Posterior Reversible Encephalopathy Syndrome and Pre-eclampsia/Eclampsia: Anesthetic Implications and Management.

Posterior reversible encephalopathy syndrome (PRES) is a rare neurologic disorder that has recently become more frequently diagnosed. While the exact etiology of PRES remains unclear, multiple diseases are associated with PRES. Moreover, there is increasing recognition of the association of PRES in pre-eclampsia/eclampsia with advancements in imaging techniques and increased awareness of the disorder. While pre-eclampsia/eclampsia alone presents unique perioperative challenges, PRES further complicates anesthetic management. Unfortunately, the anesthetic management for these critically ill and complex patients is not well elucidated and it is unclear whether the anesthetic choice may actually worsen neurologic symptoms. We describe two different presentations of PRES with pre-eclampsia/eclampsia, their anesthetic implications, and management.

Computerized Diagnostic Assistant for the Automatic Detection of Pneumothorax on Ultrasound: A Pilot Study.

INTRODUCTION: Bedside thoracic ultrasound (US) can rapidly diagnose pneumothorax (PTX) with improved accuracy over the physical examination and without the need for chest radiography (CXR); however, US is highly operator dependent. A computerized diagnostic assistant was developed by the United States Army Institute of Surgical Research to detect PTX on standard thoracic US images. This computer algorithm is designed to automatically detect sonographic signs of PTX by systematically analyzing B-mode US video clips for pleural sliding and M-mode still images for the seashore sign. This was a pilot study to estimate the diagnostic accuracy of the PTX detection computer algorithm when compared to an expert panel of US trained physicians. METHODS: This was a retrospective study using archived thoracic US obtained on adult patients presenting to the emergency department (ED) between 5/23/2011 and 8/6/2014. Emergency medicine residents, fellows, attending physicians, physician assistants, and medical students performed the US examinations and stored the images in the picture archive and communications system (PACS). The PACS was queried for all ED bedside US examinations with reported positive PTX during the study period along with a random sample of negatives. The computer algorithm then interpreted the images, and we compared the results to an independent, blinded expert panel of three physicians, each with experience reviewing over 10,000 US examinations. RESULTS: Query of the PACS system revealed 146 bedside thoracic US examinations for analysis. Thirteen examinations were indeterminate and were excluded. There were 79 true negatives, 33 true positives, 9 false negatives, and 12 false positives. The test characteristics of the algorithm when compared to the expert panel were sensitivity 79% (95 % CI [63-89]) and specificity 87% (95% CI [77-93]). For the 20 images scored as highest quality by the expert panel, the algorithm demonstrated 100% sensitivity (95% CI [56-100]) and 92% specificity (95% CI [62-100]). CONCLUSION: This novel computer algorithm has potential to aid clinicians with the identification of the sonographic signs of PTX in the absence of expert physician sonographers. Further refinement and training of the algorithm is still needed, along with prospective validation, before it can be utilized in clinical practice.

Comparison of platelet transfusion as fresh whole blood versus apheresis platelets for massively transfused combat trauma patients (CME).

BACKGROUND: At major combat hospitals, the military is able to provide blood products to include apheresis platelets (aPLT), but also has extensive experience using fresh whole blood (FWB). In massively transfused trauma patients, we compared outcomes of patients receiving FWB to those receiving aPLT. STUDY DESIGN AND METHODS: This study was a retrospective review of casualties at the military hospital in Baghdad, Iraq, between January 2004 and December 2006. Patients requiring massive transfusion (≥10 units in 24 hr) were divided into two groups: those receiving FWB (n = 85) or aPLT (n = 284) during their resuscitation. Admission characteristics, resuscitation, and survival were compared between groups. Multivariate regression analyses were performed comparing survival of patients at 24 hours and at 30 days. Secondary outcomes including adverse events and causes of death were analyzed. RESULTS: Unadjusted survival between groups receiving aPLT and FWB was similar at 24 hours (84% vs. 81%, respectively; p = 0.52) and at 30 days (60% versus 57%, respectively; p = 0.72). Multivariate regression failed to identify differences in survival between patients receiving PLT transfusions either as FWB or as aPLT at 24 hours or at 30 days. CONCLUSIONS: Survival for massively transfused trauma patients receiving FWB appears to be similar to patients resuscitated with aPLT. Prospective trials will be necessary before consideration of FWB in the routine management of civilian trauma. However, in austere environments where standard blood products are unavailable, FWB is a feasible alternative.

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.

