The practicality of including the systemic inflammatory response syndrome in the definition of polytrauma: experience of a level one trauma centre

BACKGROUND

The systemic inflammatory response syndrome (SIRS) has been advocated as a significant predictor of outcome in trauma. Recent trauma literature has proposed SIRS as a surrogate for physiological derangements characteristic of polytrauma with some authors recommending its inclusion into the definition of polytrauma. The practicality of daily SIRS collection outside of specifically designed prospective trials is unknown. The purpose of this study was to assess the availability of SIRS variables and its appropriateness for inclusion into a definition of polytrauma. We hypothesised SIRS variables would be readily available and easy to collect, thus represent an appropriate inclusion into the definition of polytrauma.

METHOD

A prospective observational study of all trauma team activation patients over 7-months (August 2009 to February 2010) at a University affiliated level-1 urban trauma centre. SIRS data (temperature>38°C or <36°C; Pulse >90 bpm; RR>20/min or a PaCO(2)<32 mmHg; WCC>12.0×10(9)L(-1), or <4.0×10(9)L(-1), or the presence of >10 immature bands) collected from presentation, at 24 h intervals until 72 h post injury. Inclusion criteria were all patients generating a trauma team activation response age >16.

RESULTS

336 patients met inclusion criteria. In 46% (155/336) serial SIRS scores could not be calculated due to missing data. Lowest rates of missing data observed on admission [3% (11/336)]. Stratified by ISS>15 (132/336), in 7% (9/132) serial SIRS scores could not be calculated due to missing data. In 123 patients ISS>15 with complete data, 81% (100/123) developed SIRS. For Abbreviated Injury Scale (AIS)>2 in at least 2 body regions (64/336) in 5% (3/64) serial SIRS scores could not be calculated, with 92% (56/61) of patients with complete data developing SIRS. For Direct ICU admissions [25% (85/336)] 5% (4/85) of patients could not have serial SIRS calculated [mean ISS 15(±11)] and 90% (73/81) developed SIRS at least once over 72 h.

CONCLUSION

Based on the experience of our level-1 trauma centre, the practicability of including SIRS into the definition of polytrauma as a surrogate for physiological derangement appears questionable even in prospective fashion.

An investigation on the head injuries of adult pedestrians by passenger cars in China

OBJECTIVE

To investigate the relative likelihood of pedestrian head injuries based on person, vehicular, and environmental factors in China.

METHODS

A team was established to collect passenger car-pedestrian accident cases occurring between 2006 and 2011 in Beijing, Shanxi Province, and Chongqing, China. Some key variables for person-, vehicle-, and environment-related factors on head injuries were analyzed using multivariate logistic regression analysis to determine relative risk/likelihood. Pedestrians were classified according to injury outcome and age. Pedestrian head injuries were scored using the Abbreviated Injury Scale (AIS).

RESULTS

A total of 285 vehicle-pedestrian crashes were collected and analyzed: 30 in Beijing, 20 in Shanxi Province, and 235 in Chongqing. The distribution in age and road type by study location differed. The injury outcome, head injury severity, and head contact site were different among 4 age groups. The variables including head contact site and impact speed were the common determinants for head injury severity. A higher pedestrian fatality risk was associated with age over 46, impact speeds over 40 km/h, and higher likelihoods of the victim's head striking the windscreen frame/A pillar and of the victim sustaining a head injury. Similarly, a higher risk of head injury was associated with being female, age over 60, impact speeds over 40 km/h, and a likelihood of the victim's head striking the vehicle rather than the ground. Impact speeds of over 40 km/h and head contact site on windscreen frame/A pillar retained a strong association with severe head injury (AIS 5-6) rate.

CONCLUSIONS

Pedestrian age, vehicle impact speed, and head contact site were common pertinent factors for the risk of pedestrian head injury and the risk of death. Further studies would be valuable to fully characterize vehicle-pedestrian crashes in China and to develop targeted injury prevention strategies based on surveillance results.

A structured autopsy-based audit of 370 firearm fatalities: Contribution to inform policy decisions and the probability of the injured arriving alive at a hospital and receiving definitive care

The objectives of this autopsy-based audit of firearm-related fatalities were to acquire data to inform policy decisions and to assess the probability of the injured arriving alive at a hospital and receiving definitive care.

EVALUATED VARIABLES

Demographics; co-morbidities; location and intention of the injury; toxicology; types of firearms; Abbreviated Injury Scale; Injury Severity Score (ISS); transfer means and time; and location of death.

RESULTS

Of a total of 370 fatalities, 85.7% were male. The median age was 38 (9-95) years. Suicides (47%) and assaults (45.1%) were the most common underlying intentions. The most seriously injured regions were the head (44.5%), thorax (25.7%), abdomen (10.7%), and spine (5.7%). Of the 370 total subjects, 4.9% had an ISS<16 and 59.5% had an ISS≤74; both groups were classified as potentially preventable deaths. The majority (84%) died at the scene, and only 9.8% left the emergency department alive for further treatment. Multivariate analyses documented that postmortem ISS is an independent factor that predicts the probability of the injured reaching a hospital alive and receiving definitive care. Individuals injured in greater Athens and those most seriously injured in the face, abdomen or spine had significantly greater chances of reaching a hospital alive and receiving definitive care, whereas those injured by a shotgun and the positive toxicology group were significantly less likely to. In conclusion, this study provides data to inform policy decisions, calls for a surveillance network and establishes a baseline for estimating the probability regarding the location of firearm-related deaths.

