a b s t r a c t

Objective: We investigated pre-hospital times, clinical characteristics and therapeutic interventions in multisys- tem trauma patients injured in mountainous areas in comparison to both urban and suburban trauma patient ad- missions.

Methods: Pre-hospital and in-hospital data collected from trauma patients included in the International Alpine Trauma Register (IATR) hosted in Bolzano, Italy (aged 16-80 yr with an ISS >= 16), were compared with trauma patient data published from those urban and suburban areas included in the Trauma Register DGU(R) (TR-DGU) of the German Trauma Society.

Results: A total of 94 patients from the IATR and 11,020 patients from the TR-DGU met the inclusion criteria. Due to longer treatment-free intervals (mean 59.1 vs. 19.7 min), total out-of-hospital time was reportedly longer in individuals injured in mountainous areas, compared to urban/suburban areas (117.4 +- 142.9 vs. 68.7 +- 28.6 min, p = 0.002), despite the more frequent Helicopter rescue (93% vs. 40%, p b 0.001). 57% of IATR patients were hypothermic at hospital arrival, mean ISS was higher (38.5 +- 15.8 vs. 28.6 +- 12.2, p b 0.001) and patients with a systolic blood pressure (SBP) <=90 mm Hg were more frequent (27% vs. 15%, p = 0.005), yet less patients had received volume therapy (82% vs. 93%, p = 0.001). However, overall no difference in hospital mortality was observed (11% vs. 17%, p = 0.159).

Conclusion: Trauma incidents in mountainous areas commonly feature significantly increased out-of-hospital time which is associated with a more severe ISS, higher risk of accidental hypothermia and more frequent hypo- tension compared to urban/suburban trauma. Nonetheless, the mortality rate of IATR patients is comparable to urban/suburban trauma patients.

(C) 2018

Introduction

Outdoor activities in the mountains have continued to gain popular- ity and have increasingly become more accessible over recent years [1]. In parallel, the number of rescue missions in mountainous environ- ments has reportedly increased [2], plus the proportion of potentially life threatening injuries incurred has notably risen [3]. Multisystem trauma in mountainous areas is expected to differ in several aspects from trauma in an urban or suburban setting. This assertion is mainly due to the remote, technically challenging environment and the num- ber of unique recreational activities encountered with an inherent risk

* Corresponding author at: Institute of Mountain Emergency Medicine, EURAC Research, Viale Druso 1, 39100 Bolzano, Italy.

E-mail address: [email protected] (S. Rauch).

of fall. The injury mechanism, pattern and severity of mountain trauma sustained by patients might be distinct from trauma in an urban/subur- ban area. However, currently only scant data exist relating to the char- acteristic differences between mountain and urban/suburban trauma admissions. The aim of this study is to describe the out-of-hospital times, clinical characteristics and therapeutic interventions utilised in multisystem trauma patients in mountainous environments in compar- ison to urban/suburban trauma patient admissions; specifically relating in-hospital data to prehospital times and Treatment interventions.

Materials and methods

Out-of-hospital and in-hospital data collected from trauma patients included in the International Alpine Trauma Register (IATR) [4] were analysed and compared with trauma patient data published from

https://doi.org/10.1016/j.ajem.2018.01.068

0735-6757/(C) 2018

those urban and suburban areas in Germany included in the TraumaRegister DGU(R) (TR-DGU) of the German Trauma Society [5]. Only trauma patients aged 16-80 years with an Injury Severity Score (ISS) >=16, whom arrived at the hospital with vital signs, were included in the analysis.

The IATR is a transnational platform for the prospective collection and storage of data relating to Severe trauma patients (ISS >=16), encoun- tered in mountainous or remote areas, that are not readily accessible by the regular emergency medical services. This registry is hosted in Bol- zano, Italy [4]. In this comparison, those patients already in cardiac ar- rest upon arrival of the rescue team, burn patients (if the burn represented the predominant injury), and drowned patients were ex- cluded from the IATR prior to analysis. Equally, in North Tyrol, Austria, patients who suffered accidents on resort prepared ski slopes were also excluded. Data collection in the IATR is based on the Utstein-Style [6], which requires comprehensive data collection on multiple parame- ters. These parameters include accident (type of outdoor activity, mech- anism of injury); mission characteristics (technical difficulty of the terrain, terrestrial rescue, air rescue or combined rescue) and timing (time of accident, time of emergency call, time of arrival of the first res- cue team, time of hospital admission). Medical data collected included:

