Prehospital Hemorrhage Control and Treatment by Clinicians: A Joint Position Statement.

Exsanguination remains the leading cause of preventable death among victims of trauma. For adult and pediatric trauma patients in the prehospital phase of care, methods to control hemorrhage and hemostatic resuscitation are described in this joint consensus opinion by the American College of Surgeons Committee on Trauma, the American College of Emergency Physicians, and the National Association of EMS Physicians.

Managing Traumatic Brain Injury: Translating Military Guidelines to the Wilderness.

Traumatic brain injury (TBI) is a common injury on the battlefield. Much of what medics do to manage these injuries on the battlefield can be translated to other austere environments, such as wilderness or disaster settings. The recognition and diagnosis of TBI can be difficult even in the hospital, but basic understanding of how to define a TBI and prevent secondary injuries can be accomplished with relatively few resources and little training. This article outlines what a TBI is and how to manage it in the field.

Tranexamic Acid Use in Prehospital Uncontrolled Hemorrhage.

The use of tranexamic acid (TXA) in the treatment of trauma patients was relatively unexplored until the landmark Clinical Randomisation of an Antifibrinolytic in Significant Haemorrhage-2 (CRASH-2) trial in 2010 demonstrated a reduction in mortality with the use of TXA. Although this trial was a randomized, double-blinded, placebo-controlled study incorporating >20,000 patients, numerous limitations and weaknesses have been described. As a result, additional studies have followed, delineating the potential risks and benefits of TXA administration. A systematic review of the literature to date reveals a mortality benefit of early (ideally <1 hour and no later than 3 hours after injury) TXA administration in the treatment of severely injured trauma patients (systolic blood pressure <90 mm Hg, heart rate >110). Combined with abundant literature showing a reduction in bleeding in elective surgery, the most significant benefit may be administration of TXA before the patient goes into shock. Those trials that failed to show a mortality benefit of TXA in the treatment of hemorrhagic shock acknowledged that most patients received blood products before TXA administration, thus confounding the results. Although the use of prehospital TXA in the severely injured trauma patient will become more clear with the trauma studies currently underway, the current literature supports the use of prehospital TXA in this high-risk population. We recommend considering a 1 g TXA bolus en route to definitive care in high-risk patients and withholding subsequent doses until hyperfibrinolysis is confirmed by thromboelastography.

Who needs a tourniquet? And who does not? Lessons learned from a review of tourniquet use in the Russo-Ukrainian war.

BACKGROUND: Extremity tourniquets have proven to be lifesaving in both civilian and military settings and should continue to be used by first responders for trauma patients with life-threatening extremity bleeding. This is especially true in combat scenarios in which both the casualty and the first responder may be confronted by the imminent threat of death from hostile fire as the extremity hemorrhage is being treated. Not every extremity wound, however, needs a tourniquet. One of the most important aspects of controlling life-threatening extremity bleeding with tourniquets is to recognize what magnitude of bleeding requires this intervention and what magnitude of bleeding does not. Multiple studies, both military and civilian, have shown that tourniquets are often applied when they are not medically indicated. Overuse of extremity tourniquets has not caused excess morbidity in either the recent conflicts in Iraq and Afghanistan or in the US urban civilian setting. In the presence of prolonged evacuation, however, applying a tourniquet when it is not medically indicated changes tourniquet application from being a lifesaving intervention to one that may cause an avoidable amputation and the development of an array of metabolic derangements and acute kidney injury collectively called prolonged tourniquet application syndrome. METHODS: The recent literature was reviewed for papers that documented the complications of tourniquet use resulting from the prolonged casualty evacuation times being seen in the current Russo-Ukrainian war. The literature was also reviewed for the incidence of tourniquet application that was found to not be medically indicated, in both the US civilian setting and from Ukraine. Finally, an in-person meeting of the US/Ukraine Tourniquet Working Group was held in Warsaw, Poland, in December of 2023. RESULTS: Unnecessary loss of extremities and life-threatening episodes of prolonged tourniquet application syndrome are currently occurring in Ukrainian combat forces because of nonindicated tourniquet use combined with the prolonged evacuation time seen in the Russo-Ukrainian war. Specific numbers of the complications experienced as a result of tourniquet use by Ukrainian forces in the current conflict are treated as classified information and are not available, but multiple sources from the Ukrainian military medical personnel and from the US advisors providing medical assistance to Ukraine have all agreed that the problem is substantial. CONCLUSION: Unnecessary tourniquet morbidity might also occur in US forces in a variety of potential future combat scenarios in which evacuation to surgical care is delayed. Prehospital trauma training programs, including but not limited to tactical combat casualty care, place insufficient emphasis on the need to avoid leaving tourniquets in place when they are not medically indicated. This aspect of training should receive emphasis in future Tactical Combat Casualty Care (TCCC) and civilian first responder curriculum development. An interim ad hoc training solution on this topic is available at the websites noted in this articles. Additional training modalities may follow in the near future. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level V.

