Amy T. Makley

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 Ringers 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.

Update on the Critical Care Management of Severe Burns

Care of the severely injured patient with burn requires correct diagnosis, appropriately tailored resuscitation, and definitive surgical management to reduce morbidity and mortality. Currently, mortality rates related to severe burn injuries continue to steadily decline due to the standardization of a multidisciplinary approach instituted at tertiary health care centers. Prompt and accurate diagnoses of burn wounds utilizing Lund-Browder diagrams allow for appropriate operative and nonoperative management. Coupled with diagnostic improvements, advances in resuscitation strategies involving rates, volumes, and fluid types have yielded demonstrable benefits related to all aspects of burn care. More recently, identification of comorbid conditions such as inhalation injury and malnutrition have produced appropriate protocols that aid the healing process in severely injured patients with burn. As more patients survive larger burn injuries, the early diagnosis and successful treatment of secondary and tertiary complications are becoming commonplace. While advances in this area are exciting, much work to elucidate immune pathways, diagnostic tests, and effective treatment regimens still remain. This review will provide an update on the critical care management of severe burns, touching on accurate diagnosis, resuscitation, and acute management of this difficult patient population.

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.

Preinjury alcohol exposure attenuates the neuroinflammatory response to traumatic brain injury

BACKGROUND Traumatic brain injury (TBI) initiates a neuroinflammatory response that increases the risk of TBI-related mortality. Acute alcohol intoxication at the time of TBI is associated with improved survival. Ethanol is recognized as a systemic immunomodulator that may also impart neuroprotection. The effects of alcohol on TBI-induced neuroinflammation, however, are unknown. We hypothesized that ethanol treatment prior to TBI may provide neuroprotection by diminishing the neuroinflammatory response to injury. MATERIALS AND METHODS Mice underwent gavage with ethanol (EtOH) or water (H2O) prior to TBI. Animals were subjected to blunt TBI or sham injury (Sham). Posttraumatic rapid righting reflex (RRR) and apnea times were assessed. Cerebral and serum samples were analyzed by ELISA for inflammatory cytokine levels. Serum neuron-specific enolase (NSE), a biomarker of injury severity, was also measured. RESULTS Neurologic recovery from TBI was more rapid in H2O-treated mice compared with EtOH-treated mice. However, EtOH/TBI mice had a 4-fold increase in RRR time compared with EtOH/Sham, whereas H2O/TBI mice had a 15-fold increase in RRR time compared with H2O/Sham. Ethanol intoxication at the time of TBI significantly increased posttraumatic apnea time. Preinjury EtOH treatment was associated with reduced levels of proinflammatory cytokines IL-6, KC, MCP-1, and MIP-1α post TBI. NSE was significantly increased post injury in the H2O/TBI group compared with H2O/Sham but was not significantly reduced by EtOH pretreatment. CONCLUSIONS Alcohol treatment prior to TBI reduces the local neuroinflammatory response to injury. The decreased neurologic and inflammatory impact of TBI in acutely intoxicated patients may be responsible for improved clinical outcomes.

Murine blood banking: characterization and comparisons to human blood.

Blood transfusion remains an essential treatment of acute anemia. Current storage processes allow the efficient administration of blood products. Erythrocytes undergo morphological and biochemical changes during storage that may affect outcomes after transfusion. A reliable small-animal model would be ideal to examine the effects of stored blood products after transfusion. The objective of this study was to characterize the storage of murine erythrocytes for future application to animal models of acute anemia. Blood samples were collected from male mice and human volunteers, separated into components, and stored. At intervals, morphological and biochemical analysis was performed. Lactate, potassium, hemoglobin, and hemolysis were determined, and cell morphology was evaluated with light microscopy. Murine packed red blood cells (pRBCs) aged more rapidly than human samples. Murine pRBCs exhibited higher lactate levels (34.9 ± 1.3 mmol/L vs. 18.1 ± 1.0 mmol/L, mouse vs. human) and more severe acidosis as indicated by pH (6.56 ± 0.02 vs. 6.79 ± 0.04, mouse vs. human). Murine pRBCs hemolyzed earlier (11.2 ± 3.7 g vs. 0.7 ± 0.3 g, mouse vs. human after 21 days of storage) and more rapidly than human pRBCs. Corpuscular changes consistent with red cell storage lesions appeared earlier in murine samples compared with human stored pRBCs. Compared with human pRBCs, murine pRBCs exhibit similar but more accelerated aging processes under standard storage conditions. Characterization of the murine red cell storage lesion will allow the application of stored blood components to future investigations into the treatment of acute anemia in experimental murine models.