i) vital signs at the scene (i.e. systolic blood pressure, respiratory rate, Glasgow Coma Scale (GCS) and body temperature); ii) out-of-hospital Advance Trauma Life Support (ATLS) interventions (i.e. endotracheal in- tubation, intravenous cannulation, fluid and drug administration); iii) ISS and Abbreviated Injury Scale based on in-hospital diagnosis;

iv) vital signs and laboratory data on admission (i.e. haemoglobin, INR, base excess, body temperature), plus out-of-hospital and in-hospital mortality ratings. In this study, patient data collected between Decem- ber 2010 and June 2013 in the provinces of North Tyrol (Austria) and South Tyrol (Italy) were analysed.

The TraumaRegister DGU(R) of the German Trauma Society (TR-DGU) was founded in 1993, and in 2013 N600 hospitals reported over 33,000 trauma cases. The majority of these hospitals actively reporting trauma admissions are situated in Germany, and with only a few regions not contributing to the registry, a representative view of trauma care in Germany is given [7]. Data from urban and suburban regions are col- prehospital management“>lected in the TR-DGU without subgroup monitoring of the location. Pre- viously, Timm and co-workers used this comprehensive database to compare German and Dutch trauma care systems (2009-2012). Specific factors such as prehospital rescue times, clinical characteristics and therapeutic actions in severe trauma cases (ISS >=16) were closely exam- ined [5]. Subsequently, data from German trauma centres published in this aforementioned analysis by Timm et al., representing severe trauma cases from urban/suburban areas, were also included in our compara- tive analysis. However, only variables available from both registers (IATR and TR-DGU), were used to inform the comparative analysis. All patients from the TR-DGU and 85% of IATR-patients were treated in a Level I trauma centre. Germany, as well as Italy and Austria, have a phy- sician based out-of-hospital approach to emergency patients and thus form a good comparison.

Statistical analysis

Data are presented as percentages or as mean +- standard deviation, as appropriate. Fisher’s exact test was used to compare proportions and Welch’s t-test to compare continuous data. Tests were two-sided and p b 0.05 was considered statistically significant. R version 3.2.3 was used for the analysis [8].

Results

During the study period, a total of 94 patients from the IATR and 11,020 patients from the TR-DGU(R) met the inclusion criteria. Mean age was 46.0 +- 16.1 yr for IATR patients and 45.8 +- 18.3 yr for TR-

DGU(R) patients (p = 0.905). The majority of patients in both registers were male (86% in IATR and 75% in TR-DGU respectively, p = 0.012).

Prehospital times and Mode of transport

Mean overall out-of-hospital time (time from accident to hospital admission), was 117.4 +- 142.9 min in mountainous areas, compared to a lesser 68.7 +- 28.6 min in urban/suburban areas (p = 0.002). In mountain trauma patients, the overall out-of-hospital time varied over a wide range from 30 min to N17 h. Similarly, the treatment-free inter- val, defined as time from accident to arrival of the first rescue personnel on scene, was longer in mountainous terrain (mean 59.1 vs. 19.7 min re- spectively; number of patients available from TR-DGU n = 8798). Within this pre-defined time fame, mean time from accident to emer- gency call was reportedly 37.0 +- 139.1 min in the IATR (not recorded in the TR-DGU). Fig. 1 shows out-of-hospital times in mountain and urban/suburban trauma patients. Out-of-hospital times were longer in mountainous compared to urban/suburban areas, despite the fact that HEMS was more frequently used for patient evacuation and transport in IATR scenarios (93% vs. 40%, p b 0.001). Out-of-hospital time intervals in mountain trauma patients grouped by rescue mission characteristics are shown in Table 1.

Mechanism and pattern of injury

Blunt trauma was the predominant injury sustained in those pa- tients included in the IATR and TR-DGU (100% and 95.6% respectively, p = 0.036). Fall was the most frequent mechanism of injury in the mountains (59.6%, see Table 2), whereas traffic accident (61.5%) was the most prevalent mechanism in urban and suburban areas. In Table 3, the type of activity preceding severe trauma in mountainous environments is compared with the mechanism of injury in urban/sub- urban trauma. The injury severity delineated by the mean ISS was 38.5

+- 15.8 in IATR patients and 28.6 +- 12.2 in patients included in TR-DGU (p b 0.001). Differences in injury patterns, displayed as Abbreviated In- jury Scale (AIS) >=3 of different body regions, are shown in Table 4 (infor- mation available for 55 patients from IATR).

