Block 2 - Shock Physiology Flashcards
What is shock?
Clinical syndrome characterized by acute circulatory failure with inadequate or inappropriately distributed tissue perfusion → imbalance between oxygen supply and demand
Hypoperfusion can trigger ___ and ____ cascades
Inflammatory and clotting
What are the types of shock?
- Obstructive
- Cardiogenic
- Distributive
- Hypovolemic
- Septic (anaphylactic)
What are the common characteristics of shock?
Acute circulatory failure that causes hypotension and inadequate tissue perfusion.
What circulatory alterations that lead to shock?
- HF
- Low BV
- Redistribution of ECF to extravascular sites
- Obstruction of blood flow
What are the factors affect CO?
- Factors that decrease blood volume
- Affect cardiac filling
- Affect contractility
- Affect HR
Systemic vascular resistance is caused by ___
- Extensive increase in systemic vascular dilation
- Fluid redistribution
- Inflammatory reactions
How many ICU patients are effected by shock?
1/3
How do you diagnose shock?
- Clinical
- Hemodynamic
- Biochemical
What is the clinical diagnoses for shock?
<90/70
Tachycardia
Tissue hypoperfusion
Renal output
Altered mental state
What are the hemodynamic diagnoses for shock?
Hyperlactemia
Hypercoagulability
Shock is ultimately a ___ of fluid in circulatory system
Deficit
How does the body compensate for shock?
- Increase HR and SNS
- Vascoconstriction
- Hypotension
- Circulating volume continues to drop
What is hemodynamic?
Forces the heart has to respond to maintain blood flow through the cardiovascular system and supply oxygen to all tissues.
What are the four facotrs that influence circulation?
- BV
- Systemic vascular tone
- HR
- Force of contraction
What it MODs and what does it cause?
Multiple organ dysfunction syndromes: Hypoxia and decreased oxygen delivery → anaerobic metabolism
What it MODs and what does it cause?
Map how metabolic mods cause shock?
What is hypovolemic shock?
Rapid blood or other ECF fluid loss.
What is cardiogenic shock?
Hypoxic damage to organs that results when the heart is unable to circulate an adequate amount of blood.
What is distributive shock?
Impaired distribution of blood flow due to extensive vasodilation and loss of vascular tone.
What is obstructive shock?
Life-threatening condition caused by obstruction of blood flow to body’s organs.
What is anaphylactic shock?
- Acute, life-threatening, IgE-mediated allergic reaction.
- re-exposure in those persons sensitive to an allergen
What are the stages of shock?
- Early, reversible, or compensated shock.
- Intermediate or progressive shock.
- Refractory or irreversible shock.
What occurs in stage 1 of shock?
- Baroreceptors respond to low blood pressure → increased sympathetic stimulation → increased heart rate and constriction of blood vessels.
- Poor kidney perfusion → activation of RAAS → reabsorb sodium and water.
Strong chance of recovery with proper treatment
What occurs in stage 2 of shock?
Decrease in perfusion → leads to cellular hypoxia → confusion and disorientation
Reversible wtith prompt treatment
What occurs in stage 3 of shock?
- Decline in heart funciton
- Kidney shutdown
- Organ injury
Death due to multiple organ dysfunction
How does hypovolemic shock cause hemodynamic instability?
H: Decrease in tissue perfusion and O2 delivery
To be classified as hypovolemic shock, a patient must loss ___ of body fluids?
15%
What causes the rapid loss of fluid and whole blood?
- Trauma
- Internal bleeding
- Edema
- Dehydration
- Postpartum hemmorage
What does fluid loss lead to in hypovolemic shock?
- Hemodynamic instability
- Decreases in tissue perfusion and oxygen delivery
- Cellular hypoxia
- Organ damage
- Death
What are the management goals for hypovolemic shock?
- Stop bleeding
- Restore circulation
What are the compensatory mech of hypovolemic shock?
- Hematologic
- Cardiovascular
- Renal
- Neuroendocrine
What occurs in the hematologic compensatory mechanism? How long does it take and why is it good?
Clotting of blood to end further blood loss (24 hr) to improve CO and perfusion pressure
What is importance of decline BP?
Increased sympathetic outflow → release of NE and epinephrine → increased SVR and HR
Decreased vagal (parasympathetic) outflow
What occurs in the renal compensatory mechanism?
Kidney responds to a decrease in perfusion pressure by releasing renin activating RAAS
What occurs in the cardiovascular compensatory mechanism? What symptoms does it cause?
- Shunts blood to vital organs requiring more oxygen.
- Decreases blood flow to less vital organs.
Cold, clammy skin and delayed capillary refill
What are the clinical manifestation of hypovolemic shock?