High-grade liver injuries with contrast extravasation managed initially with interventional radiology versus observation: A secondary analysis of a WTA multicenter study.

BACKGROUND: High-grade liver injuries with extravasation (HGLI â€‹+ â€‹Extrav) are associated with morbidity/mortality. For low-grade injuries, an observation (OBS) first-strategy is beneficial over initial angiography (IR), however, it is unclear if OBS is safe for HGLI â€‹+ â€‹Extrav. Therefore, we evaluated the management of HGLI â€‹+ â€‹Extrav patients, hypothesizing IR patients will have decreased rates of operation and mortality. METHODS: HGLI â€‹+ â€‹Extrav patients managed with initial OBS or IR were included. The primary outcome was need for operation. Secondary outcomes included liver-related complications (LRCs) and mortality. RESULTS: From 59 patients, 23 (39.0%) were managed with OBS and 36 (61.0%) with IR. 75% of IR patients underwent angioembolization, whereas 13% of OBS patients underwent any IR, all undergoing angioembolization. IR patients had an increased rate of operation (13.9% vs. 0%, p â€‹= â€‹0.049), but no difference in LRCs (44.4% vs. 43.5%) or mortality (5.6% vs. 8.7%) versus OBS patients (both p â€‹> â€‹0.05). CONCLUSION: Over 60% of patients were managed with IR initially. IR patients had an increased rate of operation yet similar rates of LRCs and mortality, suggesting initial OBS reasonable in appropriately selected HGLI â€‹+ â€‹Extrav patients.

Epidemiologic aspects of traumatic brain injury in acute combat casualties at a major military medical center: a cohort study.

OBJECTIVE: From the ongoing military conflicts in Iraq and Afghanistan, an understanding of the neuroepidemiology of traumatic brain injury (TBI) has emerged as requisite for further advancements in neurocombat casualty care. This study reports population-specific incidence data and investigates TBI identification and grading criteria with emphasis on the role of loss of consciousness (LOC) in the diagnostic rubric. METHODS: This is a cohort study of all consecutive troops acutely injured during combat operations-sustaining body-wide injuries sufficient to require immediate stateside evacuation-and admitted sequentially to our medical center during a 2-year period. A prospective exploration of the TBI identification and grading system was performed in a homogeneous population of blast-injured polytrauma inpatients. RESULTS: TBI incidence was 54.3%. Structural neuroimaging abnormalities were identified in 14.0%. Higher Injury Severity Score (ISS) was associated with abnormal neuroimaging, longer length of stay (LOS), and elevated TBI status-primarily based on autobiographical LOC. Mild TBI patients had normal neuroimaging, higher ISS, and comparable LOS to TBI-negative patients. Patients who reported LOC had a lower incidence of abnormal neuroimaging. INTERPRETATION: This study demonstrates that the methodology used to assign the diagnosis of a mild TBI in troops with complex combat-related injuries is crucial to an accurate accounting. The detection of incipient mild TBI, based on an identification system that utilizes LOC as the principal diagnostic criterion to discern among patients with outcomes of interest, misclassifies patients whose LOC may not reflect actual brain injury. Attempts to identify high-risk battlefield casualties within the current point-of-injury mild TBI case definition, which favors high sensitivity, will be at the expense of specificity.