Warm fresh whole blood is independently associated with improved survival for patients with combat-related traumatic injuries.

BACKGROUND: Increased understanding of the pathophysiology of the acute coagulopathy of trauma has lead many to question the current transfusion approach to hemorrhagic shock. We hypothesized that warm fresh whole blood (WFWB) transfusion would be associated with improved survival in patients with trauma compared with those transfused only stored component therapy (CT). METHODS: We retrospectively studied US Military combat casualty patients transfused >or=1 unit of red blood cells (RBCs). The following two groups of patients were compared: (1) WFWB, who were transfused WFWB, RBCs, and plasma but not apheresis platelets and (2) CT, who were transfused RBC, plasma, and apheresis platelets but not WFWB. The primary outcomes were 24-hour and 30-day survival. RESULTS: Of 354 patients analyzed there were 100 in the WFWB and 254 in the CT group. Patients in both groups had similar severity of injury determined by admission eye, verbal, and motor Glasgow Coma Score, base deficit, international normalized ratio, hemoglobin, systolic blood pressure, and injury severity score. Both 24-hour and 30-day survival were higher in the WFWB cohort compared with CT patients, 96 of 100 (96%) versus 223 of 254 (88%), (p = 0.018) and 95% to 82%, (p = 0.002), respectively. An increased amount (825 mL) of additives and anticoagulants were administered to the CT compared with the WFWB group, (p < 0.001). Upon multivariate logistic regression the use of WFWB and the volume of WFWB transfused was independently associated with improved 30-day survival. CONCLUSIONS: In patients with trauma with hemorrhagic shock, resuscitation strategies that include WFWB may improve 30-day survival, and may be a result of less anticoagulants and additives with WFWB use in this population.

An evaluation of the impact of apheresis platelets used in the setting of massively transfused trauma patients.

INTRODUCTION: Trauma is a major cause of morbidity and mortality worldwide. Of patients arriving to trauma centers, patients requiring massive transfusion (MT, >or=10 units in 24 hours) are a small patient subset but are at the highest risk of mortality. Transfusion of appropriate ratios of blood products to such patients has recently been an area of interest to both the civilian and military medical community. Plasma is increasingly recognized as a critical component, though less is known about appropriate ratios of platelets. Combat casualties managed at the busiest combat hospital in Iraq provided an opportunity to examine this question. METHODS: In-patient records for 8,618 trauma casualties treated at the military hospital in Baghdad more than a 3-year interval between January 2004 and December 2006 were retrospectively reviewed and patients requiring MT (n = 694) were identified. Patients who required MT in the first 24 hours and did not receive fresh whole blood were divided into study groups defined by source of platelets: (1) patient receiving a low ratio of platelets (<1:16 apheresis platelets per stored red cell unit, aPLT:RBC) (n = 214), (2) patients receiving a medium ratio of platelets (1:16 to <1:8 aPLT:RBC) (n = 154), and (3) patients receiving a high ratio of platelets (>or=1:8 aPLT:RBC) (n = 96). The primary endpoint was survival at 24 hours and at 30 days. RESULTS: At 24 hours, patients receiving a high ratio of platelets had higher survival (95%) as compared with patients receiving a medium ratio (87%) and patients receiving the lowest ratio of platelets (64%) (log-rank p = 0.04 and p < 0.001, respectively). The survival benefit for the high and medium ratio groups remained at 30 days as compared with those receiving the lowest ratio of platelets (75% and 60% vs. 43%, p < 0.001 for both comparisons). On multivariate regression, plasma:RBC ratios and aPLT:RBC were both independently associated with improved survival at 24 hours and at 30 days. CONCLUSION: Transfusion of a ratio of >or=1:8 aPLT:RBC is associated with improved survival at 24 hours and at 30 days in combat casualties requiring a MT within 24 hours of injury. Although prospective study is needed to confirm this finding, MT protocols outside of investigational research should consider incorporation of appropriate ratios of both plasma and platelets.

Novel use of a portable ventilation device with low-flow tracheal insufflation of oxygen in a Swine model.

