SHOCK
Objectives: at the end of this
lecture you would be able to :
1- define shock
2- recognize types of shock and their causes
3- correlate pathophysiologic changes with
clinical features .
4- know the broad lines of monitoring and
treatment of shock patients .
Shock
A physiological state characterized
by a significant, systemic reduction
in tissue perfusion, resulting in
decreased tissue oxygen delivery and
insufficient removal of cellular
metabolic products, resulting in
tissue injury.
SHOCK
Definition:
SHOCK is an acute circulatory failure,
characterized
by dysfunction of the
microcirculation , inadequate blood flow to
vital organs and inability of the body cell
mass to metabolize the nutrients normally.
Shock is not a synonym to hypotension!
What are the functions of the
cardio-vascular system?
Definition of Shock
Cellular level:
Reduction of mitochondrial oxygen
Anaerobic glycolysis of ATP
Accumulation of pyruvate
Lactatic Acidosis
SHOCK
Classification of Shock
A- Classification of Shock by Causes
(1) Hypovolemic shock
(2) Cardiogenic shock
(3) Neurogenic shock
(4) Anaphylactic shock
(5) Septic shock
B. Classification of Shock according to
hemodynamic changes:
⑴Hypodynamic Shock:
Cardiac Output ,
Vascular Resistace,
Cold Skin;
⑵ Hyperdynamic Shock: Cardiac Output ,
Vascular Resistace ,
Warm Skin;
Different kind of Reason
Inadequate Blood Flow
Circulatory Failure
Metabolic Disturbances
Special Clinical Syndrome
Systemic pathophysiologic responces of Shock
Redistribution of blood flow
Low blood flow
Skin,fat,skeletal
muscls,kidney,intestines
Heart,brain
normal or
Etiology & Hemodynamic
Changes in Shock
Etiology of
shock
preload
example
CVP CO
SVR VO2 sat
hypovolemic
low
low
high
low
contractility
cardiogenic
high
low
high
low
afterload
distributive
Etiology & Hemodynamic Changes
in Shock (Afterload)
ETIOLOGY
OF SHOCK
EXAMPLE
AFTERLOAD
DISTRIBUTIVE
CVP
CO
SVR
VO2 SAT
Hyperdynamic
Septic
Low/High
High
Low
High
Hypodynamic
Septic
Low/High
Low
High
Low/High
Neurogenic
Low
Low
Low
Low
Anaphylactic
Low
Low
Low
Low
Hypovolemic Shock
Decreased preload→small ventricular enddiastolic volumes →inadequate cardiac
generation of pressure and flow
Causes:
-- bleeding: trauma, GI bleeding, ruptured
aneurysms, hemorrhagic pancreatitis
-- protracted vomiting or diarrhea
-- adrenal insufficiency; diabetes insipidus
-- dehydration
-- third spacing: intestinal obstruction,
pancreatitis, cirrhosis
Classes of acute hemorrhage
Class I
Class II
Class III
Class IV
Blood
loss
< 750 cc
0-15%
750-1500
15-30%
1500-2000
30-40%
>2000cc
>40%
HR
Normal
PP
Normal
BP
Normal
Normal
UOP
Normal
Normal
Decreased
Negligible
Mental
Normal
Anxious
Confused
Lethargic
Crystalloid
Crys+blood
Crys+blood
Fluid Crystalloid
*ATLS; 2004. 70kg male
Signs & Symptoms: Hypotension, Tachycardia,
change, Oliguria, Deminished Pulses.
Markers: monitor urine output UOP, central
venous pressure CVP, blood pressure BP, heart
rate HR, hemaocrit Hct, mental state MS,
cardiac outputCO, lactic acid and pulmonary
capillary wedge pressurePCWP
Treatment: IVF (crystalloid), Trasfusion ,
Stem ongoing Blood Loss
TRUE OR FALSE ?
The earliest sign of hypovolemic
shock is hypotension .
TRUE OR FALSE
In early stage of hypovolemic
shock the skin would be warm
due to vaso-dilation .
