Lawrence J. Cook

Effect of Seating Position and Restraint Use on Injuries to Children in Motor Vehicle Crashes

Objective. To determine the effect of restraint use and seating position on injuries to children in motor vehicle crashes, with stratification by area of impact. Methods. Children <15 years old involved in serious automobile crashes in Utah from 1992 through 1996 were identified from statewide motor vehicle crash records. Serious crashes are defined as those resulting in occupant injuries with broken bones or significant bleeding or property damage exceeding

Effect of Motor Vehicle Crashes on Adverse Fetal Outcomes

750. Probabilistic methods were used to link these records with hospital records. Analysis used logistic regression controlling for age, restraint use, occupant seating position, and type of crash. Results. We studied 5751 children and found 53% were rear seat passengers. More than 40% were unrestrained. Sitting in the rear seat offered a significant protective effect (adjusted odds ratio: 1.7; 95% confidence interval: 1.6–2.0), and restraint use enhanced this effect (adjusted odds ratio: 2.7; 95% confidence interval: 2.4–3.1). Mean hospital charges were significantly greater for front seat passengers. Conclusions. Rear seat position during a motor vehicle crash provides a significant protective effect, restraint use furthers this effect, and usage rates of restraint devices are low. The rear seat protective effect is in addition to and independent of the protection offered from restraints.

Identifying Children at Very Low Risk of Clinically Important Blunt Abdominal Injuries

OBJECTIVE To assess the effect of maternal involvement in motor vehicle crashes on the likelihood of adverse pregnancy outcomes and to estimate the effect of seatbelt use in reducing the occurrence of those outcomes. METHODS Statewide motor vehicle crash, birth, and fetal death records from 1992 to 1999 were probabilistically linked. Logistic regression was used to compare the likelihood of adverse birth and fetal outcomes including low birth weight, prematurity, placental abruption, fetal distress, excessive bleeding, fetal death, and other complications among pregnant women in crashes and those not in crashes. RESULTS Of 322,704 single live resident births, 8938 mothers (2.8%) experienced a crash during pregnancy. Pregnant women using seatbelts were not significantly more at risk for adverse fetal outcomes than pregnant women not in crashes. However, pregnant women who did not wear seatbelts during a crash were 1.3 times more likely to have a low birth weight infant than pregnant women not in a crash (95% confidence interval [CI] 1.0, 1.6) and twice as likely to experience excessive maternal bleeding than belted pregnant women in a crash (95% CI 1.0, 4.2). Forty-five of 2645 fetal deaths were linked to a motor vehicle crash, with unbelted pregnant women 2.8 times more likely to experience a fetal death than belted pregnant women in crashes (95% CI 1.4, 5.6). CONCLUSION Pregnant women should be counseled to wear seatbelts throughout pregnancy and reduce crash risk.

Out-of-Hospital Endotracheal Intubation Experience and Patient Outcomes

STUDY OBJECTIVE We derive a prediction rule to identify children at very low risk for intra-abdominal injuries undergoing acute intervention and for whom computed tomography (CT) could be obviated. METHODS We prospectively enrolled children with blunt torso trauma in 20 emergency departments. We used binary recursive partitioning to create a prediction rule to identify children at very low risk of intra-abdominal injuries undergoing acute intervention (therapeutic laparotomy, angiographic embolization, blood transfusion for abdominal hemorrhage, or intravenous fluid for ≥2 nights for pancreatic/gastrointestinal injuries). We considered only historical and physical examination variables with acceptable interrater reliability. RESULTS We enrolled 12,044 children with a median age of 11.1 years (interquartile range 5.8, 15.1 years). Of the 761 (6.3%) children with intra-abdominal injuries, 203 (26.7%) received acute interventions. The prediction rule consisted of (in descending order of importance) no evidence of abdominal wall trauma or seat belt sign, Glasgow Coma Scale score greater than 13, no abdominal tenderness, no evidence of thoracic wall trauma, no complaints of abdominal pain, no decreased breath sounds, and no vomiting. The rule had a negative predictive value of 5,028 of 5,034 (99.9%; 95% confidence interval [CI] 99.7% to 100%), sensitivity of 197 of 203 (97%; 95% CI 94% to 99%), specificity of 5,028 of 11,841 (42.5%; 95% CI 41.6% to 43.4%), and negative likelihood ratio of 0.07 (95% CI 0.03 to 0.15). CONCLUSION A prediction rule consisting of 7 patient history and physical examination findings, and without laboratory or ultrasonographic information, identifies children with blunt torso trauma who are at very low risk for intra-abdominal injury undergoing acute intervention. These findings require external validation before implementation.