Real-world injury patterns associated with Hybrid III sternal deflections in frontal crash tests

OBJECTIVE

This study investigated the relationship between the peak sternal deflection measurements recorded by the Hybrid III 50th percentile male anthropometric test device (ATD) in frontal crash tests and injury and fatality outcomes for drivers in field crashes.

METHODS

ATD sternal deflection data were obtained from the Insurance Institute for Highway Safety's 64 km/h, 40 percent overlap crashworthiness evaluation tests for vehicles with seat belt crash tensioners, load limiters, and good-rated structure. The National Automotive Sampling System Crashworthiness Data System (NASS-CDS) was queried for frontal crashes of these vehicles in which the driver was restrained by a seat belt and air bag. Injury probability curves were calculated by frontal crash type using the injuries coded in NASS-CDS and peak ATD sternal deflection data. Fatality Analysis Reporting System (FARS) front-to-front crashes with exactly one driver death were also studied to determine whether the difference in measured sternal deflections for the 2 vehicles was related to the odds of fatality.

RESULTS

For center impacts, moderate overlaps, and large overlaps in NASS-CDS, the probability of the driver sustaining an Abbreviated Injury Scale (AIS) score ≥ 3 thoracic injury, or any nonextremity AIS ≥ 3 injury, increased with increasing ATD sternal deflection measured in crash tests. For small overlaps, however, these probabilities decreased with increasing deflection. For FARS crashes, the fatally injured driver more often was in the vehicle with the lower measured deflection in crash tests (55 vs. 45%). After controlling for other factors, a 5-mm difference in measured sternal deflections between the 2 vehicles was associated with a fatality odds ratio of 0.762 for the driver in the vehicle with the greater deflection (95% confidence interval = 0.373, 1.449).

CONCLUSIONS

Restraint systems that reduce peak Hybrid III sternal deflection in a moderate overlap crash test are beneficial in real-world crashes with similar or greater overlap but likely have a disbenefit in crashes with small overlap. This may occur because belt-force limiters employed to control deflections allow excursion that could produce contact with interior vehicle components in small overlaps, given the more oblique occupant motion and potential inboard movement of the air bag. Although based on a limited number of cases, this interpretation is supported by differences in skeletal fracture locations among drivers in crashes with different overlaps. Current restraint systems could be improved by designs that reduce sternal deflection in moderate and large overlap crashes without increasing occupant excursion in small overlap crashes.

The association between knee airbag deployment and knee-thigh-hip fracture injury risk in motor vehicle collisions: A matched cohort study

INTRODUCTION

In the U.S. alone, an estimated 30,000 knee-thigh-hip (KTH) injuries occur annually in frontal motor vehicle collisions. These fractures typically occur through occupant contact with the vehicle's knee bolster. Research has suggested that knee airbags (KABs) can mitigate the forces sustained during this contact, resulting in decreased injury risk; however, previous research has been limited by small sample sizes or by occurring in a controlled setting. The objective of the current study is to determine the effectiveness of KABs on KTH fracture risk using nationally representative, real-world data.

METHODS

Using combined data from the Crash Injury Research and Engineering Network and the National Automotive Sampling Survey, a matched cohort study was conducted among front-seat occupants of vehicles involved in a frontal collision occurring from 2000 to 2009. Occupants exposed to a KAB deployment were matched to occupants with no KAB deployment based on age ±5 years, sex, seatbelt use, vehicle seating position (i.e., driver or front passenger), car vehicle body type, collision impact, and sampling weight. A Cox proportional hazards model was used to calculate risk ratios (RRs) and associated 95% confidence intervals (95% CI) to estimate the association between KAB deployment and lower extremity fracture risk.

RESULTS

There was no association between KAB deployment and risk of lower extremity fracture (RR 0.83, 95% CI 0.52-1.31). A notable pattern in fracture risk, though not statistically significant, was observed, with a decreased risk of hip (RR 0.72, 95% CI 0.26-1.97) and thigh fracture (RR 0.81, 95% CI 0.32-2.05), and an increased risk of tibia/fibula (RR 1.23, 95% CI 0.52-2.90) and foot fracture (RR 1.96, 95% CI 0.72-5.32).

CONCLUSIONS

The results of the current study suggest that KABs are not associated with the risk of lower extremity fractures. However, given the small sample size of the current study, it is difficult to definitively say whether the observed injury pattern is representative of the true pattern.

African American race, obesity, and blood product transfusion are risk factors for acute kidney injury in critically ill trauma patients

PURPOSE

Acute kidney injury (AKI) is a common source of morbidity after trauma. We sought to determine novel risk factors for AKI, by Acute Kidney Injury Network (AKIN) criteria, in critically ill trauma patients.

