Ex-Vivo Kidney Perfusion With Hemoglobin-Based Oxygen Carriers, Red Blood Cells, or No Oxygen Carrier.

INTRODUCTION: Normothermic machine perfusion (NMP) of donor kidneys provides the opportunity to assess and improve organ viability prior to transplantation. This study explored the necessity of an oxygen carrier during NMP and whether the hemoglobin-based oxygen carrier (HBOC-201) is a suitable alternative to red blood cells (RBCs). METHODS: Porcine kidneys were perfused with a perfusion solution containing either no-oxygen carrier, RBCs, or HBOC-201 for 360 min at 37°C. RESULTS: Renal flow and resistance did not differ significantly between groups. NMP without an oxygen carrier showed lower oxygen consumption with higher lactate and aspartate aminotransferase levels, indicating that the use of an oxygen carrier is necessary for NMP. Cumulative urine production and creatinine clearance in the RBC group were significantly higher than in the HBOC-201 group. Oxygen consumption, injury markers, and histology did not differ significantly between these two groups. However, methemoglobin levels increased to 45% after 360 min in the HBOC-201 group. CONCLUSIONS: We conclude that HBOC-201 could be used as an alternative for RBCs, but accumulating methemoglobin levels during our perfusions indicated that HBOC-201 is probably less suitable for prolonged NMP. Perfusion with RBCs, compared to HBOC-201, resulted in more favorable renal function during NMP.

Bioinspired carbon monoxide delivery using artificial blood attenuates the progression of obliterative bronchiolitis via suppression of macrophage activation by IL-17A.

Carbon monoxide (CO) is expected to attenuate the progression of obliterative bronchiolitis (OB), which is a serious complication after lung transplantation. However, issues in terms of feasible exogenous CO supply, such as continuousness and safety, remain unsolved. Here, we applied nano red blood cells, namely hemoglobin vesicles (Hb-V), as a CO cargo based on the biomimetic concept and investigated the therapeutic potential of CO-loaded Hb-V on OB in orthotopic tracheal transplant model mice. The CO-loaded Hb-V was comprised of negatively charged liposomes encapsulating carbonylhemoglobin with a size of ca. 220 nm. The results of histological evaluation showed that allograft luminal occlusion and fibrosis were significantly ameliorated by treatment with CO-loaded Hb-V compared to treatment with saline, cyclosporine, and Hb-V. The therapeutic effects of CO-loaded Hb-V on OB were due to the suppression of M1 macrophage activation in tracheal allografts, resulting from decreased IL-17A production. Furthermore, the expression of TNF-α and TGF-ß in tracheal allografts was decreased by CO-loaded Hb-V treatment but not saline and Hb-V treatment, indicating that CO liberated from CO-loaded Hb-V inhibits epithelial-mesenchymal transition. These findings suggest that CO-loaded Hb-V exerts strong therapeutic efficacy against OB via the regulation of macrophage activation by IL-17A and TGF-ß-driven epithelial-mesenchymal transition.

Blood Substitutes and Oxygen Therapeutics: A Review.

Despite the exhaustive search for an acceptable substitute to erythrocyte transfusion, neither chemical-based products such as perfluorocarbons nor hemoglobin-based oxygen carriers have succeeded in providing a reasonable alternative to allogeneic blood transfusion. However, there remain scenarios in which blood transfusion is not an option, due to patient's religious beliefs, inability to find adequately cross-matched erythrocytes, or in remote locations. In these situations, artificial oxygen carriers may provide a mortality benefit for patients with severe, life-threatening anemia. This article provides an up-to-date review of the history and development, clinical trials, new technology, and current standing of artificial oxygen carriers as an alternative to transfusion when blood is not an option.

Immediate effects of systemic administration of normal and high O2-affinity haemoglobin vesicles as a transfusion alternative in a rat pneumonectomy model.

