ___(i.e., increased CO)
HR
Hypovolemic Shock is Due to _______ compared to the total vascular capacity
reduced blood volume
Hypovolemic Shock is Due to reduced blood volume compared to the total vascular capacity. This can be caused by what?
low diastolic filling pressure (reduced preload)
Hypovolemic Shock causes
Rapid or excessive fluid loss:
Dehydration
Burns
Gastroenteritis (e.g., vomiting, diarrhea)
Blood loss:
Hemorrhage
Solid organ injury (e.g., spleen or liver rupture)
Abdominal aortic aneurysm (AAA) rupture
Other hemorrhage
Signs and symptoms of Hypovolemic Shock
7 things
- Hypotension (decreased blood volume)
- Rapid, thready pulse (increased HR with decreased CO and difficult-to-feel pulse)
- Pale, clammy skin (blood diversion to core organs)
- Intense thirst (hypothalamic thirst response; elevated electrolytes, low water, hyperosmotic plasma with dehydration)
- Tachypnea (caused by increased CO2, reduced O2 vs tissue needs) patient is becoming acidodic
- Change in mental status (CNS hypoxia)
- Decreased urine output (reduced GFR from reduced renal perfusion)
Hypovolemic Shock: Renal Response
Decreased GFR leads to increased ____secretion
renin
Decreased GFR leads to increased renin secretion. this Results in increase of what two things?
increased angiotensin and increased SVR
increased angiotensin and increased SVR leads to ________ of arteriolar smooth muscle, and ________ secretion resulting in Na+ retention and K+ loss
Vasoconstriction
Aldosterone
Vasoconstriction of arteriolar smooth muscle
Aldosterone secretion resulting in Na+ retention and K+ loss
what will Inadequate renal perfusion will result in?
loss of renal function
– azotemia, acidemia, etc.
in Cardiogenic Shock, _____failure results in decreased CO
Cardiac pump
causes of Cardiogenic Shock (4)
- Increased ventricular filling pressure (e.g., restrictive cardiomyopathy)
- Ventricular dilation (e.g., dilated cardiomyopathy)
- Heart failure leading to hypotension and pulmonary edema
- Myocardial infarction
Compensatory mechanism in cardiogenic shock is to increase___ to ensure end organ/tissue perfusion
SVR
Compensatory mechanism in Cardiogenic Shock is to increase SVR to ensure end organ/tissue perfusion. what is a negative aspect about this?
increases cardiac work load by increasing afterload
Cardiogenic Shock: Myocardial Ischemia
Ischemia results in decreased ventricular contractility and reduced CO from________.
LV dysfunction
in cariogenic shock, Ischemia results in decreased ventricular contractility and reduced CO from LV dysfunction.
Decreased arterial pressure results in ______ (sympathetic feedback)
increased HR
As HR increases, _________ also increases
myocardial O2 requirement
Increased O2 requirement results in increased HR, which in turn increases O2 requirement. this Exacerbates myocardial ischemia, resulting in severe _______. You will Need more O2 to heart: increase supply (O2 administration, NTG) or decrease use (rest)
cardiac decompensation
type of shock that May result from any cardiac pump failure which reduces CO
Cardiogenic Shock: Other Dysfunction
examples:
Cardiomyopathy (dilated or restrictive)
Ventricular arrhythmia (flutter or fibrillation)
Mechanical abnormalities:
Valve dysfunction
Ventricular-septal defect
Ruptured ventricular wall aneurysm
in Distributive Shock, “Vasodilatory”, caused by severely decreased ____
SVR
in Distributive Shock, what increases to compensate for ↓ SVR?
heart rate
causes of Distributive Shock (5)
- Septic shock (most common)
- Systemic inflammatory response syndrome (SIRS, from burns, pancreatitis, infection)
- Anaphylaxis (IgE mediated)
- Neurogenic shock (brain/spinal cord injury)
- Addison disease crisis
Sepsis and bacterial toxins (Staph aureus toxic shock syndrome) can cause what type of shock?
Distributive Shock
Distributive Shock Results in aggressive acute phase response with what 4 things?
- Leukocytosis
- Fever
- Complement activation
- Cytokine release results in nitric oxide synthesis, causes widespread vasodilation and hypotension
Reduced diastolic blood pressure
Widened pulse pressure
Flushed warm extremities with brisk capillary refill
the above is seen with type of shock?
Early septic shock or “warm shock” (Hyperdynamic)
type of Distributive Shock
Reduced systolic and diastolic blood pressure
Pale, clammy extremities
Pressure dependent decrease in vital organ perfusion
Multiple organ dysfunction syndrome (abdominal organs, CNS, heart; also called multiple system organ failure)
the above is seen with type of shock?
Late septic shock or “cold shock” (Hypodynamic)
type of Distributive Shock
characteristics of Early septic shock or “warm shock” (Hyperdynamic)
(3 things)
- Reduced diastolic blood pressure
- Widened pulse pressure
- Flushed warm extremities with brisk capillary refill
characteristics of Late septic shock or “cold shock” (Hypodynamic)
- Reduced systolic and diastolic blood pressure
- Pale, clammy extremities
- Pressure dependent decrease in vital organ perfusion
- Multiple organ dysfunction syndrome (abdominal organs, CNS, heart; also called multiple system organ failure)
Anaphylactic shock is what type of shock?
type of Distributive Shock
in Anaphylactic shock, there is a Massive activation of _____ (tissue) and _____(blood) by binding of surface IgE to allergin
mast cells
basophils
Anaphylactic shock causes a systemic release of what 3 things?
Systemic release of histamine, serotonin, leukotrienes
Anaphylactic shock Results in _____, increased vascular permeability (loss of vascular volume to extravascular spaces)
vasodilation
Anaphylactic shock signs
Signs of edema (angioedema), dyspnea (bronchiolar smooth muscle contraction, pulmonary edema), hypotension
Obstructive Shock is caused how?
Reduced CO caused by extracardiac abnormalities:
- Massive pulmonary embolus (inadequate return to left atrium)
2. Tension pneumothorax (inadequate filling) Constrictive pericarditis (inadequate filling)
- Pulmonary HTN (inadequate return to left atrium)
- Cardiac tamponade (inadequate filling)
Prolonged Shock can lead to what two things?
Permanent CNS injury
Multiple organ dysfunction syndrome
Why might Multiple organ dysfunction syndrome occur in prolonged shock?
Because of low pressure of abdominal organs, reduced visceral blood pressure results in kidneys, intestine, liver, heart, brain