Outcomes after out-of-hospital endotracheal intubation errors ,

STUDY OBJECTIVE Previous studies suggest improved patient outcomes for providers who perform high volumes of complex medical procedures. Out-of-hospital tracheal intubation is a difficult procedure. We seek to determine the association between rescuer procedural experience and patient survival after out-of-hospital tracheal intubation. METHODS We analyzed probabilistically linked Pennsylvania statewide emergency medicine services, hospital discharge, and death data of patients receiving out-of-hospital tracheal intubation. We defined tracheal intubation experience as cumulative tracheal intubation during 2000 to 2005; low=1 to 10 tracheal intubations, medium=11 to 25 tracheal intubations, high=26 to 50 tracheal intubations, and very high=greater than 50 tracheal intubations. We identified survival on hospital discharge of patients intubated during 2003 to 2005. Using generalized estimating equations, we evaluated the association between patient survival and out-of-hospital rescuer cumulative tracheal intubation experience, adjusted for clinical covariates. RESULTS During 2003 to 2005, 4,846 rescuers performed tracheal intubation. These individuals performed tracheal intubation on 33,117 patients during 2003 to 2005 and 62,586 patients during 2000 to 2005. Among 21,753 cardiac arrests, adjusted odds of survival was higher for patients intubated by rescuers with very high tracheal intubation experience; adjusted odds ratio (OR) versus low tracheal intubation experience: very high 1.48 (95% confidence interval [CI] 1.15 to 1.89), high 1.13 (95% CI 0.98 to 1.31), and medium 1.02 (95% CI 0.91 to 1.15). Among 8,162 medical nonarrests, adjusted odds of survival were higher for patients intubated by rescuers with high and very high tracheal intubation experience; adjusted OR versus low tracheal intubation experience: very high 1.55 (95% CI 1.08 to 2.22), high 1.29 (95% CI 1.04 to 1.59), and medium 1.16 (95% CI 0.97 to 1.38). Among 3,202 trauma nonarrests, survival was not associated with rescuer tracheal intubation experience; adjusted OR versus low tracheal intubation experience: very high 1.84 (95% CI 0.89 to 3.81), high 1.25 (95% CI 0.85 to 1.85), and medium 0.92 (95% CI 0.67 to 1.26). CONCLUSION Rescuer procedural experience is associated with improved patient survival after out-of-hospital tracheal intubation of cardiac arrest and medical nonarrest patients. Rescuer procedural experience is not associated with patient survival after out-of-hospital tracheal intubation of trauma nonarrest patients.

Effect of repeal of the national maximum speed limit law on occurrence of crashes, injury crashes, and fatal crashes on Utah highways

INTRODUCTION We sought to evaluate the association between three key out-of-hospital endotracheal intubation (ETI) errors and patient outcomes. METHODS We prospectively collected multicenter data on out-of-hospital ETI attempted by Emergency Medical Service (EMS) rescuers. We probabilistically linked these data to statewide EMS, death and hospital discharge data sets. The key ETI error events were (1) endotracheal tube misplacement or dislodgement, (2) multiple ETI attempts (> or =4 laryngoscopies) and (3) failed ETI. The primary outcomes were death (survival to hospital discharge) and secondary complications identified through ICD-9 discharge diagnoses. Using Cox regression with heavyside functions, we identified the associations between out-of-hospital ETI errors and early (in the field or emergency department) and later (on or after hospital admission) death. We censored non-linked cases, adjusted for important clinical covariates, and used a shared frailty regression model to account for clustering by EMS agency. We evaluated the associations between out-of-hospital ETI errors and secondary complications using univariable odds ratios with exact 95% confidence intervals. RESULTS Of 1954 out-of-hospital ETI, 444 (22.7%) patients experienced one or more ETI errors, including tube misplacement or dislodgement in 61 (3%), multiple ETI attempts in 62 (3%) and failed ETI in 359 (15%). Of the 1196 (61%) cases linked to outcomes, 872 (73%) died and 323 (27%) survived to hospital discharge. ETI errors were not associated with early death (tube misplacement or dislodgement: Hazard Ratio 0.98, 95% CI 0.65-1.47; multiple ETI attempts: 1.22, 0.80-1.85; failed ETI: 1.10, 0.88-1.39) or later death (tube misplacement or dislodgement: 0.40, 0.10-1.62; multiple ETI attempts: 1.77, 0.23-13.30; failed ETI: 0.76, 0.47-1.25). Pneumonitis was associated with failed ETI (n=20, 19%; univariable OR 2.54; 95% CI 1.24-5.25). CONCLUSION Out-of-hospital ETI errors are not associated with mortality. Failed out-of-hospital ETI increases the odds of pneumonitis.

