Genomic surveillance of SARS-CoV-2 in US military compounds in Afghanistan reveals multiple introductions and outbreaks of Alpha and Delta variants.

BACKGROUND: With the emergence and spread of SARS-CoV-2 variants, genomic epidemiology and surveillance have proven invaluable tools for variant tracking. Here, we analyzed SARS-CoV-2 samples collected from personnel located at the US/NATO bases across Afghanistan. RESULTS: Sequencing and phylogenetic analyses revealed at least 16 independent introductions of SARS-CoV-2 into four of these relatively isolated compounds during April and May 2021, including multiple introductions of Alpha and Delta variants. Four of the introductions resulted in sustained spread of the virus within, and in two cases between, the compounds. Three of these outbreaks, one Delta and two Alpha, occurred simultaneously. CONCLUSIONS: Even in rigorously controlled and segregated environments, SARS-CoV-2 introduction and spread may occur frequently.

Ketamine versus hydromorphone patient-controlled analgesia for acute pain in trauma patients.

BACKGROUND: It is unknown whether ketamine administered via patient-controlled analgesia (PCA) provides adequate analgesia while reducing opioid consumption in the traumatically injured patient. Differences in opioid consumption, pain scores, and adverse effects between ketamine and hydromorphone PCA were studied. MATERIALS AND METHODS: This is an investigator-initiated, single-center, double-blinded, randomized, pilot trial conducted from 2014 to 2016 at a level 1 trauma center. Nonintubated trauma patients in intensive care, who were receiving PCA, were randomized to ketamine or hydromorphone PCA plus opioid analgesics for breakthrough pain. RESULTS: Twenty subjects were randomized. There was no difference in median daily breakthrough opioid use (10 [0.63-19.38] mg versus 10 [4.38-22.5] mg, P = 0.55). Subjects in the ketamine group had lower median cumulative opioid use on therapy day 1 than the hydromorphone group (4.6 [2.5-15] mg versus 41.8 [31.8-50] mg, P < 0.001), as well as in the first 48 h (10 [3.3-15] mg versus 48.5 [32.1-67.5] mg, P < 0.001) and first 72 h (10 [4.2-15] mg versus 42.5 [31.7-65.2] mg, P < 0.001) of therapy. Daily oxygen supplementation requirements were lower in the ketamine group (0.5 [0-1.5] L/min versus 2 [0.5-3] L/min, P = 0.020). Hallucinations occurred more frequently in the ketamine group (40% versus 0%, P = 0.090). CONCLUSIONS: Ketamine PCA led to lower cumulative opioid consumption and lower oxygen supplementation requirements, though hallucinations occurred more frequently with use of ketamine. Additional studies are needed to investigate the tolerability of ketamine as an alternative to traditional opioid-based PCA.

An Analysis of the Association of Arrival Hemoglobin With Overtransfusion at 24 Hours in a Trauma Population.

BACKGROUND: Hemorrhage control and resuscitative concepts have evolved in recent years, leading to aggressive use of blood products in trauma patients. There is subsequently a potential risk for overtransfusion, adverse effects, and waste associated with unnecessary transfusion. Methods for conserving blood products are of particular importance in future large-scale combat operations where supply chains are likely to be strained. This study examined the association of emergency department (ED) arrival hemoglobin (HGB) with overtransfusion among survivors at 24 hours after major trauma at a military trauma center. MATERIALS AND METHODS: We performed a retrospective cohort study of patients who had a "major trauma" activation and received any red blood cells. Overtransfusion was defined as a HGB level ≥11.0 g/dL at 24 hours (outcome variable). Multivariable logistic regression statistics were used to compare groups and adjust for confounders (injury severity score, arrival modified shock index, injury type, age, and gender). A receiver operating characteristic was constructed with overtransfusion at 24 hours as the outcome (binary) and arrival HGB (continuous) as the independent variable. RESULTS: A total of 382 patients met inclusion criteria. Overtransfusion occurred in 30.4% (n = 116) of patients, with mean ED HGB levels of 13.2 g/dL (12.9 to 13.6) versus 11.6 g/dL (11.3 to 11.8, P < .001). Receiver operating characteristic analysis showed that ED HGB was highly sensitive (0.931) for predicting 24-hour overtransfusion. In our multivariable logistic regression analysis, when adjusting for injury severity score, arrival modified shock index, injury type, age, and gender, we found that the ED HGB value had a per-unit odds ratio of 1.60 (95% CI, 1.38 to 1.86) for 24-hour overtransfusion. Hospital and intensive care unit length of stay, mechanical ventilator days, and mortality did not increase. CONCLUSION: We found that the arrival HGB value was associated with overtransfusion among 24-hour survivors in a civilian trauma setting. Our findings will inform future prospective studies that investigate blood sparing clinical practice guidelines.