MATERIALS AND METHODS

A prospective cohort of 400 patients admitted to the intensive care unit of a level 1 trauma center was followed for the development of AKI over 5 days.

RESULTS

Acute kidney injury developed in 147 (36.8%) of 400 patients. In multivariable regression analysis, independent risk factors for AKI included African American race (odds ratio [OR], 1.86; 95% confidence interval [CI], 1.08-3.18; P = .024), body mass index of 30 kg/m(2) or greater (OR, 4.72 versus normal body mass index; 95% CI, 2.59-8.61; P < .001), diabetes mellitus (OR, 3.26; 95% CI, 1.30-8.20; P = .012), abdominal Abbreviated Injury Scale score of 4 or more (OR, 3.78; 95% CI, 1.79-7.96; P < .001), and unmatched packed red blood cells administered during resuscitation (OR, 1.13 per unit; 95% CI, 1.04-1.23; P = .004). Acute Kidney Injury Network stages 1, 2, and 3 were associated with hospital mortality rates of 9.8%, 13.7%, and 30.4%, respectively, compared with 3.8% for those without AKI (P < .001).

CONCLUSIONS

Acute kidney injury in critically ill trauma patients is associated with substantial mortality. The findings of African American race, obesity, and blood product administration as independent risk factors for AKI deserve further study to elucidate underlying mechanisms.

Impact direction effect on serious-to-fatal injuries among drivers in near-side collisions according to impact location: focus on thoracic injuries

Occupant injury in real world vehicle accidents can be significantly affected by a set of crash characteristics, of which impact direction and impact location (or damage location) in general scale interval (e.g., frontal impact is frequently defined as general damage to vehicle frontal end with impact angle range of 11-1 o'clock) have been identified to associate with injury outcome. The effects of crash configuration in more specific scale of interval on the injury characteristics have not been adequately investigated. This paper presents a statistical analysis to investigate the combined effects of specific impact directions and impact locations on the serious-to-fatal injuries of driver occupants involved in near-side collisions using crash data from National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) for the calendar years of 1995-2005. The screened injury dataset is categorized by three impact locations (side front, side center and side distributed) and two impact directions (oblique impact at 10 o'clock and pure lateral impact at 9 o'clock), resulting in six crash configurations in total. The weighted counts and the risks of different types of injuries in each subgroup are calculated, with which the relative risks along with 95% confidence intervals under oblique impacts versus lateral impacts in each impact location category are computed. Accordingly, the most frequent injury patterns, the risks and the coded-sources of serious thoracic injuries in different crash configurations are identified. The approach adopted in the present study provides new perspectives into occupant injury outcomes and associated mechanism. Results of the analyses reveal the importance of consideration of the crash configurations beyond the scope of existing side-impact regulatory tests and stress the necessity of vehicle crashworthiness and restraint system design in omni-direction to better protect occupants in real-world crash scenarios.

Thin chest wall is an independent risk factor for the development of pneumothorax after chest tube removal

The factors contributing to the development of pneumothorax after removal of chest tube thoracostomy are not fully understood. We hypothesized that development of post pull pneumothorax (PPP) after chest tube removal would be significantly lower in those patients with thicker chest walls, due to the "protective" layer of adipose tissue. All patients on our trauma service who underwent chest tube thoracostomy from July 2010 to February 2011 were retrospectively reviewed. Patient age, mechanism of trauma, and chest Abbreviated Injury Scale score were analyzed. Thoracic CTs were reviewed to ascertain chest wall thickness (CW). Thickness was measured at the level of the nipple at the midaxillary line, as perpendicular distance between skin and pleural cavity. Chest X-ray reports from immediately prior and after chest tube removal were reviewed for interval development of PPP. Data are presented as average ± standard deviation. Ninety-one chest tubes were inserted into 81 patients. Patients who died before chest tube removal (n = 11), or those without thoracic CT scans (n = 13) were excluded. PPP occurred in 29.9 per cent of chest tube removals (20/67). When PPP was encountered, repeat chest tube was necessary in 20 per cent of cases (4/20). After univariate analysis, younger age, penetrating mechanism, and thin chest wall were found to be significant risk factors for development of PPP. Chest Abbreviated Injury Scale score was similar in both groups. Logistic regression showed only chest wall thickness to be an independent risk factor for development of PPP.

Comparison of risk factors for cervical spine, head, serious, and fatal injury in rollover crashes

Previous epidemiological studies of rollover crashes have focused primarily on serious and fatal injuries in general, while rollover crash testing has focused almost exclusively on cervical spine injury. The purpose of this study was to examine and compare the risk factors for cervical spine, head, serious, and fatal injury in real world rollover crashes. Rollover crashes from 1995-2008 in the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) were investigated. A large data set of 6015 raw cases (2.5 million weighted) was generated. Nonparametric univariate analyses, univariate logistic regression, and multivariate logistic regression were conducted. Complete or partial ejection, a lack of seatbelt use, a greater number of roof inversions, and older occupant age significantly increased the risk of all types of injuries studied (p<0.05). Far side seating position increased the risk of fatal, head, and cervical spine injury (p<0.05), but not serious injury in general. Higher BMI was associated with an increased risk of fatal, serious, and cervical spine injury (p<0.05), but not head injury. Greater roof crush was associated with a higher rate of fatal and cervical spine injury (p<0.05). Vehicle type, occupant height, and occupant gender had inconsistent and generally non-significant effects on injury. This study demonstrates both common and unique risk factors for different types of injuries in rollover crashes.

