Admission physiology criteria after injury on the battlefield predict medical resource utilization and patient mortality

Early Vital Sign Thresholds Associated with 24-Hour Mortality among Trauma Patients: A Trauma Quality Improvement Program (TQIP) Study

BACKGROUND

Identifying patients at imminent risk of death is critical in the management of trauma patients. This study measures the vital sign thresholds associated with death among trauma patients.

METHODS

This study included data from patients ≥15 years of age in the American College of Surgeons Trauma Quality Improvement Program (TQIP) database. Patients with vital signs of zero were excluded. Documented prehospital and emergency department (ED) vital signs included systolic pressure, heart rate, respiratory rate, and calculated shock index (SI). The area under the receiver operator curves (AUROC) was used to assess the accuracy of these variables for predicting 24-hour survival. Optimal thresholds to predict mortality were identified using Youden's Index, 90% specificity, and 90% sensitivity. Additional analyses examined patients 70+ years of age.

RESULTS

There were 1,439,221 subjects in the 2019-2020 datasets that met inclusion for this analysis with <0.1% (10,270) who died within 24 hours. The optimal threshold for prehospital systolic pressure was 110, pulse rate was 110, SI was 0.9, and respiratory rate was 15. The optimal threshold for the ED systolic was 112, pulse rate was 107, SI was 0.9, and respiratory rate was 21. Among the elderly sub-analysis, the optimal threshold for prehospital systolic was 116, pulse rate was 100, SI was 0.8, and respiratory rate was 21. The optimal threshold for ED systolic was 121, pulse rate was 95, SI was 0.8, and respiratory rate was 0.8.

CONCLUSIONS

Systolic blood pressure (SBP) and SI offered the best predictor of mortality among trauma patients. The SBP values predictive of mortality were significantly higher than the traditional 90mmHg threshold. This dataset highlights the need for better methods to guide resuscitation as initial vital signs have limited accuracy in predicting subsequent mortality.

Automated partial resuscitative endovascular balloon occlusion of the aorta reduces blood loss and hypotension in a highly lethal porcine liver injury model

BACKGROUND

Partial and intermittent resuscitative endovascular balloon occlusion of the aorta (pREBOA and iREBOA, respectively) are lifesaving techniques designed to extend therapeutic duration, mitigate ischemia, and bridge patients to definitive hemorrhage control. We hypothesized that automated pREBOA balloon titration compared with automated iREBOA would reduce blood loss and hypotensive episodes over a 90-minute intervention phase compared with iREBOA in an uncontrolled liver hemorrhage swine model.

METHODS

Twenty-four pigs underwent an uncontrolled hemorrhage by liver transection and were randomized to automated pREBOA (n = 8), iREBOA (n = 8), or control (n = 8). Once hemorrhagic shock criteria were met, controls had the REBOA catheter removed and received transfusions only for hypotension. The REBOA groups received 90 minutes of either iREBOA or pREBOA therapy. Surgical hemostasis was obtained, hemorrhage volume was quantified, and animals were transfused to euvolemia and then underwent 1.5 hours of automated critical care.

RESULTS

The control group had significantly higher mortality rate (5 of 8) compared with no deaths in both REBOA groups, demonstrating that the liver injury is highly lethal ( p = 0.03). During the intervention phase, animals in the iREBOA group spent a greater proportion of time in hypotension than the pREBOA group (20.7% [16.2-24.8%] vs. 0.76% [0.43-1.14%]; p < 0.001). The iREBOA group required significantly more transfusions than pREBOA (21.0 [20.0-24.9] mL/kg vs. 12.1 [9.5-13.9] mL/kg; p = 0.01). At surgical hemostasis, iREBOA had significantly higher hemorrhage volumes compared with pREBOA (39.2 [29.7-44.95] mL/kg vs. 24.7 [21.6-30.8] mL/kg; p = 0.04).

