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

Psychogenic shock

• Follows a sudden fright

• Bad news

• Severe pain – blow to the testis

Neurogenic shock

• Traumatic /pharmacological blockade of sympathetic system

• Dialatation of resistance arterioles & capacitance veins

• Relative hypovolaemia & hypotension

Neurogenic shock

• Low BP

• Low output

• Warm dry skin

Hypovolaemic shock

• Loss of intra vascular volume

• Haemorrhage

• Dehydration

• diarrhea

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

Burn shock

• Plasma loss

• Generalised capillary leak > 25%

• endotoxeamia

Cardiogenic shock

• MI

• Massive pulmonary embolism

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

Septic shock

• Hyperdynamic / warm

• Hypodynamic / cold

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)

Hyperdynamic / warm

• Capillary membranes leak

• Endotoxins are absorbed

• SIRS

Hypodynamic / cold

• Severe sepsis /endotoxaemia persisting

• Generalised capillary leakage

• Severe hypovolaemia

Hypodynamic / cold

• Reduced output

• Tachycardia

• vasoconstriction

Hypodynamic / cold

• Cardiac depression

• Pulm hypertension

• Pulm edema

• hypoxia

Hypodynamic / cold

• Cold , clammy , drowsy

• Convert it to hyperdynamic –plasma / colloids

Anaphylactic shock

• Drugs

• Serum

• Stings

• Shell fish

Anaphylactic shock

• Antigen combines with IgE on mast cells , basophils

• Release histamine & SRS -A

Anaphylactic shock

• Bronchospasm

• Laryngeal edema

• Resp distress – hypoxia

Anaphylactic shock

• Massive vaso dialatation

• Hypotension

• shock