Cardiovascular System
Usually two distinct phases, though the first is not seen in all patients
- Hyperdynamic phase (sympathetic overactivity)
- Transient catecholamine 'storm' (particularly adrenaline and noradrenaline) leads to:
- Intense arterial constriction and hypertension with tachycardia and increase in cardiac output
- Cushing's reflex due to massive increase in afterload with secondary baroreceptor activity causing bradycardia (occurs in about one-third of patients
- Imbalance between myocardial oxygen supply and demand, manifesting as:
- Acute myocardial injury and ST segment change
- Arrhythmias and heart blocks
- Apical ballooning and generalised LV dysfunction
- Transient catecholamine 'storm' (particularly adrenaline and noradrenaline) leads to:
- Cardiovascular collapse phase (sympathetic underactivity)
- Hypotension results from:
- Loss of sympathetic tone and profound vasodilatation
- Myocardial depression and arrhythmias:
- Depletion of high energy phosphate
- Mitochondrial inhibition
- Reduction in T3 production
- Electrolyte disturbance
- Hypovolaemia:
- Diabetes insipidus
- Osmotic diuresis (mannitol, hyperglycaemia)
- Therapeutic fluid restriction
- Asystolic cardiac arrest generally occurring within 72 hours
- Hypotension results from: