Prehospital analysis of northern trauma outcome measures: the PHANTOM study
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Original article
Prehospital analysis of northern trauma outcome
measures: the PHANTOM study
Christopher A Smith,1,2 Richard D Hardern,3 Simon LeClerc,2 Richard J Howes2
1
Emergency Department, James Abstract
Cook University Hospital, Objective To compare the mortality and morbidity of Key messages
Middlesbrough, UK
2
Research and Development traumatically injured patients who received additional
team, Great North Air prehospital care by a doctor and critical care paramedic What is already known on this subject
Ambulance Service, The Imperial enhanced care team (ECT), with those solely treated by a ►► In the UK, prehospital enhanced care teams
Centre, Darlington, UK paramedic non-ECT. (ECT) including Ground Emergency Medical
3
Emergency Department, Services or Helicopter Emergency Medical
University Hospital of North
Methods A retrospective analysis of Trauma Audit and
Research Network (TARN) data and case note review Services are staffed by doctors and critical care
Durham, Durham, UK
of all severe trauma cases (Injury Severity Score ≥9) in paramedics.
North East England from 1 January 2014 to 1 December ►► To date, it has remained unclear whether the
Correspondence to
Dr Christopher A Smith, 2017 who were treated by the North East Ambulance advanced interventions that can be delivered
Emergency Department, James Service, the Great North Air Ambulance Service or both. by an ECT generate demonstrable benefit in
Cook University Hospital, patient outcome.
Middlesbrough TS4 3BW, UK;
TARN methods were used to calculate the number of
Chrissmith30@me.com unexpected survivors or deaths in each group (W score
What this study adds
(Ws)). The Glasgow Outcome Scores were contrasted to
Received 10 May 2017 ►► In this retrospective analysis, we observed
evaluate morbidity.
Revised 21 December 2018 statistically significant benefits in adjusted
Results The ECT group treated 531 patients: there were
Accepted 24 December 2018 survival rates for severe trauma patients who
17 unexpected survivors and no unexpected deaths. The
were treated by an ECT.
non-ECT group treated 1202 patients independently:
there were no unexpected survivors and 31 unexpected
deaths. The proportion of patients requiring critical care
interventions differed between the two groups 49% broad selection criteria for these studies may dilute
versus 33% (CI for difference 12% to 20%). In the any positive outcomes.
ECT group, the Ws was 3.22 (95% CI 0.79 to 5.64). In This study addresses the gap in the current liter-
the non-ECT group, the Ws was −2.97 (95% CI −1.22 ature by focusing on the most severely injured
to −4.71). The difference between the Ws was 6.18 patients, in an attempt to establish whether there is
(95% CI 3.19 to 9.17). There was no evidence of worse a demonstrable benefit in mortality and morbidity
morbidity in the ECT group. from prehospital care delivered by an ECT. Specifi-
Conclusion This is the first UK ECT service to cally, we aimed to determine whether ECT delivered
demonstrate a risk-adjusted mortality benefit in care produces a higher proportion of unexpected
trauma patients with no detriment in morbidity: our survivors compared with standard care in severe
results demonstrate an additional 3.22 survivors per trauma patients in the North East of England.
100 severe trauma casualties when treated by an ECT.
The authors encourage other ECT services to conduct Methods
similar research. The Great North Air Ambulance Service (GNAAS)
has two bases covering a population of 4 million
people across 8000 square miles of North East and
North West England. The service operates two heli-
Introduction copters and a rapid response car, between 08:00
‘Major trauma’ describes injuries that pose a and 20:00 hours, 7 days a week. The car operates in
serious and immediate threat to life and limb. low light conditions or when the aircraft are offline
Helicopter Emergency Medical Services (HEMS), for unplanned maintenance.9 Since May 2015,
using enhanced care teams (ECTs) are common the car has also been operating overnight between
in countries where emergency medical delivery 20:00 and 08:00 hours, every Friday and Saturday.
systems are well established.1–4 Previous European GNAAS self-tasks to incidents according to specific
© Author(s) (or their studies have shown the benefit of prehospital ECTs criteria with an aim of identifying major trauma
employer(s)) 2019. No working within HEMS over standard ambulance triage positive patients. Trauma accounts for 80%
commercial re-use. See rights
and permissions. Published care.4–6 of GNAAS missions; the remainder being medical.
by BMJ. Only a few studies have evaluated UK-based ECT During the study period, the ECT was composed
models.6 7 Investigating different UK services and of a prehospital care consultant and a critical care
To cite: Smith CA,
collating outcome data can be challenging due to paramedic (CCP) 90% of the time. The remaining
Hardern RD, LeClerc S, et al.