A field evaluation of real-life motor vehicle accidents: presence of unrestrained objects and their association with distribution and severity of patient injuries

Moving objects may pose an added threat to car occupants in motor vehicle accidents (MVAs). However, to our knowledge, there have only been two case studies published on the subject. For the present study, accident reports and photo documentation from MVAs were collected on-scene by dedicated paramedics. Emergency medical service personnel on-scene were interviewed as necessary. Potentially harmful unrestrained objects in the involved motor vehicles (MVs) were identified and categorised by type, weight and hardness. Seatback offset by unrestrained objects was noted. The patient injury distribution (Abbreviated Injury Scale (AIS) body regions) and severity (AIS severity scores and New Injury Severity Score (NISS) scores) were retrospectively determined from hospital and autopsy records, and their potential relationship to unrestrained objects was explored. A total of 190 accidents involving 338 MVs and 618 individuals were included. In total, 327 individuals (53%) were injured, and 61 (10%) died. 37 of 61 were not autopsied. The mean NISS was 17 (median 8, interquartile range (IQR) 1-27). Unrestrained objects were reported for 133 motor vehicles (39%) involving 293 individuals. 35% of the unrestrained objects found in the passenger compartment weighed >2 kg. In the boot, 32% of objects weighed >20 kg. Seatback offset associated with unrestrained objects was found for 45 individuals (15%). Unrestrained objects originally located in the boot (heavy luggage, groceries and tyres were the most frequently reported) had moved into the passenger compartment on impact in 27 cases, 24 of which were associated with seatback offset. An in-depth analysis was performed on 24 patients whose injuries were highly likely to be associated with unrestrained objects, as indicated by accident reports and medical documentation. Nineteen (79%) were involved in frontal collisions, and 12 (50%) died on-scene. The mean NISS was 51.7 (median 51, IQR 27-75) in the 17 (71%) patients with seatback offset and 37.2 (median 41, IQR 22.5-50) in the 7 (29%) without seatback offset. Seatback offset was associated with more severe head and thoracic injuries and an increased incidence of abdominal and pelvic injuries. Patients injured by unrestrained objects while sitting in unharmed car seats predominantly suffered head, cervical spine and thoracic injuries. Our results indicate a need for public information campaigns. The development of car backseats that can better sustain hits from heavy objects in the cargo boot is an important area for the motor vehicle production industry to explore.

Overcoming barriers to population-based injury research: development and validation of an ICD10-to-AIS algorithm

BACKGROUND

Hospital administrative databases are a useful source of population-level data on injured patients; however, these databases use the International Classification of Diseases (ICD) system, which does not provide a direct means of estimating injury severity. We created and validated a crosswalk to derive Abbreviated Injury Scale (AIS) scores from injury-related diagnostic codes in the tenth revision of the ICD (ICD-10).

METHODS

We assessed the validity of the crosswalk using data from the Ontario Trauma Registry Comprehensive Data Set (OTRCDS). The AIS and Injury Severity Scores (ISS) derived using the algorithm were compared with those assigned by expert abstractors. We evaluated the ability of the algorithm to identify patients with AIS scores of 3 or greater. We used κ and intraclass correlation coefficients (ICC) as measures of concordance.

RESULTS

In total, 10 431 patients were identified in the OTRCDS. The algorithm accurately identified patients with at least 1 AIS score of 3 or greater (κ 0.65), as well as patients with a head AIS score of 3 or greater (κ 0.78). Mapped and abstracted ISS were similar; ICC across the entire cohort was 0.83 (95% confidence interval 0.81-0.84), indicating good agreement. When comparing mapped and abstracted ISS, the difference between scores was 10 or less in 87% of patients. Concordance between mapped and abstracted ISS was similar across strata of age, mechanism of injury and mortality.

CONCLUSION

Our ICD-10-to-AIS algorithm produces reliable estimates of injury severity from data available in administrative databases. This algorithm can facilitate the use of administrative data for population-based injury research in jurisdictions using ICD-10.

Front-to-rear crashes involving two vehicles with severe driver injury

PURPOSE

This study investigates the risk for severe-to-fatal injury (Maximum Abbreviated Injury Scale [MAIS] 4+F) to drivers in two-vehicle crashes involving front impacts into the rear of another vehicle.

METHODS

1995-2009 National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) was analyzed for driver injuries in front-to-rear crashes without rear occupants in either vehicle. The study involved 13+-year-old front outboard occupants in model year (MY) 1995+ light vehicles. Injury severity was subdivided into MAIS 0+6 and MAIS 4+F to assess the risk of severe-to-fatal injury (MAIS 4+F/MAIS 0+6). Injury risks were determined using weighted data for the drivers by impact type. Standard errors were calculated in SAS to determine ±95 percent confidence intervals. An in-depth analysis was made of individual cases with severely injured drivers in the front and rear impacts.