- <90 SBG
- Orthostatic hypotension (SBP decrease of 20 mmHg, or DBP decrease of 10 mmHg, or
Increase in HR of 15 beats/min)
How is hypovolemic shock diagnose?
1.CBC
2. Serum electrolyte
3. Blood glucose
4. PTT
5. Hematocrit
6. Serum lactate and arterial pH
What are symptoms of hypovolemic shock?
- Rapid breating
- SOB
- Tachycardia
- Weak pulse
- Pale skin and cold appendages
- Low urination
What are the treatments for hypovolemic shock?
- Maxamize O2 delivery
- Prevent further fluid loss
- Replace lost fluids
What are the hemodynamic changes of cardiogenic shock?
- Persistnet hypotension
- Reduction of CI
- Adequate or elevated filling pressures
What are cormorbidities of cardiogenic shock?
- LVHF
- Bardiac trauma
- Myocarditis
What is the cause of cariogenic shock?
Acute MI → Progressive decrease in coronary perfusion, myocardial contractility and SV, Increase in ESV→ Increased O2 demand → Hypoxia
Hpoperfusion increases ____ and ____ leading to _____ from ____
- Anaerobic metabolism
- Production of lactic acid
Acidosis and hypoxia from lysosomal breakdown, mitochondrial swelling and inflammatory cascade
____,_____,and_____ are the compensatory mechanisms involved in cariogenic shock that increase _____, _____,_____, and _____
- SNS
- RAAS
- ADH
Fluid retention, HR, Contractility. cardiac O2 and nutrient demand
How do you worsen the heart in cariogenic shock?
- Shock
- Impaired tissue metabolism
What are the clinical manifestation of cariogenic shock?
- Cyanosis
- Rapid pulse
- Low pressure, tachycardia
- Distant heart sounds
- Peripheral edema
- Jugular distention
- Crackles in lungs
What are the types of distributive shock?
- Septic
- Anaphylactic
- Neurogenic
What is anaphylaxis?
Acute, life-threatening, IgE-mediated allergic reaction that occurs on re-exposure in individuals who are sensitive to an allergen or antigen.
What is anaphylactic shock?
antibody IgE produced by plasma cells binds to membrane receptors on mast cells and basophils.
What are some triggers for anaphylactics?
- Drugs, foods, and proteins
- Animal or insect venoms
- Latex
- Heavy metal poisoning
- Exercise and exposure to cold temperature
What are the clinical manifestation of anaphylactic shock?
- Stridor
- Tachycardia
- Dyspnea
- Edema
- Brondoconstriction
- Hypotension
What is the treatment for anaphylactic shock?
- E
- Patent airway
- Beta agonists
- IV fluid expanders
- Vasopressors
What is septic shock?
Life-threatening organ dysfunction caused by dysregulated host response to infection.
Septic shock accounts for ____ of deaths in hospital patients?
40%
What is SOFA?
Sequential organ failure assessment: Assessment measure that evaluates the different systems believed to be involved in the pathogenic process of sepsis or influenced by resultant organ failure
What is the qSOFA diagnostic criteria?
- ICU
- ≥22/min
- Altered mentally
- SBP: ≤100
What is the treatment for septic shock?
- Perfusion restored with IV fluids and vasopressors
- O2 support
- Broad spectrum antibiotics
- Infection source control
What is neurogenic shock caused by?
- Blockage of sympathetic nervous system outflow to intrathoracic sympathetic chain.
- Any factor/condition that increases parasympathetic stimulation.
What are risk factors for neurogenic shock?
- Spinal cord injury above T6
- Absence of hypovolemia
What is spinal shock?
Loss of reflex function below spinal cord injury level; resolves gradually over 4 weeks
What is hypovolemic shock?
Associated with tachycardia
What are the clinical manifestations of neurogenic shock?
- Blockage of sympathetic outflow → bradycardia and vascular dilation
- Blood pools in peripheral vessels → decreased venous return and CO, hypoperfusion of organs
What is the treatment for neurogenic shock?
- Fluid replenishment
- Vasopressors
- Stabilization of spine and neck
- Airway patency
- O2
- CS
- Atropine
What are causes of obstructive shock?
- Pulmonary embolism
- Cardia tamponade
- Tension pneumothorax
What are the clinical manifestations of obstructive shock?
- Disturbances of consciousness
- Oliguria
- Hypotension
- Tachycardia
- Decreased cardiac function and circulatory failure
What is the treatment of obstructive shock?
- Pneumothorax (decrease chest tension or pressure on heart)
- Needle thoracotomy and pericardiocentesis (pericardial effusion and cardiac tamponade)
- Pulmonary emboli (surgical removal of block)