Shock Module Flashcards
When does shock occur?
When the CV system fails to serve the body’s needs
What does shock result in?
Impairment of cellular metabolism and tissue function
What is the common characteristic of all types of shock?
Decreased oxygen delivery or increased tissue demand for oxygen
What determines O2 delivery? (5)
- BP
- SVR
- CO
- SV
- O2 content
BP =
CO X SVR
SVR=
(Viscosity x length)/radius^4
CO
SV XHR
SV =
preload, afterload, contractility
O2 content =
partial pressure of oxygen, [hemoglobin]
What helps move oxygen from air to blood to tissues?
differences in partial pressure
What increases O2 demand? (5)
- increased BMR
- infection/fever
- increased work of organs
- agitation or pain
- increased workload of heart
Impaired O2 delivery will result in ___
shift from aerobic respiration to anaerobic respiration
What are the 4 different stages of response to shock?
- initial stage
- compensatory stage
- progressive stage
- refractory stage
What does the initial stage of shock entail?
cellular alterations as a result of decreased O2 delivery and utilization (no clinical symptoms are evident except for elevated lactate levels
What does the compensatory stage of shock entail?
neural, hormonal, chemical responses designed to improve tissue perfusion and oxygen delivery
What does the progressive stage of shock entail?
reached if compensatory mechanisms are unsuccessful in providing perfusion; multiple organs may shut down
What does the refractory stage of shock entail?
reached if medial interventions are unsuccessful; organ damage is extensive, permanent damage to pericardium, death is inevitable
What are the neural responses in the compensatory stage of shock?
- baroreceptors sense the decreased BP
- increased sympathetic output increased PVR, HR, CO, BP
- reduced blood flow to kidneys, GI, skin
What are the hormonal responses in the compensatory stage of shock?
- adrenal medulla releases catecholamines
- posterior pituitary releases ADH
- reduced blood flow to kidneys results in the activation of RAAS
What is the chemical response in the compensatory stage of shock?
hypoexmia and acidosis stimulate increase in respiratory depth and rate in effort to imrpove blood oxygenation and to blow off CO2 to correct for the acidosis
Hypovolemic shock disrupts homeostasis by ___
reducing BV and BP
What are types of cardiogenic shock?
- MI
- arrhythmias
- cardiomyopathy
- valve problems
- problems in ventricular flow/filling
What causes cardiogenic shock?
Reduced SV/HR
T or F: skin feels cool or cold in cardiogenic shock
TRUE
What are types o obstructive shock?
- pulmonary embolism
- pericardial effusion (tamponade)
- tension pneumo-thorax
What causes obstructive shock?
Impaired blood flow
T or F: skins appears blue in obstructive shock
TRUE
What are types of hypovolemic shock?
- bleeding
- dehydration
What causes hypovolemic shock?
REDUCEED PRELOAD
T or F: peripheral pulses are palpable in hypovolemic shock
FALSE
What are types of distributive shock?
- sepsis
- anaphylaxis
- acute spinal cord injury
- venoms
- overactive thyroid
What causes distributive
Low SVR
T or F: skin appears pink/flushed and warm in distributive shock
TRUE
Clinical changes in which vital organs serve to identify the presence of shock?
Brain, heart, kidneys
What is the mortality rate of septic shock?
24-35%
What is the mortality rate of cardiogenic shock?
35-56%
