Direct versus indirect transfer for traumatic brain injury to James Cook University Hospital: a retrospective study

Abstract

Introduction

Patients with traumatic brain injury are referred to the neurosurgical unit at James Cook University Hospital, Middlesbrough, either from local accident and emergency departments (direct transfer from the scene) or from other hospitals (indirect transfer). This study looked at the outcome in both groups.

Material and methods

This was a retrospective observational study using trauma audit research network data for patients treated for traumatic brain injury at the neurosurgery department at the neurosurgical unit at James Cook University Hospital.

Results

A total of 356 patients with traumatic brain injury were admitted under the care of neurosurgeons; 143 (40%) of these patients had a neurosurgical procedure. Of the patients undergoing a neurological procedure, 111 patients were transferred directly while 32 were indirect transfers; 213 patients were managed conservatively. Of those managed conservatively, 165 were transferred directly while 48 were indirect transfers.

We compared the length of hospital stay and Glasgow Outcome Scale score for the patients based on whether they were conservatively managed or required surgery in the direct and indirect transfer groups. The difference in the length of stay in the surgical and conservative groups following direct and indirect transfer was insignificant (p = 0.07). The time to the operation in direct and indirect transfer was also not statistically significant (p = 0.06).

Conclusion

Patients are as safe, if not safer, by reaching the nearest trauma unit with facilities for resuscitation and imaging.

Introduction

Patients with traumatic brain injury are referred to the neurosurgical unit at James Cook University Hospital (JCUH), Middlesbrough, either from local accident and emergency departments (direct transfer from the scene to the neuroscience centre) or from other hospitals (indirect transfer). There is a debate about the difference in outcome between direct and indirect transfer of these patients. A 2015 meta-analysis comparing direct and indirect transfer of patients with moderate to severe traumatic brain injury (Glasgow Coma Score, GCS, less than 13) found no significant difference in mortality.¹ A 2016 cluster randomised controlled trial compared direct and indirect transfer of patients, but it struggled to justify direct transfer.² Our study compared various parameters for the two groups to reach a conclusion to help in providing guidelines for transfer of traumatic brain injury.

Material and methods

The study period was 48 months (1 January 2014 to 31 December 2017). The study was approved by the research department of JCUH. This was a retrospective observational study using Trauma Audit Research Network (TARN) data for patients treated at the neurosurgery department at JCUH for traumatic brain injury. TARN has Health Research Authority approval for (section 251) for analysis of non-identifiable data. Patients were selected on the basis of their Abbreviated Injury Scale head scores. Patients with definite injuries on their computed tomography head scan (Abbreviated Injury Scale score greater than 2) were included. Time to theatre was measured from arrival time to JCUH for both groups of patients. Patients were received either in the emergency department or directly in the neurosurgical ward, usually by a specialty registrar. TARN does not include comprehensive long-term follow-up; and analysis of Glasgow Outcome Scale scores was completed on discharge.

We measured odds ratios and relative risks to look for associations. Analysis of means of the two groups was evaluated using the Student’s T-test. Box and whisker plots were plotted to compare the median lengths of stay for both the groups. We compared the length of hospital stay for the patients based on whether they were conservatively managed or required surgery.

We further divided surgically managed patients in each group into immediate (primarily managed with surgery) and delayed surgery (initially managed conservatively and then on deterioration converted to management with surgery) groups. Inclusion criteria for the latter (converted) group was any surgery done after 24 hours or 1,440 minutes since arrival at JCUH.

Glasgow Outcome Scale was analysed using a multivariate logistic regression analysis. This was conducted for the two groups owing to confounding factors such as age, GCS and Injury Severity Score (ISS).

Results

Between 1 January 2014 and 31 December 2017, 356 patients with traumatic brain injury were admitted under the care of neurosurgeons; 143 (40%) of these patients had a neurosurgical procedure. Of the patients undergoing a neurological procedure, 111 patients were transferred directly while 32 were indirect transfers. The mean age of the patients was 52 years, and 40 patients (5.90%) were less than 18 years of age. The two groups were compared in terms of age, GCS, ISS, types of brain injury, mechanism and associated injuries and inpatient mortality (Table 1). A total of 213 patients were managed conservatively. Of these, 165 were transferred directly while 48 were indirect transfers.

Table 1.

