Pediatric Mortality at Pediatric versus Adult Trauma Centers.

INTRODUCTION: Pediatric trauma centers (PTCs) were created to address the unique needs of injured children with the expectation that outcomes would be improved. However, prior studies to evaluate the impact of PTCs have had conflicting results. Our study was conducted to further clarify this question. We hypothesize that severely injured children ≤ 14 years of age have better outcomes at PTCs and that better survival may be due to higher emergency department (ED) survival rates than at adult trauma centers (ATCs).
METHODS: A retrospective analysis of severely injured children (ISS>15) ≤18 years of age entered into the National Trauma Data Bank (NTDB) between 2011 and 2012 was performed. Subjects were stratified into 2 age cohorts; young children (0-14 years) and adolescents (15-18 years). Primary outcomes were emergency department (ED) and in-patient (IP) mortality. Secondary outcomes included in-hospital complications, hospital and ICU length of stay, and ventilator days. Outcome differences were assessed using multilevel logistic and negative binomial regression analyses.
RESULTS: A total of 10,028 children were included. Median ISS was 22 (Interquartile range 17-29). Adjusting for confounders on multivariate analysis, children ≤ 14 had lower odds of ED (0.42[CI 0.25-0.71], p=0.001) and IP mortality (0.73[CI 0.5-0.9], p=0.02) at PTCs. There were no differences in odds of ED mortality (0.81 [CI 0.5-1.3], p=0.4) or IP mortality (1.01 [CI 0.8-1.2], p=0.88) for adolescents between centers. There were no differences in complication rates between PTCs and ATCs (OR 0.86 [CI 0.69-1.06], p=1.7) but children were more likely to be discharged to home and have more ICU and ventilator free days if treated at a PTC.
CONCLUSION: Young children but not adolescents have better ED survival at PTCs compared to ATCs.Level of Evidence: Level IV, Therapeutic. Copyright:

INTRODUCTION

Traumatic injury is the leading cause of death in infants and children within the United States (US). It has been estimated that more than 9.2 million children present to an emergency department (ED) for unintentional injuries on an annual basis.[1]

Injured children respond differently to hemodynamic stressors than adults. Their anatomy and physiology require age and size appropriate resources and pose unique challenges for timely and successful management of critical injuries. The American College of Surgeon's Committee on Trauma and other organizations have identified these unique challenges and have promoted the creation of pediatric trauma centers (PTCs) so that resources can be tailored to accommodate the unique demands of this population with the expectation that pediatric outcomes will be improved.

However, whether PTCs actually improve outcomes have been controversial.[12345678] Some adult trauma centers (ATCs) have reported pediatric survival rates equivalent to publish national standards.[29] However, interpretation of these investigations is limited due single-center data that used trauma and injury severity score (ISS) methodology to compare their pediatric outcomes to the major trauma outcomes study in which only 10.8% of the patient population included children <15 years of age.[10] In 1996, Hall et al. demonstrated better survival rates in children with blunt injuries treated at PTCs but showed no benefit for children with penetrating injuries.[3] Yet a later investigation showed that this survival advantage disappeared when corrected for injury severity, age, mechanism, and pediatric trauma score.[5] In contrast, more recent studies were able to demonstrate improved survival as well as functional outcomes in trauma centers providing dedicated pediatric resources compared to ATCs.[41112]

We believe that the conflicting results in prior investigations are due to different methodologies and patient populations between studies. Several studies included a large number of patients with minor levels of injury; a study population in which mortality and complication rates are very low and in whom outcomes are likely to be favorable regardless of the type of trauma designation.[345] At least two publications included patients that underwent secondary inter-hospital transfers from ATCS to PTCS which may have negatively affected outcomes at the receiving institutions.[1314] Many investigations included a large number of adolescents in their study. Yet, three recent studies designed specifically to compare outcomes for adolescents showed no difference in mortality between adult and PTCs suggesting that any survival benefit at PTCs is age specific.[151617]

Within the US, PTCs treat only children and are verified to possess specific resources for the management of children of all ages. Whereas ATCs are verified to meet standards for managing adult trauma, they must still resuscitate and triage pediatric trauma patients that are brought to their institutions by pre-hospital personnel. Thus, the resources dedicated to pediatric trauma is variable among ATCs particularly for the youngest age groups.