Prehospital management

Patients whom presented with a low systolic blood pressure (<=90 mm Hg) at the scene were more frequently reported in the IATR, as compared to the TR-DGU (41% vs. 19%, p b 0.001). Although the rate of patients with a low systolic blood pressure was higher in the IATR, less patients from IATR, as compared to TR-DGU, received out-of- hospital volume therapy (82% vs. 93%, p = 0.001). The majority of pa- tients received out-of-hospital analgesic treatment (82% of IATR pa- tients and 78% of TR-DGU patients, p = 0.526). The rate of Unconscious patients with GCS <= 8 was equal in both registers (34% vs.

Prehospital time intervals (min)

140

120

100

80

60

40

20

0

IATR TR-DGU

treatment free interval on-site treatment and transport time

Fig. 1. Prehospital time intervals.

Table 1

Out-of-hospital time intervals in mountain trauma patients grouped by rescue mission characteristics, in minutes.

Mission characteristics Time from accident to rescue arrival Time from rescue arrival to hospital

admission

Time from accident to hospital admission

	mean +- SD	min	max	n		mean +- SD	min	max	n		mean +- SD	min	max	n
Terrestrial rescue	81.5 +- 76.4	19	220	6		138.0 +- 108.7	38	280	6		192.4 +- 158.0	30	500	7
Air rescue	67.4 +- 175.0	12	1010	34		55.3 +- 20.4	17	120	36		118.2 +- 162.4	40	1047	40
Terrestrial rescue with air support	49.5 +- 114.1	14	769	43		54.1 +- 20.7	14	114	43		104.8 +- 119.4	49	852	44
Total	59.1 +- 139.5	12	1010	83		60.6 +- 39.4	14	280	85		117.4 +- 142.9	30	1047	91

34%, p = 0.913). Out-of-hospital Intubation rate was lower (although not reaching statistical significance) in mountainous compared to urban/suburban areas, reportedly 44% and 54% respectively (p = 0.077). Insertion of a chest tube was accomplished in 4% of IATR patients and 6% of patients included in the TR-DGU (p = 0.662).

Critically impaired vital functions and laboratory findings at hospital arrival

On hospital arrival, the rate of patients with a low systolic blood pressure was higher in IATR in comparison to TR-DGU (27% vs. 15%, p

= 0.005). Mean GCS was 10.7 +- 4.8 in patients included in the IATR and 7.9 +- 5.5 in TR-DGU(R) patients (p b 0.001). Mean haemoglobin was comparable (12.0 +- 2.2 vs. 12.1 +- 2.7 g/dl, p = 0.774), whereas mean base excess was lower in mountain than urban trauma patients (-5.4 +- 4.1 vs. -3.3 +- 5.1, p b 0.001). Body temperature on hospital arrival was available for 49 IATR-patients, of which 57% showed a body temperature of <=35 ?C; no corresponding body temperature data were reported in the analysis by Timm et al. [5]. No data on immediate in-hospital therapeutic interventions from the IATR or TR-DGU were available.

In hospital mortality

No significant difference in hospital mortality was observed be- tween patients from the IATR and TR-DGU (11% vs. 17% respectively, p = 0.159).

Discussion

Compared with urban/suburban areas, multisystem trauma patients injured in mountainous areas, represented within the IATR, presented with i) different injury mechanism, ii) longer out-of-hospital times, iii) higher frequency of HEMS dispatch, iv) higher mean ISS, v) higher fre- quency of hypotension, vi) lower base excess at hospital arrival, plus

vii) less out-of-hospital volume resuscitation compared to TR-DGU pa- tients. Conversely, patients included in the TR-DGU had a lower GCS at hospital arrival. No differences were found regarding mean patient age and pattern of injury. Also, mortality rates were not different in both registers.

