ORIGINAL ARTICLE

PRACA ORYGINALNA

BURNS IN PRACTICE OF HELICOPTER EMERGENCY MEDICAL SERVICE IN POLAND. RETROSPECTIVE ANALYSIS

OPARZENIA CIAŁA W PRAKTYCE ZAŁÓG ŚMIGŁOWCOWEJ SŁUŻBY RATOWNICTWA MEDYCZNEGO W POLSCE. ANALIZA RETROSPEKTYWNA

Patryk Rzońca1, Piotr Tomaka2, Robert Gałązkowski3

1DEPARTMENT OF EMERGRNCY MEDICINE, FACULTY OF HEALTH SCIENCES, MEDICAL UNIVERSITY OF LUBLIN, LUBLIN, POLAND

2ANAESTHESIOLOGY AND INTENSIVE CARE UNIT, LECZNA, POLAND

3DEPARTMENT OF EMERGENCY MEDICAL SERVICES, FACULTY OF HEALTH SCIENCE, MEDICAL UNIVERSITY OF WARSAW, WARSAW, POLAND

Abstract

Introduction: Burns are a huge problem for public health and a challenge for healthcare systems all around the world. They are responsible for 180.000 deaths worldwide each year. In order to ensure high quality treatment and rehabilitation of these patients burn centres are established in many countries. Another vital factor influencing the prognosis of patients with burns is quick transport that in many countries, including Poland is carried out by Helicopter Emergency Medical Service (HEMS).

The aim: To describe the operations carried out by HEMS with particular stress put on the target medical facility.

Materials and methods: The research was conducted with the method of retrospective analysis of operations performed by HEMS crews. All missions from January 2011 to December 2018 were included in the study and 2534 cases were qualified for the final analysis.

Results: The study group was predominantly male (72.72%) aged 18 years old and less (36.65%). Nearly two thirds of the patients were transported to hospitals with a burn ward (61.88%). Opioid analgesics as well as crystalloids were the most commonly administered drugs (respectively 68.55% and 64.76%). Statistical analysis showed that HEMS arrival time (20.77 minutes vs 18.60 minutes) and duration of the transport to designated hospital (40.11 minutes vs 19.66 minutes) were significantly higher in the cases of deciding to transport the patient to the hospital with the burns department (p<0.001).

Conclusions: Presented results showed that HEMS crews are more often assigned to help ground-based Medical Rescue Teams in case of patients who required treatment in burn centres. Moreover, the time and distance to the hospital with burn ward was significantly longer compared to other healthcare facilities. This confirms that the assigning of HEMS crews for the patients with severe burns was reasonable.

Key words: burn, Helicopter Emergency Medical Service, prehospital care, burn centres

Streszczenie

Wstęp: Oparzenia ciała stanowią ogromny problem dla zdrowia publicznego i wyzwanie dla systemów opieki zdrowotnej na świecie. Każdego roku odpowiedzialne są za 180 tysięcy zgonów na świecie. W celu zapewnienia wysokiej jakości leczenia i rehabilitacji pacjentów z oparzeniami ciała w wielu krajach tworzone są centra leczenia oparzeń. Kolejnym kluczowym elementem wpływającym na rokowanie pacjentów z oparzeniami ciała jest szybki transport, który w wielu krajach, w tym również w Polsce realizowany jest przez załogi Śmigłowcowej Służby Ratownictwa Medycznego (HEMS).

Cel pracy: Charakterystyka misji załóg HEMS realizowanych do pacjentów z oparzeniami ciała, ze szczególnym zwróceniem uwagi na miejsce transportu poszkodowanych.

Materiał i metody: Badania przeprowadzono metodą analizy retrospektywnej interwencji wykonanych przez załogi Śmigłowcowej Służby Ratownictwa Medycznego Lotniczego Pogotowia Ratunkowego. Do badania włączono wszystkie misje z okresu od stycznia 2011 roku do grudnia 2018 roku, w których załogi HEMS były dysponowane do pacjentów z oparzeniami ciała. Do ostatecznej analizy zakwalifikowano 2534 przypadków interwencji załóg HEMS.