Emerg Med J Epub ahead diverse dispatch protocols, team composition, 10% of cases involved a senior Pre-hospital Emer-
of print: [please include Day treatment protocols and capabilities.6 7 Previous gency Medicine trainee or specialist trained trauma
Month Year]. doi:10.1136/ studies, focused on all trauma patients rather than doctor, with a CCP. There were no days when a
emermed-2017-206848 those most severely injured.8 We believe that the double CCP crew alone provided critical care.
Smith CA, et al. Emerg Med J 2019;0:1–6. doi:10.1136/emermed-2017-206848 1Original article
There are no other prehospital critical care trauma teams in the
Table 1 Patient characteristics
North East of England.
Non-ECT ECT Difference of median
Characteristic (n=1202) (n=531) or proportion (95% CI)
Participants Male 810 (67.4%) 398 (75.0%) 7.6 (2.9 to 12.0)
A request was made to the Trauma Audit Research Network
Median age (years) 54.4 44.0 10.4 (7.7 to 13.2)
(TARN) for all patients who presented to hospitals in the North
Blunt mechanism of 1164 (96.8%) 497 (93.6%) 3.2 (1.1 to 5.8)
East Ambulance Service (NEAS) area. This included all trauma injury
units and two Major Trauma Centres (MTC's): The James Cook
Assault 144 (11.9%) 54 (10.2%) 1.8 (−1.5 to 4.9)
University Hospital, Middlesbrough and the Royal Victoria Infir-
Crush 17 (1.4%) 14 (2.6%) 1.2 (−0.2 to 3.2)
mary, Newcastle. Both MTCs have very similar survival rates
Fall 2 m 250 (20.8%) 87 (16.4%) 4.4 (0.4 to 8.2)
lines in the ED. The authors investigated 4 years of data from 1
January 2014 to 1 December 2017 during 08:00 to 20:00 hours Other 71 (5.9%) 14 (2.6%) 3.3 (1.2 to 5.1)
and 20:00 to 08:00 hours Friday and Saturday. Road traffic collision 346 (28.8%) 330 (62.2%) 33.4 (28.4 to 38.1)
Patients were included in the analysis if they were a major Median Injury Severity 20 25 5 (3.9 to 6.1)
trauma patient (Injury Severity Score (ISS) ≥9) registered in the Score
TARN database and having at least one of the following: Median Probability of 95.9 95.3 0.6 (−1.9 to 0.6)
Survival score
►► Intubated in the prehospital phase or in the ED.
Traumatic cardiac arrest 44 (3.6%) 27 (5.1%) 1.5 (−0.4 to 3.9)
►► Received blood products prehospital or in the ED.
►► Admitted direct to level 2 or 3 critical care from the ED. Mortality 212 (17.6%) 81 (15.3%) 2.4 (−1.5 to 6.0)
►► Underwent surgery within 4 hours of ED arrival. ECT, enhanced care team.
