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255 Are Certain PECARN Criteria Too Subjective to Be Accurate?
Research Forum Abstracts
253
Intraosseous Administration of CT Contrast in a Porcine Model: A Feasibility Study
Duncan L, Cohen J, Triner W, Rea J, King C/Albany Medical Center, Albany, NY
Study Objectives: Obtaining rapid intravenous (IV) access is often difficult in patients who have sustained injuries due to major trauma. Intraosseous (IO) access is a safe and reliable alternative when peripheral IV access cannot be obtained quickly. For many trauma patients, contrast-enhanced computed tomography imaging is an important element of the initial diagnostic evaluation performed in the emergency department (ED). However, minimal information has been published regarding the injection of contrast material using IO access for the purpose of obtaining a contrastenhanced computed tomography scan. This study was performed to evaluate IO administration of contrast material for a trauma-protocol computed tomography scan in an adult mini-swine model. Methods: Skeletally mature mini-swine were anesthetized and had peripheral IV and IO access established. IO access was obtained in the proximal humerus with fluoroscopic confirmation of correct needle placement. Each animal underwent contrast-enhanced trauma-protocol computed tomography scans using both routes of contrast administration. Contrast was administered using a MedRad® computerized power-injection system. computed tomography confirmation of contrast arterial phase wash-out between studies was established prior to administration of the second contrast injection. The order for route of administration (IV or IO) was randomized for each animal using block randomization. Images were evaluated for adequacy of vascular opacification by 2 board-certified radiologists. Results: All images obtained with both IV and IO contrast administration were judged to be adequately opacified to meet diagnostic criteria. One animal had partial extravasation of contrast after IO administration despite proper needle placement. Conclusion: In this swine model, injection of contrast material through a proximal humerus IO site resulted in adequate opacification of trauma-protocol computed tomography images in all animals. Our results suggest that intraosseous administration of contrast material may be a viable alternative in trauma patients when attempts at obtaining other vascular access are unsuccessful or would lead to unacceptable delays in diagnostic evaluation. Further study is warranted in human subjects to investigate the effectiveness of this methodology as well as the incidence and significance of contrast extravasation.
254
Role of Airbag Use on Head Injury Outcomes in Side versus Frontal Impact Car Crashes
Eucker S, Mutter K, Bose D, Wu E, Sochor M/University of Virginia, Charlottesville, VA
Background: Head injuries due to motor vehicle crashes (MVCs) are a leading cause of morbidity and death in young people. In 2008, there were more than 5 million MVCs in the US, and 30% were side impact. With less space available for energy absorption and effective passive protection, side impact collisions are associated with a high risk of severe injuries, particularly to the head. Dummy test evaluation of vehicle injury countermeasures has shown that side airbags are highly effective at mitigating head injuries; however, epidemiologic traffic data to support to this claim is limited. Study Objectives: The purpose of this study is to determine the effects of airbag use and impact direction on head injury outcome and severity from MVCs using data from the National Automotive Sampling System (NASS) database. NASS is a nationally representative sample of police-reported tow-away MVCs. Methods: Cases were selected from the NASS database years 2001-2010 based on age ⱖ18, front row occupant, belt restrained, not ejected, and vehicle body type car, SUV, van or truck for 3 groups: (1) frontal, (2) near-side, and (3) far-side impacts. Each group was further subcategorized into (a) airbag absent, (b) airbag present but did not deploy, (c) airbag present and did deploy, and head injury (HI) rates were compared. The sampled estimates were further weighted to represent the national distribution. Delta V (DV) is the estimated change in velocity of the vehicle before and after impact, derived based on crush measurements of the vehicle. Results: There were 11,617 frontal impact cases (4.45 million weighted). As regulations required frontal airbags in all vehicles for the years studied, all cases had airbags available and 42% of airbags deployed. Of 1335 near-side impact cases (521,000 weighted), 16% had side airbags available and 7% deployed. Of 1179 farside impact cases (470,000 weighted), 18% had side airbags available and 24% deployed. The rates of head injuries (%) for each group is presented in Table 1. For all impact directions, head injury rates were greater when airbags deployed, when available, than when they did not deploy, which is likely due to the increased DV, a surrogate for crash severity, associated with airbag deployment. However, while
S92 Annals of Emergency Medicine
the difference in DV between no airbag deployment and airbag deployment were similar among frontal, near-side, and far-side crashes when airbags were available, the increase in numbers of head injuries were greater in near-side (570%) and far-side (390%) than in frontal (300%) crashes. Conclusion: Side-impact MVCs lead to head injuries at least as often as frontal MVCs when airbags do not deploy, but appear to result in more head injuries when airbags do deploy. While this may be related to DV and crash severity, further work is needed to understand the mechanisms by which side airbag deployment leads to increased rates of head injuries. Future studies will compare head injury types among the crash groups to determine whether airbags reduce the severity of injuries.
