Article

Association of prehospital intubation with decreased survival among pediatric trauma patients in Iraq and Afghanistan

a b s t r a c t

Introduction: airway compromise is the second leading cause of Preventable death on the battlefield among US military casualties. Airway management is an important component of pediatric trauma care. Yet, intubation is a challenging skill with which many Prehospital providers have limited pediatric experience. We compare mor- tality among Pediatric trauma patients undergoing intubation in the prehospital setting versus a fixed-facility emergency department.

Methods: We queried the Department of Defense Trauma Registry (DODTR) for all pediatric encounters in Iraq and Afghanistan from January 2007 to January 2016. We compared outcomes of pediatric subjects undergoing intubation in the prehospital setting versus the emergency department (ED) setting.

Results: During this period, there were 3439 pediatric encounters (8.0% of DODTR encounters during this time). Of those, 802 (23.3%) underwent intubation (prehospital = 211, ED = 591). Compared to patients undergoing ED intubation, patients undergoing prehospital intubation had higher median composite injury severity scores (17 versus 16) and lower survival rates (66.8% versus 79.9%, p b 0.001). On univariable logistic regression anal- ysis, prehospital intubation increased mortality odds (OR 1.97, 95% CI 1.39-2.79). After adjusting for confounders, the association between prehospital intubation and death remained significant (OR 2.03, 95% CI 1.35-3.06).

Conclusions: Pediatric trauma subjects intubated in the prehospital setting had worse outcomes than those

intubated in the ED. This finding persisted after controlling for measurable confounders.

Introduction

Background

Pediatric trauma is a major cause of pediatric mortality and morbid- ity in combat zones [1-3]. Pediatric trauma patients treated during mil- itary operations in Iraq and Afghanistan have higher mortality rates compared to adult patients [4]. Hence there is a need for investigation to identify resuscitation strategies to improve outcomes in these patients.

In the adult combatant population, airway compromise is a leading cause of death on the battlefield [5,6]. Compared to adults, children have anatomic differences that pose additional challenges to endotra- cheal intubation: more anterior airways, airways that are narrower

* Corresponding author at: 3698 Chambers Pass, JBSA Fort Sam Houston, TX 78234, United States.

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

after the larynx, and proportionally larger tongues and tonsils [7]. More- over, many prehospital providers in the military have limited training and experience in treating pediatric patients. Even in the civilian setting – where prehospital providers presumably see more pediatric patients – obtaining and maintaining pediatric intubation skills is a continual chal- lenge [8-13].

Given these issues, it is perhaps unsurprising that a significant body of evidence suggests that prehospital intubation does not improve out- comes among either adult or Pediatric populations [14-18]. However, this literature arises from the civilian setting within established Trauma systems. It remains unclear whether these data apply to the airway management of pediatric patients in the austere combat environment.

Goal of this study

The goal of this study is to compare mortality among pediatric trau- ma patients undergoing intubation in the prehospital setting versus an emergency department (ED).

https://doi.org/10.1016/j.ajem.2017.11.066 0735-6757/

658 S.G. Schauer et al. / American Journal of Emergency Medicine 36 (2018) 657659

Methods

Table 1

Comparison of the prehospital and ED intubation cohorts.

Data acquisition

We identified subjects as part of a study seeking to evaluate

Prehospital (n

= 211)

Emergency department (n = 591)

p-Value?

prehospital and ED Life-saving interventions for pediatric trauma pa- tients. This US Army Institute of Surgical Research (USAISR) regulatory office reviewed protocol H-16-014 and determined it was exempt from Institutional Review Board oversight. We obtained only de- identified data.

Subjects and setting

Demographics b 1 year 1.4% (3) 2.0% (12) b 0.001

1-4 years 14.7% (31) 21.5% (127)

5-9 years 26.1% (55) 34.9% (206)

10-14 years 45.0% (95) 28.6% (169)

15-17 years 12.8% (27) 13.0% (77)

Male 75.8% (160) 76.7% (453) 0.810

Locations Afghanistan 85.8% (181) 71.1% (420) b 0.001

Iraq

14.2% (30)

28.9% (171)

Mechanism of

Explosive

53.6% (113)

47.2% (279)

0.311

injury

GSW

23.2% (39)

21.8% (129)

MVC

13.7% (29)

12.9% (76)

Injury severity

Other

Composite

14.2% (30)

