Reassessment of the tri-modal mortality distribution in the presence of a regional trauma system

The Effect of Trauma Care on the Temporal Distribution of Homicide Mortality in Jefferson County, Alabama

The distribution of time from acute traumatic injury to death has three peaks: immediate (less than or equal to one hour), early (6 to 24 hours), and late (days to weeks). It has been suggested that coordinated trauma care dampens the late peak; however, this research may be more reflective of unintentional than intentional deaths. This study examines whether a coordinated trauma system (TS) alters the temporal distribution for assault-related deaths. Data were obtained from homicides examined by the Jefferson County Coroner's/Medical Examiner's Office from 1987 to 2008. Homicides were categorized—based on year of death—as occurring in the presence of no TS, during TS implementation, in the early years of the TS, or in a mature TS. The temporal distribution of homicide mortality was compared among TS categories using a χ2 test. A Cox Markov multistate model was used to estimate proportional changes in the temporal distribution of death adjusted for assault mechanism. With a TS, after adjusting for assault mechanism, a lower proportion of homicide victims survived through the first hour (hazard ratio [HR], 0.75; 95% confidence interval [CI], 0.54 to 1.03) and from one to six hours (HR, 0.68; 95% CI, 0.49 to 0.96). Additionally, the presence of a TS was associated with a proportional decrease in deaths after 24 hours ( P = 0.0005). These results suggest that a trauma system is effective in preventing late homicide deaths; however, other means of preventing death (such as violence prevention programs) are needed to decrease the burden of immediate homicide-related deaths.

Changes in the temporal distribution of in-hospital mortality in severely injured patients-An analysis of the TraumaRegister DGU

Background

The temporal distribution of trauma mortality has been classically described as a trimodal pattern with an immediate, early and late peak. In modern health care systems this time distribution has changed.

Methods

Data from the TraumaRegister DGU was analysed retrospectively. Between 2002 and 2015, all registered in-hospital deaths with an Injury Severity Score (ISS) ≥ 16 were evaluated considering time of death, trauma mechanism, injured body area, age distribution, rates of sepsis and multiple organ failure. Pre-hospital and post-discharge trauma deaths were not considered.

Results

78 310 severely injured patients were registered, non-survivors constituted 14 816, representing an in-hospital mortality rate of 18.9%. Mean ISS of non-survivors was 36.0±16.0, 66.7% were male, mean age was 59.5±23.5. Within the first hour after admission to hospital, 10.8% of deaths occurred, after 6 hours the percentage increased to 25.5%, after 12 hours 40.0%, after 24 hours 53.2% and within the first 48 hours 61.9%. Mortality showed a constant temporal decrease. Severe head injury (defined by Abbreviated Injury Scale, AIS-Head≥3) was found in 76.4% of non-survivors. Patients with an isolated head injury showed a more distinct decrease in survival rate, which was accentuated in the first days after admission. The correlation of age and time of death showed a proportional increase with age (55-74a). The rate of sepsis and multiple organ failure among non-survivors was 11.5% and 70.1%, respectively.

Conclusion

In a modern trauma care system, the mortality distribution of severely injured patients has changed its pattern, where especially the third peak is no longer detectable.

Trauma Early Mortality Prediction Tool (TEMPT) for assessing 28-day mortality

Background

Prior mortality prediction models have incorporated severity of anatomic injury quantified by Abbreviated Injury Severity Score (AIS). Using a prospective cohort, a new score independent of AIS was developed using clinical and laboratory markers present on emergency department presentation to predict 28-day mortality.

Methods

All patients (n=1427) enrolled in an ongoing prospective cohort study were included. Demographic, laboratory, and clinical data were recorded on admission. True random number generator technique divided the cohort into derivation (n=707) and validation groups (n=720). Using Youden indices, threshold values were selected for each potential predictor in the derivation cohort. Logistic regression was used to identify independent predictors. Significant variables were equally weighted to create a new mortality prediction score, the Trauma Early Mortality Prediction Tool (TEMPT) score. Area under the curve (AUC) was tested in the validation group. Pairwise comparison of Trauma Injury Severity Score (TRISS), Revised Trauma Score, Glasgow Coma Scale, and Injury Severity Score were tested against the TEMPT score.

