Adherence to New Zealand’s Major Trauma Destination Policy: an audit of current practice

Globally, more than two-thirds (70%) of injury deaths occur in the pre-hospital setting.¹ In New Zealand, 54% of injury deaths occur pre-hospital and 45% of those deaths are estimated to be survivable or potentially survivable.² These data suggest that the health burden of major trauma in New Zealand may, in part, be reduced by optimising pre-hospital trauma care, in particular optimising the systems that determine the most appropriate destination for patients in the acute phase of care.³ International evidence confirms that cases severe enough to be classified as major trauma are likely to have better outcomes if the patient is transported directly to an advanced-level trauma centre, even if this means bypassing the nearest medical facility.⁴ With major trauma destinations taking priority over closer, non-trauma centres for transport from the incident site, appropriate resources and hospital personnel are more readily available to patients with severe injury. This model of trauma care was accredited by the American College of Surgeons in 1987 to reduce delayed secondary transfer to trauma centres and reduce pre-hospital injury deaths.^2–4

Equivalent models of major trauma response protocols have been implemented and audited internationally.^5–7 Findings from these studies reveal that destination protocols are not optimally adhered to and that certain groups experience different rates of adherence. Fitzharris et al.⁵ found a major trauma protocol adherence rate of 74% for P4 (most severe) cases by Emergency Medical Service (EMS) providers in Australia.⁵ MacKenzie et al.⁶ reported 56% of major trauma patients in a US study were transported directly to a major trauma hospital, and that compliance reduced with increasing age and with the type of criteria met in each case. The three types of criteria that could be met included injury, physiology and mechanism criteria (all including parameters/specific incident or injury characteristics used to include or exclude major trauma). Compliance was highest when the injury criteria was met either with or without another criteria (86.0–94.0%). Cases meeting mechanism and physiology criteria together had the next highest compliance rate (68.7%), and the third highest rate of compliance was seen when mechanism criteria alone was met (45.8%). The lowest level of adherence was in cases meeting physiology criteria alone (34%).⁶ A 2020 study from the Netherlands by Van Rein et al. reported a major trauma destination policy adherence rate of 72%, with a lower adherence rate of 42% in rural regions where there was an increased distance to advanced trauma centres.⁷ In addition, this study found reduced adherence for older patients, but increased adherence for paediatric patients.

New Zealand’s trauma system is divided into four regional trauma networks based on population.⁸ Each of these regions has at least one advanced-level trauma centre (seven in total), which are operational 24 hours a day, providing intensive care and advanced resources similar to a Level 1 or Level 2 American College of Surgeons Verified Trauma Centre.⁹ In addition to the seven advanced-level trauma centres, the New Zealand trauma system includes 15 mid-level trauma hospitals that are also appropriate for the direct transport of many patients with major trauma based on the criteria they meet at the scene. This makes a total of 22 trauma hospitals across the country. In 2017, New Zealand’s National Trauma Network (Te Hononga Whētuki ā-Motu, formerly known as the Major Trauma National Clinical Network) introduced a Major Trauma Destination Policy (MTDP) with the overall aim to improve major trauma survival rates in the pre-hospital trauma response phase.¹⁰ The policy requires EMS providers at the scene to assess if patients meet eligibility criteria for transport to a trauma hospital directly from the scene (Table 1).³ The New Zealand National Trauma Network uses a threshold for major trauma of an Injury Severity Score (ISS) of greater than 12.¹¹ Note, ISS is an anatomical injury scoring system.¹²

Despite the establishment of MTDPs, there is evidence world-wide that they are not strictly adhered to, causing preventable fatalities and morbidity post-major trauma.^5–7,13,14An audit of adherence to the MTDP was undertaken in 2018 by the New Zealand National Trauma Network, Hato Hone St John and Wellington Free Ambulance (WFA) when the MTDP was first introduced (in an email from B. Dicker in January 2022). The audit found that in 91% of cases, transport to the right hospital or staging as per the destination policies was adhered to. The aim of this study was to build on the findings of the 2018 audit to further explore adherence to New Zealand’s MTDP.