Wyniki: W badanej grupie dominowali mężczyźni (72,72%), pacjenci w przedziale wiekowym 18 i mniej lat (36,65%). Blisko dwie trzecie pacjentów transportowana była do szpitali z oddziałem oparzeniowym (61,88%). Najczęściej podawanymi lekami były opioidowe leki przeciwbólowe (68,55%) i krystaloidy (64,76%). Z analizy statystycznej wynika, że czas dolotu (20,77 min vs 18,60 min) i czas transportu do szpitala (40,11 min vs 19,66 min) były istotnie wyższe w przypadku decyzji o transporcie pacjenta do oddziału leczenia oparzeń (p<0,001).

Wnioski: Przedstawione wyniki badań wykazały, że załogi HEMS częściej są dysponowane do pomocy Zespołom Ratownictwa Medycznego w przypadku pacjentów, którzy wymagali leczenia w centrum leczenia oparzeń. Ponadto czas transportu i dystans do szpitala z oddziałem oparzeniowym jest istotnie dłuższy w porównaniu do szpitali bez oddziału oparzeniowego. Potwierdza to zasadność dysponowania załóg HEMS do pacjentów z ciężkimi oparzeniami ciała.

Słowa kluczowe: oparzenia, Śmigłowcowa Służba Ratownictwa Medycznego, opieka przedszpitalna, centrum oparzeniowe

Wiad Lek 2019, 72, 3, 500-505

INTRODUCTION

A burn is a damage to the skin or other tissue of an organism resulting mainly from heat or radiation but also from biological, chemical, physical and electrical factors whose effect may be local or systemic. Ultraviolet radiation radioactivity, electrical or chemical skin damage as well as smoke inhalation are also considered as burns. Globally burns are a serious problem for healthcare systems and are responsible for 180.000 deaths per year. The majority of these deaths occur in low and middle-income countries with nearly two thirds of the deaths reported in the Africa and Southeast Asia. Non-lethal burns are the main reason of prolonged hospitalisation, high morbidity, body disfiguration and disability resulting in reduced self-esteem and social exclusion [1−5].

About 1% of the Polish population suffer from burns every year. Children and elderly are particularly exposed to this kind of stress. Estimations show that burns among children up to age of seven represent a quarter of all burns. They are mainly the result of contact with hot liquids. Among adults burns are most often related to accidents at work or at home [6, 7].

Burns constitute a serious problem but the continuous development and progress of medicine promotes the development of modern medical techniques and procedures that allow to treat effectively patients with severe burns. In many countries burns centres and wards are being established as in the case of multiple trauma centres. There are seven highly specialised burn centres in Poland. Through coordinated efforts they enable treatment and rehabilitation of patients with severe burns. The rapid transport of such patient to specialised facility is crucial for the prognosis of survival [8]. Therefore in Poland as in many countries including Austria, Denmark and the USA the Helicopter Emergency Medical Service (HEMS) has been established and used to provide transport of patients with severe injuries, acute heart attacks, and burns to the suitable, specialised hospitals [9−12].

The aim of the research was to describe the characteristics of Helicopter Emergency Medical Service missions carried out for burn patients with a highlight to the target medical facility.

MATERIALS AND METHODS

The research was conducted using the method of retrospective analysis of operations performed by Helicopter Emergency Medical Services crews. All missions concerning burn patients from January 2011 to December 2018 were included in the study. Cases of cancellation, interruption of the missions as well as lack of casualties were excluded. Ultimately, 2534 cases were qualified for the final analysis. The study did not require the consent of the bioethics committee.

The research was carried out based on medical and operational documentation of Helicopter Emergency Medical Service. Under the consent of the Director of Medical Air Rescue Service. During the analysis of HEMS medical records the following data was obtained and used to complete the research: gender and age of the patients, date of intervention, clinical status parameters of patients (based on symptoms and three scales: Glasgow Coma Scale – GCS, Revised Trauma Score – RTS, National Advisory Committee for Aeronautics – NACA), medical actions undertaken during the mission and information related to the description of the HEMS mission.

Data obtained from medical records was subjected to statistical analysis using STATISTICA 13 program (StatSoft, Cracow, Poland). In the description of qualitative data the quantity (n) and percentage (%) were used whereas the mean (M) and standard deviation (SD) were used to describe quantitative data. To check the normal distribution of quantitative variables the Shapiro-Wilk normality test was used. The Chi-suqre test was used to statistically assess significant differences between quantitative variables. Non-parametric U Mann-Whitney test was used to examine the differences between the two groups. The significance level was considered p<0.05.