RESULTS

There were 215,163 drivers in the 15 years of NASS-CDS with known injuries in front-to-rear two-vehicle collisions; 624 were severely injured (MAIS 4+F) in the rear impacts and 124 in the front impacts. The risk for severe-to-fatal driver injury was 0.290 ± 0.241 percent in rear impacts and 0.058 ± 0.057 percent in front impacts. The difference was not statistically significant (P > .05). There were 13 unweighted cases with MAIS 4+F driver injury in rear impacts. Most (77%) involved intrusion in the vicinity of the driver's seating area with the seat supported upright or deformed forward. There were 5 unweighted cases with severely injured drivers in frontal impacts. Three (60%) involved intrusion due to offset frontal loading. There was only one crash where both drivers were severely injured.

CONCLUSIONS

In front-to-rear crashes with two vehicles, typically one driver was severely injured, not both. The risk of severe injury was not significantly different for drivers in the front or rear impacts. The risk was higher in rear impacts due to intrusion into the driver's seating area that supported or pushed the driver's seat forward. The risk for drivers in frontal crashes was also often related to intrusion due to offset loading and occupant compartment deformation.

Pressure-based abdominal injury criteria using isolated liver and full-body post-mortem human subject impact tests

Liver trauma research suggests that rapidly increasing internal pressure plays a role in liver injury. Previous work has shown a correlation between pressure and liver injury in pressurized ex vivo human livers when subjected to blunt impacts. The purpose of this study was to extend the investigation of this relationship between pressure and liver injury by testing full-body post-mortem human surrogates (PMHS). Pressure-related variables were compared with one another and also to previously proposed biomechanical predictors of abdominal injury. Ten PMHS were tested. The abdominal vessels were pressurized to physiological levels using saline, and a pneumatic ram impacted the right side of the specimen ribcage at a nominal velocity of 7.0 m/s. Specimens were subjected to either lateral (n = 5) or oblique (n = 5) impacts, and the impact- induced pressures were measured by transducers inserted into the hepatic veins and inferior vena cava. The liver injuries observed were similar to those documented in the Crash Injury Research Engineering Network (CIREN) trauma database. Using binary logistic regression to develop injury risk functions, it was determined the peak rate of pressure change (Ṗmax) was a statistically significant predictor of AIS ≥ 3 liver injury for both the PMHS and ex vivo testing. This suggests that Ṗmax is a good predictor of liver injury regardless of the impact boundary conditions.

Response of PMHS to high- and low-speed oblique and lateral pneumatic ram impacts

In ISO Technical Report 9790 (1999) normalized lateral and oblique thoracic force-time responses of PMHS subjected to blunt pendulum impacts at 4.3 m/s were deemed sufficiently similar to be grouped together in a single biomechanical response corridor. Shaw et al. (2006) presented results of paired oblique and lateral thoracic pneumatic ram impact tests to opposite sides of seven PMHS at sub-injurious speed (2.5 m/s). Normalized responses showed that oblique impacts resulted in more deflection and less force, whereas lateral impacts resulted in less deflection and more force. This study presents results of oblique and lateral thoracic impacts to PMHS at higher speeds (4.5 and 5.5 m/s) to assess whether lateral relative to oblique responses are different as observed by Shaw et al. or similar as observed by ISO. Twelve PMHS were impacted by a 23 kg pneumatic ram with a 152.4 mmx304.8 mm rectangular face plate at the level of the xyphoid process in either the pure lateral or 30° anterior-to-lateral oblique direction. Because these tests were potentially injurious, only one test per subject was conducted. Normalized responses demonstrate similar characteristics for both lateral and oblique impacts, indicating that it may be reasonable to combine lateral and oblique responses together at these higher speeds to define characteristic PMHS response as was done by ISO. The small number of tests conducted indicates that less chest compression may be required to obtain serious thoracic injury in oblique impacts as compared to lateral impacts at speeds of 4.5 or 5.5 m/s.

Is the TMPM-ICD9 revolution in trauma risk-adjustment compatible with imperfect administrative coding?

BACKGROUND

TMPM-ICD9 is the latest injury-severity measure based on empirical estimation from ICD-9-CM codes. It is candidate to replace expert-based AIS measures worldwide because of easier accessibility and better predictive performances. In Italy and other countries administrative ICD coding is generally less complete than dedicated AIS coding. We attempted to ascertain how this affects TMPM performances.

METHODS

Discrimination (c statistics) and calibration (calibration curves, Akaike's criterion) of hierarchical logistic regression models for hospital mortality comprising TMPM or ISS were compared using trauma-registry data on 3570 patients of years 2007-2009. The completeness of AIS vs. ICD-9-CM coding was also investigated through the ratio of the respective numbers of codes per patient. Model discrimination was further analyzed after stratification according to the above ratio (>1 and ≤ 1).