Materials and methods

This study was part of a larger Health Research Council of New Zealand study exploring predictors of survival among major trauma cases.² In the larger study, EMS data from New Zealand’s two EMS providers, Hato Hone St John and WFA, were probabilistically linked to NZTR data. To be included in the NZTR, the threshold is an ISS >12 or cases where the trauma is fatal regardless of injury severity. In this audit, the ISS values were abstracted from the NZTR dataset. The auditors were able to access and review all road-based EMS records. In a small number of instances, a combined road/aeromedical record was reviewed. This combined view was only available in limited instances in which the patient record had been transferred to an air provider (to create a merged record), and that air provider used the same electronic record as Hato Hone St John. Around 20% of patients would have had a road-based EMS attendance and aeromedical transport to the hospital. The mode of transport to the hospital was not part of the dataset collected in this audit.

A retrospective evaluation of adherence to the New Zealand MTDP for a random sample of 100 cases (ISS >12) injured between 31 November 2017–30 November 2018, and who survived to hospital, was drawn from the linked dataset.

The study methods mirrored those used in a 2018 MTDP audit conducted by the National Trauma Network (in an email from B. Dicker in January 2022). Cases where the closest hospital to the incident was an advanced-level trauma centre were excluded, on the assumption that EMS personnel by default would go to that hospital. Cases without sufficient information to classify nature or mechanism of injury were also excluded. Any cases excluded from the 100 were replaced by a randomly selected replacement case from the NZTR. The EMS electronic patient record (ePRF) was extracted from the NZTR for each case and reviewed.

Audit process

An audit team was established that included six senior paramedics and one of the study investigators (BD). The audit team received a copy of the ambulance ePRF records for all cases, and based on the information contained, addressed the following questions in relation to the MTDP:

1. According to the MTDP, which hospital did the patient’s injuries indicate that they should go directly to?
2. Which hospital did the patient go to?
3. Did the patient have unstable/life-threatening injuries that indicated that they needed to go to the closest hospital?
4. Did the patient have an injury that required a specialist hospital destination, for example spinal cord injury?

The primary outcome of interest in this study was adherence by EMS personnel to the 2019 MTDP. The 2019 protocol was used as it was the current protocol at the time the audit was conducted, and as such was familiar to the paramedics (clinical experts) reviewing the case files. In order to meet the criteria for direct transport to an advanced-level trauma centre or mid-level trauma hospital, a patient must meet the criteria detailed in the Appendices. For the purposes of the audit, adherence was indicated by the transport of injured patients from the scene to the appropriate initial destination based on meeting the respective regional MTDPs (see Appendices).

Adherence to the 2019 MTDP for all cases was determined by the outcomes of the audit team’s analysis of each ePRF. The initial review of the cases was conducted by two auditors; if there was no consensus, a third auditor blinded to the initial outcomes reviewed the case, and if the outcome aligned with two of the three auditors, this was utilised. If the first arrival facility was the same as the recommended hospital as indicated by the nature of the patient’s injuries, then the case was considered compliant. All cases that were not determined as meeting the criteria for major trauma by the auditors (i.e., no destination policy was required), or cases where patients were sufficiently unstable to need immediate medical attention were classified as adherent if they were taken to the closest hospital. Cases requiring direct transport to a specialist facility were classified as adherent if this occurred.

Other documented variables of interest included: gender, age group, date of injury, district health board (DHB) location of injury catchment, hospitals (initial hospital and on-transfers), definitive care hospital, ISS, patient status at scene and patient status at destination. In cases with multiple injuries, the primary diagnosis and most severe injuries were listed as the primary effect of the incident.

Statistical analysis

Descriptive statistics were used to describe the sample. The proportion of major trauma cases in the sample meeting the 2019 policy criteria for direct transport to one of the 22 major trauma hospitals were noted and the outcome of adherence to the MTDP was then reported.

Ethics

Ethics approval for the parent study was obtained from the Health and Disability Ethics Committee (Ref: 18NTB142).

Results

There were 1,754 cases captured by the NZTR between 31 November 2017 and 30 November 2018 (see Figure 1). Of these, 1,015 were excluded. The majority of those excluded (99.6%) were cases where the closest hospital was an advanced-level trauma centre. A random sample of 100 cases was selected from the 739 cases who met the study eligibility criteria.

View Figure 1, Table 1–3.

Of the initial 100 randomly selected cases, four did not meet the eligibility criteria (three did not have electronic EMS records, and the remaining case had insufficient information regarding the nature of injury and of the incident itself) and were subsequently replaced.

Thirteen of the random sample of patients met the criteria for direct transport to an advanced-level trauma centre (Table 1). Of these, eight were taken to the appropriate destination. Of the 43 cases requiring transport directly to a mid-level trauma hospital, 42 patients were taken to the correct facility. All low-severity and unstable cases (all of which the MTDP requires to be taken to the local hospital) were transported to the correct destination. Overall, there was a 94% adherence rate to the MTDP.