CONCLUSION

Partial REBOA animals spent significantly less time at hypotension and had decreased transfusions and blood loss. Both pREBOA and iREBOA prevented immediate death compared with controls. Further refinement of automated pREBOA is necessary, and controller algorithms may serve as vital control inputs for automated transfusion.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level III.

Assessment of the mass casualty triage during the November 2015 Paris area terrorist attacks: towards a simple triage rule

BACKROUND

Triage is key in the management of mass casualty incidents.

OBJECTIVE

The objective of this study was to assess the prehospital triage performed during the 2015 Paris area terrorist attack.

DESIGN SETTING AND PARTICIPANT

This was a retrospective cohort study that included all casualties of the attacks on 13 November 2015 in Paris area, France, that were admitted alive at the hospital within the first 24 h after the events. Patients were triaged as absolute emergency or relative emergency by a prehospital physician or nurse. This triage was then compared to the one of an expert panel that had retrospectively access to all prehospital and hospital files.

OUTCOMES MEASURES AND ANALYSIS

The primary endpoints were the rate of overtriage and undertriage, defined as number of patients misclassified in one triage category, divided by the total number of patients in this triage category.

MAIN RESULT

Among 337 casualties admitted to the hospital, 262 (78%) were triaged during prehospital care, with, respectively, 74 (28%) and 188 (72%) as absolute and relative emergencies. Among these casualties, the expert panel classified 96 (37%) patients as absolute emergencies and 166 (63%) as relative emergency. The rate of undertriage and overtriage was 36% [95% confidence interval (CI), 27-47%] and 8% (95% CI, 4-13%), respectively. Among undertriaged casualties, 8 (23%) were considered as being severely undertriaged. Among overtriaged casualties, 10 (77%) were considered as being severely overtriaged.

CONCLUSION

A simple prehospital triage for trauma casualties during the 13 November terrorist attack in Paris could have been performed triaged in 78% of casualties that were admitted to the hospital, with a 36% rate of undertriage and 8% of overtriage. Qualitative analysis of undertriage and overtriage indicate some possibilities for further improvement.

Vital sign thresholds predictive of death in the combat setting

INTRODUCTION

Identifying patients at imminent risk of death is a paramount priority in combat casualty care. This study measures the vital sign values predictive of mortality among combat casualties in Iraq and Afghanistan.

METHODS

We used data from the Department of Defense Trauma Registry from January 2007 to August 2016. We used the highest documented heart rate and the lowest documented systolic pressure in the emergency department for each casualty. We constructed receiver operator curves (ROCs) to assess the accuracy of these variables for predicting survival to hospital discharge.

RESULTS

There were 38,769 encounters of which our dataset included 15,540 (40.1%). The median age of these patients was 25 years and 97.5% were male. The most common mechanisms of injury were explosives (n = 9481, 61.0%) followed by gunshot wounds (n = 2393, 15.3%). The survival rate to hospital discharge was 97.5%. The median heart rate was 94 beats per minute (bpm) with area under the ROC of 0.631 with an optimal threshold to predict mortality of 110 bpm (sensitivity 52.2%, specificity 79.2%). The median systolic blood pressure was 128 mmHg with area under the ROC of 0.790 with an optimal threshold to predict mortality of 112 mmHg (sensitivity 68.5%, specificity 81.5%).

CONCLUSIONS

Casualties with a systolic blood pressure <112 mmHg, are at high risk of mortality, a value significantly higher than the traditional 90 mmHg threshold. Our dataset highlights the need for better methods to guide resuscitation as vital sign measurements have limited accuracy in predicting mortality.

An analysis of the incidence of hypothermia in casualties presenting to emergency departments in Iraq and Afghanistan

INTRODUCTION

Hypothermia on the battlefield has been shown to be associated with severe injury and higher mortality. The incidence of battlefield casualties presenting with hypothermia are described.

METHODS

The Department of Defense Trauma Registry (DoDTR) was queried from January 2007 to August 2016. We identified casualties with a documented temperature of <32°Celsius (C) (severe), 32-33.9 °C (moderate), 34-36 °C (mild). We defined serious injuries as those resulting in an AIS of ≥3 by body region.