255
Are Certain PECARN Criteria Too Subjective to Be Accurate?
Bastani A, Donaldson D, Shah P, Munafo S, Thomas T, Shaqiri B, Palomba K, Anderson W/Troy Beaumont Hospital, Troy, MI
Study Objectives: The Pediatric Emergency Care Applied Research Network (PECARN) head injury criteria provides a 6-step algorithm which identifies pre-verbal pediatric patients (age ⬍ 2) at very low risk for clinically important traumatic brain injury (ciTBI), obviating the need for head CT (HCT). The efficacy of the algorithm depends on the accuracy of emergency physicians in appropriately characterizing patients. To maximize the reproducibility of the algorithm, the PECARN investigators only chose criterion with kappa values whose lower bound of the one-sided 95% confidence interval (CI) was 0.4, indicating at least moderate inter-rater reliability. However, given the subjective nature of the PECARN criteria, this moderate level of inter-rater reliability may lead to inaccurate classification of patients and undercut the efficacy of the algorithm. Our objectives were to quantify the ability of independent reviewers to correctly categorize patients utilizing PECARN criteria and to identify incorrect classifications resulting in patients not receiving an otherwise appropriate HCT. Methods: We conducted a secondary analysis of a standardized chart review of all children under the age of 2 who presented to our community hospital who received a HCT between Jan 1st, 2010 and Dec 31st, 2010. Following recommended guidelines for conducting a chart review, we: 1) created a standardized data extraction; 2) utilized 2 blinded chart reviewers who received specific training prior to data extraction; and 3) held periodic meetings to evaluate coding rules and clarify data variables. All discordant data points were adjudicated by a second set of 2 blinded reviewers. Our primary outcome measure was the inter-rater reliability of the reviewers to correctly categorize patients utilizing the 6 PECARN head injury criteria. Our secondary outcomes were the ability of a second set of blinded chart reviewers to correctly adjudicate those cases where the initial reviewers were discordant and the number of patients who would have been incorrectly identified as PECARN negative due to classification errors. Data was analyzed using descriptive statistics; 95% CIs were calculated using the modified Wald method. Kappa values with 95% CIs were calculated using the Fleiss method. Results: A total of 115 pre-verbal patients received a head CT at our institution during the study period, resulting in 690 data points to be analyzed by the reviewers. A total of 50 (7.2%) data points were discordant across the 6 criteria. Three of the 6 criteria had kappa values with CIs less described than the original study: 1) “Acting abnormal per the parents”, k ⫽ 0.378 [95% CI 0.203 - 0.553]; 2) “Evidence of mental status change”; k ⫽ 0.663 [95%CI 0.043 - 1.0]; 3) “Loss of consciousness”, k⫽0.391 [95% CI -0.148 0.931]. All of the discordant data points were adjudicated by a second set of blinded reviewers. 21 (42% [CI 29.4%-55.8%]) of the cases that were reviewed remained discordant. Six patients evaluated by the initial reviewers and 3 patients evaluated by both sets of reviewers would have been incorrectly marked as PECARN negative. Conclusion: In our cohort, certain PECARN criteria had a lower inter-rater reliability than originally reported, leading to misclassification of patients who would have otherwise have received a HCT.
