Article, Traumatology

Emergency medical services (EMS) versus non-EMS transport among injured children in the United States

a b s t r a c t

Objectives: This study aimed to assess the proportions of injured children transported to trauma centers by differ- ent transportation modes and evaluate the effect of transportation mode on inter-facility transfer rates using the US national trauma registry.

Methods: We analyzed data from the 2007-2012 National Trauma Data Bank to study trends of EMS ver- sus non-EMS transport. Multivariable logistic regression was used to evaluate the association between transport mode and inter-facility transfer.

Results: There were 286,871 Pediatric trauma patients in the 2007-2012 NTDB; 45.8% arrived by ground ambu- lance, 8.6% arrived by air ambulance, and 37.5% arrived by non-EMS. From 2007 to 2012, there was no significant change in transportation mode. Moderate to severely injured patients (ISS N 15) comprised 13.3% of arrivals by ground ambulance, 26.7% of arrivals by air ambulance, and 8.3% of arrivals by non-EMS; those who used EMS were significantly less likely to be transferred to another facility than patients who used non-EMS transport. Moderate and severe pediatric patients arriving by non-EMS to adult trauma centers were more often transferred than those arriving at mixed trauma centers (45.8% and 6.8%, respectively).

Conclusions: Over one third of US pediatric trauma patients used non-EMS transport to arrive at trauma centers. Moderate to severely injured children benefit from EMS transport and professional field triage to reach the ap- propriate trauma facility. Our study suggests that national efforts are needed to increase awareness among par- ents and the general public of the benefits of EMS transportation and care.

(C) 2016

Introduction

Each year in the United States, about 7.4 million children 1-17 years old are treated for nonfatal injuries at US emergency departments and 7000 die from unintentional injuries [1]. In the past 4 decades, regional- ized trauma care has been promoted in the US as the best approach for matching patient needs with the available resources and provider ex- pertise to achieve optimal patient outcomes [2-5]. Previous research has shown that trauma centers achieve better outcomes among severe- ly injured patients than non-trauma centers; however, it has been found

? From the Center for Injury Research and Policy and Center for Pediatric Trauma Research, The Research Institute at Nationwide Children’s Hospital (H.X., K.K.W., J.S., B.K., S.J.), and the Ohio State University College of Medicine (H.X., M.M.C.).

* Corresponding author at: Center for Pediatric Trauma Research, The Research Institute at Nationwide Children’s Hospital, 700 Children’s Drive, Columbus, OH 43205, United States.

E-mail address: [email protected] (H. Xiang).

that about one-third of patients with severe injuries were treated at non-trauma centers or level III trauma centers [3,6]. Transportation to the hospital via emergency medical service (EMS) is important in caring for trauma patients for several reasons.

EMS personnel are trained professionals who have the best knowl- edge about which hospitals injured patients should be transported to in order to receive Optimal treatment [7]. Patients using non-EMS trans- port may travel to the nearest hospital rather than the most appropriate. In addition, using EMS protects patients who have sustained, for exam- ple, a spinal cord injury, and can relay the need for a trauma team acti- vation to the necessary healthcare specialists [8]. However, the Centers for Disease Control and Prevention (CDC) has estimated that only 18% of injured patients in the US were transported by EMS in 2008; this has not been well studied in pediatric trauma patients [1]. In one suburban pediatric emergency department, only 13% of High-acuity patients had arrived by ambulance, and a national study using the National Hospital Ambulatory Medical Care Survey confirmed

http://dx.doi.org/10.1016/j.ajem.2016.11.059

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476 M.M. Corrado et al. / American Journal of Emergency Medicine 35 (2017) 475478

this underutilization of EMS in the pediatric community, finding a 3- fold decrease in pediatric patients arriving by EMS compared to adult patients [9,10].

Pediatric trauma patients may require special age-appropriate treatment and medical equipment that are not universally available at non-trauma or adult trauma centers [11]. Despite these unique needs of injured children, Shah et al. found that many high-urgency pediatric patients arrive via non-EMS, lacking the specialized judgment of EMS providers [12]. In comparing non-trauma centers and level I-III trauma centers, one study found that 98% of non-trauma center patients are transferred to a higher level trauma center; this study, however, did not distinguish between pediatric and adult trauma patients [13].

