Shock
General Surgery Orientation
Medical Student Lecture Series
Dr. Peter Meade
SHOCK
SHOCK
Burning building
Desert
SHOCK
Low perfusion
Low Oxygen Delivery
Cells deprived of Oxygen
Glucose incompletely metabolized
Lactic Acidosis
Burning glucose without Oxygen = lactic acidosis
Burning wet sticks = smoke
Krebs Cycle
36 ATPs
Anaerobic glycolysis
2 ATPs
Hypoperfusion
• Anaerobic glycolysis
• Lactic Acidemia
– Low bicarbonate
– Low pH
• Multisystem Organ Failure
SHOCK
Lack of Oxygen
Delivery
Low blood pressure
i
Decreased perfusion of tissues
with Oxygen
i
Cell Damage
Inflammatory Response
SHOCK
Lack of Oxygen Delivery
(Hypoperfusion)
i
Cellular Damage
i
Inflammatory Response
Hypoperfusion causes Inflammation
Inflammation causes Hypoperfusion
What causes….
SHOCK
SHOCK
Hypovolemic
Obstructive
Cardiogenic
Distributive
SHOCK
Hypovolemic
-Hemorrhagic
-Non-hemorrhagic
dehydration, burns, GI losses, pancreatitis
Obstructive
Cardiogenic
Distributive
SHOCK
HYPOVOLEMIC
hemorrhagic
SHOCK
Lack of Oxygen
Delivery
(Hypoperfusion)
h
Hypovolemia
Bleeding / Hemorrhage
Hypoperfusion causes Inflammation
Inflammation causes Hypoperfusion
SHOCK
HYPOVOLEMIC
Non-hemorrhagic fluid losses
Open wounds
Burns- incredible fluid losses !
TREATMENT OF SHOCK
Treat the primary cause
“Source Control”
Hemorrhagic / Hypovolemic
– Stop the bleeding
– Replace blood loss, volume
Starling Curve
• Preload
• Contractility
• Afterload
Starling Curve
• Preload
• Contractility
• Afterload
Hypovolemic Shock
Hemorrhagic shock (3 categories)
1. Compensated:
– 0-20% of blood loss
– Blood pressure is maintained
– increased vascular tone
– increased blood flow to vital organs
Hypovolemic Shock
The body’s response:
Compensated shock
Baroreceptor mediated
vasoconstriction
Increased epinephrine, vasopressin, angiotensin
Results in:
Tachycardia
Tachypnea
Lowered pulse pressure
Slightly lowered urine output
Hypovolemic Shock
2. Uncompensated:
20-40% loss of blood volume
Decrease in BP
Tachycardia
Hypovolemic Shock
3. Lethal exsanguination:
40% loss of blood volume
Profound hypotension and inability to
perfuse vital organs
Hypovolemic Shock
Volume Resuscitation ~ What are my goals?
1. Rapid Responder
– Give 500cc-1 Liter crystalloid  rapid
improvement of BP/HR/Urine output
– < 20% blood loss
– Surgery consult
Hypovolemic Shock
Volume Resuscitation ~ What are my goals?
2.Transient Responder
– 500cc-1 Liter crystalloid 
improves briefly then deteriorates
– 20-40% blood loss
– Continue crystalloid infusion +/- Blood
– Surgery consult
Hypovolemic Shock
Volume Resuscitation ~ What are my goals?
3. Non Responder
– Give 2 Liters crystalloid/ 2 units Blood  no
response
– > 40% blood loss
– STAT Surgery consult!
Hypovolemic Shock
Is my volume resuscitation
adequate/inadequate?
Urine output
Vital signs
Skin perfusion
Pulse Oximetry
Acidemia
Hypovolemic Shock
Loss of circulating blood volume (Plasma)
Normal Blood Volume:
- 7% IBW in adults
- 9% IBW in children
SHOCK
Hypovolemic
Obstructive
Cardiogenic
Distributive
SHOCK
Hypovolemic
Obstructive
poor diastolic filling:
-tension pneumothorax
-pericardial tamponade
-abdominal compartment syndrome
poor systolic contraction:
-pulmonary embolus
-aortic dissection, tumors
Cardiogenic
Distributive
SHOCK
Obstructive
decreased venous return
SHOCK
Hypovolemic
Obstructive
Cardiogenic
Distributive
SHOCK
CARDIOGENIC
Pump Failure
Cardiogenic Shock
SHOCK
Hypovolemic
Obstructive
Cardiogenic
Myocardial infarction, contusion,
myocarditis
Mechanical valve failure, VSD,
ventricular wall defects
Distributive
SHOCK
Lack of Oxygen
Delivery
(Hypoperfusion)
h
Cardiogenic
Acute Myocardial infarction
Aortic or mitral valve dysfunction
Dysrhythmia
Cardiac contusion
Massive Pulmonary embolism
Cardiac Tamponade
Congestive Heart Failure
Hypoperfusion causes Inflammation
Inflammation causes Hypoperfusion
Cardiogenic Shock
Acute hypotension
low cardiac output
inadequate LV outflow
Poor end organ perfusion!
SHOCK
Hypovolemic
Obstructive
Cardiogenic
Distributive
Septic, anaphylactic, neurogenic,
pharmacologic, endocrinologic
SHOCK:
SEPTIC: Endotoxins from bacteria = Shock!
SHOCK
Lack of Oxygen
Delivery
(Hypoperfusion)
h
Septic
Septicemia, Endotoxins, Vasodilatation,
pneumonia,
urinary tract infection,
dead intestine,
necrotic tissue
Hypoperfusion causes Inflammation
Inflammation causes Hypoperfusion
Septic Shock
exaggerated endogenous inflammatory
response to invasive infection leading to:
-circulatory collapse
-multiple organ failure
-death
Septic Shock
Mortality
over 35% (sepsis with hypotension)
45% (sustained septic shock)
TREATMENT OF SHOCK
Treat the primary cause
“Source Control”
Septic
– Drain the abscess
– Treat with antibiotics, volume, pressor agents
SHOCK
Lack of Oxygen Delivery
(Hypoperfusion)
i
Cellular Damage
i
Inflammatory Response
Hypoperfusion causes Inflammation
Inflammation causes Hypoperfusion
The Inflammatory Response
It can be like using a machine gun to kill a fly on the wall….
You might get the fly, but the wall gets hit too!
Inflammatory Response
• Vasoconstriction
• Vasodilation
• Capillary leak
– Nitric Oxide, PG2, kinins, histamine serotonin
• White Cells/ Polymorphonuclear cells
– Phagocytosis: proteases, Interleukins
Inflammatory Response
Platelet Activation
PDGF
TGF-B
WBC Products
P-seletin
E-selectin
ICAM 1
WBC Proteases
IL-1, IL8
TNF