RESULTS

There were 25,484 records with at least one documented temperature and 2501 (9.8%) casualties with hypothermia within our range. Nineteen (0.75%) casualties presented with severe hypothermia, 225 (9%) with moderate, and 2257 (90%) with mild. The mean injury severity score (ISS) for non-hypothermic, mild, moderate, and severe hypothermic casualties was 8 [4-14], 14 [6-24], 21 [13-29], and 21 [9-25], (p <0.001), respectively. Survival for casualties with severe hypothermia was 57.8%, moderate 80.9%, mild hypothermia 90.9%, and non-hypothermic group 97.6%, p<0.001. When adjusting for composite injury score, patient category, mechanism of injury, and location, this finding remained significant (OR 0.27, 0.21-0.34, p<0.001). Massive transfusion was more common in hypothermia casualties n = 566 (19%) versus non-hypothermic recipients n = 1734 (6.9%), p <0.001.

CONCLUSIONS

Though the number of casualties that presented hypothermic was small, their injuries were more severe, and were more likely to receive massive blood transfusions. This cohort also had a higher mortality rate, a finding which held when adjusting for confounders. There appears to be an opportunity to improve hypothermia prevention for combat.

A consensus-based criterion standard for trauma center need

BACKGROUND

In civilian trauma care, field triage is the process applied by prehospital care providers to identify patients who are likely to have severe injuries and immediately need the resources of a trauma center. Studies of the efficacy of field triage have used various measures to define trauma center need because no "criterion standard" exists, making cross-study comparisons difficult. This study aimed to develop a consensus-based functional criterion standard definition of trauma center need.

METHODS

Local and national experts were recruited for participation. Blinded key informant interviews were conducted in order of availability until no new themes emerged. Themes identified during the interviews were used to develop a Modified Delphi survey, which was electronically delivered via Survey Monkey. The trauma center need criteria were refined iteratively based on participant responses. Participants completed additional surveys until there was at least 80% agreement for each criterion.

RESULTS

Fourteen experts were recruited. Five participated in key informant interviews. A Modified Delphi survey was administered five times (four modifications based on the expert's responses). After the fifth round, there was at least 82% agreement on each criterion. The final definition included 10 time-specific indicators: major surgery, advanced airway, blood products, admission for spinal cord injury, thoracotomy, pericardiocentesis, cesarean delivery, intracranial pressure monitoring, interventional radiology, and in-hospital death.

CONCLUSION

We developed a consensus-based functional criterion standard definition of needing the resources of a trauma center, which may help to standardize field triage research and quality assurance in trauma systems as well as allow for cross study comparisons.

Military trauma care in Birmingham: observational study of care requirements and resource utilisation

BACKGROUND

The Royal Centre for Defence Medicine is located at University Hospitals Birmingham (UHB). Since 2001 all UK military casualties injured on active duty have been repatriated here for their initial treatment. This service evaluation was performed to quantify the work undertaken, with the aim of providing a snapshot of a year's military trauma work in order to inform the delivery of trauma care in both the military and civilian setting.

METHODS

Military patients admitted with traumatic injuries over a 12-month period were identified and the hospital notes and electronic records reviewed. Data were collected focusing on three areas - the details of the injury, information about the in-patient admission, and surgical interventions performed.

RESULTS

A total of 388 patients were used in the analysis. Median total length of stay was 10.5 days (IQR: 4-26, range: 0-137 days), and a median 6.0 days (IQR: 3.0-11.0, range: 1-49 days) was spent on intensive care by 125 patients. Surgical intervention was required for 278 (71.6%) patients, with a median of 2.0 operations (IQR: 1.0-4.0, range: 1-27) or 170 min (IQR: 90.0-570.0, range 20-4735 min) operating time per patient. 77% of these patients had their first procedure within 24h of arrival. Improvised explosives accounted for 50.5% of injuries seen. Spearman rank correlation between New Injury Severity Score with length of stay demonstrated significant correlation (p<0.001), with a coefficient of 0.640. A model predicting length of stay based on New Injury Severity Score was devised for patients with battle injuries.

