Ambulance head injury guidelines: a-head of the game or in need of review?
Older adults with head injury are a challenging group of patients to the ambulance clinician. Older age, clinical frailty, comorbidities, anticoagulant and antiplatelet medications can contribute to these patients suffering a traumatic intracranial haemorrhage (tICH). However, unlike younger adults, older adults can suffer significant tICH without displaying symptoms, which can make identification and triage of these patients challenging.
Head injury guidelines are available to ambulance clinicians. However, the evidence they are built on is biased towards young, symptomatic patients with head injury, not older asymptomatic patients. Furthermore, anticoagulant medications are considered a red flag, regardless of whether the patient has no other symptoms; some paramedics find this restrictive to practice.
This study carried out by Barrett et al aimed to determine if sufficient information was available to an ambulance clinician to identify older adults at risk of a tICH and explore what factors determined whether an older adult with a head injury was conveyed or non-conveyed to the emergency department (ED). Data from older adults presenting to one ambulance service in the UK with a head injury in 2020 were included.
In this study, 60% (2111/3545) of patients were conveyed to the ED; 162 patients were found to have a tICH, and only eight patients were accepted by neurosurgery. Falls from more than 2 metres, chronic kidney disease and use of Clopidogrel were associated with tICH. Conveyance to the ED was associated with patients taking anticoagulant and antiplatelet medication or having a visible head injury or head injury symptoms. Of interest, there was a mismatch between the factors that were associated with conveyance and the presence of a tICH. While the head injury may not have been the only factor that contributed to conveyance, most patients who were conveyed to the ED were subsequently discharged (1421/2111; 68%). Finally, patients with conditions such as dementia or Alzheimer's disease were more likely to be non-conveyed, and patients were more likely to be non-conveyed when a paramedic or specialist paramedic was present.
Administering TXA—it's bleeding obvious, isn't it?
Uncontrolled haemorrhage is the leading cause of preventable death in trauma patients. Tranexamic acid (TXA) inhibits the dissolution of fibrin, thus combatting haemorrhage. The rationale behind the prehospital use of TXA is that the greatest benefit is seen with early administration, especially <1 hour after injury. A small number of randomised controlled trials (RCTs) have explored the safety and efficacy of prehospital TXA but there have been few systematic approaches to inform the evidence base.
Acharya et al conducted a systematic review and meta-analysis on the prehospital use of TXA in patients suspected of haemorrhage following traumatic injury, comparative to standard care in this subgroup of patients without TXA. Three RCTs met the inclusion criteria and all had a low risk of bias, although there was variation in the dose of TXA administered, timing of administration, and the type of trauma patient included within each RCT.
Acharya et al's (2023) meta-analysis reported that prehospital TXA does reduce the risk of 1-month mortality, aligning with the current in-hospital knowledge base and the findings of the CRASH-2 trial. Prehospital TXA was not associated with an increased risk of seizures or thromboembolic events although there was a link with a slightly increased risk of infection.
Interestingly, pooled results from two out of three RCTs showed no increase in survival with favourable functional outcome at 6 months. Nevertheless, the authors surmise that the lack of improvement in functional outcome may be due to a lack of power in the available data and hence, requires corroboration from future RCTs.