Blood transfusion and the two-insult model of post-injury multiple organ failure

Unraveling Leukocyte Profile Shifts and Platelet Dynamics Following Leukoreduced Packed Red Cell Transfusions in Very Low Birth Weight Preterm Neonates

Background Packed red blood cell (PRBC) transfusions are routine in neonatal care and the most common blood product administered to sick neonates. However, their impact on leukocyte and platelet profiles in very low birth weight (VLBW) preterm infants remains largely unexplored. This study examines leukocyte profile shifts and platelet dynamics following leukoreduced PRBC transfusions in VLBW preterm infants, offering insights to improve neonatal care and reduce unnecessary interventions. Methods The study utilized a retrospective cohort design within a single center, focusing on VLBW preterm infants who received PRBC transfusions at a level 3 NICU between January 2014 and June 2019. Data collection encompassed white blood cell (WBC) and platelet count measurements taken 24 hours before and up to 72 hours after PRBC transfusion. Neonates lacking complete blood count (CBC) data within the 72-hour post-transfusion window were excluded. A subgroup analysis distinguished the outcome between the initial PRBC transfusion and subsequent ones. The statistical significance of pre- and post-transfusion laboratory data was determined using the Wilcoxon signed ranks test and paired T-test. Results A cohort of 108 VLBW preterm infants who underwent a total of 402 PRBC transfusions was included in the analysis. The subjects exhibited a mean gestational age of 27.2 ± 2.5 weeks and a mean birth weight of 913 ± 264 grams. Analysis of pre- and post-transfusion data revealed no significant differences in total white blood cell count (WBC), absolute neutrophil count (ANC), absolute monocyte count (AMC), absolute eosinophil count, and absolute lymphocyte count. Notably, the platelet count was significantly decreased in the post-transfusion group (p < 0.001). In a subset analysis limited to the first-time transfusions among the 108 infants, a statistically significant increase was observed in total WBC, AMC, and ANC following transfusion. Conclusions The findings of this study highlight that PRBC transfusions can prompt an increase in neutrophils, monocytes, and eosinophils, coupled with a decline in platelet counts, all within a 72-hour window post-transfusion. Notably, these changes were predominantly discernible after the initial transfusion, with subsequent transfusions demonstrating consistency, except for the observed platelet count reduction. Recognizing these patterns could prove instrumental in averting undue investigations for suspected sepsis, particularly following the initial transfusion event. However, further in-depth investigations are necessary to uncover the underlying factors responsible for the shifts in leukocyte and platelet profiles triggered by PRBC transfusions.

Intraoperative Blood Loss at Different Surgical-Procedure Stages during Posterior Spinal Fusion for Idiopathic Scoliosis

Background and Objectives: Several predictive factors have been reportedly associated with intraoperative total blood loss (TBL) during posterior spinal fusion (PSF) for idiopathic scoliosis (IS). To reduce TBL, preoperative factors and interoperative factors are considered important. However, there are few reports that have evaluated bleeding patterns according to surgical stages. This study aimed to elucidate bleeding patterns at different surgical stages and determine the predictive factors for TBL during PSF surgery in patients with IS. Materials and Methods: Preoperative data, radiographic parameters, and intraoperative data of patients undergoing PSF for IS were retrospectively collected. We divided the patients into six stages: stage 1, exposure; stage 2, implant placement; stage 3, release; stage 4, correction; stage 5, bone grafting; and stage 6, closure; then we reviewed the blood loss and bleeding speed. Multiple-regression analysis was performed to generate a predictive formula for blood loss using preoperative and intraoperative factors, including blood loss at stage 1, as explanatory variables. Results: Forty-five patients (mean age: 17.6 years) were included. The mean operative time and TBL were 287.9 min and 756.5 mL, respectively. Blood loss was the highest at stage 3, followed by stage 4. Bleeding speed was the highest at stage 4, followed by stage 3. Bleeding speeds at stages 3 and 4 were significantly higher than those at stages 1 and 2. Preoperative Cobb angle, activated partial thromboplastin time (aPTT), number of fused vertebrae, and blood loss at stage 1 were significant contributing factors. Conclusions: Blood loss and bleeding speed during the release and correction stages were high. Specifically, bleeding speed significantly increased during and after the release procedure. The preoperative Cobb angle, aPTT, number of fixed vertebrae, and blood-loss volume during PSF were significantly associated with TBL. Our findings would be helpful for reducing TBL in patients undergoing PSF for IS.

The past, present, and future management of hemodynamic instability in patients with unstable pelvic ring injuries

Pelvic ring injuries presenting in hemorrhagic shock have historically had a mortality rate greater than 30%. To address this high mortality rate our institution has had a multi-disciplinary protocol for hemodynamically unstable pelvic ring injuries since 1993. In 2004, this protocol was revised to prioritize pre-peritoneal pelvic packing over angiography to rapidly control hemorrhage, reduce high-volume blood transfusions, and decrease the number of deaths from acute blood loss. This protocol has been successful in reducing deaths from hemorrhage by 30%. Despite the benefits of such a protocol, many trauma centers are not routinely stabilizing pelvic ring injuries or controlling pelvic hemorrhage. Subsequently, mortality rates remain high with a significant proportion of patients dying from acute blood loss. Trauma centers adhering to multi-disciplinary protocols that allow for rapid stabilization of the pelvis and simultaneous control of multiple sites of hemorrhage in hybrid operative suites are promising future directions for the management of patients with these lethal injuries.

Red blood cell transfusion results in adhesion of neutrophils in human endotoxemia and in critically ill patients with sepsis

BACKGROUND

Red blood cell (RBC) transfusion is associated with adverse effects, which may involve activation of the host immune response. The effect of RBC transfusion on neutrophil Reactive Oxygen Species (ROS) production and adhesion ex vivo was investigated in endotoxemic volunteers and in critically ill patients that received a RBC transfusion. We hypothesized that RBC transfusion would cause neutrophil activation, the extent of which depends on the storage time and the inflammatory status of the recipient.

STUDY DESIGN AND METHODS

Volunteers were injected with lipopolysaccharide (LPS) and transfused with either saline, fresh, or stored autologous RBCs. In addition, 47 critically ill patients with and without sepsis receiving either fresh (<8 days) or standard stored RBC (2‐35 days) were included. Neutrophils from healthy volunteers were incubated with the plasma samples from the endotoxemic volunteers and from the critically ill patients, after which priming of neutrophil ROS production and adhesion were assessed.

RESULTS

In the endotoxemia model, ex vivo neutrophil adhesion, but not ROS production, was increased after transfusion, which was not affected by RBC storage duration. In the critically ill, ex vivo neutrophil ROS production was already increased prior to transfusion and was not increased following transfusion. Neutrophil adhesion was increased following transfusion, which was more notable in the septic patients than in non‐septic patients. Transfusion of fresh RBCs, but not standard issued RBCs, resulted in enhanced ROS production in neutrophils.

CONCLUSION

RBC transfusion was associated with increased neutrophil adhesion in a model of human endotoxemia as well as in critically ill patients with sepsis.

