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TYPES OF SHOCK. Dr Farzana Salman. SHOCK. Generalized inadequate blood flow throughout the body causing tissue damage. CIRCULATORY SHOCK.
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TYPES OF SHOCK DrFarzana Salman
SHOCK Generalized inadequate blood flow throughout the body causing tissue damage
CIRCULATORY SHOCK • Depression of body functions due to reduced blood flow to the tissues because of some disorder of the cardiovascular system
STAGES OF CIRCULATORY SHOCK • Non progressive stage • Progressive stage • Irreversible stage
Causes of shock Reduced blood volume (Hypovolumic shock) • Hemorrhage • Trauma • Surgery • Burns • Dehydration • Increased vascular capacity • Neurogenic shock • Anaphylactic shock • Septic shock ↓ Venous return
Causes of shock • Obstruction to blood flow ↓ Venous return • Cardiac tamponade • Tumors in myocardium • Thromboembolism • Cardiac diseases ↓ Pumping ability • Myocardial ischemia • Congestive heart failure • Arrhythmia • Severe heart valvular dysfunctions
Manifestations • ↓BP • Tachycardia • Vasoconstriction • ↓ systolic pressure due reduced filling and reduced stroke volume • ↓ diastolic Pressure • ↓ pulse pressure • Stagnant hypoxia • Pale ,cold , clammy skin
Manifestations • Sweating • Cyanosis • ↓Urinary out put • Acidosis • ↓ Blood flow to the vital organs affected • ↓ Blood flow to brain → fainting • Death due to brain ischemia or cardiac arrest
Compensatory mechanisms • BP maintained • Baroreceptor flex • Chemoreceptor flex • CNS ischemic response • Sympathetic stimulation All of the above leads to • Vasoconstriction → ↑PR →↑BP • Venoconstriction→↑VR →↑COP →↑BP • Force and rate of heart contraction • Sympathetic stimulation • More effective in BP maintenance • Less effective in COP maintenance
Compensatory mechanisms • Reverse stress relaxation phenomenon • Rennin angiotensin system • Vasopressin • Epinephrine and norepinephrine by adrenal medulla. • Mechanisms that return the blood volume back to normal
Progressive Shock • Cardiac depression. • Vasomotor failure • Blockage of very small vessels by sludged blood • Increased capillary permeability • Release of toxins by ischemic tissues • Cardiac depression caused by endotoxin • Generalized cellular deterioration.
Progressive Shock • Tissue necrosis • Acidosis in shock
Arterial pressure at different degrees of hemorrhage Nonprogressive shock Progressive shock
Progressive shock • Increasing cardiac depression
Increased vascular capacity • Neurogenic shock • General anesthesia • Spinal anesthesia • Ischemia of brain causing vasodilatation • Vasovagal syncope • Postural syncope • Carotid sinus syncope Vasodilatation
Increased vascular capacity • Anaphylaxis • Exaggerated allergic reaction • Antigen-antibody reaction→ release of histamine, some other vasodilators • Vasodilatation • ↑permeability • Exudation of fluid → further reduction in blood volume • Blood volume to total vascular capacity reduced
Increased vascular capacity • Septic shock • Severe infection anywhere in the body • Bacteria produce toxins • Generalized Vasodilatation • Weakening of myocardium • ↑ capillary permeability • Exudation of fluid → further reduction in blood volume • Blood volume to total vascular capacity reduced
Cardiogenic shock • Many IHD patients die of sudden ventricular fibrillation • More chances in large infarction • Can develop even in small infarctions • Sometimes even after many days of infarction (but less likely)
Cardiogenic shock • Infarction • After a few days degeneration of infarcted muscle • Thinning of the site • Systolic stretch with each contraction • Worsening of the systolic stretch with the passage of time • Rupture of the heart • Collection of blood in the pericardial cavity • Cardiac tamponade • Quick death
High COP shock • Excessive metabolism • Thyrotoxicosis • Abnormal tissue perfusion pattern • Shunts • Inability of tissue to utilize O2 & nutrients • Electron transport chain poisoning
Treatment of shock • Postural change • Blood transfusion • Plasma transfusion • Transfusion of plasma substitutes • Plasma expanders- dextran • Concentrated human albumin serum • Hypertonic solutions • Sympathomimetc drugs • Glucocorticoids • Oxygen therapy