INTRODUCTION: Mechanical ventilation of intubated patients is standard to meet oxygenation and ventilation goals. This can require significant energy and oxygen resources. In military operations and mass casualty disasters, oxygen conserving strategies may be important. Low flow tracheal insufflation of oxygen (TRIO) is a technique that provides adequate oxygenation while conserving oxygen during apnea. This technique, however, is limited by increases in carbon dioxide (CO2) when used for extended periods. The addition of passive pressure release ventilation could potentially improve CO2 elimination and the acceptance of this technique. The purpose of this study was to determine whether TRIO combined with the novel configuration of a portable ventilator used to provide passive pressure release ventilation improves CO2 levels during apneic oxygenation. METHODS: Animals (n = 7) were anesthetized, paralyzed, and intubated. Oxygen (O2) was insufflated through the capillary lumen of the Boussignac endotracheal tube at 2 L/min. The low flow O2 was the only source of power and gas for ventilation. A modified Oxylator EMX transport ventilator connected to the endotracheal tube was configured to release when pressure in the subjects lungs reached 30 cm H2O. No electrical or pneumatic sources were required. Hemodynamic measurements and arterial blood gases were taken at various intervals for 2 hours. RESULTS: All pigs remained adequately oxygenated with Pao2 >390 mm Hg in all subjects at every blood gas measurement and survived the 2-hour experiment. Baseline Paco2 (43 +/- 4 mm Hg) increased and pH (7.48 +/- 0.03) decreased to 72 +/- 5 mm Hg and 7.29 +/- 0.02 at 1 hour and 83 +/- 8, 7.24 +/- 0.03 at 2 hours. This is significantly less than would be expected during apnea over this time period. Hemodynamic measurements remained stable. CONCLUSION: The combination of low flow TRIO with a modified Oxylator in this novel configuration provides acceptable Pao2, Paco2, and hemodynamic parameters for 2 hours in apneic swine. This could be a valuable technique in situations where oxygen and power are limited.

Organizational characteristics of the austere intensive care unit: the evolution of military trauma and critical care medicine; applications for civilian medical care systems.

Critical care in the U.S. military has significantly evolved in the last decade. More recently, the U.S. military has implemented organizational changes, including the use of multidisciplinary teams in austere environments to improve outcomes in severely injured polytrauma combat patients. Specifically, organizational changes in combat support hospitals located in combat zones during Operation Iraqi Freedom have led to decreased intensive care unit mortality and length of stay as well as resource use. These changes were implemented without increases in logistic support or the addition of highly technologic equipment. The mechanism for improvement in mortality is likely attributable to the adherence of basic critical care medicine fundamentals. This intensivist-directed team model provides sophisticated critical care even in the most austere environments. To optimize critically injured patients' outcomes, intensive care organizational models similar to the U.S. military, described in this article, can possibly be adapted to those of civilian care during disaster management to meet the challenges of emergency mass critical care.

Critical care in the austere environment: providing exceptional care in unusual places.

BACKGROUND: War and other disasters are inexorably linked to illness and injury. As a consequence of this, healthcare providers will be challenged to provide advanced physiological support to preserve human life. Given the mobility and modularity of modern medical systems, the ability to provide critical care outside of the confines of traditional hospitals under such circumstances has become not only a reality and periodic necessity, but an expectation. Austerity amplifies the complexity of providing high-level critical care, because resources are frequently limited, providers are asked to fill unexpected roles determined by necessity, security may be threatened, and the population at risk and their afflictions can be highly diverse. DISCUSSION: Our current deployed military medical experience and a review of published literature pertaining to civilian medical disaster response efforts support these stated challenges. The fundamentals of successful critical care practice in unusual settings include proper planning with an emphasis on attention to detail, the careful management of all resources, using the proper equipment, leveraging aeromedical evacuation assets, and employing the right people with the right skills. SUMMARY: Adherence to sound, evidence-based, routine practice, within bounds of the circumstances, must underscore everything.

Total intravenous anesthesia including ketamine versus volatile gas anesthesia for combat-related operative traumatic brain injury.

BACKGROUND: Traumatic brain injury is a leading cause of death and severe neurologic disability. The effect of anesthesia techniques on neurologic outcomes in traumatic brain injury and potential benefits of total intravenous anesthesia (TIVA) compared with volatile gas anesthesia (VGA), although proposed, has not been well evaluated. The purpose of this study was to compare TIVA versus VGA in patients with combat-related traumatic brain injury. METHODS: The authors retrospectively reviewed 252 patients who had traumatic brain injury and underwent operative neurosurgical intervention. Statistical analyses, including propensity score and matched analyses, were performed to assess differences between treatment groups (TIVA vs. VGA) and good neurologic outcome. RESULTS: Two hundred fourteen patients met inclusion criteria and were analyzed; 120 received VGA and 94 received TIVA. Good neurologic outcome (Glasgow Outcome Score 4-5) and decreased mortality were associated with TIVA compared with VGA (75% vs. 54%; P = 0.002 and 5% vs. 16%; P = 0.02, respectively). Multivariate logistic regression found admission Glasgow Coma Scale score of 8 or greater (odds ratio, 13.3; P < 0.001) and TIVA use (odds ratio, 2.3; P = 0.05) to be associated with good neurologic outcomes. After controlling for confounding factors using propensity analysis and repeated one-to-one matching of patients receiving TIVA with those receiving VGA with regard to Injury Severity Score, Glasgow Coma Scale score, base deficit, Head Abbreviated Injury Score, and craniectomy or craniotomy, the authors could not find an association between treatment and neurologic outcome. CONCLUSION: Total intravenous anesthesia often including ketamine was not associated with improved neurologic outcome compared with VGA. Multiple confounders limit conclusions that can be drawn from this retrospective study.