Effect of angioembolisation versus surgical packing on mortality in traumatic pelvic haemorrhage: A systematic review and meta-analysis

BACKGROUND

The management of complex pattern of bleeding associated with pelvic trauma remains a big challenge for trauma surgeons. We aimed to conduct a comprehensive meta-analysis to compare the outcomes of angioembolisation and pelvic packing in patients with pelvic trauma.

METHODS

We conducted a systematic search of electronic information sources, including MEDLINE; EMBASE; CINAHL; the CENTRAL; the World Health Organization International Clinical Trials Registry; ClinicalTrials.gov; ISRCTN Register, and bibliographic reference lists. The primary outcome was defined as mortality. Combined overall effect sizes were calculated using random-effects models. Results are reported as the odds ratio (OR) and 95% confidence interval (CI).

RESULTS

We identified 3 observational studies reporting a total of 120 patients undergoing angioembolisation (n=60) or pelvic packing (n=60) for pelvic trauma. Reporting of the Injury Severity Score (ISS) was variable, with higher ISS in the pelvic packing group. The risk of bias was low in two studies, and moderate in one. The pooled analysis demonstrated that angioembolisation did not significantly reduce mortality in patients with pelvic trauma compared to surgery (OR=1.99; 95% CI= 0.83-4.78, P=0.12). There was mild between-study heterogeneity (I²=0%, P=0.65).

CONCLUSION

Our analysis found no significant difference in mortality between angioembolisation and pelvic packing in patients with traumatic pelvic haemorrhage. The current level of evidence in this context is very limited and insufficient to support the superiority of a treatment modality. Future research is required.

Transfusion of Blood Products Affects Outcome in Cardiac Surgery

There remains controversy as to when patients undergoing cardiac surgery should receive a transfusion and whether a low hematocrit and its treatment with a transfusion of red cells influences outcome. The data related to this controversy are reviewed. Although the risk of known viral transmission is currently low, stored red cells do not function normally, and each unit contains activated inflammatory cells and mediators. These changes cause limited oxygen release, impaired microcirculatory flow, and immune suppression. A number of studies have observed decreased survival associated with transfusions in trauma, coronary artery bypass grafting, and intensive care unit patients. Studies that show an adverse outcome associated with low hematocrit are not definitive, because they fail to distinguish between the impact of low hematocrit per se and the possible adverse effects of transfusion, for what the low hematocrit may simply be a surrogate. The observation that a low hematocrit is associated with an adverse outcome does not necessarily prove that “treatment” of the anemia with a red cell transfusion will improve the outcome. Stored platelets contain a highly activated mixture of platelets with storage lesions and inflammatory mediators. Two retrospective post hoc multifactorial analyses suggest that platelet transfusions are associated with substantial increased morbidity and mortality. Clearly, large prospective studies are required to define the proper trigger for blood product transfusion to balance the adverse effects of anemia and platelet deficiency or dysfunction with the adverse effects of transfusion of blood products on morbidity and mortality associated with cardiac surgery and anesthesia.

LysoPCs induce Hck- and PKCδ-mediated activation of PKCγ causing p47phox phosphorylation and membrane translocation in neutrophils

Lysophosphatidylcholines (lysoPCs) are effective polymorphonuclear neutrophil (PMN) priming agents implicated in transfusion-related acute lung injury (TRALI). LysoPCs cause ligation of the G2A receptor, cytosolic Ca²⁺ flux, and activation of Hck. We hypothesize that lysoPCs induce Hck-dependent activation of protein kinase C (PKC), resulting in phosphorylation and membrane translocation of 47 kDa phagocyte oxidase protein (p47^phox). PMNs, human or murine, were primed with lysoPCs and were smeared onto slides and examined by digital microscopy or separated into subcellular fractions or whole-cell lysates. Proteins were immunoprecipitated or separated by polyacrylamide gel electrophoresis and immunoblotted for proteins of interest. Wild-type (WT) and PKCγ knockout (KO) mice were used in a 2-event model of TRALI. LysoPCs induced Hck coprecipitation with PKCδ and PKCγ and the PKCδ:PKCγ complex also had a fluorescence resonance energy transfer (FRET)⁺ interaction with lipid rafts and Wiskott-Aldrich syndrome protein family verprolin-homologous protein 2 (WAVE2). PKCγ then coprecipitated with p47^phox Immunoblotting, immunoprecipitation (IP), specific inhibitors, intracellular depletion of PKC isoforms, and PMNs from PKCγ KO mice demonstrated that Hck elicited activation/Tyr phosphorylation (Tyr311 and Tyr525) of PKCδ, which became Thr phosphorylated (Thr507). Activated PKCδ then caused activation of PKCγ, both by Tyr phosphorylation (Τyr514) and Ser phosphorylation, which induced phosphorylation and membrane translocation of p47^phox In PKCγ KO PMNs, lysoPCs induced Hck translocation but did not evidence a FRET⁺ interaction between PKCδ and PKCγ nor prime PMNs. In WT mice, lysoPCs served as the second event in a 2-event in vivo model of TRALI but did not induce TRALI in PKCγ KO mice. We conclude that lysoPCs prime PMNs through Hck-dependent activation of PKCδ, which stimulates PKCγ, resulting in translocation of phosphorylated p47^phox.

Novel role of group VIB Ca2+-independent phospholipase A2γ in leukocyte-endothelial cell interactions: An intravital microscopic study in rat mesentery

BACKGROUND

Phospholipase A2 (PLA2) is associated with a variety of inflammatory processes related to polymorphonuclear neutrophil (PMN)-endothelial cell interactions. However, the cellular and molecular mechanisms underlying the interactions and the causative isoform(s) of PLA2 remain elusive. In addition, we recently showed that calcium-independent PLA2γ (iPLA2γ), but not cytosolic PLA2 (cPLA2), is responsible for the cytotoxic functions of human PMN including respiratory bursts, degranulation, and chemotaxis. We therefore hypothesized that iPLA2γ is a prerequisite for the PMN recruitment cascade into the site of inflammation. The aim of this study was to elucidate the roles of the three major phospholipases A2, iPLA2, cPLA2 and secretory PLA2, in leukocyte rolling and adherence and in the surface expression of β2-integrins in vivo and in vitro in response to well-defined stimuli.

METHODS

Male Wistar rats were pretreated with PLA2 inhibitors selective for iPLA2β, iPLA2γ, cPLA2, or secretory PLA2. Leukocyte rolling/adherence in the mesenteric venules superfused with platelet-activating factor (PAF) were quantified by intravital microscopy. Furthermore, isolated human PMNs or whole blood were incubated with each PLA2 inhibitor and then activated with formyl-methionyl-leucyl-phenylalanine (fMLP) or PAF. PMN adherence was assessed by counting cells bound to purified fibrinogen, and the surface expression of lymphocyte function-associated antigen 1 and macrophage antigen 1 (Mac-1) was measured by flow cytometry.

RESULTS

The iPLA2γ-specific inhibitor almost completely inhibited the fMLP/PAF-induced leukocyte adherence in vivo and in vitro and also decreased the fMLP/PAF-stimulated surface expression of Mac-1 by 60% and 95%, respectively. In contrast, the other inhibitors did not affect these cellular functions.