Pre-hospital oxygen therapy.

Oxygen use in prehospital care is aimed at treating or preventing hypoxemia. However, excess oxygen delivery has important consequences in select patients, and hyperoxia can adversely impact outcome. The unique environment of prehospital care poses logistical and educational challenges. Oxygen therapy in prehospital care should be provided to patients with hypoxemia and titrated to achieve normoxemia. Changes to the current practice of oxygen delivery in prehospital care are needed.

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.

Lessons from the tip of the spear: medical advancements from Iraq and Afghanistan.

The conflicts in Iraq and Afghanistan have seen the advancement of combat medicine. The nature of the conflicts, with troops located in remote areas and faced with explosive ordinance designed to focus massive injuries on dismounted personnel, have forced military medical personnel to adapt accordingly. There has been a rekindling of interest in the use of tourniquets to stop exsanguination from extremity wounds, as well as in the transfusion of fresh whole blood from walking blood banks. These previously discarded techniques, born on battlefields long ago, have been refined and perfected and have led to an unprecedented survival for our wounded warriors. New developments in the field of applied hemostatic agents, damage control surgical techniques, and the implementation of an efficient evacuation system have also contributed to these results. The field of combat medicine has taken several concepts initially designed in civilian settings, such as temporary abdominal packing and vascular shunting, and adapted them to the military setting to provide state of the art trauma management to our troops in combat. In turn, developments in the resuscitation of the trauma patient, using increased blood and plasma products and less crystalloid, have been pioneered in conflict and transitioned to the civilian sector. Advancements made during the wars in Iraq and Afghanistan, as well as those still being developed, will shape the care of the injured patient, in both civilian and military settings, for the foreseeable future.

Use of a single ventilator to support 4 patients: laboratory evaluation of a limited concept.

INTRODUCTION: A mass-casualty respiratory failure event where patients exceed available ventilators has spurred several proposed solutions. One proposal is use of a single ventilator to support 4 patients. METHODS: A ventilator was modified to allow attachment of 4 circuits. Each circuit was connected to one chamber of 2 dual-chambered, test lungs. The ventilator was set at a tidal volume (V(T)) of 2.0 L, respiratory frequency of 10 breaths/min, and PEEP of 5 cm H(2)O. Tests were repeated with pressure targeted breaths at 15 cm H(2)O. Airway pressure, volume, and flow were measured at each chamber. The test lungs were set to simulate 4 patients using combinations of resistance (R) and compliance (C). These included equivalent C and R, constant R and variable C, constant C and variable R, and variable C and variable R. RESULTS: When R and C were equivalent the V(T) distributed to each chamber of the test lung was similar during both volume (range 428-442 mL) and pressure (range 528-544 mL) breaths. Changing C while R was constant resulted in large variations in delivered V(T) (volume range 257-621 mL, pressure range 320-762 mL). Changing R while C was constant resulted in a smaller variation in V(T) (volume range 418-460 mL, pressure range 502-554 mL) compared to only C changes. When R and C were both varied, the range of delivered V(T) in both volume (336-517 mL) and pressure (417-676 mL) breaths was greater, compared to only R changes. CONCLUSIONS: Using a single ventilator to support 4 patients is an attractive concept; however, the V(T) cannot be controlled for each subject and V(T) disparity is proportional to the variability in compliance. Along with other practical limitations, these findings cannot support the use of this concept for mass-casualty respiratory failure.