CONCLUSION

This report of 12 months work at UHB demonstrates the service commitment to these casualties, describing the burden of care and resource requirements for military trauma patients.

Initial predictors associated with outcome in injured multiple traumatic limb amputations: a Kandahar-based combat hospital experience

INTRODUCTION

Improvised explosive devices (IEDs) are the defining mechanism of injury during Operation Enduring Freedom. This is a retrospective analysis of initial management for IED blast injuries presenting with bilateral, traumatic, lower-extremity (LE) amputations with and without pelvic and perineal involvement.

METHODS

A database of trauma admissions presenting to a North Atlantic Treaty Organization (NATO) Role 3 combat hospital in southern Afghanistan over a 7-month period was created to evaluate the care of this particular injury pattern. Patients were included if they were received from point of injury with at least bilateral traumatic LE amputations and had vital signs with initial resuscitation efforts.

RESULTS

Thirty-two presented with double LE amputations (36%) and nine with triple amputations (10%). After excluding 10 patients who failed to meet the inclusion criteria, 22 patients were analysed. The mean age was 29 years, and the average ISS and admission haemoglobin were 22 and 11.3mgl(-1), respectively. Patients received an average of 54 units of blood products and underwent 1.6 operations with a mean operative time of 142.5min. The pattern of injury was associated with an increase in the total blood products required for resuscitation (pelvis n=12, p=0.028, gastrointestinal tract (GI) n=14, p=0.02, perineal n=15, p=0.036). There was no relationship between ISS or admission haemoglobin and the need for massive transfusion. Low Glasgow Coma Scale (GCS) was associated with increased 30-day mortality. Hollow viscus injury and operative hemipelvectomy were also associated with mortality.

CONCLUSIONS

Early 30-day follow-up demonstrated that IED injuries with bilateral LE amputations with and without pelvic and perineal involvement are survivable injuries. Standard measures of injury and predictors of survival bore little relationship to observed outcomes and may need to be re-evaluated. Long-term follow-up is needed to assess the extent of functional recovery and overall morbidity and mortality.

Defining and predicting surgeon utilization at forward surgical teams in Afghanistan

BACKGROUND

The forward surgical team (FST) is the US Army's smallest surgical element. These teams have supported current conflicts since 2001. The purpose of this study was to determine if surgeon utilization varied at two different FSTs and to determine factors that may predict the need for a surgeon.

METHOD

Data from two FSTs were reviewed. A t-test was used to compare the military injury severity scores (mISS) and the revised trauma scores (RTS). χ(2) analysis was used to compare types and mechanisms of injury and to compare life- or limb-saving surgeries (LLSS) and life-saving interventions among the FSTs. Logistic regression was used to determine if mISS, RTS, physiologic parameters, or laboratory values predicted the need for LLSS or life-saving intervention.

RESULTS

The 541st FST treated a larger volume of patients than the 772nd FST (n = 761 versus n = 311). The 772nd FST performed a significantly higher percentage of LLSS; however, absolute number of LLSS was 31 at both FSTs. The mISS among operative patients were similar, but RTS were significantly different (772nd FST = 7.28 versus 541st FST = 7.58, P = 0.008). The 772nd FST saw a higher percentage of motor vehicle collision and rocket-propelled grenade injuries and thoracic and neurologic injuries, and the 541st FST saw a higher percentage of blast and gunshot wound injuries and abdominal injuries. Lactate level was the most significant predictor of the need for LLSS.

CONCLUSION

Although percentage of surgical interventions varied between the two FSTs, the absolute number of needed surgical interventions was the same and was small. Lactate level predicted the need for surgical intervention in our population.

Children and terror casualties receive preference in ICU admissions

OBJECTIVE

Trauma casualties caused by terror-related events and children injured as a result of trauma may be given preference in hospital emergency departments (EDs) due to their perceived importance. We investigated whether there are differences in the treatment and hospitalization of terror-related casualties compared to other types of injury events and between children and adults injured in terror-related events.