Neurosurgical Mission to Ukraine.

Ukrainian health care before 2021 was like that in comparable middle-income countries. The conflict with Russia over the last 8 months has added significant burden to the already resource-constrained system. We describe the current neurosurgical situation in Ukraine as well as remote and in-person efforts to provide needed assistance to Ukrainian neurosurgical colleagues.

An observation-first strategy for liver injuries with "blush" on computed tomography is safe and effective.

INTRODUCTION: The management of liver injuries in hemodynamically stable patients is variable and includes primary treatment strategies of observation (OBS), angiography (interventional radiology [IR]) with angioembolization (AE), or operative intervention (OR). We aimed to evaluate the management of patients with liver injuries with active extravasation on computed tomography (CT) imaging, hypothesizing that AE will have more complications without improving outcomes compared with OBS. METHODS: This is a prospective, multicenter, observational study. Patients who underwent CT within 2 hours after arrival with extravasation (e.g., blush) on imaging were included. Exclusion criteria included cirrhosis, nontraumatic hemorrhage, transfers from outside facilities, and pregnancy. No hemodynamic exclusion criteria were used. The primary outcome was liver-specific complications. Secondary outcomes include length of stay and mortality. Angioembolization patients were compared with patients treated without AE. Propensity score matching was used to match based on penetrating mechanism, liver injury severity, arrival vital signs, and early transfusion. RESULTS: Twenty-three centers enrolled 192 patients. Forty percent of patients (n = 77) were initially OBS. Eleven OBS patients (14%) failed nonoperative management and went to IR or OR. Sixty-one patients (32%) were managed with IR, and 42 (69%) of these had AE as an initial intervention. Fifty-four patients (28%) went to OR+/- IR. After propensity score matching (n = 34 per group), there was no difference in baseline characteristics between AE and OBS. The AE group experienced more complications with a higher rate of IR-placed drains for abscess or biloma (22% vs. 0%, p = 0.01) and an increased overall length of stay ( p = 0.01). No difference was noted in transfusions or mortality. CONCLUSION: Observation is highly effective with few requiring additional interventions. Angioembolization was associated with higher rate of secondary drain placement for abscesses or biloma. Given this, a trial of OBS and avoidance of empiric AE may be warranted in hemodynamically stable, liver-injured patient with extravasation on CT. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level II.

Damage control resuscitation decreases systemic inflammation after hemorrhage.

BACKGROUND: Severe hemorrhagic shock and resuscitation initiates a dysfunctional systemic inflammatory response leading to end-organ injury. Clinical evidence supports the transfusion of high ratios of plasma and packed red blood cells (pRBCs) in the treatment of hemorrhagic shock. The effects of resuscitation with different ratios of fresh blood products on inflammation and organ injury have not yet been characterized. MATERIALS AND METHODS: Mice underwent femoral artery cannulation and pressure-controlled hemorrhage for 60 min, then resuscitation with fresh plasma and pRBCs collected from donor mice. Plasma alone, pRBCs alone, and ratios of 2:1, 1:1, and 1:2 plasma:pRBCs were used for resuscitation strategies. Mice were sacrificed to determine biochemical and hematologic parameters, serum cytokine concentrations, tissue myeloperoxidase levels, and vascular permeability. RESULTS: Compared with other resuscitation strategies, mice resuscitated with pRBCs alone exhibited increased hemoglobin levels, while other hematologic and biochemical parameters were not significantly different among groups. Compared with 1:1, mice resuscitated with varying ratios of plasma:pRBCs exhibited increased cytokine concentrations of KC, MIP-1α, and MIP-2, and increased intestinal and lung myeloperoxidase levels. Mice resuscitated with 1:1 had decreased vascular permeability in the intestine and lung as compared with other groups. CONCLUSIONS: Resuscitation with a 1:1 ratio of fresh plasma:pRBCs results in decreased systemic inflammation and attenuated organ injury. These findings support the potential advantage of transfusing blood products in physiologic ratios to improve the treatment of severe hemorrhagic shock.