BACKGROUND: Haemoglobin vesicles (HbVs) are red blood cell (RBC) substitutes with a phospholipid bilayer membrane and a polyethylene modified surface (diameter=250 nm; P50=28 Torr). They can be preserved for years and can be used in patients of all blood types without the risk of infection. Their oxygen affinity can be modified by changing the allosteric effectors. METHODS: Left pneumonectomy was performed under mechanical ventilation on rats, followed by rapid exsanguination of ~30% of the total circulating blood volume. Rat RBCs shed in 5% human serum albumin (HSA) solution (rat RBC), HbV with high oxygen affinity in 5% albumin solution (low-P50 HbV, P50=9 Torr), normal HbV suspended in 5% albumin (HbV, P50=28 Torr) or 5% HSA was infused for resuscitation. Haemodynamics and oxygenation were evaluated. RESULTS: Systemic arterial blood pressure significantly decreased after exsanguination and increased after each infusion. In the HbV, low-P50 HbV and rat RBC groups, all rats were liberated from mechanical ventilation and blood pressure was stabilised, whereas 50% of the rats in the HSA group died within 1 hour after weaning from mechanical ventilation. The PaO2 in arterial blood for 1 hour after liberation from mechanical ventilation in the rat RBC, HbV and low-P50 HbV groups was 59.4±12.5, 58.3±10.1 and 70.5±14.5 mm Hg, respectively. The PaO2 in the low-P50 HbV group was significantly higher than those in the rat RBC and HbV groups (p=0.05 for both). Serum lactate elevations due to hypoxic damage were minimised by HbV, low-P50 HbV as well as rat RBCs. CONCLUSIONS: The oxygen-carrying ability of HbV was comparable to that of rat RBCs, even under impaired lung function after pneumonectomy. HbVs with high oxygen affinity may have more beneficial effects on oxygenation in pulmonary resection.

Resuscitation with PEGylated carboxyhemoglobin preserves renal cortical oxygenation and improves skeletal muscle microcirculatory flow during endotoxemia.

PEGylated carboxyhemoglobin (PEGHbCO), which has carbon monoxide-releasing properties and plasma expansion and oxygen-carrying properties, may improve both skeletal microcirculatory flow and renal cortical microcirculatory Po2 (CµPo2) and, subsequently, limit endotoxemia-induced acute kidney injury. Anesthetized, ventilated Wistar albino rats (n = 44) underwent endotoxemic shock. CµPo2 was measured in exposed kidneys using a phosphorescence-quenching method. Rats were randomly assigned to the following five groups: 1) unresuscitated lipopolysaccharide (LPS), 2) LPS + Ringer's acetate (RA), 3) LPS + RA + 0.5 µg·kg·-1min-1 norepinephrine (NE), 4) LPS + RA + 320 mg/kg PEGHbCO, and 5) LPS + RA + PEGHbCO + NE. The total volume was 30 mL/kg in each group. A time control animal group was used. Skeletal muscle microcirculation was assessed by handheld intravital microscopy. Kidney immunohistochemistry and myeloperoxidase-stained leukocytes in glomerular and peritubular areas were analyzed. Endotoxemia-induced histological damage was assessed. Plasma levels of IL-6, heme oxygenase-1, malondialdehyde, and syndecan-1 were assessed by ELISA. CµPo2 was higher in the LPS + RA + PEGHbCO-resuscitated group, at 35 ± 6mmHg compared with 21 ± 12 mmHg for the LPS+RA group [mean difference: -13.53, 95% confidence interval: (-26.35; -0.7156), P = 0.035]. The number of nonflowing, intermittent, or sluggish capillaries was smaller in groups infused with PEGHbCO compared with RA alone (P < 0.05), while the number of normally perfused vessels was greater (P < 0.05). The addition of NE did not further improve CµPo2 or microcirculatory parameters. Endotoxemia-induced kidney immunohistochemistry and histological alterations were not mitigated by PEGHbCO 1 h after resuscitation. Renal leukocyte infiltration and plasma levels of biomarkers were similar across groups. PEGHbCO enhanced CµPo2 while restoring skeletal muscle microcirculatory flow in previously nonflowing capillaries. PEGHbCO should be further evaluated as a resuscitation fluid in mid- to long-term models of sepsis-induced acute kidney injury.

Renal Protection Against Ischemia Reperfusion Injury: Hemoglobin-based Oxygen Carrier-201 Versus Blood as an Oxygen Carrier in Ex Vivo Subnormothermic Machine Perfusion.