METHODS

Retrospective study of 121 608 trauma patients from the Israel Trauma Registry during the period of October 2000-December 2005. Of the 10 hospitals included in the registry, 6 were level I trauma centers and 4 were regional trauma centers. Patients who were hospitalized or died in the ED or were transferred between hospitals were included in the registry.

RESULTS

All analyses were controlled for Injury Severity Score (ISS). All patients with ISS 1-24 terror casualties had the highest frequency of intensive care unit (ICU) admissions when compared with patients after road traffic accidents (RTA) and other trauma. Among patients with terror-related casualties, children were admitted to ICU disproportionally to the severity of their injury. Logistic regression adjusted for injury severity and trauma type showed that both terror casualties and children have a higher probability of being admitted to the ICU.

CONCLUSIONS

Injured children are admitted to ICU more often than other age groups. Also, terror-related casualties are more frequently admitted to the ICU compared to those from other types of injury events. These differences were not directly related to a higher proportion of severe injuries among the preferred groups.

Neurointensive care

The majority of neurological admissions to military Intensive Care will be for Traumatic Brain Injury (TBI). These injuries will be either penetrating from fragmentation or missiles or blunt due to blast or impact. Intensive Care management of TBI is focused on the prevention of secondary brain injury due to insults such as hypoxia, hypotension and low Cerebral Perfusion Pressure. This management is based largely on comprehensive evidence based guidelines produced by the Brain Trauma Foundation. The most significant dilemma faced by UK military intensivists is whether we should be measuring Intracranial Pressure in patient with severe TBI in the deployed setting; and if so what technique should be used.

Continuous noninvasive tissue oximetry in the early evaluation of the combat casualty: a prospective study

BACKGROUND

We hypothesized that near-infrared spectroscopy (NIRS)-derived tissue oxygenation saturation (StO2) could assist in identifying shock in casualties arriving to a combat support hospital and predict the need for life-saving interventions (LSIs) and blood transfusions.

METHODS

We performed a prospective observational trial at a single US Army combat support hospital in Iraq from August to December 2007. Arriving casualties had NIRS-derived StO2 recorded in the emergency department. Minimum (StO2 min) and initial 2-minute averaged StO2 and tissue hemoglobin index readings were used as end points. Outcomes measured were requirement for LSIs, any blood transfusion, massive transfusion (>10 units in 24 hours), and early mortality. The data were subjected to univariate and multivariate logistic regression modeling.

RESULTS

Of the 147 combat casualties enrolled in the trial, 72 (49%) required an LSI, 42 (29%) required blood transfusion, and 10 (7%) required massive transfusion. On multivariate logistic regression analysis of the whole study group, systolic blood pressure (SBP), international normalized ratio, tissue hemoglobin index, and hematocrit predicted blood transfusion with an area under the curve of 0.90 (0.84-0.96), with a confidence interval of 95%. When just the group with an SBP >90 was analyzed, independent predictors of patients requiring blood transfusion on logistic regression analysis were StO2 min (odds ratio of 1.35) and hematocrit (odds ratio of 2.66) for an area under the curve of 0.84 (0.76-0.92).

CONCLUSIONS

NIRS-derived StO2 obtained on arrival predicts the need for blood transfusion in casualties who initially seem to be hemodynamically stable (SBP >90). Further study of this technology for use in the resuscitation of trauma patients is warranted.

New developments in massive transfusion in trauma

PURPOSE OF REVIEW

Trauma patients requiring massive transfusion represent a population at high risk for potentially preventable death. This review describes recent advances in the early recognition and treatment of the coagulopathy of trauma, as well as ongoing work to define optimal resuscitation strategies.

RECENT FINDINGS

Damage control resuscitation involves the rapid correction of hypothermia and acidosis, direct treatment of coagulopathy, and early transfusion in trauma patients. Recent evidence demonstrates improved mortality and lower overall blood product usage with higher ratios of plasma and platelets to red blood cells transfused. Adjuncts to damage control resuscitation such as factor VIIa may also be beneficial. Thrombelastography and advances in point-of-care testing may provide timely measurements to help guide massive transfusion in patients based on their individual needs.