Simulated aeromedical evacuation does not affect systemic inflammation or organ injury in a murine model of hemorrhagic shock.

Hemorrhagic shock is a primary injury amongst combat casualties. Aeromedical evacuation (AE) of casualties exposes patients to a hypobaric, hypoxic environment. The effect of this environment on the host response to hemorrhagic shock is unknown. In the present study, we sought to determine the effect of simulated AE on systemic inflammation and organ injury using a murine model of hemorrhagic shock. Mice underwent femoral artery cannulation and were hemorrhaged for 60 minutes. Mice were then resuscitated with a 1:1 ratio of plasma:packed red blood cells. At 1 or 24 hours after resuscitation, mice were exposed to a 5-hour simulated AE or remained at ground level (control). Serum was analyzed for cytokine concentrations and organs were assessed for neutrophil accumulation and vascular permeability. Mice in the simulated AE groups demonstrated reduced arterial oxygen saturation compared to ground controls. Serum cytokine concentrations, neutrophil recruitment, and vascular permeability in the lung, ileum, and colon in the simulated AE groups were not different from the ground controls. Our results demonstrate that mice exposed to simulated AE following hemorrhagic shock do not exhibit worsened systemic inflammation or organ injury compared to controls. The data suggest that AE has no adverse effect on isolated hemorrhagic shock.

The patient's voice matters: The impact of advance directives on elderly trauma patients.

BACKGROUND: Geriatric trauma rates are increasing, yet trauma centers often struggle to provide autonomy regarding decision making to these patients. Advance care planning can assist with this process. Currently, there are limited data on the impact of advance directives (ADs) in elderly trauma patients. The purpose of this study was to evaluate the prevalence of preinjury AD in geriatric trauma patients and its impact on outcomes, with the hypothesis that ADs would not be associated with an increase in mortality. METHODS: A multicenter retrospective review was conducted on patients older than 65 years with traumatic injury between 2017 and 2019. Three Level I trauma centers and one Level II trauma center were included. Exclusion criteria were readmission, burn injury, transfer to another facility, discharge from emergency department, and mortality prior to being admitted. RESULTS: There were 6,135 patients identified; 751 (12.2%) had a preinjury AD. Patients in the AD+ group were older (86 vs. 77 years, p < 0.0001), more likely to be women (67.0% vs. 54.8%, p < 0.0001), and had more comorbidities. Hospital length of stay and ventilator days were similar. In-hospital mortality occurred in 236 patients, and 75.4% of them underwent withdrawal of care (WOC). The mortality rate was higher in AD+ group (10.5% vs. 2.9%, p < 0.0001). No difference was seen in the rate of AD between the WOC+ and WOC- group (31.5% vs. 39.6%, p = 0.251). A preinjury AD was identified as an independent predictor of mortality, but not a predictor of WOC. CONCLUSION: Despite a high WOC rate in patients older than 65 years, most patients did not have an AD prior to injury. As the elderly trauma population grows, advance care planning should be better integrated into geriatric care to encourage a patient-centered approach to end-of-life care. LEVEL OF EVIDENCE: Prognostic and epidemiological, level IV.

Whole Blood Versus Conventional Blood Component Massive Transfusion Protocol Therapy in Civilian Trauma Patients.