RESULTS

The models with TMPM showed worse performances. The differences, concerned calibration (graphical evidence) in univariate models and discrimination (-1.2% of area under the ROC curve, p<0.05) in models completed with age, gender, mechanism of injury, motor GCS and systolic pressure. In parallel, ICD coding was less complete than AIS, as expected: 68% of patients had a ratio >1. The discrimination of TMPM vs. ISS models improved when the ratio changed from >1 to ≤ 1.

CONCLUSIONS

The predictive performances of TMPM-ICD9 vs. ISS were lower than in the previous studies; the sub-optimal quality of ICD coding was a main cause. Imperfect administrative coding may hence hamper the TMPM-ICD9 revolution, although in our setting the negligible differences and the ready availability of administrative data may still give reason for adopting TMPM-ICD9.

Changing to AIS 2005 and agreement of injury severity scores in a trauma registry with scores based on manual chart review

BACKGROUND

The Abbreviated Injury Scale (AIS) recently underwent a major revision from AIS 98 to AIS 05. AIS injury codes form the basis of widely used injury severity scores such as the injury severity score (ISS). ISS thresholds are often used in trauma case definitions and ISS is widely used in injury research to adjust for injury severity. This study evaluated changes from AIS 98 to AIS 05, the changes' effect on ISS distributions, and presents an application of the results.

METHODS

Injury descriptions from medical records of 137 randomly selected patients in the Oklahoma Trauma Registry (OTR) were obtained. A single trained coder used AIS 98 and AIS 05 to code each injury. ISS values were calculated and grouped into 4 categories: 1-8, 9-14, 16-24, >24. Paired ISS was compared using Kappa statistics and tests of symmetry. We identified common injury diagnoses for which AIS severity changed between versions. Estimates of the proportion of patients changing ISS groups were applied to the entire OTR to assess the impact on reporting and on a model for reimbursement.

RESULTS

OTR AIS 98 and manual AIS 98-based ISS values had a weighted Kappa of 0.71. OTR AIS 98 and manual AIS 05-based ISS values had a Kappa of 0.58. Manual AIS 98 and manual AIS 05 ISS had the highest Kappa of 0.81, however, though the scores differed by only 1 ISS category, there were 30 discordant pairs. The distribution of these discordant pairs was not symmetrical (Bowker's S=30; df=6; p<0.0001) with AIS 05-based ISS values consistently shifted to a lower ISS category. Reductions in AIS severity and ISS values using AIS 05 were common for extremity fractures and thorax injuries. The results suggest fewer patients would be reported to the OTR or be eligible for reimbursement.

DISCUSSION

Changing from AIS 98 to AIS 05 injury coding resulted in systematic changes in AIS codes and ISS. Specific injuries and body regions were differentially affected. Trauma registries and injury researchers that use AIS based injury coding can use this information to evaluate the potential impact of changes in AIS 2005.

Pedestrian injury analysis with consideration of the selectivity bias in linked police-hospital data

Evaluation of crash-related injuries by medical specialists in hospitals is believed to be more exact than rather a cursory evaluation made at the crash scene. Safety analysts sometimes reach for hospital data and use them in combination with the police crash data. One issue that needs to be addressed is the, so-called, selectivity (or selection) bias possible when data used in analysis are not coming from random sampling. If not properly addressed, this issue can lead to a considerable bias in both the model coefficient estimates and the model predictions. This paper investigates pedestrian injury severity factors using linked police-hospital data. A bivariate ordered probit model with sample selection is used to check for the presence of the selectivity bias and to account for it in the MAIS estimates on the Maximum Abbreviated Injury Scale (MAIS). The presence of the sample selection issue has been confirmed. The selectivity bias is considerable in predictions of low injury levels. The pedestrian injury analysis identified and estimated several severity factors, including pedestrian, road, and vehicle characteristics. Male and older pedestrians were found to be particularly exposed to severe injuries. Rural roads and high-speed urban roads appear to be more dangerous for pedestrians, particularly when crossing such roads. Crossing a road between intersections was found to be particularly dangerous behavior. The size and weight of the vehicle involved in a pedestrian crash were also found to have an effect on the pedestrian injury level. The relevant safety countermeasures that may improve pedestrian safety have been proposed.

Assessing the use of venous thromboembolism risk assessment profiles in the trauma population: is it necessary?

Deep venous thrombosis (DVT) and the subsequent development of venous thromboembolism (VTE) are a significant cause of mortality, morbidity, and cost of care in trauma patients. This study aims to: 1) validate 5 as a critical threshold for high risk; 2) validate risk factors associated with DVT/VTE development; 3) evaluate exogenous estrogen and smoking as risk factors; and 4) analyze daily risk assessment profile (RAP) score changes. We performed a retrospective chart review of trauma patients admitted from January 2001 through December 2005. Univariate odds ratios were performed to assess potential risk factors for VTE. Of the 110 charts reviewed, 31 patients had confirmed DVT/VTE. Three of 26 patients with an RAP score < 5 suffered a VTE; one resulted in death. Significant risk factors included femoral venous line insertion, operation longer than 2 hours, head abbreviated injury score > 2, and Glasgow Coma Scale score < 8. RAP fluctuations were due to a changing Glasgow Coma Scale score, and whether the patient received more than four transfusions, was in surgery for more than 2 hours, or required a femoral venous catheter or major venous repair. The RAP critical value (5) was not validated. We recommend all trauma patients be treated with prophylactic anticoagulants throughout the hospital stay unless clear contraindications exist.