►► Hypotensive on arrival to the ED (systolic blood pressure
(SBP)Original article Figure 1 Flow chart of results. Results criteria and 261 (11.8%) patients received critical care interven- During the study period, 1446 patients activated the NEAS tions on scene with 47 patients requiring further critical care regional prehospital major trauma tool (MTT) to warrant admis- interventions on arrival to ED. sion to a MTC (figure 1). A further 5272 (78%) did not have any The ambulance service treated 4097 trauma patients; 1202 MTT status recorded, 350 had an isolated femoral neck fracture (29%) patients met the inclusion criteria for this study and 400 and 65 had an isolated fracture of one rib: all these cases were (9.7%) required critical care interventions on arrival at the excluded. ED. Two hundred and eighty-two (6.8%) were initially treated The ECTs were tasked to 2199 trauma patients of whom 778 in trauma units: of these, 141 (43%) subsequently required (35%) were treated and transported to hospital. In 876 (39.8%), secondary transfer to MTCs. the ECT were stood down en route by the ground (paramedic The non-ECT group were older (10.4 years) than the ECT only) ambulance service. Following on scene assessment by group, had a lower ISS (20 vs 25) and had a similar Ps (95.9 vs the ECT, 436 (19.8%) were handed over to the ambulance 95.3) (table 1). Both groups had a similar proportion of patients service personnel on scene for management of injuries that did with severe head injuries (Abbreviated Injury Scale ≥4 non-ECT not require transfer to a MTC. None of these patients subse- 38.6% vs ECT 36.5%) and hypotensive (SBP
Original article
Table 3 Outcome: expected survivors versus actual survivors and Wss
Non ECT patients ECT patients
Ps survival Number Expected Actual Difference Adjusted Ps survival Number Expected Actual Difference Adjusted
band % (% of total) survivors survivors (W) difference (Ws) band % (% of total) survivors survivors (W) difference (Ws)
95–100 643 (54) 632.65 628 −0.72 −0.37 95–100 272 (51) 267.65 271 1.23 0.64
90–95 153 (13) 142.14 136 −4.01 −0.49 90–95 57 (11) 52.93 56 5.39 0.66
80–90 162 (13) 138.43 129 −5.82 −0.62 80–90 52 (10) 44.35 49 8.94 0.95
65–80 73 (6) 53.49 50 −4.78 −0.41 65–80 33 (6) 24.44 25 1.69 0.14
45–65 55 (5) 29.46 24 −9.92 −0.70 45–65 41 (8) 22.68 23 0.78 0.05
25–45 52 (4) 18.53 14 −8.71 −0.48 25–45 48 (9) 16.86 18 2.38 0.13
0–25 64 (5) 8.2 10 2.81 0.12 0–25 28 (5) 3.75 8 15.18 0.63
Total 1202 1022.9 991 −2.97 Total 531 432.66 450 3.22
(-4.71 to −1.21) (0.79 to 5.64)
ECT, enhanced care team; Ws, W scores; Ps, Probability of Survival.
group (6.4% vs 3.2% and 62% vs 29%, respectively) and a Ws was 3.22 (95% CI 0.79 to 5.64) (figure 2). There was a statis-
larger proportion of fallsOriginal article
There were three survivors of TCA in the non-ECT group
Table 4 Glasgow Outcome Score (GOS)
(average Ps 85.1), all suffered hypoxic cardiac arrest, secondary
Morbidity (GOS) Non-ECT (n=1202) ECT (n=531) to hanging, fall from a horse and drowning. All cases responded
GOS 1 (death) 211 (17.5%) 81 (15.3%) to bystander cardiopulmonary resuscitation. One patient made a
GOS 2 (prolonged disorder of 4 (0.3%) 0 (0%) good recovery and two patients had a GOS of 3.
consciousness) The only band with a greater number of actual versus expected
GOS 3 (severe) 104 (8.6%) 66 (12.4%) survivors in the non-ECT group was the 0–25 Ps band. The
GOS 4 (moderate) 135 (11.2%) 79 (14.8%) majority of these incidents took place less than three miles away
GOS 5 (good) 645 (53.6%) 290 (54.6%) from the MTC.
Limitations
may be due in part to the increased number of critical care
This study is a retrospective comparative observational study and
procedures delivered to address airway compromise and haem-
is subject to bias that a randomised control trial would seek to
orrhage in the prehospital setting.
minimise. The prospect of conducting a randomised control trial
In comparison with prior studies, children, drowning, hanging
is unlikely at this juncture as doctor-CCP ECTs are becoming
and patients in TCA who subsequently were conveyed to hospital
the established standard for pre-hospital critical care in the UK.
were included.2 This study confirms that the ECT group in fact
Although the two groups were matched with similar Ps, the
received more critical care interventions than the non-ECT
mechanism of injury varied between the two groups. Twice the
group. Novel methods, using TARN’s Ps model, allowed cases to
numbers of road traffic collisions were found in the ECT group,
be matched and analysed according to Ps bands. This adjustment
while five times the number of falls were seen in the non-ECT
takes into account differences in age and comorbidities when
group. GNAAS has specific tasking criteria, significant falls
calculating Ps.
are much more difficult to identify compared with road traffic
The greatest survival benefit was found in Ps bands lower than
collisions.