Effect of plasma and red blood cell transfusions on survival in patients with combat related traumatic injuries.

BACKGROUND: The amount and age of stored red blood cells (RBCs) are independent predictors of multiorgan failure and death in transfused critically ill patients. The independent effect of plasma transfusion on survival has not been evaluated. Our objective was to determine the independent effects of plasma and RBC transfusion on survival for patients with combat-related traumatic injuries receiving any blood products. METHODS: We performed a retrospective review of 708 patients transfused at least one unit of a blood product at one combat support hospital between November 2003 and December 2004. Admission vital signs, laboratory values, amount of blood products transfused in a 24-hour period, and Injury Severity Score (ISS) were analyzed by multivariate logistic regression to determine independent associations with in-hospital mortality. RESULTS: Seven hundred and eight of 3,287 (22%) patients admitted for traumatic injuries were transfused a blood product. Median ISS was 14 (range, 9-25). In-hospital mortality was 12%. Survival was associated with admission Glasgow Coma Scale score, SBP, temperature, hematocrit, base deficit, INR, amount of RBCs transfused, and massive transfusion. Each transfused FFP unit was independently associated with increased survival (OR: 1.17; 95% CI: [1.06-1.29]; p = 0.002); each transfused RBC unit was independently associated with decreased survival (OR: 0.86; [0.8-0.92]; p = 0.001). A subset analysis of patients (n = 567) without massive transfusion (1-9 RBC/FWB units) also revealed an independent association between each FFP unit and improved survival (OR: 1.22; 95% CI: [1.0-1.48]; p = 0.05) and between each RBC unit and decreased survival (OR: 0.77; [0.64-0.92]; p = 0.004). CONCLUSION: For trauma patients transfused at least one unit of a blood product, FFP and RBC amounts were independently associated with increased survival and decreased survival, respectively. Prospective studies are needed to determine whether the early and increased use of plasma and decreased use of RBCs affect mortality for patients with traumatic injuries requiring transfusion.

The ratio of fibrinogen to red cells transfused affects survival in casualties receiving massive transfusions at an army combat support hospital.

BACKGROUND: To treat the coagulopathy of trauma, some have suggested early and aggressive use of cryoprecipitate as a source of fibrinogen. Our objective was to determine whether increased ratios of fibrinogen to red blood cells (RBCs) decreased mortality in combat casualties requiring massive transfusion. METHODS: We performed a retrospective chart review of 252 patients at a U.S. Army combat support hospital who received a massive transfusion (>or=10 units of RBCs in 24 hours). The typical amount of fibrinogen within each blood product was used to calculate the fibrinogen-to-RBC (F:R) ratio transfused for each patient. Two groups of patients who received either a low (<0.2 g fibrinogen/RBC Unit) or high (>or=0.2 g fibrinogen/RBC Unit) F:R ratio were identified. Mortality rates and the cause of death were compared between these groups, and logistic regression was used to determine if the F:R ratio was independently associated with survival. RESULTS: Two-hundred and fifty-two patients who received a massive transfusion with a mean (SD) ISS of 21 (+/-10) and an overall mortality of 75 of 252 (30%) were included. The mean (SD) F:R ratios transfused for the low and high groups were 0.1 grams/Unit (+/-0.06), and 0.48 grams/Unit (+/-0.2), respectively (p < 0.001). Mortality was 27 of 52 (52%) and 48 of 200 (24%) in the low and high F:R ratio groups respectively (p < 0.001). Additional variables associated with survival were admission temperature, systolic blood pressure, hemoglobin, International Normalized Ratio (INR), base deficit, platelet concentration and Combined Injury Severity Score (ISS). Upon logistic regression, the F:R ratio was independently associated with mortality (odds ratio 0.37, 95% confidence interval 0.171-0.812, p = 0.013). The incidence of death from hemorrhage was higher in the low F:R group, 23/27 (85%), compared to the high F:R group, 21/48 (44%) (p < 0.001). CONCLUSIONS: In patients with combat-related trauma requiring massive transfusion, the transfusion of an increased fibrinogen: RBC ratio was independently associated with improved survival to hospital discharge, primarily by decreasing death from hemorrhage. Prospective studies are needed to evaluate the best source of fibrinogen and the optimal empiric ratio of fibrinogen to RBCs in patients requiring massive transfusion.