BACKGROUND: The optimal method of oxygen delivery to donor kidneys during ex vivo machine perfusion has not been established. We have recently reported the beneficial effects of subnormothermic (22°C) blood perfusion in the preservation of porcine donation after circulatory death kidneys. Since using blood as a clinical perfusate has limitations, including matching availability and potential presence of pathogen, we sought to assess hemoglobin-based oxygen carrier (HBOC-201) in oxygen delivery to the kidney for renal protection. METHODS: Pig kidneys (n = 5) were procured after 30 minutes of warm in situ ischemia by cross-clamping the renal arteries. Organs were flushed with histidine tryptophan ketoglutarate solution and subjected to static cold storage or pulsatile perfusion with an RM3 pump at 22°C for 4 hours with HBOC-201 and blood. Thereafter, kidneys were reperfused with normothermic (37°C) oxygenated blood for 4 hours. Blood and urine were subjected to biochemical analysis. Total urine output, urinary protein, albumin/creatinine ratio, flow rate, resistance were measured. Acute tubular necrosis, apoptosis, urinary kidney damage markers, neutrophil gelatinase-associated lipocalin 1, and interleukin 6 were also assessed. RESULTS: HBOC-201 achieved tissues oxygen saturation equivalent to blood. Furthermore, upon reperfusion, HBOC-201 treated kidneys had similar renal blood flow and function compared with blood-treated kidneys. Histologically, HBOC-201 and blood-perfused kidneys had vastly reduced acute tubular necrosis scores and degrees of terminal deoxynucleotidyl transferase 2'-deoxyuridine, 5'-triphosphate nick end labeling staining versus kidneys treated with cold storage. Urinary damage markers and IL6 levels were similarly reduced by both blood and HBOC-201. CONCLUSIONS: HBOC-201 is an excellent alternative to blood as an oxygen-carrying molecule in an ex vivo subnormothermic machine perfusion platform in kidneys.

Intravenous fluids and their use in sport: A position statement from the Australian Institute of Sport.

OBJECTIVE: The use of intravenous fluids in out-of-hospital settings has evolved from the practices used by military and emergency response teams. When used in the elite sporting environment, IV fluid use must comply with the World Anti-Doping Code. Uncertainty can arise as clinicians seek to balance the appropriate use of IV fluids in delivering athlete care against the need for World Anti-Doping Code compliance. DESIGN AND METHOD: This position statement reviews the current literature and incorporates clinical experiences to present best-practice recommendations on the clinical use of Intravenous fluids in the elite sport environment, framing recommendations in the context of the World Anti-Doping Code. RESULTS AND CONCLUSION: The World Anti-Doping Code restricts the use of Intravenous fluids in athletes under certain conditions. This report takes into account the World Anti-Doping Code and the risks of Intravenous fluid administration to provide guidelines around the judicious use of IV fluids for: 1. Treatment of severe dehydration in an athlete, 2. Management of exertional heat illness in an athlete, 3. Hypovolaemia because of trauma in sport, 4. Administering medications.

Selective aortic arch perfusion with fresh whole blood or HBOC-201 reverses hemorrhage-induced traumatic cardiac arrest in a lethal model of noncompressible torso hemorrhage.

