Intensive Care Nursing/Trauma/Head Trauma and Intracranial Pressure Management
Primary injury The occurrence at the traumatic incident and reflects the mechanical events and injury to the brain. Common mechanisms include direct impact, rapid acceleration/deceleration, penetrating injury and blast waves.
Secondary injury Occurs minutes, hours, days or even weeks after the initial injury and the damage can be averted or lessened by appropriate clinical interventions and management. Causes of secondary brain injury include haematoma, contusion, diffuse brain swelling, systemic shock and intracranial infection.
Pre-Hospital Care
Prevention of secondary injury is the goal and early activation of amubulance or retrieval services aims to improve outcomes. An example of a trauma system is the Traumatic Brain Injury Guideline (Victoria State, Australia)
- Airway (protect airway, close monitoring of GCS, secure airway if required, maintaining spinal alignment)
- Breathing (oxygen provision, SO2 monitoring and aim >90̥, ETCO2 monitoring and aim 35-40mmHg)
- Circulation (BP and HR monitoring, 2x I.V. access, blood sampling)
- Disibility (GCS and pupil check regularly, blood sugar level)
Hospital Care
"One challenge in the emergency department is that Intracranial Pressure (ICP) cannot be measured with out an extraventricular drain (EVD). In this case it is recommended that ICP is assumed to be 20mmHg and thus MAP ≥80mmHg to maintain CPP >60mmHg" (Roodenberg, 2011).
Cerebral perfusion pressure is the driving force that maintains the cerebral blood flow. It is influenced by two factors the mean arterial blood pressure and the intracranial pressure. To calculate the CPP, subtract the ICP from the MAP
CPP = MAP - ICP
References