CONCLUSION

iPLA2γ seems to be involved in leukocyte/PMN adherence in vivo and in vitro as well as in the up-regulation of Mac-1 in vitro in response to PAF/fMLP. This enzyme is therefore likely to be a major regulator in the PMN recruitment cascade.

Washed versus unwashed red blood cells for transfusion for the prevention of morbidity and mortality in preterm infants

BACKGROUND

Infants born very preterm often receive multiple red blood cell (RBC) transfusions during their initial hospitalisation. However, there is an increasing awareness of potential adverse effects of RBC transfusions in this vulnerable patient population. Modification of RBCs prior to transfusion, through washing with 0.9% saline, may reduce these adverse effects and reduce the rate of significant morbidity and mortality for preterm infants and improve outcomes for this high-risk group.

OBJECTIVES

To determine whether pre-transfusion washing of RBCs prevents morbidity and mortality in preterm infants.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 7), MEDLINE via PubMed (31 July 2015), EMBASE (31 July 2015), and CINAHL (31 July 2015). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Randomised, cluster randomised, and quasi-randomised controlled trials including preterm infants (less than 32 weeks gestation) or very low birth weight infants (less than 1500 g), or both, who received one or more washed packed RBC transfusions.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility of the trials. We identified four studies from the initial search. After further review of the full-text studies, we found one study meeting the selection criteria.

MAIN RESULTS

We included a single study enrolling a total of 21 infants for analysis in this review and reported on all-cause mortality during hospital stay, length of initial neonatal intensive care unit (NICU) stay (days), and duration of mechanical ventilation (days). There was no significant difference in mortality between the washed versus the unwashed RBCs for transfusion groups (risk ratio 1.63, 95% confidence interval (CI) 0.28 to 9.36; risk difference 0.10, 95% CI -0.26 to 0.45). There was no significant difference in the length of initial NICU stay between the washed versus the unwashed RBCs for transfusion groups (mean difference (MD) 25 days, 95% CI -21.15 to 71.15) or the duration of mechanical ventilation between the washed versus the unwashed RBCs for transfusion groups (MD 9.60 days, 95% CI -1.90 to 21.10).

AUTHORS' CONCLUSIONS

We identified a single small study. The results from this study show a high level of uncertainty, as the confidence intervals are consistent with both a large improvement or a serious harm caused by the intervention. Consequently, there is insufficient evidence to support or refute the use of washed RBCs to prevent the development of significant neonatal morbidities or mortality. Further clinical trials are required to assess the potential effects of pre-transfusion washing of RBCs for preterm or very low birth weight infants, or both, on short- and long-term outcomes.

Increased monocytes and bands following a red blood cell transfusion

OBJECTIVE

The objective of this study is to analyze the white blood cell changes that occur after a transfusion of red blood cells in order to identify a subclinical inflammatory response in neonates.

STUDY DESIGN

Retrospective analysis of infants who received a red blood cell transfusion in an intensive care nursery. White blood cell results within 24 h pre- to 48 h post-transfusion were collected and analyzed. Statistical analysis included ANOVA, T-test, Mann-Whitney U test, Pearson's correlation and multivariable linear regression.

RESULT

Monocytes (P=0.02) and bands (P=0.035) were increased post-transfusion. There were no differences in monocytes (P=0.46) or bands (P=0.56) between groups who did or did not have blood cultures obtained. There was no difference in monocytes between groups who did or did not have sepsis (P=0.88).

CONCLUSION

We identified an elevation in monocytes and bands in the 48 h following a transfusion in premature infants. Our findings support a possible pro-inflammatory response related to transfusion of red blood cells.

Gene networks specific for innate immunity define post-traumatic stress disorder

The molecular factors involved in the development of Post-Traumatic Stress Disorder (PTSD) remain poorly understood. Previous transcriptomic studies investigating the mechanisms of PTSD apply targeted approaches to identify individual genes under a cross-sectional framework lack a holistic view of the behaviours and properties of these genes at the system-level. Here we sought to apply an unsupervised gene-network based approach to a prospective experimental design using whole-transcriptome RNA-Seq gene expression from peripheral blood leukocytes of U.S. Marines (N=188), obtained both pre- and post-deployment to conflict zones. We identified discrete groups of co-regulated genes (i.e., co-expression modules) and tested them for association to PTSD. We identified one module at both pre- and post-deployment containing putative causal signatures for PTSD development displaying an over-expression of genes enriched for functions of innate-immune response and interferon signalling (Type-I and Type-II). Importantly, these results were replicated in a second non-overlapping independent dataset of U.S. Marines (N=96), further outlining the role of innate immune and interferon signalling genes within co-expression modules to explain at least part of the causal pathophysiology for PTSD development. A second module, consequential of trauma exposure, contained PTSD resiliency signatures and an over-expression of genes involved in hemostasis and wound responsiveness suggesting that chronic levels of stress impair proper wound healing during/after exposure to the battlefield while highlighting the role of the hemostatic system as a clinical indicator of chronic-based stress. These findings provide novel insights for early preventative measures and advanced PTSD detection, which may lead to interventions that delay or perhaps abrogate the development of PTSD.

Discrete roles of intracellular phospholipases A2 in human neutrophil cytotoxicity

BACKGROUND

The role of calcium-independent phospholipase A2 (iPLA2), a component of the three major PLA2 families, in acute/chronic inflammatory processes remains elusive. Previous investigations have documented iPLA2-mediated respiratory burst of neutrophils (PMNs); however, the causative isoform of iPLA2 is unidentified. We also demonstrated that the iPLA2γ-specific inhibitor attenuates trauma/hemorrhagic shock-induced lung injury. Therefore, iPLA2γ may be implicated in acute inflammation. In addition, arachidonic acid (AA), which is primarily produced by cytosolic PLA2 (cPLA2), is known to display PMN cytotoxicity, although the relationship between AA and the cytotoxic function is still being debated on. We therefore hypothesized that iPLA2γ regulates PMN cytotoxicity via AA-independent signaling pathways. The study aim was to distinguish the role of intracellular phospholipases A2, iPLA2, and cPLA2, in human PMN cytotoxicity and explore the possibility of the presence of signaling molecule(s) other than AA.

METHODS

Isolated human PMNs were incubated with the PLA2 inhibitor selective for iPLA2β, iPLA2γ, or cPLA2 and then activated with formyl-methionyl-leucyl-phenylalanine (fMLP) or phorbol 12-myristate 13-acetate (PMA). Superoxide production was assayed according to the superoxide dismutase-inhibitable cytochrome c reduction method, and the degree of elastase release was measured using a p-nitroanilide-conjugated elastase-specific substrate. In addition, chemotaxis toward platelet activating factor/fMLP was determined with a modified Boyden chamber system.

RESULTS

The iPLA2γ-specific inhibitor reduced the fMLP/PMA-stimulated superoxide generation by 90% and 30%, respectively; in addition, the inhibitor completely blocked the fMLP/PMA-activated elastase release. However, the cPLA2-specific inhibitor did not abrogate these effects to any degree at all concentrations. Likewise, the inhibitor for iPLA2γ, but not iPLA2β or cPLA2, completely inhibited the platelet activating factor/fMLP-induced chemotaxis.