Our study was conducted to clarify prior study results and determine if injured children have better outcomes if treated at a PTC. We hypothesize that severely injured children ≤ 14 years of age have better outcomes when treated at a PTC. We further hypothesize that improved survival at PTCs is due to better survival during the initial management within the ED. We believe that the greatest challenge to resuscitating young critically injured children occurs at the time of initial presentation. Prior studies have only assessed overall in hospital mortality. Assessing ED mortality separately from in-patient (IP) mortality could provide additional information that will identify weaknesses in our systems and serve as a future focus for improving pediatric outcomes at ATCs.

METHODS

We performed a retrospective analysis of pediatric data entered into the National Trauma Data Bank (NTDB) between 2011 and 2012 to compare outcomes for severely injured children ≤18 years of age treated at PTCs and ATCs. Severe injury was defined as having an ISS >15. We excluded institutions that were verified as both a PTC and an ATC because these centers maintain resources for both pediatric and adult trauma but use different age cutoffs for ED resuscitation by their adult and pediatric teams. We included all age groups in our initial analysis. We separated the adolescents (15–18 years of age) and young children (≤14 years of age) in a subsequent analysis to determine the impact of age on outcomes.

Patients were excluded if they presented to the ED without vital signs, had any abbreviated injury scale (AIS) of 6 (deemed nonsurvivable), or were transferred to or from another institution. Patients with missing data on primary outcomes were also excluded from the study.

We focused on mortality as our primary outcome but unlike prior studies we also looked for differences between ED mortality and IP mortality. ED mortality included any patient meeting inclusion criteria that expired in the ED despite attempts at resuscitation. IP mortality is defined as mortality in any patient who survived management in the ED to be admitted to an IP setting. Thus, IP outcome data in our study exclude data from patients that died within the ED. Overall mortality includes ED and IP deaths.

Secondary outcomes included IP complications, intensive care unit (ICU) length of stay (LOS), the number of ICU-free days, ventilator days, ventilator-free days, overall hospital LOS, and discharge disposition. In-hospital complications were categorized as infectious, vascular, pulmonary, renal, cardiac, or other.

Other data abstracted from the NTDB included: Age, sex, mechanism of injury, vitals on the scene and at presentation in the ED, Glasgow Coma Scale (GCS) score on presentation, and transit time to the hospital. Discharge disposition was also captured and included; discharge to home, a rehabilitation center, or skilled nursing facility (SNF). All patients were classified as either hemodynamically stable or unstable at the scene and at the time of arrival to the ED. Hemodynamic instability (HDI) was defined by the presence of hypotension determined by age-specific systolic blood pressure using the formula 70+ two times the child's age in years as the lower limit of normal.[18] We defined severe traumatic brain injury (TBI) as any brain injury with an AIS >3.

This study was approved by the Institutional Review Board of Brookdale University Hospital. Informed consent was waived because the study was conducted using de-identified data.

Data are presented as mean ± standard deviation for continuous variables, median, and interquartile range (IQR) for ordinal variables, and as proportions for categorical variables. Data points were compared using Student's t-test for continuous parametric variables, Kruskall–Wallis test for nonparametric variables, and Chi-square for categorical variables. Multiple imputations were performed to account for missing data. To account for confounding factors, multivariate regression analyses were performed for primary and secondary outcomes. For ED and IP mortality, complications, and discharge disposition, we performed mixed effect multilevel logistic regression and accounted for clustering effect at facility level. For ICU-free LOS and ventilator-free days, we performed multivariate negative binomial analysis while accounting for clustering effect at facility level. Variables that were significant on univariate analyses (P ≤ 0.05) were elected for multivariate models. Final multivariate models were chosen based on the lowest Bayesian information criterion and deviation. To determine the discrimination of the multivariate models, the area under the receiver operating characteristic was calculated. For data analyses, we used SPSS software (version 22.0, IBM, Inc. Armonk, NY, USA). All statistical analyses were conducted as two-tailed tests against a significant P ≤ 0.05.

RESULTS

There were 255,528 children between the ages of 0 and 18 years from 110 PTCs and 374 ATCs identified from the NTDB database. Of the 110 PTCs, 69 were designated as a level I trauma center and 41 were designated as a level II. Of the 374 ATCs, 74 were level I, 216 level II, 76 level III, and 8 a level IV.

