shock
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Transcript of shock
Definition
Defined as a life threatening situation where the tissue perfusion is compromised to such an extent so as to cause impaired cellular metabolism manifested in turn by serious patho physiological abnormalities
Classification
• Vasovagal• Psychogenic• Neurogenic• Hypovolaemic• Traumatic• Burns• Cardiogenic• Septic• anaphylactic
Vasovagal shock
• Pooling of blood in large vascular reservoirs- limb muscles
• Dialatation of splanchnic arteriolar bed
• Reduced venous return to heart
Vasovagal shock
• Low cardiac output
• Reflex bradycardia
• Reduced cerebral perfusion
• Loss of consciousness
Vasovagal shock
• Prostration & reflex vaso constriction
• Increases venous return & output
• Permanent damage if upright
Neurogenic shock
• Traumatic /pharmacological blockade of sympathetic system
• Dialatation of resistance arterioles & capacitance veins
• Relative hypovolaemia & hypotension
Hypovolaemic shock
• BP maintained till 10 – 15% volume loss
• Tachycardia & vasoconstriction
• Trans capillary refill 1litre in 1 hour
• Constriction of venous capacitance vessels
Traumatic shock
• Hypovolaemia
• ext bleeding / internal bleeding
• Fluid loss into contused tissues/dialated bowel
• Direct trauma –heart, NS ,resp system
Myocardial infarction
• When 50% or more of LV damaged
• Fluid overload – distention of LV – failure
• Back pressure – pulmonary edema
Myocardial infarction
• Arrhythmias – pump failure
• Hypovolaemia – excess sweating , vomiting , diarrhoea
Massive pulmonary embolism
• Deep veins
• Air embolism > 50 ml
• RVF if > 50% of pulm vasculature obstructed
Hyperdynamic / warm
• Gram negative infection
• Strangulated intestine
• Peritonitis• Leaking anastomoses
• Biliary suppuration
Hyperdynamic / warm
• Increased output
• Tachycardia
• Warm dry skin
• Blood shunted past cells which are damaged (anaerobic metabolism)
Hypodynamic / cold
• Severe sepsis /endotoxaemia persisting
• Generalised capillary leakage
• Severe hypovolaemia
Anaphylactic shock
• Antigen combines with IgE on mast cells , basophils
• Release histamine & SRS -A