Trauma is known as being a predominantly male pathology [9]. While major trauma of the elderly in the urban/suburban setting is be- coming increasingly recognised [9,10], trauma in the mountains is con- sidered a nearly exclusive problem of young sportsmen. Although our

gender, no significant difference in the mean age was found. Thus, the notion that the mountain trauma patient is nearly always young and otherwise healthy might no longer hold true.

As expected, our data support previous findings [11] that fall is the major mechanism of injury in the mountains. In our comparative anal- ysis, including only patients with severe trauma (ISS >= 16), IATR- patients demonstrated a markedly higher ISS compared to TR-DGU patients.

This finding may be unexpected, as both fall and traffic accident rep- resent a high velocity trauma leading to subsequent deceleration inju- ries. However, obvious developments in vehicle passenger protection systems (i.e. crumple zones of the vehicle, seat belts and airbags) may be an explanation. Regarding the pattern of injury, a higher rate of head/neck and chest injuries was found in mountain trauma patients, however, statistical significance was not reached (Table 4). Future anal- yses, with a higher number of mountain trauma patients are needed to either confirm or refute our current findings regarding injury pattern and severity.

Mean out-of-hospital time was reportedly approximately twice as long in mountain trauma in comparison to urban/suburban trauma sce- narios. This was mainly due to a longer treatment-free interval, whereas time from rescue arrival to hospital admission was only slightly longer in the majority of mountain trauma cases. The delay from accident to the emergency call (e.g. because of poor mobile phone reception at the site of accident), plus the extended time needed to locate the victim and reach the scene, evidently contributed to the prolonged treatment- free interval. Even if HEMS was dispatched (N90% of mountain rescue missions), mean treatment-free interval approached 1 h. Though, out- of-hospital time is crucial in the care of trauma patients. Severely in- jured patients have an increased mortality [12], length of hospital stay, and complication rate [13] with out-of-hospital times exceeding the “golden hour” [14]. In 84% of mountain trauma analysed cases, out-of- hospital time exceeded 60 min. It could thus be hypothesized that ATLS measures performed at scene and not delayed until hospital arrival might be more important in a remote environment with prolonged out- of-hospital rescue times compared to an urban setting. In fact, prehospital ATLS interventions in patients suffering trauma in a rural area seemed to improve patient outcome [15], whereas in an urban set- ting with short out-of-hospital times major interventions performed at the scene were even associated with worse outcome [16]. Whether

Table 3 Type of activity leading to severe trauma in mountainous environments and injury mech- anism in urban/suburban trauma [5]

findings also extend the evidence for the predominance of the male

Type of activity (IATR), n

= 94

% Mechanism of injury (TR-DGU), n = % 11,020

Table 2

Accident characteristics in mountain trauma patients.

Accident characteristics	n	%	Climbing Ski/snowboard	9.6% 29.8%	Traffic accident, bike Traffic accident, pedestrian	8.6% 7.4%
Fall	53	59.6%	Aviation	6.4%	High fall (N3 m)	19.8%
Avalanche accident	9	10.1%	Mountain biking	3.2%	Low fall (b3 m)	12.1%
Collision with object/other person	27	30.3%	Sledging	4.3%	Traffic accident, other	1.6%
Total	89a	100.0%	Other	12.8%	Strike, gunshot, stab	4.9%

Hiking 20.2% Traffic accident, automobile 25.3%

Mountaineering 13.8% Traffic accident, motorbike 15.7%

^a Missing data for 5 patients.

Other 4.7%

Table 4

Injury severity and pattern.

	IATR	TR-DGU	p-Value
Number of patients	94	11,020
ISS, mean +- SD	38.5 +- 15.8	28.6 +- 12.2	b0.001
AIS head/neck >=3, %	67.3%a	54.60%	0.077
AIS chest >=3, %	67.3%a	58.70%	0.218
AIS abdomen >=3, %	23.6%a	17.30%	0.212
AIS extremities >=3, %	38.2%a	35.80%	0.778

^a Calculated on 55 patients (39 patients had missing AIS).