CONCLUSION

iPLA2 is involved in extracellular reactive oxygen species production, elastase release, and chemotaxis in response to well-defined stimuli. In addition, the ineffectiveness of the cPLA2 inhibitor suggests that AA may not be relevant to these cytotoxic functions.

Unplanned Hospital Readmissions and Reoperations After Pediatric Spinal Fusion Surgery

STUDY DESIGN

Retrospective review.

OBJECTIVE

To investigate the rates and reasons for unplanned readmissions and reoperation after pediatric spinal fusion surgery at our institution and to identify risk factors by analyzing patient and surgical characteristics. Unplanned readmission and reoperation were defined as unplanned events within 90 days of the index surgery.

SUMMARY OF BACKGROUND DATA

The rate of unplanned readmission and reoperation after pediatric spinal fusion surgery is not well established.

METHODS

Clinical records were reviewed for all children who underwent spinal fusion surgical procedures for spinal deformity correction performed by 1 surgeon from 2000 through 2013 at our institution. Inclusion criteria were age of 10 to 18 years at surgery, fusion spanning more than 5 vertebral levels, and 3 months of clinical or radiographical follow-up (1002 patients met these criteria). Univariate and multivariate logistic regression models were created. Statistical significance was set at a P value of less than 0.05 for all analyses.

RESULTS

The overall 90-day unplanned readmission and reoperation rates were 8.0% and 3.8%, respectively. The most common causes of readmission were wound dehiscence (1.8%), deep wound infection (1.5%), pulmonary complications (1%), and superficial wound infection (0.9%). Univariate analysis showed that readmission was significantly associated with a higher number of levels fused, greater estimated blood loss, longer length of stay, and certain diagnoses; reoperation was significantly associated with a higher number of levels fused and certain diagnoses. On multivariate analysis, only patient diagnosis was found to be significantly associated with readmission and reoperation; patients with congenital scoliosis, genetic or syndromic scoliosis, cerebral palsy, and other neuromuscular disorders had significantly higher rates.

CONCLUSION

Unplanned readmission rate after pediatric spinal fusion surgery was 8%, most commonly for wound dehiscence and deep and superficial infections. Increased intraoperative blood loss, higher number of levels fused, and certain diagnoses are risk factors for unplanned readmission.

LEVEL OF EVIDENCE

4.

Red blood cell storage duration and trauma

Numerous retrospective clinical studies suggest that transfusion of longer stored red blood cells (RBCs) is associated with an independent risk of poorer outcomes for certain groups of patients, including trauma, intensive care, and cardiac surgery patients. Large multicenter randomized controlled trials are currently underway to address the concern about RBC storage duration. However, none of these randomized controlled trials focus specifically on trauma patients with hemorrhage. Major trauma, particularly due to road accidents, is the leading cause of critical injury in the younger-than-40-year-old age group. Severe bleeding associated with major trauma induces hemodynamic dysregulation that increases the risk of hypoxia, coagulopathy, and potentially multiorgan failure, which can be fatal. In major trauma, a multitude of stress-associated changes occur to the patient's RBCs, including morphological changes that increase cell rigidity and thereby alter blood flow hemodynamics, particularly in the microvascular vessels, and reduce RBC survival. Initial inflammatory responses induce deleterious cellular interactions, including endothelial activation, RBC adhesion, and erythrophagocytosis that are quickly followed by profound immunosuppressive responses. Stored RBCs exhibit similar biophysical characteristics to those of trauma-stressed RBCs. Whether transfusion of RBCs that exhibit storage lesion changes exacerbates the hemodynamic perturbations already active in the trauma patient is not known. This article reviews findings from several recent nonrandomized studies examining RBC storage duration and clinical outcomes in trauma patients. The rationale for further research on RBC storage duration in the trauma setting is provided.

Neutrophils release extracellular DNA traps during storage of red blood cell units

BACKGROUND

Blood transfusion is associated with an increased risk of organ damage, infection, and alloimmunity. Neutrophil extracellular traps (NETs) are extracellular chromatin fibers decorated with neutrophil granular proteins that have been linked to cytotoxicity, thrombosis, and autoimmunity. We questioned whether neutrophils in blood products release NETs during storage and thus could contribute to adverse reactions from blood transfusions.

STUDY DESIGN AND METHODS

We analyzed supernatants and blood smears of human red blood cell (RBC) units that either were or were not leukoreduced before storage for markers of NETs.

RESULTS

We identified extracellular DNA, which was associated with histones and myeloperoxidase, a marker of neutrophil granules, in supernatants and blood smears of nonleukoreduced RBC units. These markers of NETs were absent in leukoreduced RBC units. Importantly, NETs passed through blood transfusion filters and could therefore potentially be infused into patients.

CONCLUSIONS

Our studies indicate that NETs are liberated during storage of nonleukoreduced RBC units. Future studies should address whether NETs in RBC units could potentially contribute to transfusion-associated complications.

Plasma cytokines and markers of endothelial activation increase after packed red blood cell transfusion in the preterm infant

BACKGROUND

Transfusion of packed red blood cells (PRBCs) saves lives in the neonatal critical care setting and is one of the most common interventions in the preterm infant. The number and volume of PRBC transfusions are associated with several major neonatal morbidities, although a direct causal link between transfusion and major neonatal morbidity is still to be proven. Transfusion-related immunomodulation (TRIM) may underlie these adverse outcomes, yet it has received little attention in the high-risk preterm infant.

METHODS

One transfusion event was studied in infants ≤28 wk gestation between 2 and 6 wk postnatal age (n = 28). Plasma inflammatory cytokines and markers of endothelial activation were measured in the infants before and 2-4 h after transfusion, as well as in the donor pack.

RESULTS

Median (range) age at transfusion was 18 (14-39) days with the pretransfusion hemoglobin level at 9.8 (7.4-10.2) g/dl. Interleukin (IL)-1β (P = 0.01), IL-8 (P = <0.001), tumor necrosis factor-α (P = 0.008), and monocyte chemoattractant protein (P = 0.01) were increased after transfusion. A similar elevation in markers of endothelial activation was seen after transfusion with increased plasma macrophage inhibitory factor (P = 0.005) and soluble intracellular adhesion molecule-1 (P = <0.001).

CONCLUSION

Production of inflammatory cytokines and immunoactivation of the endothelium observed after the transfusion of PRBCs in the preterm infant may be a manifestation of TRIM. The implications of this emerging phenomenon within the preterm neonatal population warrant further investigation.

Angioembolization for pelvic hemorrhage control: results from the German pelvic injury register

BACKGROUND

Hemorrhage from pelvic vessels is a potentially lethal complication of pelvic fractures. There is ongoing controversy on the ideal treatment strategy for patients with pelvic hemorrhage. The aim of the study was to analyze the role of angiography and subsequent embolization in patients with pelvic fractures and computed tomography scan-proven vascular injuries.