Resuscitation with washed aged packed red blood cell units decreases the proinflammatory response in mice after hemorrhage.

BACKGROUND Resuscitation with blood products instead of crystalloid in the treatment of hemorrhagic shock has been associated with improved outcomes in trauma patients requiring massive transfusions and transfusion of fresh products results in reduced morbidity and mortality compared with aged blood. Processes to eliminate harmful components of aged blood are under investigation. We hypothesized that washing blood would reduce levels of proinflammatory mediators in stored units, and resuscitation with washed units would attenuate the proinflammatory response in mice after hemorrhagic shock. METHODS Mice underwent pressure-controlled hemorrhage and resuscitation with fresh packed red blood cells (pRBCs) or 15-day-old washed or unwashed pRBCs. Cytokine concentrations in donor samples and recipient serum were measured. In addition, cytokine concentrations were measured in 15-day-old units that underwent three interval washes versus one poststorage wash. RESULTS Blood stored for 15 days demonstrated increased levels of interleukin 1&agr;, keratinocyte chemoattractant, macrophage inflammatory protein 1&agr;, and macrophage inflammatory protein 2 compared with fresh units. Washing 15-day-old pRBCs reduced concentrations of these cytokines. Cytokine levels in stored units that underwent multiple washes versus a single wash were not different. Mice resuscitated with 15-day-old unwashed pRBCs had increased levels of serum cytokines compared with mice resuscitated with fresh and 15-day-old washed pRBCs. CONCLUSION Aged pRBC units have elevated levels of proinflammatory cytokines compared with fresh units, and washing aged units after storage reduces cytokine concentrations. Resuscitation with washed units blunts the proinflammatory response in mice after hemorrhage. Washing aged pRBCs may improve the safety profile of aged units and may result in improved outcomes in subjects after hemorrhagic shock and resuscitation.

All the bang without the bucks: Defining essential point-of-care testing for traumatic coagulopathy

BACKGROUND Rapid assessment and treatment of coagulopathy reduces postinjury morbidity and mortality. Although thrombelastography (TEG) may be more accurate and efficient than conventional coagulation tests, it requires significant financial and personnel investments. We hypothesized that point-of-care international normalized ratio (POC INR) may provide a rapid and accurate alternative to TEG. METHODS A retrospective review of sequential trauma patients who underwent both POC INR and rapid TEG (r-TEG) testing upon presentation to a Level I trauma center from July 2012 to December 2013 was performed. POC INR was compared with r-TEG values (R value, K time, &agr; angle, maximum amplitude, percent clot lysis in 30 minutes) and transfusion requirements. Vital signs, admission laboratory values, and injury severity were analyzed. POC INR and venous blood gas testing was performed in the emergency department. All results and Pearson correlations noted were significant if p < 0.05. RESULTS We identified 628 trauma patients with concomitant r-TEG and POC INR testing. Median Injury Severity Score (ISS) was 13, 20% arrived in shock (base value < −5), 21% were transfused, and 11% died. POC INR correlated with all r-TEG values, with stronger correlations for patients in shock. POC INR and r-TEG had similar correlations with blood products transfused at 4 hours and 24 hours, but only POC INR predicted substantial bleeding and massive transfusion. POC INR also correlated strongly with standard INR testing. POC INR test duration was less than 1 minute, compared with at least 30 minutes for r-TEG. Total cohort charges for POC INR were estimated at

Damage control resuscitation decreases systemic inflammation after hemorrhage.

21,980 versus

Microparticles impact coagulation after traumatic brain injury

396,896 for r-TEG. CONCLUSION POC INR testing is faster and cheaper than r-TEG. In addition, POC INR correlates not only with r-TEG values but also with acute blood product transfusions. POC INR provides a practical alternative for rapid coagulopathy assessment in the trauma patient at institutions that lack TEG capability. LEVEL OF EVIDENCE Diagnostic study, level III. Therapeutic/care management study, level IV.

Posttraumatic stress disorder in the pediatric trauma patient.

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.