Adherence to the MTDP is increased with age, as compliance improved with every increase in age bracket (Table 2).

Compliance increased with injury severity (Table 3), in contrast to the adherence of “threat to life” status, whereby this audit shows highest adherence in cases with “no” or “unlikely” threat to life both at the scene and in hospital. Adherence to the MTDP varied with different levels of responsiveness, with no clear trend evident. In terms of nature of injury, in particular the injury of different organ systems, intra-abdominal injuries had the lowest level of compliance.

Discussion

The aim of this study was to evaluate adherence to New Zealand’s MTDP. The 94% adherence rate is high when compared with similar international audits.^5,7 A major contrast can be seen when comparing this study to Newgard et al.’s audit of the triage and destination of low-risk cases in the USA, as 34% of low-risk cases were still transported to advanced-level trauma centres against major trauma protocol recommendations.¹⁵

Interestingly, although all patients fitted the criteria for major trauma with an ISS >12, over one-third of patients were determined by the paramedics as having a final status of being low acuity (clinical status) using the Emergency Ambulance Service Clinical Guidelines.³ This finding suggests that there may be subsequent patient deterioration or differences in diagnostic capacity using the extensive in-hospital capabilities compared with those available in the pre-hospital environment, meaning that some injuries are occult/not able to be recognised pre-hospital. This finding may provide impetus for optimising EMS training or bringing further diagnostic techniques to the pre-hospital environment. Training of EMS personnel is variable internationally; in New Zealand, there are currently five levels of practice.¹⁶ Of these practice levels, intensive care paramedics (ICP; postgraduate certificate qualified) and critical care paramedics (CCP; postgraduate diploma qualified) are the only qualified personnel that can perform endotracheal intubation, an advanced airway technique. In the rural setting, 74% of EMS attendance is by an ICP or CCP paramedic.¹⁷ Increasing the proportion of CCP or ICP presence would increase the ability to provide critical advanced airway care at the injury site. CCPs or ICPs may also have a higher degree of clinical gestalt, which could enable a higher proportion of bypass of nearby hospitals to go directly to a major trauma centre. However, there would be challenges in resourcing such skills within the rural sector; in addition, the potential for skill attrition would be high due to low exposure to critical incidents. Other potential techniques for future investigation could be tools such as point-of-care ultrasound or lactate measurements, which could provide useful adjuncts to pre-hospital triage.^18,19 The introduction of other more physiological decision support tools, such as the pre-hospital National Early Warning Score, may also aid in supporting future bypass protocols.²⁰ Any changes in decision support tools and criteria would need to be carefully considered to ensure that such tools do not become overly cumbersome and complex.

This audit found that compliance was high in cases that were not classified as requiring transport to an advanced-level trauma centre at the scene. In comparison, cases needing to bypass the nearest hospital for advanced-level trauma facilities had a significantly lower compliance rate than cases that the protocol dictated should be taken to the nearest hospital—whether due to low severity or because they were unstable—were taken to the appropriate destination. Contrastingly, audits internationally demonstrate higher compliance when protocol requires bypass of nearest medical facilities compared to compliance to destination policy when injuries are less severe, which is the opposite trend to New Zealand.^6,21 MacKenzie et al.’s audit of compliance to major trauma destination protocols in the US found that there was higher compliance to protocols in cases of major trauma than cases that did not meet criteria for direct transport to an advanced-level trauma centre.⁶ An audit from the Netherlands conducted by Voskens et al. found that compliance increased with severity, with a 69% compliance rate in non-severe injury (not classified as major trauma) compared with a 78% compliance rate in more severe injuries that do classify as major trauma.²¹ The reasons that a case may not have bypassed the closest centre despite the protocol may include: EMS providers not feeling confident to spend longer in transit with cases of major trauma, reduced awareness of the protocol and criteria for bypass of the nearest hospital or reduced capability to detect occult injury and therefore an under-estimation of severity. Reduced ability to pick up intra-abdominal injury at the scene, as evidenced by a lower compliance rate for major trauma characterised by intra-abdominal injury compared with other natures of injury, may have also contributed to cases of non-compliance to the MTDP.