METHODS

The data from the prospective multicenter German pelvic injury registry were analyzed. Of 5,040 patients with pelvic fractures, 152 patients with associated vascular injuries were identified. Patients undergoing angioembolization (n = 17) were compared with those undergoing conventional measures for hemorrhage control (n = 135) with regard to demographic and physiologic parameters, fracture type distribution, and treatment measures. Outcome measures were mortality, requirement for blood transfusions, complications, and hospital length of stay.

RESULTS

Embolization and nonembolization groups were comparable with regard to age, sex, Injury Severity Score, Hannover Polytrauma Score, initial hemoglobin levels, blood pressure, fracture distribution, and conventional measures. Blood transfusion requirement was significantly prolonged in the embolization group. This resulted in a higher adult respiratory distress syndrome incidence and a tendency toward increased multiple organ failure rate in this group. There was no significant difference in overall mortality rate when compared with the nonembolization group (17.6% vs. 32.6%, respectively; p = 0.27). None of the patients undergoing embolization died from exsanguination when compared with 20.6% in the nonembolization group (p = 0.038).

CONCLUSION

Angioembolization alongside with conventional measures is an effective complementary means for hemorrhage control in patients sustaining pelvic fracture-related vascular lesions. It might prove even more effective when performed early enough to avoid prolonged blood transfusion requirement. Further studies without the mentioned limitations of the study are desired.

LEVEL OF EVIDENCE

Therapeutic study, level IV.

The effect of RBC transfusions on cytokine gene expression after cardiac surgery in patients developing post-operative multiple organ failure

AIM

To determine the effect of red blood cell (RBC) transfusions during cardiac surgery on cytokine gene expression (GE) in relation to multiple organ failure (MOF) development after systemic inflammatory response syndrome (SIRS).

BACKGROUND

RBC transfusion in cardiac surgery patients is dose-dependently associated with post-operative MOF, possibly acting as a second hit after cardiopulmonary bypass.

METHODS

For this observational study, 29 patients divided into four groups of cardiac surgery patients were selected from a randomised controlled trial (RCT). Group 1: no-RBC, no-MOF (N = 8); group 2: MOF, no-RBC (N = 7); group 3: RBC, no-MOF (N = 6); group 4: RBC and MOF (N = 8). Selection was based on age, gender, number of (leukocyte-depleted) RBC transfusions, type and duration of surgery. A 114 cytokine GE array was applied to blood samples withdrawn before and 24 h after surgery. Expression of selected genes was confirmed with reverse transcriptase real time-polymerase chain reaction (RT-PCR).

RESULTS

Nineteen of the 39 detectable genes showed a significant change in GE after surgery. Confirmed by RT-PCR, transfused MOF patients exhibit significantly less downregulation of CD40 ligand than control patients. Patients who would develop MOF show significantly larger increases in GE of transforming growth factor-α (TGF-α), tumour necrosis factor (TNF)-superfamily members 10 and 13B (TNFsf10/13B).

CONCLUSIONS

When tested at 24 h after surgery, cytokine GE in peripheral blood leucocytes showed no significant differences between those transfused and those not transfused. Some alterations were seen in those developing MOF compared to those who did not, but the findings offer no role of leukocyte depleted (LD) RBC transfusion in the development of MOF.

[Clinical impact of length of storage before red blood cell transfusion]

Presently, red blood cell units are stored up to 42 days in France and Canada. Length of storage of red blood cell units is not based on clinical outcomes: it is rather based on a decision made by some experts in the 1940s that red blood cell units can be stored as long as the average hemolysis is lower than 1% and the proportion of red blood cells still alive 24 hours post-transfusion is higher than 70%. Data reported recently suggest that transfusion with older red blood cell units may jeopardize the outcome of severely ill patients. In this paper, we comment the data already published on this question, and we summarize the randomized clinical trials presently on-going that were undertaken to address the relationship between length of storage of red blood cell units and outcomes of transfused patients.

Emerging Role for Use of Liposomes in the Biopreservation of Red Blood Cells

SUMMARY: Biopreservation is the process of maintaining the integrity and functionality of cells held outside the native environment for extended storage times. The development of red blood cell (RBC) biopreservation techniques that maintain in vitro RBC viability and function represents the foundation of modern blood banking. The biopreservation of RBCs for clinical use can be categorized based on the techniques used to achieve biologic stability, including hypothermic storage and cryopreservation. This review will examine the emerging role of liposomes in the RBC biopreservation, including the incorporation of liposomes into RBC membranes as an effective approach for minimizing RBC hypothermic storage membrane lesion and use of liposomes as a permeabilization strategy for the intracellular accumulation of novel intracellular cryoprotectants. Integration of current biopreservation research with blood banking practices offers enormous potential for future improvements of safety and efficacy of RBC transfusion.

Intravenous delivery of the plasma fraction of stored packed erythrocytes promotes pancreatic cancer growth in immunocompetent mice

BACKGROUND

Perioperative blood transfusion in pancreatic cancer patients has been linked to decreased survival; however, a causal mechanism has not been determined. During the processing and storage of packed erythrocytes, biologically active molecules accumulated in the acellular plasma fraction; therefore, the authors hypothesized that the plasma fraction of stored packed erythrocytes promoted tumor progression.

METHODS

Proliferation and migration of murine pancreatic cancer and control cells were determined in vitro in response to the plasma fraction from leukocyte and nonleukocyte-reduced fresh versus stored packed erythrocytes. Last, an immunocompetent murine model was used to assess the effect of the plasma fraction of stored and processed packed erythrocytes on pancreatic cancer progression.

RESULTS

Incubation of pancreatic cancer cells with the plasma fraction of packed erythrocytes increased proliferation and migration. Intravenous delivery of the acellular plasma fraction to mice with pancreatic cancer significantly increased the tumor weight in both leukocyte-reduced and nonleukocyte-reduced packed-erythrocyte groups (P<.01), although tumor growth and morbidity were greatest in the nonleukocyte-reduced group.

CONCLUSIONS

The plasma fraction of stored packed erythrocytes promoted murine pancreatic cancer proliferation and migration in vitro and when administered intravenously, significantly augmented pancreatic cancer growth in immunocompetent mice.

1H-NMR-based metabolic signatures of clinical outcomes in trauma patients--beyond lactate and base deficit

The determination of reliable biomarkers capable to predict clinical outcome of a trauma patient remains essential toward better therapeutic management of the patient in the intensive care unit. Assessment of global metabolic profiling using quantitative nuclear magnetic resonance (NMR)-based metabolomics offers an attractive modern methodology for fast and comprehensive determination of multiple circulating metabolites and for establishing metabolic phenotype of survivors versus nonsurvivors. Multivariate data analysis on 43 quantitative metabolic parameters identified three lipid metabolites, triacylglycerol, glycerol heads of phospholipids, and monounsaturated fatty acids, as being the most discriminative markers to separate survivors versus nonsurvivors at the time of admission. Glucose and glutamate were intermediate predictors, followed by lactate and hydroxybutyrate as two low-weight predictors. Ultimately, cellular and subcellular failure in nonsurviving trauma patients results in multiple systemic biochemical effects and in changes in circulating metabolites in the blood that are characteristic for decreased lipid synthesis and urea cycle activity in the liver, and for increased hyperglycemia, lactic, and ketoacidosis.