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.

New strategies for massive transfusion in the bleeding trauma patient.

Trauma continues to be the leading cause of death among those younger than 40 years. A major cause of death within the first 24 hours is hemorrhage. Many of these patients present with severe coagulopathy and require massive transfusion. Earlier control of coagulopathy has been shown to improve survival. To address coagulopathy sooner, changes in the way we identify and resuscitate the exsanguinating trauma patient have evolved. These changes include early identification of at-risk patients and early, aggressive transfusion of plasma and platelets. This article reviews the key massive transfusion triggers and resuscitation strategy of damage control resuscitation.

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.

All massive transfusion criteria are not created equal: defining the predictive value of individual transfusion triggers to better determine who benefits from blood.

BACKGROUND: As familiarity with military massive transfusion (MT) triggers has increased, there is a growing interest in applying these in the civilian population to initiate MT protocols (MTP) earlier. We hypothesize that these triggers do not have equal predictability for MT and understanding the contribution of each would improve our ability to initiate the MTP earlier. METHODS: All patients presenting to a Level I trauma center from October 2007 to September 2008 requiring immediate operation were included in this study. Emergency department records, operative logs, and blood transfusion data from arrival to procedure end were analyzed using multivariate regression techniques. Triggers included systolic blood pressure (SBP) <90 mm Hg, hemoglobin <11 g/dL, temperature <35.5°C, International normalized ratio (INR) >1.5, and base deficit ≥6. RESULTS: One hundred seventy patients required immediate operation with an overall survival of 91%. Transfusion of packed red blood cells was noted in 45% (77 of 170) with the mean number of transfused units highest in those meeting SBP (12.9 Units) or INR (12.3 Units) triggers. The triggers do not contribute equal predictive value for the need for transfusion with INR being the most predictive (odds ratio, 16.7; 95% confidence interval, 2-137) for any transfusion and highly predictive for the need for MT (odds ratio, 11.3; 95% confidence interval, 3-47). In fact, if patients met either INR or SBP triggers alone, they were likely to receive MT (p = 0.018 and 0.003, respectively). CONCLUSION: Triggers have differential predictive values for need for transfusion. Defining the individual utility of each criterion will help to identify those most likely to benefit from an early initiation of the MTP.

AB569, a non-toxic combination of acidified nitrite and EDTA, is effective at killing the notorious Iraq/Afghanistan combat wound pathogens, multi-drug resistant Acinetobacter baumannii and Acinetobacter spp.

Multi-drug resistant (MDR) Acinetobacter baumannii (Ab) and Acinetobacter spp. present monumental global health challenges. These organisms represent model Gram-negative pathogens with known antibiotic resistance and biofilm-forming properties. Herein, a novel, nontoxic biocide, AB569, consisting of acidified nitrite (A-NO2-) and ethylenediaminetetraacetic acid (EDTA), demonstrated bactericidal activity against all Ab and Acinetobacter spp. strains, respectively. Average fractional inhibitory concentrations (FICs) of 0.25 mM EDTA plus 4 mM A-NO2- were observed across several clinical reference and multiple combat wound isolates from the Iraq/Afghanistan wars. Importantly, toxicity testing on human dermal fibroblasts (HDFa) revealed an upper toxicity limit of 3 mM EDTA plus 64 mM A-NO2-, and thus are in the therapeutic range for effective Ab and Acinetobacter spp. treatment. Following treatment of Ab strain ATCC 19606 with AB569, quantitative PCR analysis of selected genes products to be responsive to AB569 revealed up-regulation of iron regulated genes involved in siderophore production, siderophore biosynthesis non-ribosomal peptide synthetase module (SBNRPSM), and siderophore biosynthesis protein monooxygenase (SBPM) when compared to untreated organisms. Taken together, treating Ab infections with AB569 at inhibitory concentrations reveals the potential clinical application of preventing Ab from gaining an early growth advantage during infection followed by extensive bactericidal activity upon subsequent exposures.