Volume , . : October
253
Intraosseous Administration of CT Contrast in a Porcine Model: A Feasibility Study
Duncan L, Cohen J, Triner W, Rea J, King C/Albany Medical Center, Albany, NY
Study Objectives: Obtaining rapid intravenous (IV) access is often difficult in patients who have sustained injuries due to major trauma. Intraosseous (IO) access is a safe and reliable alternative when peripheral IV access cannot be obtained quickly. For many trauma patients, contrast-enhanced computed tomography imaging is an important element of the initial diagnostic evaluation performed in the emergency department (ED). However, minimal information has been published regarding the injection of contrast material using IO access for the purpose of obtaining a contrastenhanced computed tomography scan. This study was performed to evaluate IO administration of contrast material for a trauma-protocol computed tomography scan in an adult mini-swine model. Methods: Skeletally mature mini-swine were anesthetized and had peripheral IV and IO access established. IO access was obtained in the proximal humerus with fluoroscopic confirmation of correct needle placement. Each animal underwent contrast-enhanced trauma-protocol computed tomography scans using both routes of contrast administration. Contrast was administered using a MedRad® computerized power-injection system. computed tomography confirmation of contrast arterial phase wash-out between studies was established prior to administration of the second contrast injection. The order for route of administration (IV or IO) was randomized for each animal using block randomization. Images were evaluated for adequacy of vascular opacification by 2 board-certified radiologists. Results: All images obtained with both IV and IO contrast administration were judged to be adequately opacified to meet diagnostic criteria. One animal had partial extravasation of contrast after IO administration despite proper needle placement. Conclusion: In this swine model, injection of contrast material through a proximal humerus IO site resulted in adequate opacification of trauma-protocol computed tomography images in all animals. Our results suggest that intraosseous administration of contrast material may be a viable alternative in trauma patients when attempts at obtaining other vascular access are unsuccessful or would lead to unacceptable delays in diagnostic evaluation. Further study is warranted in human subjects to investigate the effectiveness of this methodology as well as the incidence and significance of contrast extravasation.
254
Role of Airbag Use on Head Injury Outcomes in Side versus Frontal Impact Car Crashes
Eucker S, Mutter K, Bose D, Wu E, Sochor M/University of Virginia, Charlottesville, VA
Background: Head injuries due to motor vehicle crashes (MVCs) are a leading cause of morbidity and death in young people. In 2008, there were more than 5 million MVCs in the US, and 30% were side impact. With less space available for energy absorption and effective passive protection, side impact collisions are associated with a high risk of severe injuries, particularly to the head. Dummy test evaluation of vehicle injury countermeasures has shown that side airbags are highly effective at mitigating head injuries; however, epidemiologic traffic data to support to this claim is limited. Study Objectives: The purpose of this study is to determine the effects of airbag use and impact direction on head injury outcome and severity from MVCs using data from the National Automotive Sampling System (NASS) database. NASS is a nationally representative sample of police-reported tow-away MVCs. Methods: Cases were selected from the NASS database years 2001-2010 based on age ⱖ18, front row occupant, belt restrained, not ejected, and vehicle body type car, SUV, van or truck for 3 groups: (1) frontal, (2) near-side, and (3) far-side impacts. Each group was further subcategorized into (a) airbag absent, (b) airbag present but did not deploy, (c) airbag present and did deploy, and head injury (HI) rates were compared. The sampled estimates were further weighted to represent the national distribution. Delta V (DV) is the estimated change in velocity of the vehicle before and after impact, derived based on crush measurements of the vehicle. Results: There were 11,617 frontal impact cases (4.45 million weighted). As regulations required frontal airbags in all vehicles for the years studied, all cases had airbags available and 42% of airbags deployed. Of 1335 near-side impact cases (521,000 weighted), 16% had side airbags available and 7% deployed. Of 1179 farside impact cases (470,000 weighted), 18% had side airbags available and 24% deployed. The rates of head injuries (%) for each group is presented in Table 1. For all impact directions, head injury rates were greater when airbags deployed, when available, than when they did not deploy, which is likely due to the increased DV, a surrogate for crash severity, associated with airbag deployment. However, while
S92 Annals of Emergency Medicine
the difference in DV between no airbag deployment and airbag deployment were similar among frontal, near-side, and far-side crashes when airbags were available, the increase in numbers of head injuries were greater in near-side (570%) and far-side (390%) than in frontal (300%) crashes. Conclusion: Side-impact MVCs lead to head injuries at least as often as frontal MVCs when airbags do not deploy, but appear to result in more head injuries when airbags do deploy. While this may be related to DV and crash severity, further work is needed to understand the mechanisms by which side airbag deployment leads to increased rates of head injuries. Future studies will compare head injury types among the crash groups to determine whether airbags reduce the severity of injuries.