BACKGROUND: Military data demonstrating an improved survival rate with whole blood (WB) have led to a shift toward the use of WB in civilian trauma. The purpose of this study is to compare a low-titer group O WB (LTOWB) massive transfusion protocol (MTP) to conventional blood component therapy (BCT) MTP in civilian trauma patients. METHODS: Trauma patients 15 years or older who had MTP activations from February 2019 to December 2020 were included. Patients with a LTOWB MTP activation were compared to BCT MTP patients from a historic cohort. RESULTS: 299 patients were identified, 169 received LTOWB and 130 received BCT. There were no differences in age, gender, or injury type. The Injury Severity Score was higher in the BCT group (27 vs 25, P = .006). The LTOWB group had a longer transport time (33 min vs 26 min, P < .001) and a lower arrival temperature (35.8 vs 36.1, P < .001). Other hemodynamic parameters were similar between the groups. The LTOWB group had a lower in-hospital mortality rate compared to the BCT group (19.5% vs 30.0%, P = .035). There were no differences in total transfusion volumes at 4 hours and 24 hours. No differences were seen in transfusion reactions or hospital complications. Multivariable logistic regression identified ISS, age, and 24-hour transfusion volume as predictors of mortality. DISCUSSION: Resuscitating severely injured trauma patient with LTOWB is safe and may be associated with an improved survival.

AAST multicenter prospective analysis of prehospital tourniquet use for extremity trauma.

BACKGROUND: Tourniquet use for extremity hemorrhage control has seen a recent increase in civilian usage. Previous retrospective studies demonstrated that tourniquets improve outcomes for major extremity trauma (MET). No prospective study has been conducted to date. The objective of this study was to evaluate outcomes in MET patients with prehospital tourniquet use. We hypothesized that prehospital tourniquet use in MET decreases the incidence of patients arriving to the trauma center in shock. METHODS: Data were collected prospectively for adult patients with MET at 26 Level I and 3 Level II trauma centers from 2015 to 2020. Limbs with tourniquets applied in the prehospital setting were included in the tourniquet group and limbs without prehospital tourniquets were enrolled in the control group. RESULTS: A total of 1,392 injured limbs were enrolled with 1,130 tourniquets, including 962 prehospital tourniquets. The control group consisted of 262 limbs without prehospital tourniquets and 88 with tourniquets placed upon hospital arrival. Prehospital improvised tourniquets were placed in 42 patients. Tourniquets effectively controlled bleeding in 87.7% of limbs. Tourniquet and control groups were similarly matched for demographics, Injury Severity Score, and prehospital vital signs (p > 0.05). Despite higher limb injury severity, patients in the tourniquet group were less likely to arrive in shock compared with the control group (13.0% vs. 17.4%, p = 0.04). The incidence of limb complications was not significantly higher in the tourniquet group (p > 0.05). CONCLUSION: This study is the first prospective analysis of prehospital tourniquet use for civilian extremity trauma. Prehospital tourniquet application was associated with decreased incidence of arrival in shock without increasing limb complications. We found widespread tourniquet use, high effectiveness, and a low number of improvised tourniquets. This study provides further evidence that tourniquets are being widely and safely adopted to improve outcomes in civilians with MET. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level IV.

Hypobaric hypoxia exacerbates the neuroinflammatory response to traumatic brain injury.

OBJECTIVE: To determine the inflammatory effects of time-dependent exposure to the hypobaric environment of simulated aeromedical evacuation following traumatic brain injury (TBI). METHODS: Mice were subjected to a blunt TBI or sham injury. Righting reflex response (RRR) time was assessed as an indicator of neurologic recovery. Three or 24 h (Early and Delayed groups, respectively) after TBI, mice were exposed to hypobaric flight conditions (Fly) or ground-level control (No Fly) for 5 h. Arterial blood gas samples were obtained from all groups during simulated flight. Serum and cortical brain samples were analyzed for inflammatory cytokines after flight. Neuron specific enolase (NSE) was measured as a serum biomarker of TBI severity. RESULTS: TBI resulted in prolonged RRR time compared with sham injury. After TBI alone, serum levels of interleukin-6 (IL-6) and keratinocyte-derived chemokine (KC) were increased by 6 h post-injury. Simulated flight significantly reduced arterial oxygen saturation levels in the Fly group. Post-injury altitude exposure increased cerebral levels of IL-6 and macrophage inflammatory protein-1α (MIP-1α), as well as serum NSE in the Early but not Delayed Flight group compared to ground-level controls. CONCLUSIONS: The hypobaric environment of aeromedical evacuation results in significant hypoxia. Early, but not delayed, exposure to a hypobaric environment following TBI increases the neuroinflammatory response to injury and the severity of secondary brain injury. Optimization of the post-injury time to fly using serum cytokine and biomarker levels may reduce the potential secondary cerebral injury induced by aeromedical evacuation.