A recent analysis of the NHAMCS has shown that within the past 10 years, there has been no change in the percentage of patients using EMS transportation [14]. The specific patterns and needs of pediatric trauma patients, however, have not been well-studied. The purpose of our study was to look specifically at pediatric trauma patients and assess the proportion who are transported by different transportation modes, identify risk factors for not using EMS transportation, and evaluate how non-EMS transportation affects outcomes after injury. Findings from this research study are of national significance and will provide scientific evidence to fill knowledge gaps in pediatric emergency care for injured children in the United States.

Methods

Data source and study population

The National Trauma Data Bank (NTDB) is the largest US trauma reg- istry assembled. We utilized NTDB data from 2007 to 2012. The study population was injured children (<= 15 years) defined by the ICD-9-CM Diagnosis codes 800-959 [15,16]. Patients who had injuries due to the following conditions were excluded: late effects (905-909); superficial injuries (910-924); foreign bodies (930-939); burns (940-949) [17].

The NTDB contains variables describing the different transportation modes (ground versus helicopter versus fixed-wing ambulance), in ad- dition to non-EMS transportation modes (private or public vehicle or walk-in; police). We included patient demographics, insurance status and the following injury characteristics: injury mechanism, injury type (penetrating vs. blunt) and injury severity. We used injury severity scores (ISS) in the NTDB (generated by the ICD 90 Mapping Program). We excluded patients who were transferred in from other medical facil- ities. We described hospitals by mean pediatric trauma patient volume and trauma center type (adult, pediatric, or mixed center). The NTDB only includes data from hospitals with trauma center designation (ei- ther by American College of Surgeons verification or state designation).

Statistical analyses

We assessed the trends of each transportation mode utilized by in- jured US children during 2007-2012. To identify risk factors associated with EMS versus non-EMS transport, we used multivariable logistic re- gression models to calculate odds ratios of being transported by EMS personnel. The dependent variable was transportation to the hospital by EMS or non-EMS. The independent variables included patient, family, and hospital characteristics.

We then restricted our analysis to moderately and severely injured children because these children are at the highest risk of mortality and adverse outcomes and should be immediately transferred to higher level trauma centers. To assess and compare potential outcomes be- tween those who were transported by EMS versus non-EMS, we used Multivariable logistic regression models where the dependent variables included transfer to another facility (Yes/No), in-hospital mortality, and length of stay. The independent variable of interest was EMS versus non-EMS transport. Potential confounders included age, gender, race, insurance, mechanism of injury, ISS, trauma center type, and mean

pediatric volume of the hospital. Statistical significance was indicated by P-values b 0.05.

Results

A total of 286,871 pediatric patients under 16 years old from the NTDB were included in this study (Table 1). From 2007 to 2012, pediat- ric patients were more likely to use ground ambulance than any other form of transportation to get to the ED (45.8%). The second most com- mon form of transportation was private/public vehicle/walk-in (37.5%). There was no significant change in the pattern of transportation mode between 2007 and 2012.

Patient characteristics by transportation mode

Table 2 shows patient characteristics by transportation mode. Most patients were male (65.0%) and over half were White (57.4%). The ma- jority of injuries were blunt (94.9%) and the most common mechanism was a fall (44.1%). The most common ISS was between 4 and 8 (49.8%). Patients who used non-EMS were more likely to be children be- tween the ages of 5-10 (35.5%), males (63.8%), and White (61.8%). Non-EMS transported pediatric trauma patients were more likely to be transported to an adult trauma center (48.1%) and EDs of hospitals with average pediatric inpatient volumes between 1 and 126 patients (41.2%). Patients most likely to use ground ambulance were trauma pa- tients between 11 and 15 years old (47.1%), transported to adult trauma centers (43.4%), and to EDs of hospitals with average pediatric inpatient volumes of 1-126 (31.5%). The majority of pediatric trauma patients who used air ambulance were involved in road accidents (71.8%) and

sustained Blunt injuries (96.1%).