The low level of compliance for intra-abdominal injuries found in this audit compared with other injury types may suggest that this injury type is less likely to be picked up correctly at the scene, and that recognition of intra-abdominal injuries is not as accurate using standard evaluation techniques at the scene. This suggests that increasing proficiency of detecting intra-abdominal injury at the scene may be a significant factor in increasing adherence rates to the major trauma destination policy. Practical applications of this finding could include training and resource allocation adjustments for FAST scanning/bedside ultrasound at the scene of trauma, or more education around the signs and symptoms of intra-abdominal injury that can be used effectively in the field. The numbers in each nature of injury category were relatively low, and therefore the findings need to be interpreted with caution. No previous published literature was located that had investigated the relationship between nature of injury and adherence to MTDPs.

A strength of this study is its alignment with methodology used in a 2018 New Zealand audit of the MTDP (in an email from B. Dicker in January 2022). The 2018 audit covered the period between 1 July 2017 and 30 June 2018, the present audit covering 31 November 2017 to 30 November 2018, so there is a minor difference in time period, but they are very similar in terms of trauma policy, both just over 1 year following the implementation of the MTDP. Our current methodology, however, has key differences. Firstly, the 2018 National Trauma Network audit over-reported compliance by auditing cases occurring in areas where the closest hospital was, by default, a major trauma hospital. The current methodology excluded cases that occurred in proximity to an advanced-level trauma centre, thereby reducing the possibility of over-reporting compliance. Interestingly, despite the 2018 study finding a 91% compliance rate to the MTDP with the reported limitation of over-estimating adherence, this study’s adherence rate was 94%.

A New Zealand study looking at theoretical access to timely advanced-level trauma care identified lower access for Māori (New Zealand’s Indigenous population) and older people.²² These groups also have high rates of injury incidence^14,23 and a disproportionate burden of morbidity post-injury.^24,25 This audit found a difference in adherence for Māori compared with non-Māori patients, with 87.5% and 97.1% adherence rates respectively. This is a notable finding, as effective and adhered-to MTDPs can therefore potentially reduce the health burden on these already vulnerable communities. Due to the sample size of only 100 patients and use of a predominantly rural cohort, we were unable to report on Pacific peoples due to very small numbers. This is a key consideration for future analysis with a larger sample size. Given the exclusion of cases whereby the closest hospital was an advanced-level trauma centre, there were no cases from major centres included. Therefore, while this audit has a large representation of rural communities in the population, there is no way to compare those outcomes with the outcomes of urban communities.

The generalisability of the findings of this audit is limited by the random sample of 100 cases. Additionally, the low numbers of children in the present sample and cases with a high scene ISS (>49) reflect the New Zealand major trauma population but limit the generalisability of these findings to these groups. The experience of the EMS providers who attended the incident was not available in the data reviewed for this study. This information would have been helpful to provide insight into factors that may have impacted adherence. In addition, not all types of major trauma are represented, for example burns or penetrating injuries, limiting the audits’ ability to assess MTDP adherence for these injury types. This audit used the 2019 MTDP to determine outcomes of adherence for cases occurring in 2017 for reasons outlined above. Therefore, this audit may have been limited by some minor changes between the 2017 and 2019 destination policies. Although the cohort is 6 years old, there have been no significant shifts in practice since this time; therefore, the results are likely to still be relevant. In addition, the use of a cohort derived during the COVID-19 epidemic may have resulted in some unknown effects on destination adherence. However, it should be noted that due to New Zealand’s strict border closure restrictions during COVID-19, the country did not experience the extent of the overwhelming impact on health services (including EMS) that other countries experienced. A future audit comparing a post-COVID period would be of interest.

Conclusion

The present study found high adherence to the New Zealand MTDP, with the majority (94%) of cases being taken to the appropriate destination directly from the incident scene. Contrastingly to the overall outcome, of those cases classified as meeting the criteria for direct transport to an advanced-level trauma centre, in just over 60% of cases the MTDP was adhered to.

In cases where the appropriate action was to bypass the nearest medical facility, this audit reveals potential scope for improvement, particularly when the injury severity is high. In order to make improvements, it is key that emergency services understand the reasons for the instances when there is non-adherence. Future investigations could seek to inform paramedics of patient final outcomes and whether knowledge of this would lead them to make different decisions in future. Moreover, are there changes that could be made to the pre-hospital destination guidelines to reduce the subjectivity; for instance, perhaps incorporation of physiological measures and/or additional decision support via telehealth or similar need to be made available to paramedics on scene.

View Appendix.