Divergent adaptive and innate immunological responses are observed in humans following blunt trauma.

BACKGROUND: The immune response to trauma has traditionally been modeled to consist of the systemic inflammatory response syndrome (SIRS) followed by the compensatory anti-inflammatory response syndrome (CARS). We investigated these responses in a homogenous cohort of male, severe blunt trauma patients admitted to a University Hospital surgical intensive care unit (SICU). After obtaining consent, peripheral blood was drawn up to 96 hours following injury. The enumeration and functionality of both myeloid and lymphocyte cell populations were determined. RESULTS: Neutrophil numbers were observed to be elevated in trauma patients as compared to healthy controls. Further, neutrophils isolated from trauma patients had increased raft formation and phospho-Akt. Consistent with this, the neutrophils had increased oxidative burst compared to healthy controls. In direct contrast, blood from trauma patients contained decreased naïve T cell numbers. Upon activation with a T cell specific mitogen, trauma patient T cells produced less IFN-gamma as compared to those from healthy controls. Consistent with these results, upon activation, trauma patient T cells were observed to have decreased T cell receptor mediated signaling. CONCLUSIONS: These results suggest that following trauma, there are concurrent and divergent immunological responses. These consist of a hyper-inflammatory response by the innate arm of the immune system concurrent with a hypo-inflammatory response by the adaptive arm.

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.

Maximizing oxygen delivery during mechanical ventilation with a portable oxygen concentrator.

BACKGROUND: Transportation of the critically ill or injured war fighter requires the coordinated care and judicious use of resources. Availability of oxygen (O2) supplies for the mechanically ventilated patient is crucial. Size and weight of cylinders makes transport difficult and presents an increased risk of fire. A proposed solution is to use a portable oxygen concentrator (POC) for mechanical ventilation. We tested the SeQual Eclipse II POC paired with the Impact 754 and Pulmonetics LTV-1200 ventilators in the laboratory and evaluated the fraction of inspired oxygen (FIO2) across a range of minute volumes. METHODS: Each ventilator was attached to a test lung and pressure, volume, flow, and inspired oxygen (FIO2) was measured by a gas or flow analyzer. Ventilators were tested at a tidal volume (VT) of 500 mL; an inspiratory time of 1.0 second; respiratory rates of 10, 20, and 30 breaths per minute; and positive end-expiratory pressure of 0 and 10 cm H2O. The LTV 1200 was tested with and without the expiratory bias flow. The Eclipse II was modified to provide pulse dosing on inspiration at 3 volumes (64, 128, and 192 mL) and continuous flow at 1 L/min to 3 L/min. Six combinations of ventilator settings were used with each POC setting for evaluation. O2 was injected at the ventilator gas outlet and patient y-piece for pulse dose and continuous flow. Additionally, continuous flow O2 was injected into the oxygen inlet port of the LTV 1200, and a reservoir bag, on the inlet port of the Impact 754. All tests were done with both ventilators using continuous flow, wall source O2 as a control. We also measured the FIO2 with the concentrator on the highest pulse dose setting while decreasing ventilator VT to compensate for the added volume. RESULTS: The delivered FIO2 was highest when oxygen was injected into the ventilator circuit at the patient y-piece using pulse dosing, with the VT corrected. The next highest FIO2 was with continuous flow at the inlet (LTV), and reservoir (Impact). Electrical power consumption was less during pulse dose operation. SUMMARY: Oxygen is a finite resource, which is cumbersome to transport and may present a fire hazard. The relatively high FIO2 delivered by the POC makes this method of O2 delivery a viable alternative to O2 cylinders. However, patients requiring an FIO2 of 1.0 would require additional compressed oxygen. This system allows O2 delivery up to 76% solely using electricity. An integrated ventilator or POC capable of automatically compensating VT for POC output is desirable. Further patient testing needs to be done to validate these laboratory findings.