Transfer rates in moderate and severe pediatric trauma patients

Table 3 shows transfer rates by trauma center type and transporta- tion mode for moderate and severe pediatric trauma patients (ISS N 15). Over 27% of these pediatric patients using adult trauma cen- ters (ATCs) were transferred to another facility. Patients who were transported via ground and air ambulance were less likely to be trans- ferred compared to patients who used non-EMS transportation. Patients transported via ground ambulance were less likely to be transferred compared to non-EMS transported patients (adult trauma center: AOR 0.69, 95% CI 0.61-0.78; mixed trauma center: AOR 0.42, 95% CI 0.31- 0.56), and patients who were transported via air ambulance were also less likely to be transferred compared to non-EMS transported trauma patients (adult trauma center: AOR 0.30, 95% CI 0.25-0.37; mixed trau- ma center: AOR 0.22, 95% CI 0.14-0.36). Those who arrived at pediatric trauma centers were extremely unlikely to be transferred (0.2%). There were too few patients who were transferred out of pediatric trauma centers to calculate meaningful transfer rates (n = 8), so odds ratios are not reported.

Mortality and length of stay

Table 4 shows mortality rates and lengths of stay for moderate and severe pediatric trauma patients (ISS N 15).

Compared to non-EMS transported pediatric trauma patients, in- hospital mortality was significantly higher in patients who used ground ambulance (AOR 5.41, 95% CI 3.96-7.39) or air ambulance (AOR 5.53, 95% CI 3.99-7.66). Patients who used ground or air ambulance had a longer LOS (6.6 +- 9.6 days, 9.5 +- 12.5 days, respectively) than non- EMS transported patients (2.8 +- 4.2 days, P b 0.01). More than fourty five percent of patients used ground ambulance and 8.6% used air ambulance between 2007 and 2012 (Table 1). Multivariate models (Table 4) showed that patients who used ground ambulance had a shorter LOS (1.95 days longer than private transport) compared to air ambulance (4.42 days longer than private transport).

M.M. Corrado et al. / American Journal of Emergency Medicine 35 (2017) 475478 477

Table 1

Transportation mode by year among pediatric trauma patients, NTDB 2007-2012.

Transportation mode

Year

2007

2008

2009

2010

2011

2012

Total

Private/public vehicle/walk-in

10 749

14 919

17 686

20 168

21 559

22 468

107 549

Ground ambulance

15 514

20 959

21 342

23 966

24 414

25 195

131 390

Helicopter ambulance

3608

4540

4081

4184

4159

3959

24 531

Fixed-wing Ambulance

11

14

12

11

9

15

72

Police

311

343

334

200

158

214

1560

Other

336

122

129

182

111

121

1001

Missing

5130

3811

3238

3164

2760

2665

20 768

Total

35 659

44 708

46 822

51 875

53 170

54 637

286 871

% of private/public vehicle/walk-in

30.1

33.4

37.8

38.9

40.5

41.1

37.5

% of Ambulance transported

53.7

57.1

54.3

54.3

53.8

53.4

54.4

% of ground ambulance

43.5

46.9

45.6

46.2

45.9

46.1

45.8

% of air ambulance

10.1

10.2

8.7

8.1

7.8

7.3

8.6

Discussion

Our study investigated the proportion of injured US children who are transported by EMS versus non-EMS from 2007 to 2012. Our finding that there had not been a significant change in transportation by EMS versus non-EMS from 2007 to 2012 supports previous research using the NHAMCS that there has been no change in EMS transportation usage in the past 10 years [14].

Table 2

Characteristics of pediatric trauma patients by transportation mode, NTDB 2007-2012.

Although inter-facility transfer is commonly used as an outcome measure, this factor is also under-studied in the pediatric population [8,18,19]. Over 45% of pediatric trauma patients with moderate to se- vere injuries (ISS N 15) transported via non-EMS to an adult trauma cen- ter required inter-facility transfer; in contrast, those who used EMS to reach an adult trauma center were less likely to require subsequent inter-facility transfer. As previously discussed, this may be due to prox- imity or field triage guidelines used by the trained EMS personnel. For children with minor injuries, EMS transportation may not be necessary; [18,20-22] however, for parents of moderately injured children who forego EMS transportation due to the expensive cost and co-pay, com-

Private/public vehicle/walk-in

Ground ambulance

Air ambulance

munities may benefit from education about the increased capabilities of pediatric trauma centers to care for their children.