Development and validation of a complementary map to enhance the existing 1998 to 2008 Abbreviated Injury Scale map

INTRODUCTION

Many trauma registries have used the Abbreviated Injury Scale 1990 Revision Update 98 (AIS98) to classify injuries. In the current AIS version (Abbreviated Injury Scale 2005 Update 2008 - AIS08), injury classification and specificity differ substantially from AIS98, and the mapping tools provided in the AIS08 dictionary are incomplete. As a result, data from different AIS versions cannot currently be compared. The aim of this study was to develop an additional AIS98 to AIS08 mapping tool to complement the current AIS dictionary map, and then to evaluate the completed map (produced by combining these two maps) using double-coded data. The value of additional information provided by free text descriptions accompanying assigned codes was also assessed.

METHODS

Using a modified Delphi process, a panel of expert AIS coders established plausible AIS08 equivalents for the 153 AIS98 codes which currently have no AIS08 map. A series of major trauma patients whose injuries had been double-coded in AIS98 and AIS08 was used to assess the maps; both of the AIS datasets had already been mapped to another AIS version using the AIS dictionary maps. Following application of the completed (enhanced) map with or without free text evaluation, up to six AIS codes were available for each injury. Datasets were assessed for agreement in injury severity measures, and the relative performances of the maps in accurately describing the trauma population were evaluated.

RESULTS

The double-coded injuries sustained by 109 patients were used to assess the maps. For data conversion from AIS98, both the enhanced map and the enhanced map with free text description resulted in higher levels of accuracy and agreement with directly coded AIS08 data than the currently available dictionary map. Paired comparisons demonstrated significant differences between direct coding and the dictionary maps, but not with either of the enhanced maps.

CONCLUSIONS

The newly-developed AIS98 to AIS08 complementary map enabled transformation of the trauma population description given by AIS98 into an AIS08 estimate which was statistically indistinguishable from directly coded AIS08 data. It is recommended that the enhanced map should be adopted for dataset conversion, using free text descriptions if available.

Incidence rate and risk factors of missed injuries in major trauma patients

This study was designed to determine the incidence rate and risk factors of missed injuries in major trauma patients in the emergency department (ED). Hospital records of all 976 trauma patients visiting the ED and admitted to intensive care units (ICUs) of a medical center in Taiwan from 2006 to 2007 were reviewed. Missed injuries were defined as those not identified in the ED but recognized later in the ICUs. Clinically significant injuries were those with an Abbreviated Injury Scale of ≥ 2. In the 2-year period, there were 133 missed injuries in 118 patients in the ED, for a prevalence of 12.1%; 87 injuries were clinically significant in 78 patients, for a prevalence of 8.0%. The estimated incidence rate per 100 person-hours was 3.2 for missed injuries and 2.1 for clinically significant missed injuries. The most commonly involved body region of missed injuries was the head/neck, followed by the chest and extremities. Results of a Cox regression analysis showed that a younger age, more-severe injury, polytrauma, and the absence of soft-tissue injuries were significantly associated with missed injuries, while younger ages, more-severe injuries, and the presence of chest and pelvic injuries were also significantly associated with clinically significant missed injuries. In conclusion, a considerable number of injuries, particularly to the head/neck, may be undetected in the ED, while young people and patients with certain injury patterns such as severity levels, polytrauma, and the presence of a chest or pelvic injury are more likely to have missed injuries and/or clinically significant missed injuries.

A clinical prediction rule for ambulation outcomes after traumatic spinal cord injury: a longitudinal cohort study

BACKGROUND

Traumatic spinal cord injury is a serious disorder in which early prediction of ambulation is important to counsel patients and to plan rehabilitation. We developed a reliable, validated prediction rule to assess a patient's chances of walking independently after such injury.

METHODS

We undertook a longitudinal cohort study of adult patients with traumatic spinal cord injury, with early (within the first 15 days after injury) and late (1-year follow-up) clinical examinations, who were admitted to one of 19 European centres between July, 2001, and June, 2008. A clinical prediction rule based on age and neurological variables was derived from the international standards for neurological classification of spinal cord injury with a multivariate logistic regression model. Primary outcome measure 1 year after injury was independent indoor walking based on the Spinal Cord Independence Measure. Model performances were quantified with respect to discrimination (area under receiver-operating-characteristics curve [AUC]). Temporal validation was done in a second group of patients from July, 2008, to December, 2009.

FINDINGS

Of 1442 patients with spinal cord injury, 492 had available outcome measures. A combination of age (<65 vs ≥65 years), motor scores of the quadriceps femoris (L3), gastrocsoleus (S1) muscles, and light touch sensation of dermatomes L3 and S1 showed excellent discrimination in distinguishing independent walkers from dependent walkers and non-walkers (AUC 0·956, 95% CI 0·936-0·976, p<0·0001). Temporal validation in 99 patients confirmed excellent discriminating ability of the prediction rule (AUC 0·967, 0·939-0·995, p<0·0001).