RESULTS

The study group was predominantly male (72.72%). The widest age range was eighteen years or younger (36.65%) and the average age for the whole group was 32.80. The vast majority of patients suffered from thermal burns (90.21%) which mostly involved multiple body regions (63.69%). In the analysed group 27.70% of the patients required endotracheal intubation and 26.95% of them required mechanical ventilation. Opioids as well as crystalloids were the most commonly administered drugs (respectively 68.55% and 64.76%). The mean GCS score for the whole group of patients was 13.24 points, RTS – 11.14 points while on the NACA scale patients were assigned to the 4th category (Table 1).

Interventions of HEMS were most frequent in urban areas (53.02%), in summer (35.06%), as part of inter-hospital medical transport (69.48%) and to provide the support to the ground-based medical rescue teams (91.54%). Nearly two thirds of patients were transported to hospitals with burn ward (61.88%). The average HEMS time response was 8.68 minutes (8.36). Average HEMS arrival time at the scene was 19.90 minutes (SD 9.49), with mean distance of 55.59 kilometres (SD 33.10). On-site proceedings took 24.77 minutes on average (SD 13.19) and overall time of patient supervision was 56.53 minutes (SD 31.83). Transportation to hospital lasted 32.71 minutes on average (SD 24.94) with a mean distance of 96.58 kilometres (SD 70.55) (Table 2).

The statistical analysis showed that women were significantly more frequently transported to the hospital with the burn ward (63.90% vs. 56.58%). Additionally, the mean age was higher in patients who were admitted to the burn ward (41.18 years vs. 19.19 years). The analysis shows that burn ward was more often reached by patients in the urban area (69.04% vs. 50.00%) and by those eligible for inter-hospital medical transfer (51.14% vs 8.41%) as well as when HEMS provide assistance for ground-based medical rescue teams (63.17 vs 48.13%). Patients with airways thermal injury (67.01%) and multiple body area burns (68.82%) were significantly more often transported to the burn ward. The analysis of the clinical status of the patients showed that those transported to burn wards were significantly more severely affected which is reflected in GCS (12.73 vs 13.99), RTS (10.89 vs 11.52) and NACA scale (4 vs 3.67). In the same time these patients were more likely to require endotracheal intubation, mechanical ventilation and medication.

The analysis of the time and distance covered during missions concerning burn patients shows that the time of arrival (20.77 minutes vs 18.60 minutes), on-site proceedings (26.37 minutes vs 22.12 minutes), the time of transport to hospital (40.11 minutes vs 19.66 minutes), the distance to the place of the event (58.80 kilometres vs 50.77 kilometres ) as well as transport to the hospital (120.01 vs 54.83 kilometres) were significantly higher when the patient was transported to the burns department (p<0.0001). Detailed statistical analysis is presented in Table 3.

DISCUSSION

Ubiquitous prevalence of the problem of burns led the authors to undertake the research on the HEMS missions concerning burned patients with stressing the target medial facility. Data of our research showed that the study group was predominantly male aged eighteen years old and younger (mean age 32.80). A study by Wejnarowski et al. on the optimising the transport duration of burned patients by HEMS showed that man were the main group of patients, while the children under the age of five and the adults between the age of fifty and sixty were the most numerous groups [13]. Chrzanowska-Wąsik et al. performed an analysis of burned adults hospitalized in the Eastern Burns Treatment and Reconstructive Surgery Centre in Łęczna which shows that again were a dominant group and the average age of patients was 48.5 years [8]. Similarly the analysis by Nadolny et al. for medical emergency operations performed by Emergency Medical Rescue Teams on burned patients shows that main victims are adult men [14]. Men and adults were also the main victims of severe body burns in a study carried out by Lam et al. [15]. On the other hand, the Newberry et al. study on patients access to healthcare in India showed that women and people aged 25-34 were the dominant group of respondents [16].

Nadolny et al showed that the following drugs were successively used in burned patients: analgesics, crystalloids and sedatives. In adult patients morphine and 0.9% solution of natrium chloride was used most frequently, while in children paracetamol and morphine appeared to be most common [14]. On the other hand, the analysis of our studies shows that the burned patients received mainly opioids and crystalloids from HEMS crews.

This analysis showed that HEMS crews treated patients with multiple burns more frequently. Due to their severe clinical condition, the analysed group of patients was most often transported to centres with burn wards. Sheridan et al., who analysed the cases of burns in the USA, confirmed the legitimacy of transporting patients with severe body burns in their studies. The authors proved that delayed transport of the burned patient to the burns centre adversely affects the improvement of the outcome, which results, among other things, from prolonged transport time [17].