Results

There was no difference between baseline characteristics between derivation and validation groups. In multiple logistic regression, a model with presence of traumatic brain injury, increased age, elevated systolic blood pressure, decreased base excess, prolonged partial thromboplastin time, increased international normalized ratio (INR), and decreased temperature accurately predicted mortality at 28 days (AUC 0.93, 95% CI 0.90 to 0.96, P<0.001). In the validation cohort, this score, termed TEMPT, predicted 28-day mortality with an AUC 0.94 (95% CI 0.92 to 0.97). The TEMPT score preformed similarly to the revised TRISS score for severely injured patients and was highly predictive in those having mild to moderate injury.

Discussion

TEMPT is a simple AIS-independent mortality prediction tool applicable very early following injury. TEMPT provides an AIS-independent score that could be used for early identification of those at risk of doing poorly following even minor injury.

Level of evidence

Level II.

Decomposition analysis of the effects of vehicle safety technologies on the motor vehicle collision-related mortality rate from 1994 to 2015

OBJECTIVE

Though the mortality rate for motor vehicle collisions (MVCs) has been decreasing since the 1960s with the advent of the first federal seat belt laws in 1968, MVC remains a leading cause of death for individuals aged 1 to 44 years. The purpose of this study is to examine the effects of frontal (FABs) and side airbags (SABs) and electronic stability control (ESC) on the components of the MVC mortality rate.

METHODS

The MVC mortality rate from 1994 to 2015 was separated into its components of exposure of vehicles, exposure of travel, collision density, injury incidence, and case fatality rate. Year was categorized on the availability of safety technology in vehicles: 1994-1997 (first-generation FABs mandated), 1998-2001 (sled-certified, second-generation FABs mandated), 2002-2006 (increasing prevalence of SABs and ESC), 2007-2011 (advanced airbags mandated), and 2012-2015 (ESC mandated, SAB in over 90% of vehicles, introduction of advanced safety systems). Relative contributions (RCs) of the components to changes in the MVC-related mortality rate were calculated as the absolute value of the component's beta coefficient divided by the sum of the absolute values of all components' beta coefficients. Negative binomial regression-estimated rate ratios (RRs) for the changes in the rate of each component by year category compared to the prior year category.

RESULTS

Significant decreases in the MVC mortality rate were observed for 2007-2011 and 2012-2015. The decrease in 2007-2011 was due in most part to an 18% decrease in the injury incidence (RR = 0.82, P < .0001, RC = 63%), though there was a noted contribution by the decrease in vehicle miles traveled (RR = 0.95, P < .0001, RC = 15%). The continued decrease in mortality in 2012-2015 was due is most part to the 10% decreased case fatality rate (RR = 0.90, P < .0001, RC = 66%) because there was no significant change in the vehicle miles traveled and injury incidence.

CONCLUSIONS

The results of this study highlight the effects of vehicle safety technologies on the MVC-related mortality rate and can help direct prevention efforts. Through the study period, there was no meaningful contribution to decreases in the MVC-related mortality rate due to components related to exposure (i.e., vehicles per population and the rate of vehicle miles traveled), suggesting that prevention efforts at decreasing exposure prevalence would have little effect on the MVC-related mortality rate. Instead, prevention efforts should continue to focus on event-phase methods to decrease injury occurrence and mitigate injury severity during the collision.

Time-based trauma-related mortality patterns in a newly created trauma system

BACKGROUND

Data on time-based trauma mortality (TTM) patterns in developing countries are lacking.

OBJECTIVE

Our objective was to analyze the TTM in a newly established trauma center.

METHODS

A retrospective analysis of all trauma-related mortality between 2010 and 2012 was conducted in Qatar. Based on the time of injury, deceased cases were categorized into immediate (pre-hospital), early (first 24 h), and late (>24 h) groups. TTM was analyzed and compared.

