Serum Indicators of Oxidative Damage from Embedded Metal Fragments in a Rat Model.

Injuries suffered in armed conflicts often result in embedded metal fragments. Standard surgical guidance recommends leaving embedded fragments in place except under certain circumstances in an attempt to avoid the potential morbidity that extensive surgery often brings. However, technological advances in weapon systems and insurgent use of improvised explosive devices now mean that practically any metal can be found in these types of wounds. Unfortunately, in many cases, the long-term toxicological properties of embedded metals are not known, further complicating treatment decisions. Because of concerns over embedded metal fragment injuries, the U.S. Departments of Defense and Veterans' Affairs developed a list of "metals of concern" for these types of injuries. In this study, we selected eight of these metals including tungsten, nickel, cobalt, iron, copper, aluminum, lead, and depleted uranium to investigate the long-term health effects using a rodent model developed in our Institute to study embedded fragment injuries. In this report, we show that metals surgically implanted into the gastrocnemius muscle of laboratory rats to simulate a shrapnel wound induce a variety of cytokines including IFN-γ, IL-4, IL-5, IL-6, IL-10, and IL-13. TNF-α and KC/GRO were not affected, and IL-1ß was below the limit of detection. Serum levels of C-reactive protein were also affected, increasing with some metals and decreasing with others. The TBARS assay, an assessment of lipid peroxidation, demonstrated that implanted aluminum and lead increased markers of lipid peroxidation in serum. Taken together, the results suggest that serum cytokine levels, as well as other indicators of oxidative damage, may prove useful in identifying potential adverse health effects of embedded metals.

Noninvasive SpO2/FiO2 ratio as surrogate for PaO2/FiO2 ratio during simulated prolonged field care and ground and high-altitude evacuation.

BACKGROUND: Diagnosis of lung injury requires invasive blood draws to measure oxygen tension in blood. This capability is nonexistent in austere settings and during prolonged field care (PFC), that is, medical care characterized by inability to evacuate casualties from the point of injury for up to 72 hours. We analyzed pulse-oximeter-derived noninvasive SpO2 and assessed the SpO2/FiO2 ratio (SFR) as a surrogate for the PaO2/FiO2 ratio (PFR), an accepted marker of lung function. We hypothesized that SFR is a suitable surrogate for PFR in a data set from animal models of combat-relevant trauma, PFC, and aeromedical evacuation. METHODS: Data from anesthetized swine (N = 30) subjected to combat relevant trauma, resuscitation, and critical care interventions were analyzed. Pairwise correlations and Bland-Altman and regression analyses were performed to compare PFR and SFR, based on averaged SpO2 values obtained from two monitoring devices. RESULTS: We performed 683 pairwise correlations. SpO2/FiO2 ratio was numerically higher than PFR with a 313 cutoff values for acute respiratory distress syndrome (ARDS) (PFR ≥300). Sensitivity/specificity for detection of mild ARDS was 75%/73% with a 200 to 300 PFR range corresponding to 252 to 312 SFR range. For moderate ARDS, sensitivity/specificity was 61%/93% with a 100 to 200 PFR range corresponding to 191 to 251 SFR range. For severe ARDS, sensitivity/specificity was 49%/97% with a 0 to 100 PFR range corresponding to 0 to 190 SFR range. For all groups, areas under the receiver operating characteristic curves ranged from 0.76 to 0.98. CONCLUSION: SpO2/FiO2 ratio is a useful surrogate for PFR when arterial blood gas testing is not available during dynamically changing physiologic conditions, for example, during austere conditions, PFC, or aeromedical evacuation, and may permit early detection of casualties in need of lung-specific life-saving interventions. Studies in critically ill humans are warranted.

Low Vitamin D States Observed in U.S. Marines and Navy Sailors with Early Multi-Symptom Illness.

Research has implicated immune system inflammation as an underlying etiology of multi-symptom illnesses, and vitamin D has been shown to have a significant role in immune system function. In this retrospective review performed on the medical charts of service members who presented with signs and symptoms of multi-symptom illnesses, we focused on serum 25(OH)D3 levels and looked for associations of vitamin D status (deficient, insufficient, and normal) with age (20-31 years versus 31-56 years) and deployment status (war zones versus other). Two groups (U.S. Marines and Navy Sailors) were sampled and both showed high incidences of below normal vitamin D levels. However, with the Marines, age-related differences in serum levels (p = 0.009) were found only among those who deployed to Iraq/Afghanistan in comparison to those in non-combat locations. The comparison within the Navy sample showed that mobilized sailors had lower 25(OH)D3 levels than the group that did not deploy (p = 0.04). In addition, 100% of the sailors who deployed had below normal levels versus only 33% in the cadre group. The data suggest that personnel returning from a war zone with signs of early multi-symptom illness should be checked for low vitamin D status.

How shall we transfuse Hippolyta?

The US Department of Defense recently made the decision to open direct ground combat roles to women. Blood product transfusion is an essential component of the US Military guidelines for tactical combat casualty care and damage control resuscitation, but blood transfusion carries with it the specific side effect of alloimmunization-a uniquely significant side effect for young women who may desire subsequent pregnancies. Presently to be considered are the changes that may need to be made to blood transfusion in the setting of battlefield medicine to optimally care for combat-injured women, as a majority of the existing data regarding the risks of transfusion in the trauma setting involve predominantly men. This article delves into the possibility of a new cohort of women at risk for hemolytic disease of the fetus and newborn, the need for women's health professionals to appropriately counsel women considering serving in direct ground combat roles about this specific risk, and the appropriate steps that should be considered to provide these women optimal medical care.

Resuscitation During Critical Care Transportation in Afghanistan.

OBJECTIVE: These data describe the critical care procedures performed on, and the resuscitation markers of, critically wounded personnel in Afghanistan following point of injury (POI) transports and intratheater transports. Providing this information may help inform discussion on the design of critical care transportation platforms for future conflicts. METHODS: The Department of Defense Trauma Registry (DoDTR) was queried for descriptive data on combat casualties with Injury Severity Score (ISS) greater than 15 who were transported in Operation Enduring Freedom (OEF) from 1 January 2010 to 31 December 2010. Both POI transportation events and interfacility transportation events were reviewed. Base deficit (BD) was evaluated as a maker of resuscitation, and international normalized ratio (INR) was evaluated as a measure of coagulopathy. RESULTS: There were 1198 transportation events that occurred during the study period--634 (53%) transports from the POI and 564 (47%) intratheater transports. Critical care interventions were performed during 147 (12.3%) transportation events, including intubation, cricothyrotomy, double-lumen endotracheal tube placement, needle or tube thoracostomy, central venous access placement, and cardiopulmonary resuscitation. The mean BD on arrival in the emergency department was -5.4 mEq/L for POI transports and 0.68 mEq/L intratheater transports (ρ<.001). The mean INR on arrival in the emergency department was 1.48 for POI transports and 1.21 for intratheater transports (ρ<.001). CONCLUSIONS: Critical care interventions were needed frequently during evacuation of severely injured personnel. Furthermore, many troops arrived acidotic and coagulopathic following initial transport from POI. Together, these data suggest that a platform capable of damage control resuscitation and critical care interventions may be warranted on longer transports of more critically injured patients.