Severity
There are many ways the severity, or seriousness, of an injury can be measured. Measures that may indicate the severity of an injury are:
- ED triage categories and waiting times
- patient’s status at end of ED episode and urgency of hospital admission
- length of stay in hospital
- time in intensive care unit (ICU) and receipt of continuous ventilator support (CVS)
- deaths in hospital
- numbers and types of injuries and procedures.
Every presentation to an ED is assigned 1 of 5 triage categories based on the urgency with which the patient requires medical care. Each category has a clinically appropriate waiting time cut-off between the patient being triaged and seen for medical assessment (NSW Health 2022). Based on these waiting time cut-offs, 69% of ED presentations for head injuries were seen within recommended time limits. (Table 9).
Triage category | Clinically appropriate waiting time cut-off | Presentations | Percentage (%) of head injuries | Percentage (%) seen on time |
|---|---|---|---|---|
Resuscitation | Immediate (within seconds) | 3,058 | 0.8 | 99.7 |
Emergency | Within 10 minutes | 34,638 | 9 | 70.8 |
Urgent | Within 30 minutes | 143,550 | 35 | 62.4 |
Semi-urgent | Within 60 minutes | 197,577 | 49 | 70.3 |
Non-urgent | Within 120 minutes | 27,037 | 7 | 84.1 |
Total | Total | 405,866 | 100 | 68.7 |
Source: AIHW National Non-admitted Patient Emergency Department Care (NNAPEDC) Database
In 2020–21:
- Just under half of ED presentations for head injuries were triaged as Semi-urgent (49%).
- the 0–4 age group made up a quarter of semi-urgent cases (25%) (Figure 15).
- over half of cases in the 65 and over age group were triaged as Urgent (51%)
- Nearly a quarter of cases had a waiting time over one hour
- Almost a third (31%) of ED presentations for head injuries were attended to within 10 minutes.
Figure 15: Number of ED presentations for head injuries, by triage category and age group, 2020–21
A stacked bar chart showing the proportion age groups make up for each triage category. The 25–44 age group makes up the largest proportion of presentations across all triage categories except for semi-urgent, where the 0–4 age group has 25% of cases.
Compared to all injury ED presentations, head injuries saw a higher proportion of cases classified as Urgent (27% and 35% respectively), and a lower proportion of cases classified as Semi-urgent (53% and 49% respectively) or Non-urgent (11% and 7% respectively). Proportions for Resuscitation and Emergency are comparable.
Most ED presentations for head injuries had an end status of departed without being admitted or referred to another hospital (83%).
- 58,400 presentations resulted in being admitted to hospital (14%), with an additional 1.2% referred to another hospital for admission.
- Presentations for those aged 65 and over made up over a third of cases admitted to hospital (37%), with a proportion 2.5 times greater than the population at large.
- Compared with all injury ED presentation, head injuries saw a slightly lower proportion of patients admitted to hospital (17% and 14% respectively) and slightly higher proportion of patients who departed without being admitted or referred to another hospital (81% and 83% respectively).
Concussive injuries were most likely to be admitted to hospital
17% of concussive injuries were triaged as either Resuscitation or Emergency, nearly double the proportion for all head injuries (9%). Of the top 5 ED head injury diagnoses, concussive injuries had the highest proportion of cases admitted to hospital (29%).
For 2020–21 hospitalisations, head injury hospitalisations were more severe compared with total injuries for all measures apart from average length of stay (AIHW 2023b). Head injuries representing an additional diagnosis had hospitalisations that were severe than where head injury was the primary diagnosis for all measures apart from in-hospital deaths (Table 10).
| Principal | Additional | All injuries |
|---|---|---|---|
Average length of stay (days) | 3.2 | 6.6 | 4.4 |
Percentage (%) with time in ICU | 2.2 | 6.0 | 2.2 |
Percentage (%) with time on CVS | 1.7 | 3.3 | 1.2 |
Percentage (%) with urgent admission | 89 | 98 | 80 |
Deaths in hospital (per 1,000 cases) | 10.2 | 9.4 | 5.3 |
Source: AIHW National Hospital Morbidity Database.
ICU = Intensive Care Unit
CVS = Continuous ventilator support
Intracranial injuries were the most severe head injury across all five measures of severity (Figure 16).
Figure 16: Hospitalisations: severity of head injury by injury site, 2020–21
An interactive dashboard comparing head injury hospitalisation measures of severity against all injury hospitalisations. All five measures of severity show that intracranial injuries are the most severe out of all head injury sites.
Notes:
- Breakdown by head injury site only includes cases where the principal diagnosis was an in-scope head injury diagnosis.
- Approved level 3 adult ICU, NICU or an approved paediatric ICU.
Source: AIHW National Hospital Morbidity Database.
AIHW (2023b) Injury in Australia, AIHW, Australian Government, accessed 6 July 2023.
NSW Health (New South Wales Health) (2022) Hospital triage, NSW Health, NSW State Government, accessed 13 July 2023.