Closing the "care in the air" capability gap for severe lung injury: the Landstuhl Acute Lung Rescue Team and extracorporeal lung support.

BACKGROUND: The success of US Air Force Critical Care Air Transport Teams (CCATT) in transporting critically ill and injured patients enabled changes in military medical force deployment and casualty care practice. Even so, a subset of casualties remains who exceed even CCATT capabilities for movement. These patients led to the creation of the Landstuhl Acute Lung Rescue Team (ALeRT) to close the "care in the air" capability gap. METHODS: The ALeRT Registry was queried for the period between November 1, 2005, and June 30, 2010. Additionally, Landstuhl Regional Medical Center critical care patient transfers to host nation medical centers were reviewed for cases using extracorporeal lung support systems. RESULTS: For the review period, US Central Command activated the ALeRT on 40 occasions. The ALeRT successfully evacuated patients on 24 of 27 missions launched (89%). Three patients were too unstable for ALeRT evacuation. Of the 13 remaining activations, four patients died and nine patients improved sufficiently for standard CCATT movement. The ALeRT initiated pumpless extracorporeal lung assistance six times, but only once to facilitate evacuation. Two patients were supported with full extracorporeal membrane oxygenation support after evacuation due to progressive respiratory failure. CONCLUSIONS: ALeRT successfully transported 24 casualties from the combat zones to Germany. Without the ALeRT, these patients would have remained in the combat theater as significant consumers of limited deployed medical resources. Pumpless extracorporeal lung assistance is already within the ALeRT armamentarium, but has only been used for one aeromedical evacuation. Modern extracorporeal membrane oxygenation systems hold promise as a feasible capability for aeromedical evacuation.

Executive summary: Guidelines for the prevention of infections associated with combat-related injuries: 2011 update: endorsed by the Infectious Diseases Society of America and the Surgical Infection Society.

Despite advances in resuscitation and surgical management of combat wounds, infection remains a concerning and potentially preventable complication of combat-related injuries. Interventions currently used to prevent these infections have not been either clearly defined or subjected to rigorous clinical trials. Current infection prevention measures and wound management practices are derived from retrospective review of wartime experiences, from civilian trauma data, and from in vitro and animal data. This update to the guidelines published in 2008 incorporates evidence that has become available since 2007. These guidelines focus on care provided within hours to days of injury, chiefly within the combat zone, to those combat-injured patients with open wounds or burns. New in this update are a consolidation of antimicrobial agent recommendations to a backbone of high-dose cefazolin with or without metronidazole for most postinjury indications and recommendations for redosing of antimicrobial agents, for use of negative pressure wound therapy, and for oxygen supplementation in flight.

Guidelines for the prevention of infections associated with combat-related injuries: 2011 update: endorsed by the Infectious Diseases Society of America and the Surgical Infection Society.

Despite advances in resuscitation and surgical management of combat wounds, infection remains a concerning and potentially preventable complication of combat-related injuries. Interventions currently used to prevent these infections have not been either clearly defined or subjected to rigorous clinical trials. Current infection prevention measures and wound management practices are derived from retrospective review of wartime experiences, from civilian trauma data, and from in vitro and animal data. This update to the guidelines published in 2008 incorporates evidence that has become available since 2007. These guidelines focus on care provided within hours to days of injury, chiefly within the combat zone, to those combat-injured patients with open wounds or burns. New in this update are a consolidation of antimicrobial agent recommendations to a backbone of high-dose cefazolin with or without metronidazole for most postinjury indications, and recommendations for redosing of antimicrobial agents, for use of negative pressure wound therapy, and for oxygen supplementation in flight.