Motor vehicle crash characteristics and medical outcomes among older drivers in Utah, 1992-1995

Speed limits were increased in Utah and other States after repeal of the national maximum speed limit law (NMSL) in 1995. This study analyzed effects of the increased speed limit on Utah highways on crash rates, fatality crash rates, and injury crash rates. Annual (1992-1999) rates of crashes, fatality crashes, and injury crashes for the following highway categories were calculated: urban Interstate segments (current speed limit 60-65 miles per hour (mph)); rural Interstate segments (current speed limit 70-75 mph); 55 mph rural non-Interstate highway segments; and high-speed non-Interstate highways (current speed limit 60-65 mph). Data were analyzed using autoregressive integrative moving average intervention time series analysis techniques. There were significant increases in total crash rates on urban (60-65 mph) Interstate segments (confounded by extensive ongoing highway construction on these highways), and in fatal crash rates on high-speed (60-65 mph) rural non-Interstate segments. The following variables were unaffected: total, fatality, and injury crash rates on rural Interstate segments; fatality and injury crash rates on urban Interstate segments; total and injury crash rates on high-speed non-Interstate segments. These results show an adverse effect on crash occurrence for subsets of crash types and highways, but do not show a major overall effect of NMSL repeal and increased speed limit on crash occurrence on Utah highways.

Evaluating the Use of Existing Data Sources, Probabilistic Linkage, and Multiple Imputation to Build Population-based Injury Databases Across Phases of Trauma Care

STUDY OBJECTIVE We sought to compare the characteristics and medical outcomes of motor vehicle crashes for drivers 70 years and older with those of drivers between the ages of 30 and 39 years. METHODS We probabilistically linked statewide motor vehicle crash and hospital discharge data between the years of 1992 and 1995 for the state of Utah. We calculated the odds of older drivers exhibiting certain motor vehicle crash characteristics compared with younger drivers. Adjusting for nighttime crash, high-speed crash, and seatbelt use, we calculated the odds of an older driver being killed or hospitalized compared with those of a younger driver. RESULTS During the study years, there were 14,466 drivers older than 69 years and 68,706 drivers between the ages of 30 and 39 years involved in motor vehicle crashes in Utah. Older drivers were less likely to have crashes involving drug or alcohol use (odds ratio [OR] 0.1; 95% confidence interval [CI] 0.1 to 0.2) and less likely to have crashes at high speed (OR 0.6; 95% CI 0.6 to 0.7). Although older drivers were no more likely to have a crash involving a right-hand turn (OR 1.0; 95% CI 0.9 to 1.1) than younger drivers, they were over twice as likely to have a crash involving a left-hand turn (OR 2.3; 95% CI 2.2 to 2.5). Also, older drivers were more likely to be killed or hospitalized than younger drivers (OR, 3.5; P <.001). Among belted drivers, an older driver was nearly 7 times more likely to be killed or hospitalized than a younger driver (OR 6. 9; 95% CI 5.4 to 8.9). CONCLUSION Older drivers do have distinctive motor vehicle crash patterns. Interventions must be taken to reduce the number of left-hand turn crashes involving older drivers. In addition, further research is needed to design, implement, and evaluate countermeasures that may enable older drivers to continue driving while keeping public safety in the forefront.

A population-based study of crashes involving 16- and 17-year-old drivers : The potential benefit of graduated driver licensing restrictions

OBJECTIVES The objective was to evaluate the process of using existing data sources, probabilistic linkage, and multiple imputation to create large population-based injury databases matched to outcomes. METHODS This was a retrospective cohort study of injured children and adults transported by 94 emergency medical systems (EMS) agencies to 122 hospitals in seven regions of the western United States over a 36-month period (2006 to 2008). All injured patients evaluated by EMS personnel within specific geographic catchment areas were included, regardless of field disposition or outcome. The authors performed probabilistic linkage of EMS records to four hospital and postdischarge data sources (emergency department [ED] data, patient discharge data, trauma registries, and vital statistics files) and then handled missing values using multiple imputation. The authors compare and evaluate matched records, match rates (proportion of matches among eligible patients), and injury outcomes within and across sites. RESULTS There were 381,719 injured patients evaluated by EMS personnel in the seven regions. Among transported patients, match rates ranged from 14.9% to 87.5% and were directly affected by the availability of hospital data sources and proportion of missing values for key linkage variables. For vital statistics records (1-year mortality), estimated match rates ranged from 88.0% to 98.7%. Use of multiple imputation (compared to complete case analysis) reduced bias for injury outcomes, although sample size, percentage missing, type of variable, and combined-site versus single-site imputation models all affected the resulting estimates and variance. CONCLUSIONS This project demonstrates the feasibility and describes the process of constructing population-based injury databases across multiple phases of care using existing data sources and commonly available analytic methods. Attention to key linkage variables and decisions for handling missing values can be used to increase match rates between data sources, minimize bias, and preserve sampling design.

The Joint Commission Children’s Asthma Care Quality Measures and Asthma Readmissions

Objective. To evaluate the potential effectiveness of graduated driver licensing programs using population-based linked data for motor vehicle crashes (MVCs) that involved teenaged drivers (TDs). Methods. Utah crash, inpatient hospital discharge, and emergency department databases were analyzed and probabilistically linked. We computed hospital charges and compared violations, contributing factors, seatbelt use, and passengers for TDs (16–17 years old) relative to adult drivers (18–59 years old). Results. TDs comprised 5.8% of the study population, but were involved in 19.0% of MVCs. TD crashes resulted in