RESULTS

A total of 4,966 trauma patients were admitted to the trauma center over 3 years; of them, 333 trauma-related deaths (6.8 %) were documented and reviewed. The death pattern peaked immediately post-trauma (n = 142), followed by 96 deaths within the first 24 h, 19 deaths within the time period >24 to 48 h, 50 deaths within the 3rd and 7th day (second peak), and 26 deaths after the 1st week. The majority of the deceased were males, with a mean age of 36 ± 17 years. Motor vehicle crashes (43.5 %) were the commonest mechanism of injury. At presentation, median injury severity score (ISS) was 32 (range 9-75). Bleeding, abdominal, and pelvic injuries were higher in the early group, whereas head injuries were observed more in the late mortality group. Co-morbidities and in-hospital complications were predominantly encountered in the late group. Head injury (odds ratio [OR] 3.760; 95 % confidence interval [CI] 1.311-10.797) was an independent predictor for late death, whereas the need for blood transfusion was a predictor for early death (OR 3.233; 95 % CI 1.125-9.345).

CONCLUSION

The distribution of mortality shows a bimodal pattern. The high rate of death at the scene highlights the importance of pre-hospital care and the need for injury prevention programs.

A Comparison of Invasive Airway Management and Rates of Pneumonia in Prehospital and Hospital Settings

INTRODUCTION

Infection is a major cause of morbidity and mortality in trauma. Infection in trauma is poorly understood. The impact of prehospital invasive airway management (IAM) on the incidence of pneumonia and health services utilization is unknown. We hypothesized that trauma patients exposed to prehospital IAM will suffer higher rates of pneumonia compared to no IAM or exposure to IAM performed in the hospital. We hypothesized that patients who develop pneumonia subsequent to prehospital IAM will have longer intensive care unit (ICU) and hospital length of stay (LOS) compared to patients who acquired pneumonia after IAM performed in the hospital.

METHODS

This is an observational cohort study of data previously collected for the Resuscitation Outcomes Consortium hypertonic resuscitation randomized trial. Patients were included if traumatic injury resulted in shock, traumatic brain injury, or both. Patients were excluded if they died 24 hours after injury, or pneumonia data were missing. Adjusted and unadjusted logistic regression was used to calculate the odds ratio of pneumonia if exposed in the prehospital setting compared to no exposure or exposure in the hospital.

RESULTS

Of 2,222 patients enrolled in the hypertonic resuscitation trial, 1,676 patients met enrollment criteria for this study. Four and a half percent of patients suffered pneumonia. IAM in the prehospital setting resulted in 6.8-fold increase (C.I. 2.0, 23.0, p = 0.003) in the adjusted odds of developing pneumonia compared to not being intubated, while in-hospital intubation resulted in 4.8-fold increase (C.I. 1.4, 16.6, p = 0.01), which was not statistically significantly different to the odds ratio of prehospital IAM. There were no statistically significant increases in health services utilization resulting from pneumonia incurred after IAM.

CONCLUSION

Exposure to IAM in prehospital and hospital settings results in an increase in pneumonia, but there does not appear to be a link between the source of pneumonia and an increase in ICU or hospital LOS.

Detailed description of all deaths in both the shock and traumatic brain injury hypertonic saline trials of the Resuscitation Outcomes Consortium

OBJECTIVE

To identify causes and timing of mortality in trauma patients to determine targets for future studies.

BACKGROUND

In trials conducted by the Resuscitation Outcomes Consortium in patients with traumatic hypovolemic shock (shock) or traumatic brain injury (TBI), hypertonic saline failed to improve survival. Selecting appropriate candidates is challenging.

METHODS

Retrospective review of patients enrolled in multicenter, randomized trials performed from 2006 to 2009. Inclusion criteria were as follows: injured patients, age 15 years or more with hypovolemic shock [systolic blood pressure (SBP) ≤ 70 mm Hg or SBP 71-90 mm Hg with heart rate ≥ 108) or severe TBI [Glasgow Coma Score (GCS) ≤ 8]. Initial fluid administered was 250 mL of either 7.5% saline with 6% dextran 70, 7.5% saline or 0.9% saline.