mountain trauma patients benefit from ATLS interventions at the scene is currently unknown. Yet, in mountainous environments, ATLS mea- sures are not always easily accomplished [17,18]. Multiple factors may inhibit those necessary measures, such as: unavailable equipment in terrestrial rescue or winch operations, device malfunction due to envi- ronmental conditions (low temperatures, humidity), limited drug, fluid or oxygen supply, freezing of fluids in severe cold, or transporta- tion issues like the risk of displacement of the endotracheal tube during transport over difficult terrain. In our analyses, the rate of prehospital intravenous cannulation and administration of Analgesic drugs was sim- ilar in mountain and urban/suburban trauma patients. However, the rate of prehospital intubation was lower in IATR patients, although the number of patients with a GCS <= 8, a widely accepted indication for ad- vanced airway management [19], was comparable. Also, we found a sig- nificantly lower frequency of intravenous fluid administration in patients suffering trauma in mountainous environments despite a sig- nificantly higher rate of hypotensive patients. Unfortunately, data on type and amount of volume therapy were not comparable between the two registers. Likewise, on hospital arrival, the rate of hypotensive patients was higher after mountain trauma, as was the frequency of se- vere head/neck injuries - a contraindication to permissive hypotension [20]. These findings might indicate that during difficult scenarios pertaining specifically to mountain rescue missions, volume therapy alone is often insufficient or not feasible to increase blood pressure to desired levels. Although evidence to support the use of vasopressors in trauma patients is limited, the addition and careful titration of cate- cholamines, especially in patients with traumatic brain injury, could avoid life-threatening hypotension and improve tissue perfusion [21]. In addition, limiting the amount of fluids reduces the risk of dilutional coagulopathy and iatrogenic hypothermia, which can both aggravate the “lethal triad of trauma” consisting of coagulopathy, hypothermia and acidosis.

In the IATR, 57% of trauma patients showed a body temperature of

<=35 ?C on hospital arrival, compared to a hypothermia rate of 17.6% found in a further analysis of data from the TR-DGU by Trentzsch et al. [22]. Surprisingly, although IATR patients had a higher mean ISS, longer out-of-hospital times, a higher rate of hypotension (both at the scene and on hospital arrival), a higher frequency of hypothermia and a lower base excess on hospital arrival, mortality rate was not different when compared to TR-DGU patients. The lower mean GCS on hospital arrival of urban/suburban trauma patients from the TR-DGU might partly counterbalance the numerous negative prognostic factors found in IATR patients and be a possible explanation for the similar mortality rates in both registers. However, the GCS was lower only on hospital ar- rival (and not at the scene) and might -at least in part- be explained by a more frequent prehospital anaesthesia induction and intubation in the TR-DGU patients.

Limitations

The number of cases collected in the IATR is limited and some data are missing, therefore the conclusions on specific Treatment protocols of mountain trauma causalities drawn from our analysis must be interpreted cautiously. This highlights a need to inform future definition with further in-depth analyses using a larger sample size.

Conclusion

Despite the fact that the injuries sustained are associated to different activities in both mountains vs. urban/suburban areas, there are no dif- ferences in injury pattern. However, rescue missions in mountainous environments are associated with an increased out-of-hospital time, due to a significantly longer treatment-free interval, plus there is an in- creased risk to develop accidental hypothermia. This could partially ex- plain why trauma patients from the IATR demonstrated a markedly higher ISS compared to urban/suburban trauma cases, plus were more frequently reportedly hypotensive both at the scene and on hospital ar- rival, despite helicopter rescue in over 90% of cases. Nevertheless, the implementation of an already advanced prehospital treatment strategy could explain the lack of difference in hospital mortality. Thus, in future strategies developed for the treatment of severe mountain trauma pa- tients there needs to be clear consideration of the potential trauma en- vironment and consequential logistical complexities commonly encountered during mountain rescue operations. Equally, specific focus should be given to the development of out-of-hospital ATLS in- ventions for the treatment of hypotensive and hypothermic patients.

Acknowledgments

We would like to acknowledge the support of the following people in collecting the data: Manfred Brandstatter, Clemens Dengg, Gerold Druge, Markus Falk, Ernst Fop, Andreas Frasnelli, Lukas Gasteiger, Georg Hofer, Margareth Kettner, Wolfgang Lunz, Franz Ploner, Georg Rammlmair, Alberto Trincanato, Peter Zanon, Wolfgang Voelckel.

We would like to acknowledge the support of the following people for linguistic revision: Rachel Turner.

Funding

This research did not receive any specific grant from funding agen- cies in the public, commercial, or not-for-profit sectors.

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