The effect of recombinant activated factor VII on mortality in combat-related casualties with severe trauma and massive transfusion.

BACKGROUND: The majority of patients with potentially survivable combat-related injuries die from hemorrhage. Our objective was to determine whether the use of recombinant activated factor VII (rFVIIa) decreased mortality in combat casualties with severe trauma who received massive transfusions and if its use was associated with increased severe thrombotic events. METHODS: We retrospectively reviewed a database of combat casualty patients with severe trauma (Injury Severity Score [ISS] >15) and massive transfusion (red blood cell [RBCs] >/=10 units/24 hours) admitted to one combat support hospital in Baghdad, Iraq, between December 2003 and October 2005. Admission vital signs and laboratory data, blood products, ISS, 24-hour and 30-day mortality, and severe thrombotic events were compared between patients who received rFVIIa (rFVIIa) and did not receive rFVIIa (rFVIIa). RESULTS: Of 124 patients in this study, 49 patients received rFVIIa and 75 did not. ISS, laboratory values, and admission vitals did not differ between rFVIIa and rFVIIa groups, except for systolic blood pressure (mm Hg) 105 +/- 33 and 92 +/- 28, p = 0.02 and temperature ( degrees F) 96.3 +/- 2.1 and 95.2 +/- 2.4, p = 0.03, respectively. Interactions between all vital signs and laboratory values measured upon admission, to include systolic blood pressure and temperature, were not significant when measured between rFVIIa use and 30-day mortality. Twenty-four-hour mortality was 7 of 49 (14%) in rFVIIa and 26 of 75 (35%) in rFVIIa, (p = 0.01); 30-day mortality was 15 of 49 (31%) and 38 of 75 (51%), (p = 0.03). Death from hemorrhage was 8 of 14 (57%) for rFVIIa patients compared with 29 of 37 (78%) for rFVIIa patients, (p = 0.12). The incidence of severe thrombotic events was similar in both groups. CONCLUSIONS: The early use of rFVIIa was associated with decreased 30-day mortality in severely injured combat casualties requiring massive transfusion, but was not associated with increased risk of severe thrombotic events.

Fresh whole blood transfusions in coalition military, foreign national, and enemy combatant patients during Operation Iraqi Freedom at a U.S. combat support hospital.

BACKGROUND: United States military doctrine permits the use of fresh whole blood (FWB), donated by U.S. military personnel on site, for casualties with life-threatening injuries at combat support hospitals. U.S. Military Medical Department policy dictates that all patients treated at military facilities during combat (coalition military personnel, foreign nationals, and enemy combatants) are to be treated equally. The objectives of this study were to describe admission vital signs and laboratory values and injury location for patients transfused with FWB, and to determine if FWB was employed equally among all patient personnel categories at a combat support hospital. METHODS: This retrospective cohort study evaluated admission vital signs and laboratory values, injury location, and personnel category for all patients receiving FWB at a U.S. Army combat support hospital in Baghdad, Iraq, between January and December 2004. RESULTS: Eighty-seven patients received 545 units of FWB. Upon admission, the average (+/-S.D.) heart rate was 144 bpm (+/-25); systolic blood pressure, 106 mmHg (+/-33); base deficit, 9 (+/-6.5); hemoglobin, 9.0 g/dl (+/-2.6); platelet concentration, 81.9 x 10(3)/mm(3) (+/-81); international normalized ratio (INR), 2.0 (+/-1.1); and temperature 95.7 degrees F (+/-2.6). The percentages of intensive care patients who received FWB by personnel category were as follows: coalition soldiers, 51/592 (8.6%); foreign nationals, 25/347 (7.2%); and enemy combatants, 11/128 (8.5% (p = 0.38). The amount of FWB transfused by personnel category was as follows: coalition soldier, 4 units (1-35); foreign national, 4 units (1-36); and enemy combatant, 4 units (1-11) (p = 0.9). CONCLUSIONS: Fresh whole blood was used for anemic, acidemic, hypothermic, coagulopathic patients with life-threatening traumatic injuries in hemorrhagic shock, and it was transfused in equal percentages and amounts for coalition soldiers, foreign nationals, and enemy combatants.