Of the 255,528 children in the database, 245,500 were excluded for meeting one or more of the following exclusion criteria: An ISS ≤ 15 (121,819), no signs of life at presentation (2809), having any AIS > 5 (18,778), transferred to or from another facility (101,323), had missing information on facility (481), or missing information on mechanism (290). After all the exclusions, we were left with 10,028 children with severe injury in our study population.

Analysis for children ≤18 years of age

Of the 10,028 patients under study, 3900 (39%) were taken directly to a PTC and 6128 (61%) were taken directly to an ATC. As shown in Table 1, the majority of injured children were male and victims of blunt trauma. Children presenting to ATCs were older, more likely to have a penetrating mechanism, and shorter transit times compared to PTCs. Mortality was significantly higher at ATCs for both ED mortality (5% ATC vs. 2.9% PTC, P < 0.001) and IP mortality (11.2% ATC vs. 9.2% PTC, P = 0.001) for the entire population on univariate analysis.

Table 1

Demographics and mortality by trauma center for all patients ≤18 years of age

Variable	PTC (n=3900)	ATC (n=6128)	P
Age (years), mean±SD	11±3	14±5	<0.001
Male gender, n (%)	2619 (67)	4230 (69)	0.05
Mechanism of injury
Penetrating	358 (9.2)	970 (15.8)	<0.001
Stab wounds	43 (1.1)	128 (2.1)	<0.001
GSW	307 (7.9)	838 (13.7)	<0.001
Other	8 (0.2)	4 (0.07)
Blunt	3542 (90.8)	5158 (84.2)	<0.001
HDI at scene, n (%)	357 (10.5)	800 (14.6)	<0.001
HDI in ED, n (%)	317 (8.3)	637 (10.6)	<0.001
TT, median (IQR)	60 (43-85)	58 (41-81)	<0.001
ISS, median (IQR)	22 (17-29)	22 (17-29)	0.64
GCS, median (IQR)	14 (4-15)	14 (3-15)	0.06
GCS blunt, median (IQR)	14 (4-15)	14 (3-15)	0.06
GCS penetrating, median (IQR)	15 (3-15)	15 (3-15)	0.67
Severe TBI, n (%)	1128 (31)	1905 (33)	0.05
GCS <9, n (%)	1227 (32)	1905 (34)	0.15
NS interventions, n (%)	97 (2.5)	163 (2.7)	0.65
ICP monitoring, n (%)	52 (1.3)	80 (1.4)	0.93
Craniotomy*, n (%)	45 (1.2)	83 (1.4)	0.41
ED mortality, n (%)	112 (2.9)	305 (5)	<0.001
IP mortality, n (%)	357 (9.2)	684 (11.2)	0.001

PTC: Pediatric trauma centers, SD: Standard deviation, GSW: Gunshot wounds, HDI: Hemodynamic instability, ED: Emergency Department, IQR: Interquartile range, ISS: Injury severity score, GCS: Glasgow Coma Scale, TBI: Traumatic brain injury, ICP: Intracranial pressure, IP: In-patient NS: Neurosurgery, ATC: Adult trauma center, TT: Tube thoracostomy

Age stratified analysis

The study population was then stratified into two age cohorts; children ≤14 years of age and children ≥15 years of age for further analysis. The demographic data and patient characteristics for these cohorts are displayed in Table 2. There were more adolescents triaged to the ATCs and more young children triaged to PTCs. The major injury mechanism for both age cohorts was blunt trauma but the ATCs treated a higher proportion of gunshot wounds compared to the PTCs. There was no difference in median ISS between age cohorts at either center. The median ISS in both cohorts was 22 with an IQR of 17–29 confirming the presence of severe trauma. There were proportionally more children with severe TBI and the median GCS was slightly lower at ATCs for the younger age group (13 [3-15] vs. 14 [5-15], P = 0.001) than at the PTCs. Despite this lower median GCS, there was no difference in the percentage of patients with a GCS <9 between centers and the rate of intracranial pressure monitoring and the rate of craniotomy and craniectomy performed for children with a GCS <9 were the same at both centers for both age cohorts [Table 2].