Comparison of the two groups in terms of age, Glasgow Coma Score, Injury Severity Score, types of brain injury, mechanism and associated injuries and inpatient mortality

	Directa	Indirectb
Glasgow Coma Score, n (%):
3–8	158 (67)	20 (25)
9–12	64 (23)	51 (64)
13–15	27 (10)	9 (11)
Mean Injury Severity Score	27	22
Mechanisms/patient, n (%):
Blows	38 (14)	21 (26)
Falls ≤ 2m	87 (32)	37 (46)
Falls > 2m	68 (25)	13 (16)
Road traffic accident	81 (29)	8 (10)
Shooting	1 (0.36)	–
Other	1 (0.36)	1 (1)
Type of brain injury/patient, n (%):
Contusion	152 (55)	8 (10)
Subdural haematoma	166 (60)	55 (69)
Subarachnoid haemorrhage	146 (53)	19 (24)
Extradural haematoma	41 (15)	8 (10)
Intracerebral haematoma	120 (44)	34 (43)
Pneumocephalus	50 (18)	11 (14)
Brainstem compression	36 (13)	8 (10)
Diffuse axonal injury	24 (9)	3 (4)
Cerebellar injury	16 (6)	3 (3)
Base of skull fracture	93 (34)	20 (25)
Skull vault fracture	106 (38)	19 (24)
Spinal fracture	25 (9)	6 (8)
Associated injuries/patient, n (%):
Face	81 (29)	9 (11)
Chest	67 (24)	6 (8)
Abdomen	12 (4)	3 (4)
Spine	42 (15)	6 (8)
Pelvis	19 (7)	2 (3)
Limbs	62 (23)	6 (8)
Other	9 (3)	3 (4)
Inpatient mortality, n (%)	100 (36)	8 (10)

^a 276 (78%) patients; mean age 52.8 years

^b 80 (22%) patients; mean age 50.6 years

The median length of hospital stay for surgically managed patients following direct and indirect transfer was 46 days compared with 27 days, which was not statistically significant (p = 0.07; Fig 1). Similarly, we compared the length of stay for patients managed conservatively between direct and indirect transfers to our centre (Fig 2). The median number of days was 6 compared with 25 days, respectively, which was not statistically significant (p = 0.31).

Figure 1.

Box and whisker plots for length of hospital stay for patients who were directly transferred compared with patients who were indirectly transferred

Figure 2.

Box and whisker plots for length of hospital stay comparing patients who were surgically managed and conservatively managed when they were either directly transferred or indirectly transferred

We then compared Glasgow Outcome Scale (GOS) scores in indirect and direct transfers, broadly grouped as either surgically or conservatively managed. In patients who were surgically managed (Fig 3), around 12.5% of patients had a worse outcome (GOS scores 1, 2 and 3) when they were indirectly transferred as opposed to 22.5% of patients in the directly transferred group, who had a worse outcome (GOS scores 1, 2 and 3) at discharge. However, the odds ratio was 0.4, which was not statistically significant (p = 0.2).

Figure 3.

Glasgow Outcome Scale (GOS) score in patients managed surgically

On the other hand, in patients managed conservatively (Fig 4), around 10.41% of patients had a worse outcome (GOS scores 1, 2 and 3) when they were indirectly transferred as opposed to 49.69% of patients in the directly transferred group, who had a worse outcome (GOS scores 1, 2 and 3) at discharge. The odds ratio was 0.1 (95% confidence interval, CI, 0.0444–0.3121), which was statistically significant (p < 0.001). These findings suggest that patients who were conservatively managed and indirectly transferred were less likely (10% of direct transfers) to have a worse GOS score even though they had a longer length of hospital stay.

Figure 4.

Glasgow Outcome Scale (GOS) score in conservatively managed patients

We also looked at the time to operation in the two groups (ie directly transferred vs indirectly transferred; Table 2). The median for direct and indirect transfers was 607.5 minutes and 345 minutes, respectively (Fig 5). However, the difference between the two groups was not statistically significant (p = 0.07).

Table 2.

Conversion to surgery and time to surgery in both groups

	Direct	Indirect
Surgeries, n (%):
Total	111 (40)	32 (40)
Primary	71 (26)	24 (30)
Conversions	40 (15)	8 (10)
Time to surgery in minutes, mean (median):
Primary	346.5 (159)	246.8 (65)
Converted	22,519.7 (6,766)	8,857.6 (5,499)

Figure 5.

Median time to operation

We further divided these surgically managed patients in each group into patients who had immediate surgery (primarily managed surgically) and those whose surgery was delayed (initially managed conservatively and then on deterioration converted to management with surgery). The inclusion criteria for the latter (converted) group was any surgery done after 24 hours or 1,440 minutes for arrival in JCUH.

On comparing the conversion rates to surgical management in both groups (direct vs indirect transfers), we found the conversion rate in the direct group to be 0.12 (Poisson 95% CI 0.09–0.16) and in the indirect group to be 0.08 (95% CI 0.04–0.16). The difference between the two rates was not statistically significant.