BACKGROUND: Hemorrhage-induced traumatic cardiac arrest (HiTCA) has a dismal survival rate. Previous studies demonstrated selective aortic arch perfusion (SAAP) with fresh whole blood (FWB) improved the rate of return of spontaneous circulation (ROSC) after HiTCA, compared with resuscitative endovascular balloon occlusion of the aorta and cardiopulmonary resuscitation (CPR). Hemoglobin-based oxygen carriers, such as hemoglobin-based oxygen carrier (HBOC)-201, may alleviate the logistical constraints of using FWB in a prehospital setting. It is unknown whether SAAP with HBOC-201 is equivalent in efficacy to FWB, whether conversion from SAAP to extracorporeal life support (ECLS) is feasible, and whether physiologic derangement post-SAAP therapy is reversible. METHODS: Twenty-six swine (79 ± 4 kg) were anesthetized and underwent HiTCA which was induced via liver injury and controlled hemorrhage. Following arrest, swine were randomly allocated to resuscitation using SAAP with FWB (n = 12) or HBOC-201 (n = 14). After SAAP was initiated, animals were monitored for a 20-minute prehospital period prior to a 40-minute damage control surgery and resuscitation phase, followed by 260 minutes of critical care. Primary outcomes included rate of ROSC, survival, conversion to ECLS, and correction of physiology. RESULTS: Baseline physiologic measurements were similar between groups. ROSC was achieved in 100% of the FWB animals and 86% of the HBOC-201 animals (p = 0.483). Survival (t = 320 minutes) was 92% (11/12) in the FWB group and 67% (8/12) in the HBOC-201 group (p = 0.120). Conversion to ECLS was successful in 100% of both groups. Lactate peaked at 80 minutes in both groups, and significantly improved by the end of the experiment in the HBOC-201 group (p = 0.001) but not in the FWB group (p = 0.104). There was no significant difference in peak or end lactate between groups. CONCLUSION: Selective aortic arch perfusion is effective in eliciting ROSC after HiTCA in a swine model, using either FWB or HBOC-201. Transition from SAAP to ECLS after definitive hemorrhage control is feasible, resulting in high overall survival and improvement in lactic acidosis over the study period.

Artificial oxygen carriers and red blood cell substitutes: A historic overview and recent developments toward military and clinical relevance.

Packed red blood cells are a critical component in the resuscitation of hemorrhagic shock. The availability of donor-derived blood products, however, suffers from issues of supply, immunogenicity, and pathogenic contamination. Deployment in remote or austere environments, such as the battlefield, is further hindered by the inherent perishability of blood products. To address the significant limitations of allogenic packed red blood cells and the urgent medical need for better resuscitative therapies for both combat casualties and civilians, there has been significant research invested in developing safe, effective, and field deployable artificial oxygen carriers. This article provides a comprehensive review of the most important technologies in the field of artificial oxygen carriers including cell-free and encapsulated hemoglobin-based oxygen carriers, perfluorocarbon emulsions, natural hemoglobin alternatives, as well as other novel technologies. Their development status, clinical, and military relevance are discussed. LEVEL OF EVIDENCE: Systematic review.

Optimal crystalloid volume ratio for blood replacement for maintaining hemodynamic stability and lung function: an experimental randomized controlled study.

BACKGROUND: Crystalloids are first line in fluid resuscitation therapy, however there is a lack of evidence-based recommendations on the volume to be administered. Therefore, we aimed at comparing the systemic hemodynamic and respiratory effects of volume replacement therapy with a 1:1 ratio to the historical 1:3 ratio. METHODS: Anesthetized, ventilated rats randomly included in 3 groups: blood withdrawal and replacement with crystalloid in 1:1 ratio (Group 1, n = 11), traditional 1:3 ratio (Group 3, n = 12) and a control group with no interventions (Group C, n = 9). Arterial blood of 5% of the total blood volume was withdrawn 7 times, and replaced stepwise with different volume rations of Ringer's acetate, according to group assignments. Airway resistance (Raw), respiratory tissue damping (G) and tissue elastance (H), mean arterial pressure (MAP) and heart rate (HR) were assessed following each step of fluid replacement with a crystalloid (CR1-CR6). Lung edema index was measured from histological samples. RESULTS: Raw decreased in Groups 1 and 3 following CR3 (p < 0.02) without differences between the groups. H elevated in all groups (p < 0.02), with significantly higher changes in Group 3 compared to Groups C and 1 (both p = 0.03). No differences in MAP or HR were present between Groups 1 and 3. Lung edema was noted in Group 3 (p < 0.05). CONCLUSIONS: Fluid resuscitation therapy by administering a 1:1 blood replacement ratio revealed adequate compensation capacity and physiological homeostasis similar with no lung stiffening and pulmonary edema. Therefore, considering this ratio promotes the restrictive fluid administration in the presence of continuous and occult bleeding.

Oxygenated theranostic nanoplatforms with intracellular agglomeration behavior for improving the treatment efficacy of hypoxic tumors.