Imaging utilization during explosive multiple casualty incidents.

BACKGROUND: Emergency radiology is a vital tool in the evaluation of victims of explosive multiple casualty incidents (MCIs). Prior reports estimate that approximately 50% of explosive MCI patients required imaging, including 7% to 22% who required computed tomography (CT) studies. This report describes the contemporary utilization of emergency radiology during the evaluation of explosive MCI victims in a modern US military trauma hospital in Iraq. We hypothesized that a much higher number of patients received imaging than has been reported previously in the literature. METHODS: We performed a retrospective chart review of records from 3 MCIs managed at the US Air Force Theater Hospital, Balad AB, Iraq between February and April 2008. All three incidents were the result of improvised explosive devices. RESULTS: Overall, 50 patients had a mean Injury Severity Score of 19 and a mortality of 8%. Ninety-two percent received imaging during their emergency department evaluation, including 90% who received CT, 70% who received X-rays, and 38% who received extended focused abdominal sonography for trauma ultrasound examinations. Overall, patients had a mean of 3.5 CTs and 1.9 X-rays during their initial assessment. Of the CTs, 93% were part of a trauma pan-scan, and 49% of the CT results were clinically significant. CONCLUSION: These results are significantly different from previous reports and indicate that victims of explosive MCIs will require more imaging, especially CT, than previously anticipated. These data will allow improved integration of radiology staffing and resource allocation into disaster management plans designed to prepare for future explosive MCIs.

Resuscitation with fresh whole blood ameliorates the inflammatory response after hemorrhagic shock.

BACKGROUND: Hemorrhagic shock is the leading cause of potentially preventable death after traumatic injury. Hemorrhage and subsequent resuscitation may result in a dysfunctional systemic inflammatory response and multisystem organ failure, leading to delayed mortality. Clinical evidence supports improved survival and reduced morbidity when fresh blood products are used as resuscitation strategies. We hypothesized that the transfusion of fresh whole blood (FWB) attenuates systemic inflammation and reduces organ injury when compared with conventional crystalloid resuscitation after hemorrhagic shock. METHODS: Male mice underwent femoral artery cannulation and hemorrhage to a systolic blood pressure of 25 mm Hg +/- 5 mm Hg. After 60 minutes, the mice were resuscitated with either FWB or lactated Ringer's solution (LR). Mice were decannulated and killed at intervals for tissue histology, serum cytokine analysis, and vascular permeability studies. Separate groups of mice were followed for survival studies. RESULTS: When compared with FWB, mice resuscitated with LR required increased resuscitation fluid volume to reach goal systolic blood pressure. When compared with sham or FWB-resuscitated mice, LR resuscitation resulted in increased serum cytokine levels of macrophage inflammatory protein-1alpha, interleukin-6, interleukin-10, macrophage-derived chemokine, KC, and granulocyte macrophage colony stimulating factor as well as increased lung injury and pulmonary capillary permeability. No survival differences were seen between animals resuscitated with LR or FWB. CONCLUSIONS: Resuscitation with LR results in increased systemic inflammation, vascular permeability, and lung injury after hemorrhagic shock. Resuscitation with FWB attenuates the inflammation and lung injury seen with crystalloid resuscitation. These findings suggest that resuscitation strategies using fresh blood products potentially reduce systemic inflammation and organ injury after hemorrhagic shock.

Recognition and management of major vessel injury during laparoscopy.