Discussion

Traumatic brain injury is the leading cause of death and disability among young people.³ Despite advances in prehospital and inpatient care, the majority of patients with traumatic brain injury have unfavourable outcomes, resulting in a high burden of individual morbidity and a growing cost to society through loss of productivity.

The importance of time from injury to evacuation of intracranial haematomas is well established. A study of 82 patients with acute traumatic subdural haematoma showed 30% mortality when surgery was undertaken within four hours of injury, compared with 90% mortality after four hours.⁴ A similar study of 83 patients with epidural haematoma found that the mean time from deterioration in GCS to surgery was 1.9 hours for patients who survived with good outcomes, compared with 15.7 hours for patients who died.⁵ Despite the importance of early neurosurgical intervention, it remains unclear whether patients with traumatic brain injury who require a neurosurgical procedure achieve better outcomes through direct transfer to tertiary neuroscience centres or indirect transfer after stabilisation at their nearest emergency department.

A retrospective observational cohort study using data from the New York State Trauma Registry between 1996 and 1998 compared the mortality rate of adults with moderate-to-severe traumatic brain injury (GCS less than 13) immediately transferred to a neuroscience centre compared with those taken to their nearest hospital first.⁶ The results favoured direct transfer to a neuroscience centre (OR 0.88, 95% CI 0.64–1.22) but did not reach statistical significance. A further multicentre study in New York State in 2006 showed a highly significant 50% increase in mortality associated with indirect transport of patients with traumatic brain injury after controlling for arterial hypotension, age, prehospital pupillary status and GCS.⁷ However, a 2015 UK meta-analysis comparing direct and indirect transfer of patients with moderate-to-severe traumatic brain injury (GCS less than 13) found no significant difference in mortality, although patients who were not transferred to a neuroscience centre after stabilisation were excluded from the studies that were analysed.¹ In the UK, according to the 2014 National Institute for Health and Care Excellence (NICE) clinical guideline for head injury assessment and early management, patients with an isolated head injury should be transported to a hospital with facilities to resuscitate and manage multiple injuries, which may or may not be a neuroscience centre, depending on geographical location.⁸

The British Army, similarly, airlifts soldiers with traumatic brain injury to general operative facilities before they are transferred to facilities with access to neurosurgical care.⁹ In contrast, the American Brain Trauma Foundation guideline for prehospital management of traumatic brain injury recommends that patients with severe traumatic brain injury (GCS less than 9) are transported directly from the scene of injury to a facility capable of immediate CT, prompt neurosurgical care and the ability to monitor intracranial pressure and treat intracranial hypertension.¹⁰ The guideline also recommends that patients with moderate traumatic brain injury (GCS 9–13), and therefore the potential for intracranial injury, should be transported directly to a neuroscience centre for further evaluation.

According to the 2016 NICE clinical guideline for major trauma assessment and initial management, the optimal destination for patients with major trauma is usually a major trauma centre, but in some locations or circumstances, intermediate care in a trauma unit might be needed for urgent treatment, as outlined by local trauma network guidelines.¹¹ Local trauma networks therefore operate their own trauma unit bypass tools, which include criteria for head injuries that divert more severe cases of traumatic brain injury to major trauma and neuroscience centres and milder cases to local trauma units. However, these local guidelines vary across the UK and are not evidence based. As such, the optimal prehospital transfer strategy for traumatic brain injury remains unclear.

In an attempt to better inform head injury management in the UK, a cluster randomised controlled trial was designed in 2016 to compare direct and indirect transfer of patients with isolated traumatic brain injury and a stable airway, breathing and circulation to neuroscience centres from 76 ambulance stations. However, fewer than 25% of patients recruited to the study were found to have traumatic brain injury on CT and only 7% sustained injuries requiring neurosurgery. The authors concluded that the sample size required to produce significant results from a randomised controlled study design would not be practically feasible in this patient group.² This is the HITS-NS study, which struggled to justify direct transfer.

In our study, there was no significant difference in length of stay but indirectly transferred patients showed better GOS score. This result could be because patients with poor GCS and expected poor prognosis and those not fit for neurosurgical intervention are usually not considered for transfer.

Limitations

One of the major limitations of the study is the small numbers of indirect transfers (n = 80), of which only 32 were managed surgically. This limits the power of the study to show the difference in time to theatre. The second limitation is that the outcome comparison is not adjusted for confounders such as age, GCS, pupils and severity of injury.

Conclusion

Keeping the above-mentioned limitations in mind, we can conclude that in a well-organised and connected healthcare system as in the UK, with no commercial conflicts of interest, patients are as safe, if not safer by reaching the nearest trauma unit with facilities for resuscitation and imaging.