RESULTS

A total of 2061 subjects were enrolled (809 shock, 1252 TBI) and 571 (27.7%) died. Survivors were younger than nonsurvivors [30 (interquartile range 23) vs 42 (34)] and had a higher GCS, though similar hemodynamics. Most deaths occurred despite ongoing resuscitation. Forty-six percent of deaths in the TBI cohort were within 24 hours, compared with 82% in the shock cohort and 72% in the cohort with both shock and TBI. Median time to death was 29 hours in the TBI cohort, 2 hours in the shock cohort, and 4 hours in patients with both. Sepsis and multiple organ dysfunction accounted for 2% of deaths.

CONCLUSIONS

Most deaths from trauma with shock or TBI occur within 24 hours from hypovolemic shock or TBI. Novel resuscitation strategies should focus on early deaths, though prevention may have a greater impact.

Prehospital response model and time to CT scan in blunt trauma patients; an exploratory analysis of data from the head injury retrieval trial

Background

It has been suggested that prehospital care teams that can provide advanced prehospital interventions may decrease the transit time through the ED to CT scan and subsequent surgery. This study is an exploratory analysis of data from the Head Injury Retrieval Trial (HIRT) examining the relationship between prehospital team type and time intervals during the prehospital and ED phases of management.

Methods

Three prehospital care models were compared; road paramedics, and two physician staffed Helicopter Emergency Medical Services (HEMS) - HIRT HEMS and the Greater Sydney Area (GSA) HEMS. Data on prehospital and ED time intervals for patients who were randomised into the HIRT were extracted from the trial database. Additionally, data on interventions at the scene and in the ED, plus prehospital entrapment rate was also extracted. Subgroups of patients that were not trapped or who were intubated at the scene were also specifically examined.

Results

A total of 3125 incidents were randomised in the trial yielding 505 cases with significant injury that were treated by road paramedics, 302 patients treated by the HIRT HEMS and 45 patients treated by GSA HEMS. The total time from emergency call to CT scan was non-significantly faster in the HIRT HEMS group compared with road paramedics (medians of 1.9 hours vs. 2.1 hours P = 0.43) but the rate of prehospital intubation was 41% higher in the HIRT HEMS group (46.4% vs. 5.3% P < 0.001). Most time intervals for the GSA HEMS were significantly longer with a regression analysis indicating that GSA HEMS scene times were 13 (95% CI, 7–18) minutes longer than the HIRT HEMS independent of injury severity, entrapment or interventions performed on scene.

Conclusion

This study suggests that well-rehearsed and efficient interventions carried out on-scene, by a highly trained physician and paramedic team can allow earlier critical care treatment of severely injured patients without increasing the time elapsed between injury and hospital-based intervention. There is also indication that role specialisation improves time intervals in physician staffed HEMS which should be confirmed with purpose designed trials.

Ultrasoft microgels displaying emergent platelet-like behaviours

Efforts to create platelet-like structures for the augmentation of haemostasis have focused solely on recapitulating aspects of platelet adhesion; more complex platelet behaviours such as clot contraction are assumed to be inaccessible to synthetic systems. Here, we report the creation of fully synthetic platelet-like particles (PLPs) that augment clotting in vitro under physiological flow conditions and achieve wound-triggered haemostasis and decreased bleeding times in vivo in a traumatic injury model. PLPs were synthesized by combining highly deformable microgel particles with molecular-recognition motifs identified through directed evolution. In vitro and in silico analyses demonstrate that PLPs actively collapse fibrin networks, an emergent behaviour that mimics in vivo clot contraction. Mechanistically, clot collapse is intimately linked to the unique deformability and affinity of PLPs for fibrin fibres, as evidenced by dissipative particle dynamics simulations. Our findings should inform the future design of a broader class of dynamic, biosynthetic composite materials.