Our results suggest that non-EMS transportation did not have a sig- nificant negative impact on in-hospital mortality or LOS, but these find- ings should be interpreted with caveats. One plausible reason could be that non-EMS transported patients were significantly more likely to be transferred out of the hospital [13]. Trauma patients who originally ar- rived by EMS may be field triaged to the appropriate hospital and be sig- nificantly less likely to be transferred out of the trauma center.

Male

68 638

63.8

86 681

66.0

15 863

64.5

Unfortunately, we do not know the final outcomes of these non-EMS

Female

38 812

36.1

44 648

34.0

8730

35.5

transported patients after transfer from the trauma center. A second ca-

Race

White

66 450

61.8

67 612

51.5

17 087

69.5

veat is that pediatric trauma patients who used EMS were not matched

Black

15 347

14.3

28 539

21.7

2189

8.9

Other

25 752

23.9

35 239

26.8

5327

21.7

Table 3

Mechanism

Transfer rates by trauma center type and transportation mode, moderate and severe pedi-

Fall

70 383

65.4

41 646

31.7

4309

17.5

atric trauma (ISS N 15), NTDB 2007-2012.

# patients

%

# patients

%

# patients

%

Total

107 549

100.0 131 390

100.0

24 603

100.0

Age

b 1

15 111

14.1 10 193

7.8

1342

5.5

1-4

23 805

22.1 21 461

16.3

3931

16.0

5-10

38 129

35.5 37 818

28.8

7157

29.1

11-15

30 504

28.4 61 918

47.1

12 173

49.5

Gender

Road accident

Struck by/against

17 858

14 797

16.6

13.8

66 839

14 363

50.9

10.9

17 658

1499

71.8

6.1

# Patients

Transfer-out

% Transfer AOR? 95% CI

Cut/pierce

3187

3.0

3492

2.7

426

1.7

Total

30 748

4365

14.2

Firearm

970

0.9

4678

3.6

542

2.2

Adult center

Other Injury type

Blunt

354

103 387

0.3

96.1

372

123 211

0.3

93.8

169

23 634

0.7

96.1

Private/public vehicle/walk-in

(ref.)

4168

1910

45.8

1.00

Penetrating Severity (ISS)

1-3

4162

15 426

3.9

14.3

8179

24 940

6.2

19.0

969

3092

3.9

12.6

Ground ambulance

Air ambulance

7935

2145

1878

187

23.7

8.7

0.69

0.30

(0.61-0.78)

(0.25-0.37)

4-8

68 668

63.8

55 391

42.2

7301

29.7

Subtotal

14 248

3975

27.9

9-15

9748

9.1

22 245

16.9

5314

21.6

Pediatric center

16-24

8214

7.6

12 515

9.5

3924

15.9

Private/public

1408

1

0.1

25-75

Payment Private

706

51 171

0.7

47.6

4997

56 570

3.8

43.1

2662

11 002

10.8

44.7

vehicle/walk-in

Ground ambulance

2200

3

0.1

Public

36 704

34.1

43 597

33.2

7666

31.2

Air ambulance

984

4

0.4

Self-pay

6671

6.2

10 854

8.3

2045

8.3

Subtotal

4592

8

0.2

Other

Trauma center type Adult center

13 003

51 775

12.1

48.1

20 369

57 006

15.5

43.4

3890

7637

15.8

31.0

Mixed center

Private/public vehicle/walk-in

2440

166

6.8

1.00

Pediatric center

18 745

17.4

20 503

15.6

4601

18.7

(ref.)

