**5. Outcome**

The outcome of patients who sustain TBI and concomitant haemorrhagic shock is unfavourable. It has been reported that 33-50% of patients die before they can reach the hospital [21]. These patients' significant causes of mortality are exsanguination and its sequelae, multi-organ dysfunction and coagulopathy [13]. Brain injury-related insults aggravate cardiovascular dysfunction and result in poorer outcomes [22]. TBI can cause cerebral oedema, requiring a higher systemic blood pressure to maintain cerebral perfusion. On the other hand, systemic hypotension in haemorrhagic shock results in decreased mean arterial pressure and subsequent decreased cerebral perfusion pressure. This interdependent impairment of haemodynamic regulatory mechanisms in a vicious cycle further leads to unfavourable outcomes [22].