Association between length of storage of red blood cell units and outcome of critically ill children: a prospective observational study

INTRODUCTION

Transfusion is a common treatment in pediatric intensive care units (PICUs). Studies in adults suggest that prolonged storage of red blood cell units is associated with worse clinical outcome. No prospective study has been conducted in children. Our objectives were to assess the clinical impact of the length of storage of red blood cell units on clinical outcome of critically ill children.

METHODS

Prospective, observational study conducted in 30 North American centers, in consecutive patients aged <18 years with a stay >or= 48 hours in a PICU. The primary outcome measure was the incidence of multiple organ dysfunction syndrome after transfusion. The secondary outcomes were 28-day mortality and PICU length of stay. Odds ratios were adjusted for gender, age, number of organ dysfunctions at admission, total number of transfusions, and total dose of transfusion, using a multiple logistic regression model.

RESULTS

The median length of storage was 14 days in 296 patients with documented length of storage. For patients receiving blood stored >or= 14 days, the adjusted odds ratio for an increased incidence of multiple organ dysfunction syndrome was 1.87 (95% CI 1.04;3.27, P = 0.03). There was also a significant difference in the total PICU length of stay (adjusted median difference +3.7 days, P < 0.001) and no significant change in mortality.

CONCLUSIONS

In critically ill children, transfusion of red blood cell units stored for >or= 14 days is independently associated with an increased occurrence of multiple organ dysfunction syndrome and prolonged PICU stay.

Association between length of storage of red blood cell units and outcome of critically ill children: a prospective observational study

INTRODUCTION

Transfusion is a common treatment in pediatric intensive care units (PICUs). Studies in adults suggest that prolonged storage of red blood cell units is associated with worse clinical outcome. No prospective study has been conducted in children. Our objectives were to assess the clinical impact of the length of storage of red blood cell units on clinical outcome of critically ill children.

METHODS

Prospective, observational study conducted in 30 North American centers, in consecutive patients aged <18 years with a stay >or= 48 hours in a PICU. The primary outcome measure was the incidence of multiple organ dysfunction syndrome after transfusion. The secondary outcomes were 28-day mortality and PICU length of stay. Odds ratios were adjusted for gender, age, number of organ dysfunctions at admission, total number of transfusions, and total dose of transfusion, using a multiple logistic regression model.

RESULTS

The median length of storage was 14 days in 296 patients with documented length of storage. For patients receiving blood stored >or= 14 days, the adjusted odds ratio for an increased incidence of multiple organ dysfunction syndrome was 1.87 (95% CI 1.04;3.27, P = 0.03). There was also a significant difference in the total PICU length of stay (adjusted median difference +3.7 days, P < 0.001) and no significant change in mortality.

CONCLUSIONS

In critically ill children, transfusion of red blood cell units stored for >or= 14 days is independently associated with an increased occurrence of multiple organ dysfunction syndrome and prolonged PICU stay.

Laparotomy attenuates lipopolysaccharide-induced gastric bleeding in the rat

Lipopolysaccharide (LPS) increases systemic inflammation and causes duodenogastric reflux of bile and gastric bleeding. Laparotomy prevents gastric injury from the luminal irritant bile, but its effects on LPS-induced gastric injury are unknown. We hypothesized that laparotomy would diminish inflammation and attenuate gastric bleeding caused by LPS. In the rat, laparotomy, done either before or after administration of LPS, attenuated LPS-induced bile reflux, gastric bleeding, and cyclooxygenase-2, but not inducible nitric oxide synthase, expression when compared to controls given LPS. Laparotomy also blunted LPS-induced changes in serum cytokine production. These data suggest that laparotomy has gastroprotective effects by preventing LPS-induced bile reflux and gastric bleeding and by a mechanism mediated, at least in part by cyclooxygenase-2.

Hemorrhage and subsequent allogenic red blood cell transfusion are associated with characteristic monocyte messenger RNA expression patterns in patients after multiple injury-a genome wide view

INTRODUCTION

As outcome to severe trauma is frequently affected by massive blood loss and consecutive hemorrhagic shock, replacement of red blood cell (RBC) units remains indispensable. Administration of RBC units is an independent risk factor for adverse outcome in patients with trauma. The impact of massive blood transfusion or uncrossmatched blood transfusion on the patients' immune response in the early posttraumatic period remains unclear.

MATERIAL

Thirteen patients presenting with blunt multiple injuries (Injury Severity Score >16) were studied. Monocytes were obtained on admission and at 6, 12, 24, 48, and 72 hours after trauma. Biotinylated complementary RNA targets were hybridized to Affymetrix HG U 133A microarrays. The data were analyzed by a supervised analysis based on whether the patients received massive blood transfusions, and then subsequently, by hierarchical clustering, and by Ingenuity pathway analysis.

RESULTS

Supervised analysis identified 224 probe sets to be differentially expressed (p < 0.001) in patients who received massive blood transfusion, when compared with those who did not. In addition, 331 probe sets were found differentially expressed (p < 0.001) in patients who received uncrossmatched RBC units in comparison with those who exclusively gained crossmatched ones. Functional pathway analysis of the respectively identified gene expression profiles suggests a contributory role by the AKT/PI3Kinase pathway, the mitogen-activated protein-kinase pathway, the Ubiquitin pathway, and the diverse inflammatory networks.

CONCLUSION

We exhibited for the first time a serial, sequential screening analysis of monocyte messenger RNA expression patterns in patients with multiple trauma indicating a strongly significant association between the patients' genomic response in blood monocytes and massive or uncrossmatched RBC substitution.

Use of leukoreduced blood does not reduce infection, organ failure, or mortality following trauma

Background

Leukoreduced (LR) blood has been demonstrated to reduce morbidity and mortality in high-risk surgical patients, but not in trauma patients. The objective of the present study was to determine the effect of LR blood on morbidity and mortality. We hypothesized that the use of LR blood does not improve outcome in trauma patients.

Methods

This study was a retrospective cohort analysis of trauma patients transfused at a level 1 Trauma Center from 2001 to 2004. Between 2002 and 2003, LR blood was transfused. Prior to that time and subsequent to it, non-leukoreduced (NLR) blood was transfused. This created two historical comparison groups. Data collected included patient demographics, units of blood transfused, intensive care unit (ICU) and hospital days, ventilator days, injury severity score (ISS), mortality, presence of acute respiratory distress syndrome (ARDS), and infectious complications. A multiple organ dysfunction syndrome (MODS) score was calculated.

Results

The distribution of patients was as follows: 284 patients received only NLR blood, 153 received only LR blood, and 58 received at least one unit of each. The mean ISS was similar (NLR: 26, LR: 24; P > 0.1). No differences were seen between groups in units transfused (6.2 vs. 5.5), number of ICU days (8.2 vs. 9.0), number of hospital days (16.9 vs. 18.6), number of ventilator days (6.1 vs. 5.7), incidence of ARDS (8.3% vs. 8.5%), MODS score (5.5 vs. 5.9), mortality rate (15.1% vs. 15.7%), or infection rate (36% vs. 30%) (P > 0.1).

Conclusions

This study represents the largest series comparing trauma patients who received either LR or standard blood transfusions. The use of LR blood does not improve outcome in trauma patients.

