Introduction

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INTRODUCTION

Head injury accounts for 3–4% of emergency department attendances, with around 1500 cases per 100 /uni00A0 000 population per year in the UK. Annual mortality attributable to head injury is estimated at 9 per 100 /uni00A0 000, and it remains the leading cause of death and disability from childhood to early middle age, with an estimated 2% of the US population su ff ering long term disability as a result of head injury . Road tra ffi c accidents are the leading cause of head injury , responsible for up to 50% of cases. Other common mechanisms of injury include falls and assault. There is significant geographical variation, for e xample firearms are the third leading cause in the USA. Traumatic brain injury (TBI) can be considered as the combination of primary injury sustained on impact, and hence not medically modifiable, and secondary injury developing in the following hours and days. Understanding the importance of intracranial pressur e (ICP) and related parameters is key to minimising secondary injury and improving outcomes.