Condition severity

The following measures may indicate the severity of patients’ conditions: length of stay in hospital and whether the patient needed intensive care and/or continuous ventilatory support. In addition to a TBI diagnosis, many patients had other non-TBI related diagnoses and the data presented here indicate the patients’ condition to all diagnoses, not only the TBI diagnoses.

Length of stay in hospital

The average number of days patients in the cohort stayed in hospital for an initial TBI was 6.8 days. The average length of stay varied by type of TBI diagnosis (Figure 12; Table S5), with concussive injuries requiring the shortest stays in hospital.

Figure 12: Average number of days cohort patients were hospitalised for initial TBI by TBI diagnosis

This column graph shows that patients in the cohort with an additional diagnosis of non-concussive TBI spent the longest average time in hospital (21.2 days). The next longest stays were for those with a principal diagnosis of traumatic subdural haemorrhage (18.7 days), other TBI (17.4 days) and traumatic subarachnoid haemorrhage (14.7 days). Those with a principal diagnosis of concussion spent the least average time in hospital (1.6 days).

Continuous ventilator support

One measure that may indicate the severity of a hospitalised injury is the need for continuous ventilator support (CVS).

Definition of continuous ventilator support

“CVS or invasive ventilation refers to the application of ventilation via an invasive artificial airway […] provided via an endotracheal tube (ETT) or a tracheostomy tube. With CVS, the patient receives continuous variable degrees of assistance to meet respiratory requirements in an uninterrupted continuous fashion.”

– ACHI Coding standard 1006 (ACHI 8th edition)

Overall, 8.3% of patients in the cohort received CVS, reflecting the large number of concussion TBIs, which were much less likely to require CVS than other patients with other types of TBI. Only 2.6% of concussion TBI cases (where TBI was the principal or an additional diagnosis) received CVS (Table 3; Table S6). Among cases with a type of TBI other than concussion (as either a principal or an additional TBI), 24% of patients received CVS.

Table 3: Number and percentage of cohort patients who received CVS during initial TBI hospitalisation by TBI diagnosis
Type of TBI diagnosis Number of patients with CVS % of patients with CVS
Principal diagnosis – Concussion 148 1.5
Principal diagnosis – Traumatic subarachnoid haemorrhage 296 25.9
Principal diagnosis – Traumatic subdural haemorrhage 366 25.5
Principal diagnosis – Other TBI 486 24.6
Additional diagnosis – Concussion 299 4.1
Additional diagnosis – Non-concussive TBI 350 21.4
Total 1,941 8.3

Source: AIHW NIHSI AA v0.5.

Intensive care

Another measure that may indicate the severity of a hospitalised injury is the percentage of cases involving time in an intensive care unit (ICU). Eleven per cent of patients in the cohort spent time in an ICU, but there was a marked difference according to type of TBI diagnosis. Only 4.2% of concussion TBI cases (where TBI was the principal or additional diagnosis) spent time in an intensive care unit (Table 4; Table S6). Among cases with a type of TBI (as either a principal or an additional TBI) other than concussion, 31% of patients spent time in an ICU.

Table 4: Number and percentage of cohort patients with time in ICU during initial TBI hospitalisation by TBI diagnosis
Type of TBI diagnosis Number of patients with time in ICU % of patients with time in ICU
Principal diagnosis – Concussion 188 1.9
Principal diagnosis – Traumatic subarachnoid haemorrhage 355 31.1
Principal diagnosis – Traumatic subdural haemorrhage 471 32.8
Principal diagnosis – Other TBI 562 28.5
Additional diagnosis – Concussion 529 7.3
Additional diagnosis – Non-concussive TBI 500 30.6
Total 2,605 11.1

Source: AIHW NIHSI AA v0.5.