Septic/Inflammatory Shock
This type is due to infection/sepsis: G(-/+ )
speticemia, pneumonia, peritonitis, meningitis,
cholangitis, pyelonephritis, necrotic tissue,
pancreatitis, wet gangrene, toxic shock
syndrome, etc.
Mechanism:
It is due to release of inflammatory mediators
which leads to
1-Disruption of the microvascular endothelium
2-Cutaneous arteriolar dilation and sequestration
of blood in cutaneous venules and small veins
Signs:
Early– warm with vasodilation (hyper dynamic
circulation), often adequate urine output, fever and
tachypnea.
Late-- vasoconstriction, hypotension, oliguria,
altered mental status (hypodynamic circulation).
Findings:
Early : hyperglycemia, respiratory alkalosis,
hemoconcentration, WBC typically normal or low.
Late : Leukocytosis, lactic acidosis
VeryLate :Disseminated Intravascular Coagulation &
Multi-Organ System Failure.
Treatment :
Intravenous fluid IVF, Blood
transfusion, antibiotics, Drainage (ie
abscess) vasopressor agents .
TRUE OR FALSE
In hyperdynamic state of septic
shock there is rapid washout of
metabolites because of increased
blood supply to the tissues
Cardiogenic Shock
Mechanism: Intrinsic abnormality of heart →
inability to deliver blood into the vascular
tree with adequate power
Causes:
1. Cardiomyopathies: myocardial ischemia,
myocardial infarction, cardiomyopathy,
myocardiditis, myocardial contusion
2- Mechanical: cardiac valvular insufficiency,
papillary muscle rupture, septal defects,
aortic stenosis
3- Arrythmias: bradyarrythmias (heart
block), tachyarrythmias (atrial
fibrillation, atrial flutter, ventricular
fibrillation)
4- Obstructive disorders: pulmonary
embolism PE, tension peneumothorax,
pericardial tamponade, constrictive
pericaditis, severe pulmonary
hypertension
Signs and symptoms : Dyspnea, rales, gallop, low
BP, oliguria
Monitor/findings: CXR pulmonary venous
congestion, elevated CVP, Low CO.
Treatment : this will be according to cause eg
Congestive heart failure CHF– diuretics &
vasodilators +/- pressors.
Left ventricular LV failure – pressors ,
decrease afterload, intraaortic ballon pump &
ventricular assist device.
Neurogenic Shock
Mechanism: Loss of autonomic innervation
of the cardiovascular system (arterioles,
venules, small veins, including the heart)
Causes:
*Spinal cord injury
*Regional anesthesia
*Drugs
* Neurological disorders
Characterized by loss of vascular
tone & reflexes.
Signs: Hypotension, Bradycardia,
Accompanying Neurological
deficits.
Treatment : IVF, vasoactive
medications if refractory
Anaphylactic shock:
This type occurs due to binding of a foreign
antigen to immunogloin E (IGE) on the
mast cells and basophils , releasing large
amounts of histamine and SRS-A ( slowrelease substance-anaphylaxis) which will
produce bronchospasm , laryngeal edema
and respiratory distress with hypoxia ,
massive vasodilatation hypotension and
shock.This type occurs on exposure to
penicillin , anesthetic drugs , serum
Monitoring of shock
1-General monitoring
Heart rate
Breathing
Monitoring of shock
2．Colour and temprature
of skin
Monitoring of shock
3．BP
Systolic Pressure was
lower than 12kPa(90mmHg)
4. Urina
Oliguria
Monitoring of shock
Special monitoring
1.CVP
5-10cmH2O
CVP<5cmH2O
Inadequecy of blood volume
CVP>12cmH2O
Cardiac dysfunction
2.Lung arterial pressure
3.Cardiac output
4.Blood gas
PO2 75-100mmHg
Pco2 40mmHg
PH 7.35—7.45
5.Coagulation test
Treatment of the shock
Position of Body
30。
TRUE OR FALSE
* shock in intestinal obstruction
is multifactorial .