The retrospective analysis shows that women, patients over the age of 18, patients from rural areas and patients with multiple burns were more likely to be transported to burns wards. Furthermore, they required more frequent endotracheal intubation and mechanical ventilation. Clinical status analysis based on GCS, RTS and the NACA scale showed that patients who were transported to burns treatment centres were in a worse clinical condition. Bell et al. (2012) conducted an analysis of patients with burns transported to burn centres in Canada. He discovered that these were predominantly men whose average age was lower. The analysed group of patients required tracheal intubation and air transport more often [18].

The next part of this retrospective analysis compared the duration of the helicopter mission and the distance travelled to the place of the incident and the distance to the hospital. The time of arrival at the scene (20.77 minutes vs. 18.60 minutes), duration of transport to hospital (40.11 minutes vs. 19.66 minutes), distance to site (58.80 kilometres vs. 50.77 kilometres) and distance to hospital (120.01 kilometres vs. 54.83 kilometres) were significantly greater when the patient was transported to a burns treatment facility. Similar results were obtained by Bell et al. In his study, the time of transport to the burn centre exceeded 4 hours in 70% of the cases. His and our results confirm that HEMS missions to patients with severe burns are justifiable. This reduces both the time it takes for the patient to reach the patient and the time it takes for the patient to reach the selected hospital. This is also confirmed by studies by Moens et al. and Chen et al.. They show that both the time of reaching the burned patient and the time of transport to the hospital are shorter if they are carried out by the HEMS crew [19, 20].

CONCLUSIONS

Burns are a significant reason for calling the Helicopter Medical Rescue Service. Commonly they concern men and young people. Patients treated by HEMS crews most often suffer from thermal burns, affecting multiple body regions, and consequently they are transported to burns treatment centres. Our research shows that both the time and distance to a unit specialised in the treatment of burns are significantly longer. Therefore, it appears to be appropriate to call HEMS for burns, especially for those requiring treatment in a burn centre. Shortening the time of reaching the patient to hospital improves outcome of prognosis, which has been confirmed by numerous authors.

References

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2. Peck MD. Epidemiology of burns throughout the World. Part II: intentional burns in adults. Burns. 2012; 38(5):630-7. doi: 10.1016/j.burns.2011.12.028.

3. Hettiaratchy S, Dziewulski P. ABC of burns: pathophysiology and types of burns. BMJ. 2004; 328(7453):1427-1429. doi: 10.1136/bmj.328.7453.1427.

4. Peck MD, Kruger GE, van der Merwe AE, Godakumbura W, Ahuja RB. Burns and fires from non-electric domestic appliances in low and middle income countries Part I. The scope of the problem. Burns. 2008;34(3):303. doi: 10.1016/j.burns.2007.08.014.

5. Mock C, Peck M, Peden M et al. A WHO plan for burn prevention and care. World Health Organization 2008. https://apps.who.int/iris/bitstream/handle/10665/97852/9789241596299_eng.pdf;jsessionid=B7FA6E2874399624B57F57446DAD6CAA?sequence=1 (accessed on 24 February 2019).

6. Topczewska-Cabanek A, Pernach A, Nitsch-Osuch A et al. Burns as a cause of hospitalising children in one of Warsaw’s hospitals in 2008–2012. Fam Med Prim Care Rev 2014;16(3):297-299.

7. Chrapusta A, Jędrys J, Budzyńska A et al. The analysis of death rate among burn victims and difficulties with interpretation of epidemiological data. Leczenie Ran 2014;11(2):79-83. doi: dx.doi.org/10.15374/LR2014010.

8. Chrzanowska-Wąsik M, Chemperek E, Sokołowski D, Goniewicz M, Bednarz K, Rzońca P. Burn analysis in adult patients hospitalized in the East Centre of Burn Treatment and Reconstructive Surgery in Łęczna. J Edu Health Sport. 2017;7(4):410-419. doi: http://dx.doi.org/10.5281/zenodo.495655.

9. Rzońca P, Gałązowski R, Podgórski M. Role of Polish Medical Air Rescue in National Medical Rescue System. Disaster Emerg Med J 2017;2:64-68.