Table 2

Demographics and patient characteristics by trauma center and age cohorts

	0-14 years old			15-18 years old
	PTC (n=2315)	ATC (n=1805)	P	PTC (n=1585)	ATC (n=4323)	P
Age (years), mean±SD	7.5±4.6	7±5	0.001	16.9±1	16.7±1	0.001
Male gender, n (%)	1501 (65)	1181 (65)	0.7	118 (70)	3049 (70)	0.99
Mechanism of injury
Penetrating	133 (6)	207 (11)	<0.001	225 (14)	763 (18)	0.002
Stab wounds	8 (0.3)	6 (0.3)	0.99	35 (2)	122 (3)	0.20
GSW	117 (5)	196 (11)	<0.001	190 (12)	642 (15)	0.005
Blunt	2182 (94)	1598 (88)	<0.001	1360 (86)	3560 (82)	0.002
HDI prehospital, n (%)	195 (10)	229 (15)	<0.001	162 (11)	571 (15)	0.003
Penetrating	34 (28)	48 (26)	0.69	52 (25)	209 (31)	0.11
Blunt	161 (9)	181 (13)	<0.001	110 (9)	362 (11)	0.04
HDI in ED, n (%)	173 (8)	219 (12)	<0.001	144 (9)	418 (10)	0.51
Penetrating	19 (15)	48 (24)	0.06	47 (22)	160 (22)	0.92
Blunt	154 (7)	171 (11)	<0.001	97 (7)	258 (7)	0.95
TT (min), median (IQR)	57 (42-83)	55 (40-76)	<0.001	64 (46-88)	59 (42-83)	0.001
Prehospital HDI	48 (34-66)	44 (33-64)	0.24	51 (39-75)	50 (35-73)	0.41
No prehospital HDI	60 (44-85)	58 (43-79)	0.013	64 (47-87)	61 (44-84)	<0.001
ISS, median (IQR)	22 (17-29)	22 (17-29)	0.29	22 (17-29)	22 (17-29)	0.51
GCS, median (IQR)	14 (5-15)	13 (3-15)	0.001	15 (3-15)	14 (3-15)	0.23
Severe TBI, n (%)	678 (31)	654 (38)	<0.001	450 (31)	1251 (31)	0.99
GCS<9, n (%)	721 (31)	580 (32)	0.49	505 (32)	1484 (34)	0.07
NS interventions GCS<9	43 (5.6)	37 (6)	0.81	23 (4.5)	70 (4.7)	0.99
ICP monitoring	26 (3.4)	19 (3.1)	0.76	16 (3.2)	50 (3.3)	0.88
Craniotomy*	17 (2.2)	18 (2.9)	0.49	7 (1.4)	20 (1.3)	0.99
ED mortality, n (%)	70 (3)	130 (7.2)	<0.001	42 (2.6)	175 (4)	0.012
IP mortality, n (%)	202 (8.7)	215 (12)	0.001	155 (9.8)	469 (10.8)	0.25

PTC: Pediatric trauma centers, SD: Standard deviation, GSW: Gunshot wounds, HDI: Hemodynamic instability, ED: Emergency department, IQR: Interquartile range, ISS: Injury severity score, GCS: Glasgow Coma Scale, TBI: Traumatic brain injury, ICP: Intracranial pressure, IP: In-patient, NS: Neurosurgery, ATC: Adult trauma center, TT: Tube thoracostomy

There were also more children in both the age groups brought to ATCs that were hypotensive in the prehospital setting [Table 2]. The ATCs had a higher proportion of children ≤ 14 years with HDI in the ED compared to PTCs as well but there was no difference at either center in the percentage of adolescent children with HDI in the ED.

Transit times were then analyzed by age cohort based on the presence or absence of HDI [Table 2]. For each age cohort, transit times to PTCs were significantly longer compared to ATCs for patients who were normotensive in the prehospital setting but there was no difference in transit times between centers for patients who were hemodynamically unstable in the field.

Table 3 shows mortality comparisons between trauma centers based on HDI. ED mortality rate was significantly higher at ATCs compared to the PTCs for children ≤14 years of age who were hemodynamically unstable in the field (38% vs. 20%; P < 0.001) or unstable in the ED (43% vs. 27%; P = 0.001). However, there was no difference in ED mortality rates among the hemodynamically unstable adolescents at either center. In addition, there was no difference in IP mortality rates for the hemodynamically unstable children in either age group at either center.

