Post on 29-Dec-2015
Shock
Dr. Afsar Saeed Shaikh
M.B.B.S, M.Phil. Assistant Professor of Chemical PathologyPathology Department, KEMU, Lahore.
INTRODUCTION
Cardiovascular Collapse Final common pathway Definition:
‘A clinical entity characterized by systemic hypoperfusion caused by reduction either in cardiac output OR in the effective circulatory blood volume’
INTRODUCTION Clinical Effects of Shock:
Hypotension Impaired tissue perfusion Cellular hypoxia
Shock ETIOLOGICAL
CLASSIFICATION: Cardiogenic Shock Hypovolemic Shock Septic Shock (Endotoxin Shock) Neurogenic Shock Anaphylactic Shock
Stages of Shock FIRST stage; Non-progressive
Stage: Reflex compensatory
mechanisms
are activated Profusion of vital organ is
maintained
Stages of Shock 2nd Stage; Progressive Stage:
Tissue hypoperfusion Circulatory & metabolic
imbalances leading to Acidosis
Stages of Shock 3rd Stage; Irreversible Stage:
Cellular & tissue injury Even with correction of
hemodynamic defects, survival is not possible
Mechanism of different Stages of Shock
1. Non-progressive Stage : Neurohumoral Mechanisms
maintain cardiac output and blood pressure:
• Baroreceptors reflexes• Release of catecholamine• Activation of renin-angoitensin axis• ADH release• Generalized sympathetic
stimulation
Mechanism of different Stages of shock
1. Non-progressive Stage : Different Clinical Outcome of
these compensatory mechanisms:
• Tachycardia• Peripheral vasoconstriction
(cool & pale skin)• Renal conservation of fluid
Mechanism of different Stages of shock
2. Progressive Stage : Widespread hypoxia:• Anaerobic glycolysis• Production of lactic acidosis• pH lead to blunting of
vasomotor response leading to vasodilatation
• Peripheral pooling of blood• cardiac output
Mechanism of different Stages of shock
2. Progressive Stage : Different Clinical Outcome of
these failing mechanisms:• Feeble, failing pulse• Mental confusion• urine output
Mechanism of different Stages of shock
3. Irreversible Stage : Widespread Cellular injury:• Damage to the organelle of cells• Leakage of lysosomal enzymes• Production of nitric oxide by
cells• Worsened myocardial
contractility
Mechanism of different Stages of shock
3. Irreversible Stage : Different Clinical Outcome of
cellular injury:• Septic shock (entry of intestinal
flora into circulation)• Complete renal shutdown (acute
tubular necrosis)• Downward clinical spiral
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