INTERPRETATION

Our prediction rule, including age and four neurological tests, can give an early prognosis of an individual's ability to walk after traumatic spinal cord injury, which can be used to set rehabilitation goals and might improve the ability to stratify patients in interventional trials.

FUNDING

Internationale Stiftung für Forschung in Paraplegie.

Assessment of the effects and limitations of the 1998 to 2008 Abbreviated Injury Scale map using a large population-based dataset

BACKGROUND

Trauma systems should consistently monitor a given trauma population over a period of time. The Abbreviated Injury Scale (AIS) and derived scores such as the Injury Severity Score (ISS) are commonly used to quantify injury severities in trauma registries. To reflect contemporary trauma management and treatment, the most recent version of the AIS (AIS08) contains many codes which differ in severity from their equivalents in the earlier 1998 version (AIS98). Consequently, the adoption of AIS08 may impede comparisons between data coded using different AIS versions. It may also affect the number of patients classified as major trauma.

METHODS

The entire AIS98-coded injury dataset of a large population based trauma registry was retrieved and mapped to AIS08 using the currently available AIS98-AIS08 dictionary map. The percentage of codes which had increased or decreased in severity, or could not be mapped, was examined in conjunction with the effect of these changes to the calculated ISS. The potential for free text information accompanying AIS coding to improve the quality of AIS mapping was explored.

RESULTS

A total of 128280 AIS98-coded injuries were evaluated in 32134 patients, 15471 patients of whom were classified as major trauma. Although only 4.5% of dictionary codes decreased in severity from AIS98 to AIS08, this represented almost 13% of injuries in the registry. In 4.9% of patients, no injuries could be mapped. ISS was potentially unreliable in one-third of patients, as they had at least one AIS98 code which could not be mapped. Using AIS08, the number of patients classified as major trauma decreased by between 17.3% and 30.3%. Evaluation of free text descriptions for some injuries demonstrated the potential to improve mapping between AIS versions.

CONCLUSIONS

Converting AIS98-coded data to AIS08 results in a significant decrease in the number of patients classified as major trauma. Many AIS98 codes are missing from the existing AIS map, and across a trauma population the AIS08 dataset estimates which it produces are of insufficient quality to be used in practice. However, it may be possible to improve AIS98 to AIS08 mapping to the point where it is useful to established registries.

Pediatric short-distance household falls: biomechanics and associated injury severity

OBJECTIVES

Short-distance household falls are a common occurrence in young children, but are also a common false history given by caretakers to conceal abusive trauma. The purpose of this study was to determine the severity of injuries that result from accidental short-distance household falls in children, and to investigate the association of fall environment and biomechanical measures with injury outcomes.

METHODS

Children aged 0-4 years who presented to the Emergency Department with a history of a short furniture fall were included in the study. Detailed case-based biomechanical assessments were performed using data collected through medical records, interviews, and fall scene investigations. Injuries were rated using the Abbreviated Injury Scale (AIS). Each case was reviewed by a child abuse expert; cases with a vague or inconsistent history and cases being actively investigated for child abuse were excluded.

RESULTS

79 subjects were enrolled in the study; 15 had no injuries, 45 had minor (AIS 1) injuries, 17 had moderate (AIS 2) injuries, and 2 had serious (AIS 3) injuries. No subjects had injuries classified as AIS 4 or higher, and there were no fatalities. Children with moderate or serious injuries resulting from a short-distance household fall tended to have fallen from greater heights, have greater impact velocities, and have a lower body mass index than those with minor or no injuries.

CONCLUSION

Children aged 0-4 years involved in a short-distance household fall did not sustain severe or life-threatening injuries, and no children in this study had moderate or serious injuries to multiple body regions. Biomechanical measures were found to be associated with injury severity outcomes in short-distance household falls. Knowledge of relationships between biomechanical measures and injury outcomes can aid clinicians when assessing whether a child's injuries were the result of a short-distance fall or some other cause.

Pattern of animal-related injuries in Iran

Animal related injuries as most common causes of human morbidity have different pattern by geographical zones. We aimed to explore the main descriptive epidemiology of animal-related injuries in both rural and urban areas in Iran. Between 2000 and 2004, we collected the data of all the cases of animal related trauma hospitalized for more than 24 hours in eight cities (Tehran, Mashhad, Ahwaz, Shiraz, Tabriz, Qom, Kermanshah, and Babol). Further evaluations were conducted on 17753 eligible subjects. Of 17753 traumatic patients, 40 subjects (0.2%), had animal-related injuries. The highest rate was seen in Tabriz with 11 cases. Upper and lower extremities were the most frequent sites of trauma and they were injured in 13 and 11 cases respectively. Dog bite and cow-related injuries were responsible for 40% and 32.5% of injuries respectively. Amputation of the phalanx was done in 2 cases due to dog bite and bull gore occurred. One thoracotomy, one laparatomy and one craniotomy were done. One patient needed fasciatomy due to snake bite. Educating the patients could decrease the incidence of morbidity of these injuries.