Table 3

Mortality rate associated with hemodynamic instability in field or emergency department

	0-14 years old			15-18 years old
	PTC	ATC	P	PTC	ATC	P
Prehospital HDI	195 (10)	229 (15)	<0.001	162 (11)	571 (15)	0.003
ED mortality	39 (20)	86 (38)	<0.001	21 (13)	90 (16)	0.45
IP mortality	58 (30)	55 (24)	0.18	31 (19)	126 (22)	0.44
ED HDI	173 (8)	219 (12)	<0.001	144 (9)	418 (10)	0.51
ED mortality	47 (27)	94 (43)	0.001	28 (19)	102 (24)	0.25
In-hospital mortality	54 (31)	60 (27)	0.43	44 (30)	121 (30)	0.75

HDI: Hemodynamic instability, ED: Emergency department, PTC: Pediatric trauma centers, IP: In-patient, ATC: Adult trauma center

IP complications were higher in ATC (18% vs. 15%, P = 0.004) in the younger age group while there was no difference in complications in the adolescent group between centers [Table 2]. Overall hospital LOS, ICU LOS, ICU-free days, and ventilator-free days were greater in the younger cohort at the PTCs but there was no difference in any of these variables between centers for the adolescents. For both age groups, children at PTCs were more likely to be discharged to home.

Outcome analysis adjusted for confounders

Mixed effect logistic regression confirmed an interaction between age and ED mortality (odds ratio [OR] 0.07 [0.05–0.9], P = 0.001) but not with IP mortality (OR 0.004 [−0.01–0.01], P = 0.27) [Table 4]. While controlling for age, sex, mechanism of injury, injury severity, HDI, trauma center volume, transit time, and patterns of severe injury we demonstrated that ED mortality was lower for all children managed at PTCs compared to ATCs (OR 0.5 [confidence interval (CI) 0.4–0.7], P = 0.009) but there was no difference in IP mortality between centers (OR 0.9 [0.9–1.5], P = 0.23) [Table 4]. On subanalysis with age stratification, children ≤14 years of age had lower odds of death in the ED at PTCs (OR 0.42 [CI 0.25–0.71], P = 0.001) while there was no statistical difference for children 15–18 years of age (OR 0.81 [CI 0.5–1.3], P = 0.40) between centers [Table 5]. Similarly, the younger cohort had lower odds of IP death at the PTCs (OR 0.73 [CI 0.5–0.9], P = 0.02) but there was no difference in IP mortality for the adolescents treated at either center.