17 (11-25)

18.1% (107)

16 (10-25)

0.003

scores AISBR1

3 (0-4)

0 (0-3)

b 0.001

AISBR2

0 (0-1)

0 (0-1)

0.139

AISBR3

0 (0-2)

0 (0-2)

0.625

AISBR4

0 (0-1)

0 (0-1)

0.411

AISBR5

0 (0-2)

0 (0-2)

0.608

AISBR6

1 (0-1)

1 (0-1)

b 0.001

We queried the Department of Defense Trauma Registry (DODTR) for all pediatric encounters from January 2007 to January 2016. We in- cluded subjects with missing data if there was a documented age or es- timated age within the records. We sought all available prehospital care and fixed-facility based care on the initial search to create the research database. This is a retrospective review of prospectively collected re- cords. Within the dataset, we searched for all pediatric subjects with a documented intubation performed within the prehospital or ED setting. We placed subjects with a documented intubation in both settings into

Hospital data ventilator days

2 (1-4) 2 (1-4) 0.633

the prehospital category for analysis. Subjects were excluded if they also

had a documented cricothyrotomy. We stratified subjects into age cate-

ICU LOS 3 (1-5) 3 (2-6) 0.161

Hospital LOS 4 (1-10) 5 (2-10) 0.034

gories based on Centers for Disease Control year age groupings: b 1, 1-4, 5-9, 10-14, and 15-17 [19].

Department of Defense Trauma Registry (DODTR) description

Discharged alive

GSW = gunshot wound.

MVC = Motor vehicle collision. ED = Emergency department.

66.8% (141) 79.9% (472) b 0.001

The DODTR, formerly known as the Joint Theater Trauma Registry (JTTR), is the data repository for DoD trauma-related injuries in the combat setting [20,21]. This system is managed by the Joint Trauma Sys- tem. The DODTR includes documentation regarding demographics, injury-producing incidents, diagnoses, treatments, and outcomes of in- juries sustained by US/non-US military and US/non-US civilian person- nel in wartime and peacetime from the point of injury to final disposition. Subjects are enrolled in the DODTR if they are admitted to a Role3 (fixed-facility) or FST (forward surgical team) with an injury di- agnosis using the International Classification of Disease 9th Edition (ICD-9) between 800 and 959.9, near-drowning/drowning with associ- ated injury (ICD-9994.1) or inhalational injury (ICD-9987.9), and trau- ma occurring within 72 h from presentation.

Analysis

We performed all statistical analysis using Microsoft Excel (version 10, Redmond, Washington) and JMP Statistical Discovery from SAS (version 13, Cary, NC). We used a student t-test for continuous vari- ables, Wilcoxon Rank Sum test for ordinal variables, and chi-squared test for nominal variables. We performed univariable and multivariable binary logistic regression analyses to determine odds.

Results

During the study period, there were 42,790 total encounters docu- mented in the DODTR. Within that group, there were 3439 pediatric en- counters (8.0% of total encounters). There were 18 subjects that underwent prehospital cricothyrotomy and were excluded. After re- moval of duplicates and categorization (prehospital versus ED), there were 802 pediatric subjects available for comparison (prehospital = 211, ED = 591), representing 23.3% of the total pediatric encounters. The prehospital intubation cohort had a higher proportion of 10-14- year-old patients, worse composite injury severity scores, higher mor- tality rates and higher proportion of patients treated in Afghanistan than Iraq (Table 1). One subject (2-year-old male) in the prehospital

AISBR = Abbreviated Injury Score by body region. AISBR1 = Head/neck.

AISBR2 = Face.

AISBR3 = Thorax. AISBR4 = Abdomen. AISBR5 = Extremity.

AISBR6 = External (including superficial wounds from all the body regions, burns). ICU = Intensive care unit.

LOS = Length of stay.

* p-Values are based on a comparison between the cohorts.

cohort had an attempted supraglottic airway – it is unclear whether it was before or after the intubation; he died.

On univariable logistic regression analysis, prehospital intubation significantly increased the odds of death (OR 1.97, 95% CI 1.39-2.79). We then performed a multivariable logistic regression analysis control- ling for injury severity scores, age group, location and mechanism of in- jury – the association between prehospital intubation and death remained significant (OR 2.03, 95% CI 1.35-3.06).