Performance of portable ventilators for mass-casualty care.

INTRODUCTION: Disasters and mass-casualty scenarios may overwhelm medical resources regardless of the level of preparation. Disaster response requires medical equipment, such as ventilators, that can be operated under adverse circumstances and should be able to provide respiratory support for a variety of patient populations. OBJECTIVE: The objective of this study was to evaluate the performance of three portable ventilators designed to provide ventilatory support outside the hospital setting and in mass-casualty incidents, and their adherence to the Task Force for Mass Critical Care recommendations for mass-casualty care ventilators. METHODS: Each device was evaluated at minimum and maximum respiratory rate and tidal volume settings to determine the accuracy of set versus delivered VT at lung compliance settings of 0.02, 0.08 and 0.1 L/cm H20 with corresponding resistance settings of 10, 25, and 5 cm H2O/L/sec, to simulate patients with ARDS, severe asthma, and normal lungs. Additionally, different FIO2 settings with each device (if applicable) were evaluated to determine accuracy of FIO2 delivery and evaluate the effect on delivered VT. Ventilators also were tested for duration of battery life. RESULTS: VT decreased with all three devices as compliance decreased. The decrease was more pronounced when the internal compressor was activated. At the 0.65 FIO2 setting on the MCV 200, the measured FIO2 varied widely depending on the set VT. Battery life range was 311-582 minutes with the 73X having the longest battery life. Delivered VT decreased toward the end of battery life with the SAVe having the largest decrease. The respiratory rate on the SAVe also decreased approaching the end of battery life. CONCLUSION: The 73X and MCV 200 were the closest to satisfying the Task Force for Mass Critical Care requirements for mass casualty ventilators, although neither had the capability to provide PEEP. The 73X provided the most consistent tidal volume delivery across all compliances, had the longest battery duration and the least decline in VT at the end of battery life.

Laboratory evaluation of the SAVe simplified automated resuscitator.

OBJECTIVE: To evaluate the SAVe simplified automated ventilator in a laboratory setting to determine performance characteristics, accuracy of tidal volume delivery at various lung compliance, and battery life at sea level and at altitude. METHODS: Three SAVe ventilators were used for the evaluation. Each ventilator was attached to a test lung with volume, pressure, and flow measured with a fixed orifice pneumotachometer and FIO2 measured with a fast-response oxygen analyzer. All measurements were made at sea level, 4,000, 8,000, 12,000, and 18,000 feet. RESULTS: Delivered tidal volume and inspiratory time varied when changing lung model conditions as well as between devices within the same lung model condition. The largest reduction in tidal volume was at the lowest compliance. CONCLUSIONS: The SAVe could potentially be used for ventilatory support of carefully selected military casualties but caregivers must be aware of the limitations.

Traumatic brain injury and aeromedical evacuation: when is the brain fit to fly?

BACKGROUND: To review the inflammatory sequelae of traumatic brain injury (TBI) and altitude exposure and discuss the potential impact of aeromedical evacuation (AE) on this process. METHODS: Literature review and expert opinion regarding the inflammatory effects of TBI and AE. RESULTS: Traumatic brain injury has been called the signature injury of the current military conflict. As a result of the increasing incidence of blast injury, TBI is responsible for significant mortality and enduring morbidity in injured soldiers. Common secondary insults resulting from post-traumatic cerebral inflammation are recognized to adversely impact outcome. AE utilizing Critical Care Air Transport Teams has become a standard of care practice following battlefield injury, to quickly and safely transport critically injured soldiers to more sophisticated echelons of care. Exposure to the hypobaric conditions of the AE process may impose an additional physiologic risk on the TBI patient as well as a "second hit" inflammatory stimulus. CONCLUSIONS: We review the known inflammatory effects of TBI and altitude exposure and propose that optimizing the post-traumatic inflammatory profile may assist in determining an ideal time to fly for head-injured soldiers.