Transfusion-related acute lung injury (TRALI): current concepts and misconceptions

Transfusion-related acute lung injury (TRALI) is the most common cause of serious morbidity and mortality due to hemotherapy. Although the pathogenesis has been related to the infusion of donor antibodies into the recipient, antibody negative TRALI has been reported. Changes in transfusion practices, especially the use of male-only plasma, have decreased the number of antibody-mediated cases and deaths; however, TRALI still occurs. The neutrophil appears to be the effector cell in TRALI and the pathophysiology is centered on neutrophil-mediated endothelial cell cytotoxicity resulting in capillary leak and ALI. This review will detail the pathophysiology of TRALI including recent pre-clinical data, provide insight into newer areas of research, and critically assess current practices to decrease it prevalence and to make transfusion safer.

Length of storage and in vitro immunomodulation induced by prestorage leukoreduced red blood cells

BACKGROUND

The relationship between length of storage of red blood cell (RBC) units and biochemical changes has been well studied, but little is known about the progression of cellular immunomodulative properties in blood recipients. This study aims to quantify in vitro T-cell activation and cytokine release by white blood cells, after incubation with supernatants from leukoreduced RBCs.

STUDY DESIGN AND METHODS

Whole blood cultures were incubated with supernatant from five leukoreduced RBC units stored for 1, 6, 10, 15, 24, and 42 days. Supernatant-induced T-cell activation was evaluated by quantifying CD25 expression. Supernatant-induced cytokine production was determined by measuring interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-alpha levels.

RESULTS

No cytokines were detected in RBC supernatants even after 42 days of storage. However, IL-6 levels in whole blood culture increased significantly when incubated with supernatant from RBC units stored for 1, 6, and 15 days, by factors of 1.7 +/- 0.3, 1.7 +/- 0.3, and 1.4 +/- 0.3, respectively. TNF-alpha levels were significantly decreased on Days 24 and 42 of storage by factors of 0.50 +/- 0.42 and 0.33 +/- 0.21, respectively. IL-10 levels were significantly increased on Days 1 and 42 of storage by factors of 2.3 +/- 1.3 and 3.2 +/- 2.8, respectively. After an initial increase in IL-6 and TNF-alpha production, there was a significant linear decrease in their levels measured from units stored for longer times. No significant changes in CD25 expression were observed over time.

CONCLUSION

Although no cytokines were measured in the supernatants from leukoreduced RBCs, these supernatants exhibited variable immunomodulatory effects related to their length of storage.

Validation of postinjury multiple organ failure scores

Most multiple organ failure (MOF) scores were developed over a decade ago, but little has been done in terms of validation and to understand the differences between populations identified by each of them. Given the lack of a gold standard, validation must rely on association with objective adverse outcomes. Thus, we propose to (a) validate two widely accepted MOF scores (Denver and Marshall), examining their association with adverse outcomes in a postinjury population; and (b) compare risk factors, characteristics, and outcomes of patients identified by each score. The Denver MOF score grades (from 0-3) four organ dysfunctions (lung, kidney, liver, and heart) and defines MOF as a total score more than 3. The Marshall score grades, in addition, central nervous system and hematologic dysfunction (total of six organs on a 0- to 4-point scale). Using a prospectively collected data set, MOF was scored daily by both scores for 1,389 consecutive trauma patients with Injury Severity Score of more than 15 admitted from 1992 to 2004. Risk factors, clinical outcomes (death, ventilator-free days), and resource utilization outcomes (mechanical ventilation time, length of stay in the intensive care unit) were evaluated. Both scores were associated with areas under the receiver operating characteristic curves of 80 or greater (ideal value = 100), with values for the Denver score being slightly greater (albeit not significantly) regarding prediction of most outcomes. Values of sensitivity and specificity were more than 70% for death and ventilator-free days (with the Denver score showing a consistent trend toward greater specificity), but either sensitivity or specificity was less than 70% for mechanical ventilation time and length of stay in the intensive care unit, suggesting that these scores are appropriately biased toward clinical outcomes as opposed to resource utilization. Both scores performed well, with the Denver MOF score showing greater specificity, which, coupled with its simplicity, makes it an attractive tool for both the research and clinical environments. Basic concepts of each score can probably be combined to produce an improved MOF score.

The USA Multicenter Prehosptial Hemoglobin-based Oxygen Carrier Resuscitation Trial: scientific rationale, study design, and results

Human polymerized hemoglobin (PolyHeme) is a universally compatible oxygen carrier developed for use when red blood cells are unavailable and oxygen-carrying replacement is needed to treat life-threatening anemia. This multicenter phase III trial assessed survival of patients resuscitated with a hemoglobin-based oxygen carrier starting at the scene of injury. Patients resuscitated with PolyHeme had outcomes comparable to those receiving the standard of care including rapid access to stored red blood cells. Although there were more adverse events in the PolyHeme group compared with control patients receiving blood, the observed safety profile is acceptable for the intended population. The benefit-to-risk ratio of PolyHeme is favorable when blood is needed but is not available or an option.

The platelet as an immune cell-CD40 ligand and transfusion immunomodulation

The discovery that platelets possess cell membrane, cytoplasmic, and secreted forms of the co-stimulatory molecule CD40 ligand (CD40L, also known as CD154) has led to a revolution in the view of this anucleate, differentiated cell fragment, previously thought only to be involved in blood clotting (hemostasis). During the last decade, it has become clear that platelets function in innate and adaptive immunity and possess pro-inflammatory, as well as pro-thrombotic properties. They interact not only with other platelets and endothelial cells, but also with lymphocytes, dendritic cells, and structural cells such as fibroblasts. Soluble forms of CD40L (sCD40L) in the human circulation are almost entirely derived from platelets. Elevated levels of CD40L are associated with clinically important conditions, such as vascular disease, abnormal clotting (thrombosis), lung injury, and autoimmune disease. Each year millions of platelet transfusions are given to patients that contain large amounts of sCD40L. sCD40L in the supernatant of stored platelets can induce cytokines, chemokines, and lipid mediators by activating CD40 bearing cells. Increased levels of sCD40L in transfused blood are associated with transfusion-related acute lung injury, a potentially fatal complication, as well as more common, milder transfusion reactions such as fever and rigors. These effects come under the rubric of transfusion immunomodulation, which postulates that transfusion recipient biology, particularly immune function, is dramatically altered by transfusion of stored allogeneic blood.

Direct retroperitoneal pelvic packing versus pelvic angiography: A comparison of two management protocols for haemodynamically unstable pelvic fractures

OBJECTIVE

To evaluate the outcomes of haemodynamically unstable cases of pelvic ring injury treated with a protocol focused on either direct retroperitoneal pelvic packing or early pelvic angiography and embolisation.

METHODS

A retrospective review of a prospectively collected database in an academic level I trauma centre, treating matched haemodynamically unstable cases of pelvic fracture with either pelvic packing (PACK group, n=20) or early pelvic angiography (ANGIO group, n=20). Physiological markers of haemorrhage, time to intervention, transfusion requirements, complications and early mortality were recorded.