Mixed center

Mean pediatric volume (1)1-126

28 009

44 298

26.0

41.2

47 579

41 378

36.2

31.5

11 640

4077

47.3

16.6

Ground ambulance

Air ambulance

6278

3190

182

34

2.9

1.1

0.42

0.22

(0.31-0.56)

(0.14-0.36)

(2)127-330

24 004

22.3

36 283

27.6

6929

28.2

Subtotal

11 908

382

3.2

* Adjusted by age, gender, race, insurance, mechanism of injury, ISS, mean pediatric volume of the hospital.

(3)331-743

20 438

19.0

31 643

24.1

7947

32.3

(4)744-1453

18 809

17.5

22 086

16.8

5650

23.0

478 M.M. Corrado et al. / American Journal of Emergency Medicine 35 (2017) 475478

Table 4

Mortality rates and length of stay, moderate and severe pediatric trauma (ISS N 15), NTDB 2007-2012.

Raw data Multivariate modelinga

Mortality

# Patients

Died in ED or in hospital

% Death

AOR

95% CI

P value

Private/public vehicle/walk-in (ref.)

6379

67

1.1

1.00

Ground ambulance

14 923

1715

11.5

5.41

(3.96-7.39)

b0.0001

Air ambulance

6277

775

12.3

5.53

(3.99-7.66)

b0.0001

length of stay in hospital

# Patients

Mean LOS

SD

Parameter estimate

95% CI

P value

Private/public vehicle/walk-in (ref.)

6365

2.8

4.2

0.00

Ground ambulance

14 879

6.6

9.6

1.95

(1.61-2.29)

b0.0001

Air ambulance

6265

9.5

12.5

4.42

(4.01-4.84)

b0.0001

Raw data Multivariate modelingb

a Logistic regression model, adjusted by age, gender, race, insurance, mechanism of injury, ISS, trauma center type, and mean pediatric volume of the hospital.

b Linear regression model, adjusted by age, gender, race, insurance, mechanism of injury, ISS, trauma center type, and mean pediatric volume of the hospital.

by in-hospital mortality risk or underlying factors determining LOS, such as transportation time, an important factor in treating severely in- jured patients [8,22]. The first hour after injury, or “golden hour,” is im- portant in determining trauma outcomes, and although EMS transport ensures appropriate field triage, it may take more than 1 h to receive care. Our study was not able to control for transport time because it was not reported by private transporters.

The large number of trauma centers and pediatric trauma cases in the NTDB are major strengths of this study; there are, however, several limitations related to the data source. The NTDB is a convenience sample drawn from trauma registries, thus the data may not be representative of all hospitals. The majority (77.78%) of cases in the NTDB are from a level I trauma center [23]. Data from non-trauma centers are necessary to assess how children with different injury severities are transported to different levels of trauma centers, and how EMS and non-EMS transpor- tation affects inter-facility transfer rates and final outcomes. Currently, there is no national data source that captures data on non-trauma cen- ters, Trauma center levels, inter-facility transfer rates, and subsequent outcomes. Future studies need to address this challenge and find a way to track trauma patients’ medical care encounters in the regional Trauma system and link patients’ outcomes with trajectories of care. An- other limitation is that travel time in those transported via non-EMS was not known. Thus, we do not know whether travel time was signif- icant in determining transfer to an adult versus pediatric trauma center.

Conclusions

Our study found that 37.5% of US pediatric trauma patients reached the ED via non-EMS transportation, and over 45% of pediatric trauma patients transported via non-EMS to an adult trauma center required inter-facility transfer. Our findings underscore a need for national policy discussion about how to implement field triage guidelines and educate parents and caregivers on the importance of using EMS for transporta- tion of children with moderate to severe injuries.

Acknowledgements

This study is funded in part by a grant (R01/HS2426301) from the Agency for Healthcare Research and Quality (AHRQ) and a grant from the Health Resources and Services Administration (HRSA) of the U.S. Department of Health and Human Services (HHS) under R40/MC29448: Emergency medical care of Severely Injured U.S. Children. Ms. Michelle Corrado received a 2015 Alpha Omega Alpha Honor Medical Society Carolyn L. Kuckein Student Research Fellow- ship. The conclusions are those of the author and should not be con- strued as the official position or policy of AHRQ, HRSA, HHS or the

U.S. Government.

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