Download - SHOCK
SHOCK
Dr Begashaw M (MD)
Introduction
• is a life-threatening condition• occurs when the circulatory system fails to
deliver oxygen and nutrients to the body tissues & becomes unable to remove waste products
• may rapidly progress to an irreversible state with subsequent multi-organ failure and death
DEFINITION
• a pathological state causing inadequate oxygen delivery to the peripheral tissues and resulting in lactic acidosis, cellular hypoxia & disruption of normal metabolic condition
CLASSIFICATION
1. Hypovolemic 2. Cardiogenic 3. Obstructive4. Distributive - Septic shock - Neurogenic shock - Anaphylactic shock
Shock• Hypovolemic
– Hemorrhage– Anemia– Fluid loss
• Obstructive– Aortic valve stenosis
• Distributive– Sepsis– Thyrotoxicosis– Anaphylaxis
• Cardiogenic– Decompensated CHF– Acute coronary syndrome– Dysrhythmia – Myocarditis
Cardiogenic•CHF•ACS•Dysrhythmia
Distributive•Sepsis•ThyrotoxicosisObstructive•Aortic valve stenosis
Hypovolemic•Hemorrhage•Anemia
Preload
Afterload
InotropyShock
MAP = (SV x HR) x SVR
Preload
Afterload
Contractility
Arterialpressure
Cardiacoutput
Peripheralresistance
Heartrate
Strokevolume
Leftventricular
size
Myocardialfiber
shortening
Cardiac Performance
Cardiovascular & metabolic characteristics of shock
Hypovolemic shock
• inadequate vascular volume• results from loss of fluid from circulation, either
directly or indirectlyE.g▪ Hemorrhage• Loss of plasma due to burn• Loss of water & electrolytes in diarrhea• Third space loss
Where do pt bleed enough to die?
• Remember, there are only 5 places into which a person can bleed enough to cause hemodynamic instability– Chest– Peritoneum– Retroperitoneum– Thighs– World
Not the mediastinum
Cardiogenic shock
• impaired cardiac function• myocardial infarction • pericardial tamponade
Obstructive Shock
• Resistance to cardiac outflow– ↑ afterload– Aortic stenosis– Tension pneumothorax
Septic Shock (vasogenic shock)
• as a result of the systemic effect of infection• result of a septicemia with endotoxin and
exotoxin release by gram-negative and gram-positive bacteria
• impaired extraction as a result of impaired metabolism
Neurogenic shock
• disruption of the sympathetic nervous system
- to pain - loss of sympathetic tone, as in spinal cord
injuries
PATHOPHYSIOLOGY OF SHOCK
• stimulates a physiologic response - conserve perfusion to the vital organs (heart
and brain) - vasoconstriction of skin, splanchnic & renal
vessels leads to renal cortical necrosis and acute renal failure
Hypovolemic shock: physiology
• Reduced blood volume• Reduced preload• Reduced stroke volume• Reduced cardiac output Response to shock - physiology
– Cathecholamines , ADH– Vasoconstriction, tachycardia– Improve venous return and CO
CLINICAL FEATURES
• Tachycardia• Feeble pulse• Narrow pulse pressure• Cold extremities (except septic shock)• Sweating, anxiety• Breathlessness / Hyperventilation• Confusion leading to unconscious state
ClassParameter I II III IV
Blood loss (ml) <750 750–15001500–2000 >2000
Blood loss (%) <15% 15–30% 30–40% >40%Pulse rate (beats/min) <100 >100 >120 >140
Blood pressure Normal Decreased Decreased Decreased
Respiratory rate (breaths/min) 14–20 20–30 30–40 >35
Urine output (ml/hour) >30 20–30 5–15 Negligible
Mental status Normal Anxious Confused Lethargic
Classification of Hemorrhage
MANAGEMENT OF SHOCK
• restoring oxygen delivery to the cells of vital organs
General Management
Priority-ABC• Stop bleeding• Fluid resuscitation-crystalloids• Head down position-flat • Transfusion• Oxygen , inotropic • Monitoring -determine hourly urine output, BP,
pulse rate
Specific Management
Hypovolemic Shock• Restore vascular volume• Fluid and blood replacement• Oxygen support
Specific Management
Septic Shock• antibiotics• Inotropic –adrenaline,dopamine• Surgical eradication of the infection focusCardiogenic shock• InotropesNeurogenic shock• Pain relief• Treat the causes, give supportive measures - inotropic support
COMPLICATIONS OF SHOCK
1. Shock lung (ARDS)2. Acute renal failure3. Gastrointestinal ulceration4. Disseminated intravascular coagulation5. Multiorgan failure6. Death
Questions?