RESULTS

The PACK group underwent operative packing at a median of 45min from admission; the median time to angiography in the ANGIO group was 130min. The PACK group, but not the ANGIO group, demonstrated a significant decrease in blood transfusions over the next 24h post intervention. In the ANGIO group, ten people required embolisation and six died, two from acute haemorrhage; in the PACK group, three people required embolisation; four died, none due to uncontrolled haemorrhage.

CONCLUSIONS

Pelvic packing is as effective as pelvic angiography for stabilising haemodynamically unstable casualties with pelvic fractures, decreases need for pelvic embolisation and post-procedure blood transfusions, and may reduce early mortality due to exsanguination from pelvic haemorrhage.

Independent determinants of early death in critically ill surgical patients

Abnormalities in cardiocirculatory, respiratory, or coagulatory parameters are frequent after major surgery, but so far, no study has investigated their predictive value for early intensive care unit (ICU) mortality. We aimed to describe and quantify the relation between these parameters that are routinely determined on ICU admission and early death after complex surgery. Individual patient data were available from a local ICU database. We performed a retrospective observational cohort study using prospectively collected data from March 1, 1993, through February 28, 2005. A cohort of 4,214 cases who were admitted to the ICU immediately after operation was analyzed. We studied age, sex, number of red blood cell units transfused on admission day, and admission values for heart rate, systolic blood pressure, hemoglobin concentration, partial thromboplastin time, prothrombin time, respiratory function (Pao2/Fio2 ratio), and body temperature for their association with 4-day mortality. Effects were adjusted for the underlying disease and for disease severity during the first 24 h after admission. We used generalized additive models to fit continuous variables individually before combining them into the final generalized model. We found an independent linear association between the number of transfused red blood cell units, partial thromboplastin time, and body temperature with acute outcome. A smoothed model described the independent interaction between admission blood pressure and early death. Only values of less than 80 mmHg were associated with an increased risk of 4-day mortality. According to these results, bleeding complications after ICU admission should be treated aggressively to prevent early death of the patient. However, normotensive conditions do not seem to be required to prevent early mortality. Whether rapid rewarming may improve outcome needs further rigorous study.

Effects of leukoreduced blood on acute lung injury after trauma: a randomized controlled trial

OBJECTIVE

The requirement for a blood transfusion after trauma is associated with an increased risk of acute lung injury. Residual leukocytes contaminating red cells are potential mediators of this syndrome. The goal of this trial was to test our hypothesis that prestorage leukoreduction of blood would reduce rates of posttraumatic lung injury.

DESIGN

Double blind, randomized, controlled clinical trial.

SETTING

University-affiliated level I trauma center in King County, Seattle, WA.

PATIENTS

Two hundred sixty-eight injured patients requiring red blood cell transfusion within 24 hrs of injury.

INTERVENTIONS

Prestorage leukoreduced vs. standard allogeneic blood transfusions.

MEASUREMENTS AND MAIN RESULTS

We compared the incidence of acute lung injury and acute respiratory distress syndrome at early (< or = 72 hrs) and late (> 72 hrs) time points after injury. In a subset, we compared plasma levels of surfactant protein-D and von Willebrand factor antigen between intervention arms. Rates of acute lung injury (relative risk [RR] 1.06, 95% confidence interval [CI] .69-1.640) and acute respiratory distress syndrome (RR .96, 95% CI 0.48-1.91) were not statistically different between intervention arms early after injury. Similarly, no statistically significant effect of leukoreduced transfusion on rates of acute lung injury (RR .88, 95% CI .54-1.44) or acute respiratory distress syndrome (RR .95, 95% CI .58-1.57) was observed to occur late after injury. There was no significant difference in the number of ventilator-free days or in other ventilator parameters between intervention arms. No statistically significant effect of leukoreduced blood on plasma levels of surfactant protein-D or von Willebrand factor antigen was identified.

CONCLUSIONS

Prestorage leukoreduction had no effect on the incidence or timing of lung injury or on plasma measures of systemic alveolar and endothelial inflammation in a population of trauma patients requiring transfusion. The relationship between transfusion and lung injury is not obviously explained by mechanistic pathways involving the presence of transfused leukocytes.

The systemic inflammatory response syndrome induces functional changes and relative hyporesponsiveness in neutrophils

PURPOSE

To study the effects of systemic inflammatory response syndrome (SIRS) on polymorhonuclear neutrophil (PMN) function and phenotype by comparing neutrophils from critically ill patients with SIRS against those from healthy blood donors.

MATERIAL AND METHODS

Intensive care unit patients (n = 110) who met at least one SIRS criterion were recruited to the study. One hundred healthy blood donors were recruited as normal controls.

RESULTS

Polymorphonuclear cells from critically ill patients with SIRS were more resistant to activation than PMNs from healthy donors, but when stimulated had an exaggerated microbicidal response. Buffer-treated PMNs from patients with SIRS had significantly higher CD43 surface expression that may inhibit heterotypic cellular contact or ligand stimulation of membrane receptors, had significantly lower expression of IgG receptor CD16, demonstrated resistance to shedding of L-selectin when primed by platelet-activating factor which could be pro-inflammatory, and had reduced respiratory burst when primed by platelet-activating factor than activated by formyl-Met-Leu-Phe.

CONCLUSION

The phenotypic and functional changes observed in neutrophils in the critically ill indicate that they require a higher level of stimulus to become activated. This may represent an auto-protective mechanism where the neutrophils in the already inflamed host may, by this mechanism, avoid excessive inflammation reducing the risk of further host cell injury and death.

Use of recombinant activated factor VII to arrest uncontrolled bleeding: a case series

A retrospective analysis is described to assess the effects of using recombinant activated factor VII to control bleeding in a series of patients who had failed to respond to conventional hemostatic measures. In all, 18 patients (aged 16-65 years) with a range of conditions resulting in bleeding refractory to conventional methods of control were treated with recombinant activated factor VII (60-120 Amicrog/kg; 1-4 doses). The effects of recombinant activated factor VII on bleeding were noted together with the patients' transfusion requirements and hematological parameters. Administration of recombinant activated factor VII successfully stopped bleeding in 17 of the 18 patients. Therapy with recombinant activated factor VII significantly decreased transfusion requirements for packed red blood cells, fresh frozen plasma, platelets, and cryoprecipitate compared with pretreatment values along with significant improvement in hemostasis. In various serious bleeding situations, treatment with recombinant activated factor VII may effectively arrest bleeding, which has remained refractory to conventional methods of control.

Role of biological modifiers regulating the immune response after trauma

Trauma induces a profound immunological dysfunction. This is characterised by an early state of hyperinflammation, followed by a phase of immunosuppression with increased susceptibility to infection and multiple organ failure. Therapeutic strategies directed at restoring immune homeostasis after traumatic injuries have largely failed in translation from "bench to bedside". The present review illustrates the role of biological modifiers of the posttraumatic immune response by portraying different modalities of therapeutic immune modulation. The emphasis is placed on anti-inflammatory (steroids) and immune-stimulatory (interferon) pharmacological strategies and modified resuscitative strategies, as well as more unconventional immunomodulatory approaches, such as immunonutrition.