Table 4

Primary and secondary outcomes

Variable	ED mortality		IP mortality
	OR (95% CI)	P	OR (95% CI)	P
Age in years	0.07 (0.05-0.9)	0.001	0.004 (−0.01-0.01)	0.27
Male sex	1.1 (0.8-1.9)	0.65	1.8 (1.3-2.9)	0.71
White race	0.6 (0.12-1.9)	0.45	-	-
Uninsured	4.1 (3.3-5.1)	<0.001	3.4 (1.1-4.9)	<0.001
Penetrating mechanism	1.6 (1.1-2.4)	0.02	4.3 (1.9-4.8)	<0.001
PTC	0.5 (0.4-0.7)	0.009	0.91 (0.9-1.5)	0.23
HDI in field	5.4 (3.9-7.4)	<0.001	2.5 (2.1-3.1)	<0.001
ED HDI	19.2 (12.9-23.9)	<0.001	2.9 (2.3-3.5)	<0.001
Volume
≤50	1.9 (0.9-2.8)	0.33	0.8 (0.6-1.1)	0.21
51-100	1.4 (0.9-2.4)	0.55	0.9 (0.7-1.2)	0.84
>100	Reference	Reference	Reference	Reference
Body region with AIS >3
Head	2.5 (1.1-4.6)	0.001	5.9 (4.8-7.3)	<0.001
Extremity	0.8 (0.4-1.9)	0.09	0.9 (0.7-1.1)	0.44
Variable	In-hospital complications		Discharge to home
	OR (95% CI)	P	OR (95% CI)	P
Age in years	−0.01 (−0.02-0.009)	0.001	0.02 (0.01-0.03)	0.001
Penetrating mechanism	2.2 (1.1-2.9)	0.002	0.81 (0.6-0.8)	0.003
PTC	1.1 (0.9-1.8)	0.45	1.5 (1.1-1.7)	<0.001
Prehospital HDI	3.1 (2.2-3.9)	<0.001	0.4 (0.3-0.6)	<0.001
ED HDI	3.9 (2.1-4.2)	<0.001	0.22 (0.19-0.24)	<0.001
Case volume
≤50	0.8 (0.6-1.9)	0.22	0.58 (0.4-0.83)	0.003
51-100	1.3 (0.89-2.1)	0.89	0.83 (0.57-1.22)	0.36
>100	Reference	-	Reference	-
Serious injury pattern
Head	2.1 (1.9-2.3)	<0.001	0.22 (0.35-0.43)	<0.001
Neck	2.1 (1.7-3.9)	<0.001	0.5 (0.4-0.9)	0.003
Thorax	1.3 (1.1-1.9)	<0.001	1.1 (0.7-1.3)	0.45
Abdomen	1.4 (1.1-1.6)	<0.001	0.51 (0.28-1.7)	0.33
Extremity	0.01 (0.01-0.05)	<0.001	0.05 (0.02-0.07)	<0.001
In-hospital complications	-	-	0.19 (0.16-0.21)	<0.001
Variable	ICU free length of stay		Ventilator free days
	β (95% CI)	P	β (95% CI)	P
Age in years	0.015 (0.01-0.02)	<0.001	0.002 (−0.003-0.007)	0.36
Penetrating mechanism	−0.11 (−0.03-−0.21)	<0.001	−0.11 (−0.09-−0.14)	0.001
PTC	0.20 (0.15-0.21)	<0.001	0.07 (0.009-0.14)	0.01
Prehospital HDI	0.30 (0.02-0.28)	<0.001	0.69 (0.4-0.8)	<0.001
ED HDI	0.01 (0.03-0.11)	<0.001	0.004 (−0.1-0.1)	0.95
Case volumes
≤50	0.04 (−0.03-0.11)	0.31	0.39 (0.29-0.5)	<0.001
51-100	0.01 (−0.03-0.06)	0.63	0.28 (0.17-0.39)	<0.001
>100	Reference	-	Reference	-
Serious injury pattern
Head	0.28 (0.23-0.32)	<0.001	0.01 (−0.01-0.04)	0.425
In-hospital complication	0.6 (0.5-0.6)	<0.001	0.65 (0.5-0.7)	<0.001

OR: Odds ratio, CI: Confidence interval, HDI: Hemodynamic instability, ED: Emergency department, PTC: Pediatric trauma centers, IP: In-patient

Table 5

Mortality analysis by age cohort and trauma center type

Multivariable logistic regression analysis comparing PTC mortality to ATC mortality by age cohort*
	≤18 years age		≤14 years age		15-18 years age
	OR (95% CI)	P	OR (95% CI)	P	OR (95% CI)	P
ED mortality	0.6 (0.4-0.8)	0.009	0.42 (0.25-0.71)	0.001	0.81 (0.5-1.3)	0.40
Blunt	0.54 (0.35-0.83)	0.005	0.4 (0.21-0.71)	0.002	0.74 (0.4-1.3)	0.34
Penetrating	0.96 (0.5-1.8)	0.91	0.9 (0.26-3.2)	0.89	0.91 (0.41-2.1)	0.82
IP mortality	0.86 (0.7-1.1)	0.10	0.73 (0.5-0.9)	0.02	1.01 (0.8-1.2)	0.88
Blunt	0.8 (0.72-1.07)	0.21	0.75 (0.5-1.03)	0.05	1.06 (0.8-1.3)	0.67
Penetrating	0.92 (0.61-1.4)	0.71	0.75 (0.3-1.5)	0.43	0.94 (0.5-1.5)	0.82
Mixed effect multilevel logistic regression analysis testing for an interaction of age with mortality by trauma centers type
	≤18 years age		≤14 years age		15-18 years age
	OR (95% CI)	P	OR (95% CI)	P	OR (95% CI)	P
ED mortality PTC	1.006 (0.97-1.03)	0.67	1.009 (0.96-1.06)	0.72	0.97 (0.76-1.23)	0.83
ED mortality ATC	1.043 (1.02-1.06)	<0.001	1.06 (1.02-1.11)	0.003	1.01 (0.87-1.1)	0.86
IP mortality PTC	1.01 (0.99-1.04)	0.24	1.03 (0.99-1.07)	0.072	0.95 (0.80-1.13)	0.60
IP mortality ATC	1.09 (0.92-1.02)	0.29	1.01 (0.98-1.04)	0.47	1.02 (0.92-1.17)	0.42