Discussion

In this retrospective cohort study comparing intubation outcomes for pediatric subjects, we found higher mortality among patients intubated in the prehospital setting compared to the ED setting. Those undergoing prehospital intubation had significantly higher injury sever- ity scores suggesting these patients may have been more critically in- jured at baseline – however, this difference may be more statistically significant than clinically significant. On multivariable logistic regres- sion analysis controlling for confounders, including injury severity scores, the worse survival rates among those undergoing prehospital in- tubations persisted. These findings suggest that prehospital providers should consider deferring intubation of pediatric trauma patients until arrival to the ED and in the prehospital environment instead focus upon less invasive measures. This conclusion mirrors the findings from the civilian setting [14,17].

The reasons for the persistently worse outcomes in the prehospital intubation cohort are likely multifactorial. First, most of the prehospital providers in this setting are physicians and physician assistants (both

S.G. Schauer et al. / American Journal of Emergency Medicine 36 (2018) 657659 659

collectively called medical officers) that have little-to-no training specif- ic to pediatric trauma care. Even though pediatricians often deploy to battalion-level positions, including battalion aid stations, it is not clear how many of them have sufficient training to proficiently perform intu- bations and manage trauma. However, even if many of these medical of- ficers had pediatric-specific airway training during their clinical rotations, data suggest that intubation skills quickly degrade without routine utilization [8,22,23]. In addition to this, battalion-level medical units generally have a very limited supply of pediatric supplies and al- most certainly have no advanced airway devices (i.e., Laryngeal Mask Airway(TM)). rapid sequence induction medications are also relatively limited. Moreover, these units generally do not have access to video lar- yngoscopy despite this technology becoming increasingly ubiquitous in the civilian setting [24]. The equipment maintained by far forward units is almost exclusively designed and calibrated to care for the adult com- batant population. For example, the SAVe(TM) (AutoMedx, Coppell, Texas, USA) ventilator has pre-programmed settings appropriate for an adult. Second, we noted that a higher proportion of those undergoing prehospital intubation were in Afghanistan. This is likely attributable to differences in the medical rules of eligibility between the two the- aters. The longer and more complicated transportation issues in Afghanistan, given its sparse population density and Challenging terrain compared to Iraq, may have simultaneously contributed to an increased likelihood of intubations being performed in the prehospital setting and increased likelihood of poor outcomes in trauma patients. We did, how- ever, control for that location confounder during the multivariable anal- ysis and found that the association between prehospital intubation and death remained significant.

This study has several limitations. First, the observational nature of our investigation means that we can only demonstrate correlation and not causation given the potential for confounding. We used logistic re- gression to control for those potential confounders for which we had data, but we cannot control for unmeasured confounders. Second, for inclusion into the DODTR, subjects must arrive at the FST or fixed- facility alive or with on-going interventions. Thus, the database does not capture those that died before reaching the fixed-facility or FST. However, we do not believe including these cases would have a material impact on our findings. To the extent that any of these subjects underwent prehospital intubation, their inclusion in the study would have resulted in even higher observed mortality among these patients. That said, it is possible that a gravely injured subset of the pediatric trau- ma population exists among whom survival to fixed-facility depends upon prehospital advanced airway management. As our database ex- cludes all subjects not surviving to fixed-facility unless receiving on- going interventions, we are unable to characterize subjects that died on the battlefield. Third, we do not have sufficient data to determine transport times. It is possible that prehospital intubation subjects had longer times from injury to arrival at the FST or fixed-facility. If true, these longer transport times would potentially increase the need for air- way protection with concomitant higher mortality rates from delays to surgical intervention. Fourth, we included data even if it was incomplete in the DODTR. To the extent that missing data were more likely for con- founding variables based upon the location of intubation, it is possible that our results may have some underlying bias [25]. Lastly, we do not have sufficient data to calculate Revised Trauma Scores or match up physiologic data, such as vital signs, to the time in which the procedure occurred which may have affected the decision to intubate.

Conclusions

Pediatric trauma subjects intubated in the prehospital setting had worse outcomes than those intubated in the ED. This finding persisted after controlling for measurable confounders.

Funding

We received no funding for this study.

Conflicts of interest

We have no conflicts of interest to report.

Disclaimer

Opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Air Force, the Department of the Army, or the Department of Defense.

Acknowledgements

We would like to thank the Joint Trauma System Data Analysis Branch for their efforts with data acquisition.

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