95–100 suggesting the impact of ECT care is most pronounced
Over 50% of GNAAS missions take place in Cumbria (North
in more severe trauma cases. ECTs had little impact on those
West England). We were unable to include these missions due to
patients with a likelihood of survival. Patients in the 80–90 Ps
difficulties in obtaining TARN and local ambulance data.
band with a lower ISS may have sustained isolated injuries signif-
There have been a number of advances within GNAAS during
icant enough to cause physiological derangement, hypoxia and
the study period. Thoracotomy only began as an established
hypotension which were then addressed by critical care interven-
procedure for the service in early 2015 as did the use of prehos-
tions performed by the ECT. The ECT group had more hypo-
pital packed red blood cell transfusions: 95 patients (18%) were
tensive patients (SBPOriginal article
benefit selected patients with severe trauma. We recommend 4 Taylor C, Jan S, Curtis K, et al. The cost-effectiveness of physician staffed Helicopter
that other services use the TARN methodology to identify the Emergency Medical Service (HEMS) transport to a major trauma centre in NSW,
Australia. Injury 2012;43:1843–9.
impact of ECTs on outcome.
5 Taylor CB, Stevenson M, Jan S, et al. A systematic review of the costs and benefits of
helicopter emergency medical services. Injury 2010;41:10–20.
Collaborators Sophie Jones (TARN analyst) 6 Littlewood N, Parker A, Hearns S, et al. The UK helicopter ambulance tasking study.
Contributors CAS devised the study, collated TARN prehospital and hospital data, Injury 2010;41:27–9.
performed statistical analysis and wrote the article. RDH advised with statistical 7 Hyde P, Mackenzie R, Ng G, et al. Availability and utilisation of physician-based pre-
analysis and reviewed the article. SL reviewed the article. RJH collated data and hospital critical care support to the NHS ambulance service in England, Wales and
reviewed the article. Sophie Jones aided with data collection via TARN. Northern Ireland. Emerg Med J 2012;29:177–81.
Funding The authors have not declared a specific grant for this research from any 8 Andruszkow H, Schweigkofler U, Lefering R, et al. Impact of helicopter emergency
funding agency in the public, commercial or not-for-profit sectors. medical service in traumatized patients: which patient benefits most? PLoS One
2016;11:e0146897.
Competing interests SL is a Medical Director of GNAAS and EM consultant at
9 Community-powered Emergency Care. Annual report 2015/16 GNAAS. https://www.
JCUH. CAS is Deputy Medical Director and EM consultant at JCUH. RJH is PHEM and
EM consultant at GNAAS and RVI. greatnorthairambulance.co.uk/corporate-documents/ (Accessed 2 May 2018).
10 Consensus statement. A framework for safe and effective intubation by paramedics.
Patient consent for publication Not required. https://www.collegeofparamedics.co.uk/news/paramedic-intubation-consensus-
Provenance and peer review Not commissioned; externally peer reviewed. statementhttps://www.tarn.ac.uk/Content.aspx?ca=4&c=3515 (Accessed 7 May
2018).
11 TARN. Explanation of Tarn probability of survival model. https://www.tarn.ac.uk/
References Content.aspx?ca=4&c=3515 (Accessed 2 May 2018).
1 Den Hartog D, Romeo J, Ringburg AN, et al. Survival benefit of physician-staffed
Helicopter Emergency Medical Services (HEMS) assistance for severely injured 12 Younge PA, Coats TJ, Gurney D, et al. Interpretation of the Ws statistic: application to
patients. Injury 2015;46:1281–6. an integrated trauma system. J Trauma 1997;43:511–5.
2 Galvagno SM, Sikorski R, Hirshon JM, et al. Helicopter emergency medical services for 13 Bonett DG, Price RM. Statistical inference for a linear function of medians: confidence
adults with major trauma. Cochrane Database Syst Rev 2015(12):CD009228. intervals, hypothesis testing, and sample size requirements. Psychol Methods
3 Giannakopoulos GF, Kolodzinskyi MN, Christiaans HM, et al. Helicopter emergency 2002;7:370–83.
medical services save lives: outcome in a cohort of 1073 polytraumatized patients. Eur 14 Joint Royal Colleges Ambulance Liaison Committee. UK ambulance services clinical
J Emerg Med 2013;20:79–85. practice guidelines. https://www.jrcalc.org.uk/guidelines/ (Accessed 2 May 2018).
6 Smith CA, et al. Emerg Med J 2019;0:1–6. doi:10.1136/emermed-2017-206848You can also read