OR: Odds ratio, CI: Confidence interval, ED: Emergency department, IP: In-patient, PTC: Pediatric trauma centers, ATC: Adult trauma center. P is significant if <0.05

There was no difference between PTCs and ATCs for IP complications (OR 0.86 [CI 0.69–1.06], P = 1.7) after controlling for confounders [Table 4]. Children were more likely to be discharged to home (OR 1.3 [CI 1.1–1.6], P < 0.001), have more ICU-free days (β 0.19 [CI 0.15–0.26], P < 0.001 and ventilator-free days (β 0.07 [CI 0.009–0.14], P = 0.01) at a PTC [Table 4].

DISCUSSION

Our study was conducted to determine if children with traumatic injury have better outcomes if managed at a PTC. We used a national trauma sample of injured children within the US and studied only children with severe injury. The injury severity and patterns of injury were similar between groups at both centers as was the management of severe head injury.

In our study, 59% of all injuries occurred within the adolescent age group. The majority of who were triaged to an ATC (73% vs. 27%). Adolescents had a higher percentage of penetrating injuries than the younger children. Thus, there were more penetrating injuries treated at the ATCs (15%) compared to the PTCs (9.2%) which is consistent with that of several other series.[3461219] The majority of all children ≤14 years of age in our study population were triaged directly to a PTC but a significant proportion (46%) were still triaged to ATCs. Despite the higher number of young children triaged to the PTCs, the ATCs treated more young children with penetrating injuries (11% vs. 6%, P < 0.001).

Our overall in-hospital mortality was 12% at the PTCs and 16% at the ATCs for the entire patient population. These rates are somewhat high compared to rates reported in some prior studies but is explained by the fact that we included only patients with severe injury. When Potoka et al. performed a subanalysis using only children with an ISS >15, they found an overall mortality rate of 12% in centers with pediatric specialization and mortality rates between 16% and 22% in ATCs which is similar to our results.[4]

Survival was better at PTCs for all children ≤18 years of age compared to an ATC in our unadjusted analysis which is consistent with several other studies.[3461219] However, in our study, when children were further stratified by age and adjusted for confounders, we found that the difference in mortality between centers for the 15–18 year olds became insignificant demonstrating that there is no difference in mortality for injured adolescents treated at adult or PTCs. This is consistent with three recent publications that showed no difference in outcomes between centers for the adolescent population.[151617]

A unique aspect of our investigation is our differentiation between ED and IP mortality. In our study, the younger children treated at PTCs had better odds of ED survival compared to those treated at ATCs. Interestingly, this survival advantage was only seen in the subgroup of young children sustaining blunt trauma when further stratified by mechanism. It is not clear why there was no difference in ED mortality for the children with a penetrating mechanism but this finding is the same as the results of two prior studies.[38] Hall et al. reported better outcomes for children with blunt injuries treated at PTCs but concluded that older children with penetrating injuries had equivalent mortality whether treated in an adult or pediatric center.[3] Miyata et al. also demonstrated no difference in mortality between centers in their study using only children with penetrating injuries.[8]

In our study, proportionately more children with HDI were brought to ATCs compared to the PTCs for both the age groups. Because HDI is an important risk factor for mortality we sought to specifically compare mortality rates for the hemodynamically unstable children in each age cohort by trauma center. We demonstrated that the rate of ED mortality was higher for children ≤14 years of age at ATCs compared to that in PTCs but there was no difference in ED mortality between centers for adolescents with HDI. Furthermore, there was no difference IP mortality for hemodynamically unstable children in either age cohort at either center. These findings further support our hypothesis that the difference in in-hospital mortality between adult and PTCs is primarily due to a higher ED mortality in children ≤14 years.