The ratio of blood products transfused affects mortality in patients receiving massive transfusions at a combat support hospital.

BACKGROUND: Patients with severe traumatic injuries often present with coagulopathy and require massive transfusion. The risk of death from hemorrhagic shock increases in this population. To treat the coagulopathy of trauma, some have suggested early, aggressive correction using a 1:1 ratio of plasma to red blood cell (RBC) units. METHODS: We performed a retrospective chart review of 246 patients at a US Army combat support hospital, each of who received a massive transfusion (>/=10 units of RBCs in 24 hours). Three groups of patients were constructed according to the plasma to RBC ratio transfused during massive transfusion. Mortality rates and the cause of death were compared among groups. RESULTS: For the low ratio group the plasma to RBC median ratio was 1:8 (interquartile range, 0:12-1:5), for the medium ratio group, 1:2.5 (interquartile range, 1:3.0-1:2.3), and for the high ratio group, 1:1.4 (interquartile range, 1:1.7-1:1.2) (p < 0.001). Median Injury Severity Score (ISS) was 18 for all groups (interquartile range, 14-25). For low, medium, and high plasma to RBC ratios, overall mortality rates were 65%, 34%, and 19%, (p < 0.001); and hemorrhage mortality rates were 92.5%, 78%, and 37%, respectively, (p < 0.001). Upon logistic regression, plasma to RBC ratio was independently associated with survival (odds ratio 8.6, 95% confidence interval 2.1-35.2). CONCLUSIONS: In patients with combat-related trauma requiring massive transfusion, a high 1:1.4 plasma to RBC ratio is independently associated with improved survival to hospital discharge, primarily by decreasing death from hemorrhage. For practical purposes, massive transfusion protocols should utilize a 1:1 ratio of plasma to RBCs for all patients who are hypocoagulable with traumatic injuries.

Risks associated with fresh whole blood and red blood cell transfusions in a combat support hospital.

OBJECTIVE: Fresh whole blood (FWB) and red blood cells (RBCs) are transfused to injured casualties in combat support hospitals. We evaluated the risks of FWB and RBCs transfused to combat-related casualties. DESIGN: Retrospective chart review. SETTING: Deployed U.S. Army combat support hospitals. SUBJECTS: Donors of FWB and recipients of FWB and RBCs. MEASUREMENTS AND RESULTS: The storage age of RBCs at transfusion was measured as an indicator of overall risk associated with the storage lesion of RBCs between January 2004 and December 2004 at one combat support hospital. Between April 2004 and December 2004, FWB was prescreened only at one combat support hospital for human immunodeficiency virus, hepatitis C virus, and hepatitis B surface antigen before transfusion. To estimate the general incidence of infectious agent contamination in FWB units, samples collected between May 2003 and February 2006 were tested retrospectively for human immunodeficiency virus, hepatitis B surface antigen, hepatitis C virus, and human lymphotropic virus. Results were compared between FWB samples prescreened and not prescreened for infectious agents before transfusion. At one combat support hospital in 2004, 87 patients were transfused 545 units of FWB and 685 patients were transfused 5,294 units of RBCs with a mean age at transfusion of 33 days (+/- 6 days). Retrospective testing of 2,831 samples from FWB donor units transfused in Iraq and Afghanistan between May 2003 and February 2006 indicated that three of 2,831 (0.11%) were positive for hepatitis C virus recombinant immunoblot assay, two of 2,831 (0.07%) were positive for human lymphotropic virus enzyme immunoassay, and none of 2,831 were positive for both human immunodeficiency virus 1/2 and hepatitis B surface antigen by Western blot and neutralization methods, respectively. The differences in the incidence of hepatitis C virus contamination of FWB donor units between those prescreened for hepatitis C virus (zero of 406; 0%) and not prescreened (three of 2,425; 0.12%) were not significant (p = .48). CONCLUSIONS: The risk of infectious disease transmission with FWB transfusion can be minimized by rapid screening tests before transfusion. Because of the potential adverse outcomes of transfusing RBCs of increased storage age to combat-related trauma patients, the risks and benefits of FWB transfusions must be balanced with those of transfusing old RBCs in patients with life-threatening traumatic injuries.