Traumatic coagulopathy--part 1: Pathophysiology and diagnosis

OBJECTIVE

To review the current literature in reference to the pathophysiology and diagnostic modalities available for acute traumatic coagulopathy (ATC) in relationship to traumatic hemorrhagic shock.

ETIOLOGY

Posttraumatic hemorrhage is responsible for one of the leading causes of preventable human deaths worldwide. Acute traumatic coagulopathy is an endogenous hypocoagulable condition that has been observed during the immediate (< 1 hour) posttraumatic period. Phenotypically, ATC manifests as a state of systemic hypocoagulability and hyperfibrinolysis. Although different functional mechanisms have been proposed for causing ATC, it is universally thought to be a manifestation of severe tissue injury, shock-induced hypoperfusion, systemic inflammation, and endothelial damage. Excessive activation of the thrombin-thrombomodulin activated Protein C pathway, catecholamine-induced endothelial damage as well as disseminated intravascular coagulation (DIC) with a fibrinolytic phenotype are all hypotheses that have been proposed in attempts to explain the functional mechanism of ATC.

DIAGNOSIS

An accurate and reliable test remains to be validated for ATC. Traditional coagulation assays (activated partial thromboplastin times and prothrombin times) along with platelet count and fibrinogen concentrations have been used more commonly. Viscoelastic tests (thromboelastography and rotational thromboelastometry) are currently being investigated as a more predictive modality for identifying and guiding therapy for ATC.

THERAPY

Damage control resuscitation and hemostatic resuscitation are gaining favor as the optimal resuscitative strategies for hemorrhagic shock and ATC. Antifibrinolytics may also play a role when hyperfibrinolysis is present.

PROGNOSIS

Massive hemorrhage accounts for 30-56% of prehospital posttraumatic deaths in people, with coagulopathic hemorrhage remaining one of the major causes of preventable deaths within the first 24 hours posttrauma. Ten to twenty-five percent of human trauma patients experience ATC, which has been shown to prolong hemorrhage, deter resuscitative efforts, promote sepsis, and increase mortality by at least 4-fold. Prognosis in veterinary patients is not currently known.

Do-not-resuscitate orders in trauma patients may bias mortality-based effect estimates: an evaluation using the PROMMTT study

BACKGROUND

The impact of do-not-resuscitate (DNR) orders has not been systematically evaluated in acute trauma research. We determined the frequency, timing, and impact on mortality-based effect estimates for patients with DNR orders in the Prospective Observational Multicenter Major Trauma Transfusion (PROMMTT) study.

METHODS

Trauma patients surviving at least 30 minutes and transfused one or greater unit of red blood cell within 6 hours of admission (n = 1,245) from 10 Level 1 centers were enrolled. We report descriptive statistics and results from survival analysis to compare the association of blood product transfusion ratios with outcome defined as mortality and as a composite, DNR, and death.

RESULTS

DNRs were reported for 95 patients (7.6%), with 94 in-hospital deaths. There were 172 deaths without DNRs. Of 90 known DNR order times, the median was 53 hours (interquartile range, 9-186 hours) after admission; the median DNR-to-death time was 10 hours (2-32 hours). DNRs were for comfort measures only (43%), no cardiopulmonary resuscitation (40%), and no intubation or cardiopulmonary resuscitation (16%). Compared with the 116 non-DNR deaths that occurred after the earliest DNR order (2 hours), the DNR decedents were significantly older with a less severe base deficit, fewer red blood cell and plasma transfusions, and a later median time of death (98 [21-230] hours vs. 17 [4-91] hours). In multivariable Cox models that accounted for time-varying blood product ratios, the associations were consistent, regardless of whether outcome was defined as mortality or the composite.

CONCLUSION

DNR orders were instituted after the 24-hour period of highest mortality risk and more often in older patients not in severe shock. Findings from the primary PROMMTT analyses of the impact of blood product ratios on survival did not materially change when the original mortality outcome was redefined as a composite of DNR or death. DNR orders are potentially an important mediating variable that should be systematically evaluated in trauma research.