Transit times for the hemodynamically unstable children were the same for both trauma centers but interestingly the transit times for children normotensive in the field were significantly longer to the PTC. Although not conclusive, this finding suggests the preferential triage of more critical children to ATCs when primary transport to a PTC would result in longer transit times. It is important to re-iterate that we did control for both transit time and HDI in our mixed effect logistic regression and multivariate negative binomial regression models.

We found no difference in complications between adult and pediatric centers once adjusted for confounders. However, ICU-free days, ventilator days, and hospital LOS were slightly longer at the PTCs compared to ATCs. The clinical significance of this finding is unclear given that there were slightly more ventilator-free days at the PTC but these findings may be the result of more critically injured children surviving ED management to be admitted.

There was no difference in the proportion of patients discharged to a rehabilitation center or to a SNF between institutions but we found that a higher percentage of the children were discharged directly to home from the PTCs. We caution against over interpretation of discharge location when studying outcomes in the pediatric population. We do not feel that discharge to home, by itself, serves as a good surrogate for functional outcome in young patients. There are limited options for IP rehabilitation for the very young and parents are often better able to care for young children with residual disabilities at home compared to full grown adolescents.

One of the strengths of our study is the use of a national database to compare a large number of diverse PTCs and ATCs from different regional trauma systems. We used a mixed effect logistic regression and multivariate negative binomial regression models to control for clustering of the population, case volume, and multiple confounders. We were able to account for the conflicting outcome results reported in prior publications by including all children ≤ 18 years of age and subsequently stratifying them into age cohorts to assess age related differences in outcomes. Although ATCs in our study received proportionally more children with severe TBI, HDI, and penetrating injuries these variables were controlled for in our models.

Limitations

We recognize certain limitations of our study. The retrospective use of large data sets such as the NTDB cannot assure that some unmeasured variables contributed to our findings. We excluded a significant number of patients in our study design. Although we believe that the exclusions helped to make our study stronger, we cannot rule out the possibility that their exclusion may have influenced our results. We did not include data from combined pediatric and ATCs in our study. It has been our experience that different combined centers use different age cutoffs for the management by adult and pediatric teams. We felt that the inability to control for these differences would make it difficult to interpret outcome data and thus chose to exclude combined centers from analysis. It is unlikely that including these centers in our investigation would have changed our conclusions however, since Sathya et al. have previously shown that combined trauma centers had mortality rates slightly better than stand-alone ATCs but worse than stand-alone PTCs.[12] Similarly, we did not analyze our data based on level of trauma center designation or ACS verification. These aspects have been previously studied and have been shown to effect outcome to some degree.[46712] We had concerns that further stratification of our data by these additional criteria would reduce patient volumes in our analyses to a level that would compromise statistical validity. Finally, we cannot exclude the possibility that occult bias was introduced by prehospital providers who may have preferentially triaged some patients to a particular type of trauma center when triage to either a pediatric or an ATCs was an option.

CONCLUSION

We have provided further evidence that young children with severe traumatic injury treated at PTCs have better survival than those treated at ATCs. The survival benefit is only seen in children ≤14 years of age sustaining blunt injury. Our data suggest that the better overall survival is actually the result of better survival in the ED. We suspect that pediatric resources, commitment, and expertise within the ED vary widely among ATCs and likely contributed to these results.

Despite the better survival at PTCs for the younger children we are not proposing that prehospital personnel bypass a nearby ATC at the risk of longer transit times for critically injured children. Rather, if we are to assure that we are providing the best quality of care to our pediatric population moving forward, in lieu of creating more PTCs, future efforts must focus attention on improving care across all ATCs treating young trauma victims. Attempts should be made to determine safe time frames in which hemodynamically stable and unstable children can be preferentially triaged directly to a PTC. However, most important, our data suggest that trauma systems need to further evaluate ED resources and processes of care within ATCs and find ways to standardize care between adult and pediatric centers for injured children.

Research quality and ethics statement

This study was approved by the Institutional Review Board / Ethics Committee approval number is Protocol 16-22 . The authors followed applicable EQUATOR Network () guidelines during the conduct of this research project.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.