SUMMARY

As optimal resuscitation strategies continue to evolve, recent efforts have focused on early and aggressive treatment of coagulopathy, with higher ratios of plasma and platelets to red blood cells transfused. Early evidence suggests that such strategies have a beneficial outcome in regards to trauma-related mortality.

Facial reconstruction by biosurgery: cell transplantation versus cell homing

The face distinguishes one human being from another. When the face is disfigured because of trauma, tumor removal, congenital anomalies, or chronic diseases, the patient has a strong desire for functional and esthetic restoration. Current practice of facial reconstruction using autologous grafts, synthetic fillers, and prostheses is frequently below the surgeon's and patient's expectations. Facial reconstruction is yet to take advantage of recent advances in seemingly unrelated fields of stem cell biology, chemical engineering, biomaterials, and tissue engineering. "Biosurgery," a new concept that we propose, will incorporate novel principles and strategies of bioactive cues, biopolymers, and/or cells to restore facial defects. Small facial defects can likely be reconstructed by cell homing and without cell transplantation. A critical advantage of cell homing is that agilely recruited endogenous cells have the potential to harness the host's innate capacity for regeneration, thus accelerating the rate of regulatory and commercialization processes for product development. Large facial defects, however, may not be restorable without cell delivery per our understanding at this time. New breakthrough in biosurgery will likely originate from integrated strategies of cell biology, cytokine biology, chemical engineering, biomaterials, and tissue engineering. Regardless of cell homing or cell delivery approaches, biosurgery not only will minimize surgical trauma and repetitive procedures, but also produce long-lasting results. At the same time, caution must be exercised against the development of products that lack scientific basis or dogmatic combination of cells, biomaterials, and biomolecules. Together, scientifically derived biosurgery will undoubtedly develop into new technologies that offer increasingly natural reconstruction and/or augmentation of the face.

Is there one optimal medical treatment and evacuation chain for all situations: "scoop-and-run" or "stay-and-play"

In 2006, the Ministry of Defense of the Netherlands initiated a targeted agenda program for the World Congress on Disaster and Emergency Medicine in Amsterdam in 2007 (15WCDEM). The issue to be discussed was if there is one "golden" treatment and evacuation system that is applicable for different military and civilian situations. And, if there is not such a system, which parameters are important to construct the most optimal system for each different situation. This issue is related to the applicability and evidence base of the standards of the North Atlantic Treaty Organization. A group of experts started a website discussion on the issue during December 2006. During the 15WCDEM, several other participants were active in the discussion. Using the different experiences and the outcome of the discussions, it was concluded that there is not one "golden" medical emergency system, there are no "golden" timelines, and no "golden" skills. A medical system should be flexible and be able to adjust on each specific, local situation. First responder and non-medical people with medical skills (first responders) are essential in the front line of the emergency medical systems. More research is needed on the medical techniques and skills that are most effective early in the treatment and evacuation systems. Lessons learned from the military system are relevant for the civilian emergency medical services and vice-versa. The World Association for Disaster and Emergency Medicine can be an important platform to share and exchange information between these two systems. The target of the platform should be to obtain a generic picture of the important elements in prehospital emergency medical care.

