1) initial non-progressive phase (compensatory mechanisms)
-Neurohumoral mechanisms act to maintain cardiac output and blood pressure
-Ex. Release of catecholamines, ADH, activation of reninangiotensin-aldosterone pathway, generalized sympathetic stimulation
-Net effect: tachycardia, peripheral vasoconstriction, renal conservation of fluid
2) progressive phase
-Widespread tissue hypoxia commences:
- ↓ pH due to lactic acid production (anaerobic glycolysis)
- ↓ vasomotor response with arteriolar dilatation and blood pooling in the peripheral circulation
- Vital organs begin to fail (AKI)
-clinically confused, urine output ↓
3) irreversible stage
-Widespread anoxic cellular injury occurs
Leakage of lysosomal enzymes
Marked electrolyte disturbances
↓ Myocardial contractility
Complete renal shutdown due to acute tubular necrosis
Multi-organ system failure ensues
May develop disseminated intravascular coagulation