Strengthening neurotrauma care systems in low and middle income countries

PRIMARY OBJECTIVE

To review basic elements to be considered in the development of effective neurotrauma care systems in low- and middle-income countries. Neurotrauma occurs more frequently in developing countries. The survival rate among neurotrauma patients depends in large part on the degree of sophistication of the trauma system.

RESEARCH DESIGN

A critical review of the literature was undertaken.

RESULTS

In developing countries, there are difficulties in fully integrating the resources for care if the local and regional trauma systems are poorly structured. Factors like inadequate emergency and neurointensive care, low compensation compared with elective procedures or high medico-legal risks may result in a lack of interest from the few available neurosurgeons to be fully integrated in neurotrauma care. Appropriate structuring of trauma systems according to countries needs and their functionality is a key element that would facilitate the optimal use of resources for integral neurotrauma care.

CONCLUSIONS

In order to implement an efficient trauma system, organization of low cost resources such as trauma registries and quality control programmes are required. The participation of medical associations in legislative and government processes is also an important factor for the appropriate development and organization of an effective trauma system in under-privileged areas.

The distribution of survival times after injury

INTRODUCTION

The distribution of survival times after injury has been described as "trimodal," but several studies have not confirmed this. The purpose of this study was to clarify the distribution of survival times after injury.

METHODS

We defined survival time (t(s)) as the interval between injury time and declared death time. We constructed histograms for t(s) ≤ 150 min from the 2004-2007 Fatality Analysis Reporting System (FARS, for traffic crashes) and National Violent Death Reporting System (NVDRS, for homicides). We estimated statistical models in which death times known only within intervals were treated as interval-censored. For confirmation, we also obtained EMS response times (t(r)), prehospital times (t(p)), and hospital times (t(h)) for decedents in the 2008 National Trauma Data Bank (NTDB) with t(s) = t(p) + t(h) ≤ 150. We approximated times until circulatory arrest (t(x)) as t(r) for patients pulseless at the injury scene, t(p) for other patients pulseless at hospital admission, and t(s) for the rest; for any declared t(s), we calculated mean t(x)/t(s). We used this ratio to estimate t(x) for hospital deaths in FARS or NVDRS and provide independent support for using interval-censored methods.

RESULTS

FARS and NVDRS deaths were most frequent in the first few minutes. Both showed a second peak at 35-40 min after injury, corresponding to peaks in hospital deaths. Third peaks were not present. Estimated t(x) in FARS and NVDRS did not show second peaks and were similar to estimates treating some death times as interval-censored.

CONCLUSIONS

Increases in frequency of survival times at 35-40 min are primarily artifacts created because declaration of death in hospitals is delayed until completing resuscitative attempts. By avoiding these artifacts, interval censoring methods are useful for analysis of injury survival times.

Rural high north: a high rate of fatal injury and prehospital death

Background

Finnmark County is the northernmost county in Norway. For several decades, the rate of mortality after injury in this sparsely inhabited region has remained above the national average. Following documentation of this discrepancy for the period 1991–1995, improvements to the trauma system were implemented. The present study aims to assess whether trauma-related mortality rates have subsequently improved.

Methods

All injury-associated fatalities in Finnmark from 1995–2004 were identified retrospectively from the National Registry of Death and reviewed. Low-energy trauma in elderly individuals and poisonings were excluded.

Results

A total of 453 cases of trauma-related death occurred during the study period, and 327 of those met the inclusion criteria. Information was retrievable for 266 cases. The majority of deaths (86%) occurred in the prehospital phase. The main causes of death were suicide (33%) and road traffic accidents (21%). Drowning and snowmobile injuries accounted for an unexpectedly high proportion (12 and 8%, respectively). The time of death did not show trimodal distribution. Compared to the previous study period, there was a significant overall decline in injury-related mortality, yet there was no change in place of death, mechanism of injury, or time from injury until death.

Conclusions

Changes in injury-related mortality cannot be linked to improvements in the trauma system. There was no change in the epidemiological patterns of injury. The high rate of on-scene mortality indicates that any major improvement in the number of injury-related deaths lies in targeted prevention.