When an accident occurs and there is an impact to an individual’s head, their brain tissue can be damaged resulting in a brain injury (Mauk 2012). Primary injuries to the brain include cerebral contusions, lacerations and diffuse axonal injury which can then be followed by secondary injuries, such as cerebral oedema, hypotension, hypoxia and electrolyte imbalances (Chua et al. 2007; Mauk 2012).
At the time of the injury, in addition to the individual losing consciousness and various other symptoms of a brain injury, they also may experience post-traumatic amnaesia, or PTA.
Recently it was Brain Injury Awareness Week. The second largest cause of brain injury in people following stroke is from accidents or trauma, and commonly called a traumatic brain injury, or TBI (Brain Injury Australia 2016). Nearly half of all TBIs are caused by falls, one in three are from a motor vehicle accident, and one in six are from an assault (Brain Injury Australia 2016). With over 700,000 Australians suffering from brain injury, it is important to raise awareness of the causes and consequences.
PTA is defined as ‘the period of time in which the brain is unable to lay down continuous day-to-day memories’ (Khan et al. 2003). During this time, the individual with the TBI may be disorientated and unable to connect memories or events. For example, they may engage in conversation but then forget they have spoken to someone, or they may have breakfast and then forget they have eaten. There may also be permanent memory loss, including no recollection of the accident or the events leading up to it (Acquired Brain Injury 2016).
In Australia, the most common way to assess PTA is by using the Westmead PTA Scale (Khan et al. 2003). The Westmead Scale was developed in the 1980’s to fill a gap in the assessment tools used to determine the presence of PTA in patients (Shores et al. 1986). It is a brief bedside tool that consists of twelve questions posed to the patient to assess their orientation to person, place and time, as well as their ability to consistently retain new information from one day to the next. It is completed every day until the patient achieves a perfect score for three consecutive days. When this occurs they are deemed out of PTA.
PTA duration can be a predictor of outcomes in patients with a TBI. A PTA duration of over twenty four hours can be indicative of a severe TBI, and a PTA of more than four weeks can often be a sign of a very severe brain injury (Chua et al. 2007). The duration of PTA can predict the presence of any chronic cognitive deficits, the development of psychiatric disorders, and the ability of the individual to return to work (Chua et al. 2007). It is a long recovery for someone who has experienced a TBI. Generally if an individual has PTA for over three weeks, they can expect to still have cognitive deficits a year after their injury occurred (Chua et al. 2007).
The severity of a TBI ranges from concussion through to someone who is in a persistent vegetative state. There are three classifications of brain injury, which depend on the length of time, loss of consciousness (LOC), the length of PTA and the mechanism of the injury. These are:
As well as length of time in PTA being a predictor of outcomes, certain pre-existing factors have also been found to be linked to worse outcomes following a TBI, including:
(Chua et al. 2007)
Every patient with a TBI who experiences PTA will be different, so therefore different strategies will need to be implemented for different individuals. When a patient is experiencing PTA, it is important for the nurse to ensure they provide a safe environment and respond to their physical needs (Mauk 2012). Some strategies to use while the patient is experiencing PTA include:
The patient’s family must also be included in their care and be informed of treatment plans. This can be a very distressing time for family members and loved ones, therefore it is important they are kept informed of what their loved one is going through, and that recovery can be a slow and long process.
(For further reading see Rehabilitative Care of a Patient Following Polytrauma)