10. Osler M, Mårtensson S, Prescott E, Carlsen K. Impact of gender, co-morbidity and social factors on labour market affiliation after first admission for acute coronary syndrome. A cohort study of Danish patients 2001-2009. PLoS One 2014;9:e86758. doi: 10.1371/journal.pone.0086758.

11. Gunnarsson SI, Mitchell J, Busch MS, Larson B, Gharacholou SM, Li Z et al. Outcomes of Physician-Staffed Versus Non-Physician-Staffed Helicopter Transport for ST-Elevation Myocardial Infarction. J Am Heart Assoc. 2017;6:e004936. doi: 10.1161/JAHA.116.004936.

12. Řsterĺs Ř, Heltne JK, Vikenes BC, Assmus J, Brattebř G. Factors influencing on-scene time in a rural Norwegian helicopter emergency medical service: a retrospective observational study. Scand J Trauma Resusc Emerg Med. 2017;25:97. doi: 10.1186/s13049-017-0442-5.

13. Wejnarski A, Podgórski M, Kamecki A, Świeżewski SP. Rola Lotniczego Pogotowia Ratunkowego w optymalizacji czasu transportu pacjentów oparzonych. [The role of the Polish Medical Air Rescue in optimization of transport time of patients with burns]. Anest Rat 2016;10:34-45.

14. Nadolny K, Ładny JR, Ślęzak D, Komza M, Gałązkowski R. Analiza medycznych czynności ratunkowych wykonywanych przez zespoły ratownictwa medycznego z całej Polski u pacjentów z ranami oparzeniowymi. [Analysis of medical rescue operations performed by medical rescue teams from all over Poland in patients with burn wounds]. Wiad Lek. 2019;72(1):26-30.

15. Lam NN, Huong HTX, Tuan CA. Mass burn injuries: an analysis of characteristics and outcomes in a developing country. Ann Burns Fire Disasters. 2017;30(3):210-213.

16. Newberry JA, Bills CB, Pirrotta EA et al. Emerg Med J 2019;36:176-182. doi:10.1136/emermed-2018-207900.

17. Sheridan R, Weber J, Prelack K et al. Early burn center transfer shortens the length of hospitalization and reduces complications in children with serious burn injuries. J Burn Care Rehabil 1999;20:347-50.

18. Bell N, Simons R, Hameed SM, Schuurman N, Wheeler S. Does direct transport to provincial burn centres improve outcomes? A spatial epidemiology of severe burn injury in British Columbia, 2001-2006. Can J Surg. 2012;55(2):110-116. doi: 10.1503/cjs.014708.

19. Moens D, Stipulante S, Donneau AF, Hartstein G, Pirotte O, D’orio V et al. Air versus ground transport of patients with acute myocardial infarction: experience in a rural-based helicopter medical service. Eur J Emerg Med. 2015; 22(4): 273-8.

20. Chen X, Gestring ML, Rosengart MR, Peitzman AB, Billiar TR, Sperry JL, et al. Logistics of air medical transport: When and where does helicopter transport reduce prehospital time for trauma? J Trauma Acute Care Surg. 2018;85(1):174-181.

Conflict of interest:

The Authors declare no conflict of interest.

Correspondig author

Patryk Rzońca

Department of Emergency Medicine, Faculty of Health Sciences,
Medical University of Lublin,

4-6 Staszica St., 20-081 Lublin, Poland

e-mail: patryk.rzonca@gmail.com

Received: 20.02.2019

Accepted: 15.03.2019

Table 1. Characteristics of the test group.

Sex – n (%)

Female

691 (27.28)

Male

1842 (72.72)

Age – n (%)

≤18 years

927 (36.65)

19 – 34 years

354 (14.00)

35 – 49 years

427 (16.88)

50 – 64 years

482 (19.26)

65 – 79 years

210 (8.30)

≥80 years

124 (4.90)

Age (years) M (SD)

32.80 (27.03)

Type of burn – n (%)

Thermal

2285 (90.21)

Chemical

248 (9.79)

Burn location – n (%)

Head and neck

344 (13.58)

Trunk

337 (13.30)

Limbs

142 (5.61)

Airways

97 (3.83)

Multiple body area

1613 (63.68)

Endotracheal intubation – n (%)

Yes

702 (27.70)

No

1832 (72.30)

Mechanical ventilation – n (%)

Yes

683 (26.95)

No

1851 (73.05)

Medication – n (%)

Benzodiazepines

877 (34.61)

Anaesthetics

674 (26.60)

Crystalloids

1641 (64.76)

Opioids

1737 (68.55)

Muscle relaxants

344 (13.58)

GCS M (SD)

13.24 (3.86)

RTS M (SD)

11.14 (2.24)

NACA scale M (SD)

4.00 (1.28)

Table 2. HEMS mission characteristics.