Tissue Oxygen Saturation Predicts the Need for Early Blood Transfusion in Trauma Patients

Near-infrared spectroscopy (NIRS) has been used to measure regional tissue oxygen saturation (StO2) in skeletal muscle as an indicator of perfusion in trauma patients. In an effort to prospectively examine the usefulness of StO2 in identifying trauma patients in hemorrhagic shock, we evaluated the need for blood transfusion within 24 hours of injury as a marker of significant hemorrhage. A 6-month prospective, observational study was conducted at a university-affiliated, urban Level I trauma center using a convenience sample of 26 trauma patients thought to be at high risk for hemorrhagic shock. Baseline demographic data, vital signs, laboratory values, and amounts of fluid and blood products administered were collected. NIRS-derived StO2 values were measured for 1 hour after arrival to the trauma bay and the minimum value noted. A minimum StO2 less than 70 per cent correlated with the need for blood transfusion with a sensitivity of 88 per cent and a specificity of 78 per cent. The positive predictive value was 64 per cent and the negative predictive value was 93 per cent. The need for blood transfusion within 24 hours of arrival was not predicted by hypotension, tachycardia, arterial lactate, base deficit, or hemoglobin. StO2 may represent an important screening tool for identifying trauma patients who require blood transfusion or other limited medical resources.

Out-of-hospital combat casualty care in the current war in Iraq

STUDY OBJECTIVE

We describe outcomes for battle casualties receiving initial treatment at a US Army consolidated battalion aid station augmented with emergency medicine practitioners, advanced medic treatment protocols, and active medical direction. Battalion aid stations are mobile facilities integral to combat units, providing initial phases of advanced trauma life support and then evacuation. The setting was a forward base in central Iraq, with units engaged in urban combat operations.

METHODS

This was a retrospective observational study. Rates of battle casualties, mechanism, evacuations, and outcome were calculated. Corresponding Iraqi theater-wide US casualty rates were also calculated for indirect comparison.

RESULTS

The study population consisted of 1.1% of the total US military population in the Iraqi theater. Data were available for all battle casualties. The study facility's battle casualty rate was 22.2%. The case fatality rate was 7.14%, and the out-of-theater evacuation rate was 27%. Analysis of evacuated patients revealed a study average Injury Severity Score of 10 (95% confidence interval [CI] 8 to 12). Concurrent theater aggregate US casualty rates are provided for contextual reference and include battle casualty rate of 6.7%, case fatality rate of 10.45%, out-of-theater evacuation rate of 18%, and average out-of-theater evacuation casualty Injury Severity Score of 10 (95% CI 9.5 to 10.5).

CONCLUSION

The study battalion aid station experienced high casualty and evacuation rates while also demonstrating relatively low case fatality rates. A relatively high proportion of patients were evacuated out of the combat zone, reflecting both the battle casualty rate and number of patients surviving. Future effort should focus on improving out-of-hospital combat casualty data collection and prospective validation of emergency medicine-based out-of-hospital battlefield care and medical direction.

Military nursing research: translation to disaster response and day-to-day critical care nursing

Where to begin? How do you identify nursing care requirements for military operations, disaster, and humanitarian response, and how do you modify care under these unique conditions? This article presents a framework for identifying areas of critical care nursing that are performed on a day-to-day basis that may also be provided during a contingency operation, and discusses how that care may be changed by the austere conditions associated with a contingency response. Examples from various disasters, military operations, and military nursing research are used to illustrate the use of this framework. Examples are presented of how the results of this military nursing research inform disaster nursing and day-to-day critical care nursing practice.

Clinical review: allocating ventilators during large-scale disasters--problems, planning, and process

Catastrophic disasters, particularly a pandemic of influenza, may force difficult allocation decisions when demand for mechanical ventilation greatly exceeds available resources. These situations demand integrated incident management responses on the part of the health care facility and community, including resource management, provider liability protection, community education and information, and health care facility decision-making processes designed to allocate resources as justly as possible. If inadequate resources are available despite optimal incident management, a process that is evidence-based and as objective as possible should be used to allocate ventilators. The process and decision tools should be codified pre-event by the local and regional healthcare entities, public health agencies, and the community. A proposed decision tool uses predictive scoring systems, disease-specific prognostic factors, response to current mechanical ventilation, duration of current and expected therapies, and underlying disease states to guide decisions about which patients will receive mechanical ventilation. Although research in the specifics of the decision tools remains nascent, critical care physicians are urged to work with their health care facilities, public health agencies, and communities to ensure that a just and clinically sound systematic approach to these situations is in place prior to their occurrence.