Laparoscopy is one of the most commonly performed procedures in the United States. Injury to a major retroperitoneal vessel occurs in 0.3% to 1.0% of procedures, most commonly during laparoscopic entry while placing the Veress needle or primary trocar. Fatal outcome can be related to massive gas embolism or exsanguination. Recommended treatment for gas embolism can range from supportive measures to external chest compression and insertion of a central line to withdraw gas from the right side of the heart. Recommended treatment of major vessel injury with massive hemorrhage consists of rapid laparotomy and control of hemorrhage using direct pressure until a surgeon experienced in vascular procedures arrives. When a major vessel injury occurs in a surgical facility distant from a medical center and without an available surgeon with vascular experience, based on the trauma literature, we recommend temporary control of blood loss using abdominal packing and closure (i.e., "damage control surgery") and judicious resuscitation (i.e., "damage control resuscitation") before transportation to a medical center.

Surgical response to multiple casualty incidents following single explosive events.

BACKGROUND: Modern publications on response to single explosive events are from non-US hospitals, predate current resuscitation guidelines and lack detail on surgical and intensive care unit (ICU) requirements. The objective of this study is to provide a contemporary account of surge response to multiple casualty incidences following explosive events managed at a US trauma hospital in Iraq. METHODS: Observational study and retrospective chart review of 72-hour transfusion, operating room, and ICU resource utilization from 3 multiple casualty incidences managed at the US Air Force Theater Hospital, Balad AB, Iraq between February and April 2008. RESULTS: Fifty patients were treated with a mean injury severity score of 19. Forty-eight percent (n = 24) of casualties required blood transfusion with 4 patients receiving 43% (N = 74 units) of the packed red blood cells (pRBC). An average of 3.5 and 3.8 units of pRBC and plasma, respectively, was transfused per casualty (pRBC:plasma ratio of 1:1.1). Seventy-six percent (n = 38) of patients required immediate operation upon initial presentation. A total of 191 procedures were performed in parallel during 75 operations (3.8 procedures per casualty). Fifty percent (n = 25) of patients required ICU admission with nearly the same number (n = 24) requiring mechanical ventilator support beyond that required for operation. All cause, in-hospital mortality was 8% (n = 4). CONCLUSIONS: Results from this study provide a contemporary assessment of transfusion, surgical, and intensive care resource requirements after a single explosive event. Data from this experience may translate into useful guidelines for emergency planners worldwide.

Gammadelta T cells mitigate the organ injury and mortality of sepsis.

Sepsis is a difficult condition to treat and is associated with a high mortality rate. Sepsis is known to cause a marked depletion of lymphocytes, although the function of different lymphocyte subsets in the response to sepsis is unclear. gammadelta T cells are found largely in epithelial-rich tissues, and previous studies of gammadelta T cells in models of sepsis have yielded divergent results. In the present study, we examined the function of gammadelta T cells during sepsis in mice using cecal ligation and puncture (CLP). Mice deficient in gammadelta T cells had decreased survival times and increased tissue damage after CLP compared with wild-type mice. Furthermore, bacterial load was increased in gammadelta T cell-deficient mice, yet antibiotic treatment did not change mortality. Additionally, we found that recruitment of neutrophils and myeloid suppressor cells to the site of infection was diminished in gammadelta T cell-deficient mice. Finally, we found that circulating levels of IFN-gamma were increased, and systemic levels of IL-10 were decreased in gammadelta T cell-deficient mice after CLP compared with wild-type mice. gammadelta T cell-deficient mice also had increased intestinal permeability after CLP compared with wild-type mice. Neutralization of IFN-gamma abrogated the increase in intestinal permeability in gammadelta T cell-deficient mice. The intestines taken from gammadelta T cell-deficient mice had decreased myeloperoxidase yet had increased tissue damage as compared with wild-type mice. Collectively, our data suggest that gammadelta T cells modulate the response to sepsis and may be a potential therapeutic target.