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ShockShock
General Surgery OrientationGeneral Surgery OrientationMedical Student Lecture SeriesMedical Student Lecture Series
Dr. Peter MeadeDr. Peter Meade
SHOCK
SHOCK
Burning building Desert
SHOCK
Lack of Oxygen Delivery
Low blood pressure
Decreased perfusion of tissues with Oxygen
Inflammatory Response
Cell Damage
SHOCKLack of Oxygen Delivery
(Hypoperfusion)
Cellular Damage
Inflammatory Response
Hypoperfusion causes Inflammation
Inflammation causes Hypoperfusion
What causes….
SHOCK
SHOCK
Most common forms in surgery:
Hypovolemic
Septic
Cardiogenic
SHOCK
Lack of Oxygen Delivery
(Hypoperfusion)
HypovolemiaBleeding / Hemorrhage
Vomiting
Pancreatitis
Burns
Trauma
Hypoperfusion causes Inflammation
Inflammation causes Hypoperfusion
SHOCK HYPOVOLEMIC
hemorrhagic
SHOCK HYPOVOLEMIC
Non-hemorrhagic fluid losses
Open wounds Burns- incredible fluid losses !
SHOCK:SEPTIC: Endotoxins from bacteria = Shock!
SHOCK
Lack of Oxygen Delivery(Hypoperfusion)
Septic
Septicemia, Endotoxins, Vasodilatation, pneumonia,
urinary tract infection, dead intestine, necrotic tissue
Hypoperfusion causes Inflammation
Inflammation causes Hypoperfusion
SHOCK CARDIOGENIC
Pump Failure Cardiogenic Shock
SHOCKLack of Oxygen
Delivery(Hypoperfusion)
Cardiogenic
Acute Myocardial infarctionAortic or mitral valve dysfunction
DysrhythmiaCardiac contusion
Massive Pulmonary embolismCardiac Tamponade
Congestive Heart Failure
Hypoperfusion causes Inflammation
Inflammation causes Hypoperfusion
SHOCKLack of Oxygen Delivery
(Hypoperfusion)
Cellular Damage
Inflammatory Response
Hypoperfusion causes Inflammation
Inflammation causes Hypoperfusion
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
The Inflammatory ResponseIt 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!
Hypoperfusion
• Anaerobic glycolysis
• Lactic Acidemia– Low bicarbonate– Low pH
• Multisystem Organ Failure
Krebs Cycle
36 ATPs
Anaerobic glycolysis
2 ATPs
Burning glucose without Oxygen = lactic acidosisBurning wet sticks = smoke
TREATMENT OF SHOCK
Treat the primary cause
“Source Control”
Hemorrhagic / Hypovolemic– Stop the bleeding– Replace blood loss, volume
Septic– Drain the abscess– Treat with antibiotics, volume, pressor agents
Starling Curve
• Preload
• Contractility
• Afterload
Starling Curve
• Preload
• Contractility
• Afterload
Hypovolemic Shock
Loss of circulating blood volume (Plasma)
Normal Blood Volume:
- 7% IBW in adults
- 9% IBW in children
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 mediatedvasoconstriction
Increased epinephrine, vasopressin, angiotensin
Results in:TachycardiaTachypneaLowered pulse pressureSlightly lowered urine output
Hypovolemic Shock
The Organs who win:BrainHeartKidneysLiver
The Organs who lose:SkinGI tractSkeletal Muscle
Hypovolemic Shock
But why
The body will make whatever adjustsments it can to maintain….
AdequateCardiacOutput
Brain and heart perfusions remain near normal less critical organ systems stressed by ischemia..
Hypovolemic Shock
2. Uncompensated:
20-40% loss of blood volume
Decrease in BP
Tachycardia
Hypovolemic Shock
The body’s response:
Uncompensated shock
vasoconstrictive mechanisms
FAIL to maintain systemic perfusion pressure.
• Increased cardiac output• Increased respiration• Sodium retention
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 signsSkin perfusionPulse OximetryAcidemia
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)
Septic ShockManagement:Identify and treat the infectious source
eg – simple incision & drainage? Exploratory laparotomy?
Amputation?
Volume resuscitation
Restoration of perfusion pressure (may need pressors!)
Cardiogenic Shock
Acute hypotension
low cardiac output
inadequate LV outflow
Poor end organ perfusion!
Cardiogenic Shock
Causes most likely to see on the surgery wards:Causes most likely to see on the surgery wards:
Acute MIAcute MI
Arrhythmia (A. fib)Arrhythmia (A. fib)
Cardiac Contusion Cardiac Contusion
Cardiac TamponadeCardiac Tamponade
Massive Pulmonary EmbolismMassive Pulmonary Embolism
Decompensated Congestive Heart FailureDecompensated Congestive Heart Failure