255
Are Certain PECARN Criteria Too Subjective to Be Accurate?
Bastani A, Donaldson D, Shah P, Munafo S, Thomas T, Shaqiri B, Palomba K, Anderson W/Troy Beaumont Hospital, Troy, MI
Study Objectives: The Pediatric Emergency Care Applied Research Network (PECARN) head injury criteria provides a 6-step algorithm which identifies pre-verbal pediatric patients (age ⬍ 2) at very low risk for clinically important traumatic brain injury (ciTBI), obviating the need for head CT (HCT). The efficacy of the algorithm depends on the accuracy of emergency physicians in appropriately characterizing patients. To maximize the reproducibility of the algorithm, the PECARN investigators only chose criterion with kappa values whose lower bound of the one-sided 95% confidence interval (CI) was 0.4, indicating at least moderate inter-rater reliability. However, given the subjective nature of the PECARN criteria, this moderate level of inter-rater reliability may lead to inaccurate classification of patients and undercut the efficacy of the algorithm. Our objectives were to quantify the ability of independent reviewers to correctly categorize patients utilizing PECARN criteria and to identify incorrect classifications resulting in patients not receiving an otherwise appropriate HCT. Methods: We conducted a secondary analysis of a standardized chart review of all children under the age of 2 who presented to our community hospital who received a HCT between Jan 1st, 2010 and Dec 31st, 2010. Following recommended guidelines for conducting a chart review, we: 1) created a standardized data extraction; 2) utilized 2 blinded chart reviewers who received specific training prior to data extraction; and 3) held periodic meetings to evaluate coding rules and clarify data variables. All discordant data points were adjudicated by a second set of 2 blinded reviewers. Our primary outcome measure was the inter-rater reliability of the reviewers to correctly categorize patients utilizing the 6 PECARN head injury criteria. Our secondary outcomes were the ability of a second set of blinded chart reviewers to correctly adjudicate those cases where the initial reviewers were discordant and the number of patients who would have been incorrectly identified as PECARN negative due to classification errors. Data was analyzed using descriptive statistics; 95% CIs were calculated using the modified Wald method. Kappa values with 95% CIs were calculated using the Fleiss method. Results: A total of 115 pre-verbal patients received a head CT at our institution during the study period, resulting in 690 data points to be analyzed by the reviewers. A total of 50 (7.2%) data points were discordant across the 6 criteria. Three of the 6 criteria had kappa values with CIs less described than the original study: 1) “Acting abnormal per the parents”, k ⫽ 0.378 [95% CI 0.203 - 0.553]; 2) “Evidence of mental status change”; k ⫽ 0.663 [95%CI 0.043 - 1.0]; 3) “Loss of consciousness”, k⫽0.391 [95% CI -0.148 0.931]. All of the discordant data points were adjudicated by a second set of blinded reviewers. 21 (42% [CI 29.4%-55.8%]) of the cases that were reviewed remained discordant. Six patients evaluated by the initial reviewers and 3 patients evaluated by both sets of reviewers would have been incorrectly marked as PECARN negative. Conclusion: In our cohort, certain PECARN criteria had a lower inter-rater reliability than originally reported, leading to misclassification of patients who would have otherwise have received a HCT.
Volume , . : October