Event location – n (%)

Urban

1266 (53.02)

Rural

1122 (46.98)

Season – n (%)

Spring

766 (30.24)

Summer

888 (35.06)

Autumn

517 (20.41)

Winter

362 (14.29)

Type of mission – n (%)

Emergency flight

773 (30.52)

Inter-hospital medical transport

1760 (69.48)

Transport to burn centre or burn ward – n (%)

Yes

1568 (61.88)

No

966 (38.12)

First on site – n (%)

Ground-based EMS

2316 (91.54)

HEMS

214 (8.46)

Response time (min) M(SD)

8.68 (8.36)

Time to reach the place of call (min) M(SD)

19.90 (9.49)

Duration of action at the place of call (min) M(SD)

24.77 (13.19)

To hospital transport time (min) M(SD)

32.71 (24.94)

Overall time of patient supervision M(SD)

56.53 (31.83)

Distance from the place of call (km) M(SD)

55.59 (33.10)

Distance to hospital (km) M(SD)

96.58 (70.55)

Table 3. Relationship between the place of transport, sociodemographic data, type of mission, clinical condition and treatment.

Variables

Burn unit hospital

Non-Burn unit hospital

p-value

Sex – n (%)

0.0008

Female

391 (56.58)

300 (43.42)

Male

1177 (63.90)

665 (36.10)

Age – n (%)

0.0000

≤ 18 years

304 (32.79)

623 (67.21)

19 – 34 years

275 (77.68)

79 (22.32)

35 – 49 years

330 (77.28)

97 (22.72)

50 – 64 years

392 (80.49)

95 (19.51)

65 – 79 years

162 (77.14)

48 (22.86)

80 and more years

103 (83.06)

21 (16.94)

Age average M (SD)

41.18 (24.82)

19.19 (24.85)

0.0000

Event location – n (%)

0.0000

Urban

874 (69.04)

392 (30.96)

Rural

561 (50.00)

561 (50.00)

Type of mission n (%)

0.0000

Inter-hospital medical transport

900 (51.14)

860 (48.86)

Emergency flight

65 (8.41)

708 (91.59)

Burn location – n (%)

0.0000

Head and neck

179 (52.03)

165 (47.97)

Trunk

142 (42.14)

195 (57.86)

Limbs

72 (50.70)

70 (49.30)

Airways

65 (67.01)

32 (32.99)

Multiple body area

1110 (68.82)

503 (31.18)

First on site – n (%)

0.0000

HEMS

103 (48.13)

111 (51.87)

Ground-based EMS

1463 (63.17)

853 (36.83)

Endotracheal intubation – n (%)

599 (85.33)

103 (14.67)

0.0000

Mechanical ventilation – n (%)

580 (84.92)

103 (15.08)

0.0000

Medication – n (%)

Benzodiazepines

595 (67.84)

282 (32.16)

0.0000

Anaesthetics

443 (65.73)

231 (34.27)

0.0163

Crystalloids

1114 (67.89)

527 (32.11)

0.0000

Opioids

1132 (65.17)

605 (34.83)

0.0000

Muscle relaxants

288 (83.72)

56 (16.28)

0.0000

GCS M (SD)

12.73 (4.30)

13.99 (2.90)

0.0000

RTS M (SD)

10.89 (2.46)

11.52 (1.80)

0.0000

NACA scale M (SD)

4.21 (1.22)

3.67 (1.29)

0.0000

Time to reach the place of call (min) M (SD)

20.77 (10.59)

18.60 (7.35)

0.0000

On-site proceedings (min) M (SD)

26.37 (13.64)

22.12 (11.95)

0.0000

Duration of transport (min) M (SD)

40.11 (27.35)

19.66 (11.54)

0.0000

Overall time of patient supervision (min) M (SD)

65.70 (34.85)

41.55 (17.98)

0.0000

Distance from the destination to the hospital (km) M (SD)

58.80 (37.08)

50.77 (25.25)

0.0000

Transport distance (km) M (SD)

120.01 (74.37)

54.83 (35.67)

0.0000