Hypoxia plays vital roles in the development of tumor resistance against typical anticancer therapies and local reoxygenation has proved effective to overcome the hypoxia-induced chemoresistance. Perfluorocarbon (PFC) is an FDA approved oxygen carrier and currently vigorously investigated for oxygen delivery to tumors. This study reports a perfluorocarbon and etoposide (EP) loaded porous hollow Fe3O4-based theranostic nanoplatform capable of delivering oxygen to solid tumors to enhance their susceptibility against EP. Results show that oxygen could be released at a moderate rate from the porous hollow magnetic Fe3O4 nanoparticles (PHMNPs) over an extended period of time, therefore effectively reducing the hypoxia-induced EP resistance of tumor cells. Moreover, the surface of PHMNPs was modified with lactobionic acid (LA)-containing amphiphilic polymers via hydrophobic interaction, which could provide targeting effect against certain types of tumors. The hydrophilic moiety would be subsequently shed by the intratumoral GSH after cellular internalization and result in the agglomeration of nanocarriers inside tumor cells, consequently impeding the nanoparticle exocytosis to enhance their intracellular retention. The enhanced retention could elevate the intracellular EP level and effectively boost the tumor cell killing effect. In addition to the therapeutic benefits, the Fe3O4 nanocage could also be used for the magnetic resonance imaging of the tumor area. The assorted benefits of the composite nanosystem are anticipated to be advantageous for the treatment of drug-resistant hypoxic tumors.

Efficacy of the perfluorocarbon dodecafluoropentane as an adjunct to pre-hospital resuscitation.

BACKGROUND: Hemorrhage is the most common cause of preventable death in the pre-hospital phase in trauma, with a critical capability gap optimizing pre-hospital resuscitation in austere environments. One promising avenue is the concept of a multi-functional resuscitation fluid (MRF) that contains a blood product backbone with agents that promote clotting and enhance oxygen delivery. Oxygen therapeutics, such as hemoglobin based oxygen carriers(HBOCs) and perfluorocarbons(PFCs), may be a critical MRF component. Our purpose was to assess the efficacy of resuscitation with a PFC, dodecafluoropentane(DDFPe), compared to fresh whole blood(FWB). METHODS AND FINDINGS: Forty-five swine(78±5kg) underwent splenectomy and controlled hemorrhage via femoral arterial catheter until shock physiology(lactate = 7.0) was achieved prior to randomization into the following groups: 1) Control-no intervention, 2)Hextend-500mL, 3)FFP-500mL, 4)FFP+DDFPe-500mL, 5)FWB-500mL. Animals were observed for an additional 180 minutes following randomization. RESULTS: Baseline physiologic values did not statistically differ. At T = 60min, FWB had significantly decreased lactate(p = 0.001) and DDFPe was not statistically different from control. There was no statistical significance in tissue oxygenation(StO2) between groups at T = 60min. Survival was highest in the FWB and Hextend groups(30% at 180min). Kaplan-Meier analysis showed decreased survival of DDFPe+FFP in comparison to FWB(p<0.05) and was not significantly different from control or FFP. Four animals who received DDFPe died within 10 minutes of administration. This study was limited by a group receiving DDFPe alone, however this would not be feasible in this lethal swine model as DDFPe given its small volume. CONCLUSION: DDFPe administration with FFP does not improve survival or enhance tissue oxygenation. However, given similar survival rates of Hextend and FWB, there is evidence that an ideal MRF should contain an element of volume expansion to enhance oxygen delivery.

The effects of hemoglobin glutamer-200 and iNO on pulmonary vascular tone and arterial oxygenation in an experimental acute respiratory distress syndrome.

INTRODUCTION: Hemoglobin-based oxygen carriers (HBOC) have been developed as an alternative to blood transfusions. Their nitric-oxide-scavenging properties HBOC also induce vasoconstriction. In acute lung injury, an excess of nitric oxide results in a general vasodilation, reducing oxygenation by impairing the hypoxic pulmonary vasoconstriction. Inhaled nitric oxide (iNO) is used to correct the ventilation perfusion mismatch. We hypothesized that the additional use of HBOC might increase this effect. In a rodent model of ARDS we evaluated the combined effect of HBOC and iNO on vascular tone and gas exchange. METHODS: ARDS was induced in anaesthetized Wistar rats by saline lavage and aggressive ventilation. Two groups received either hydroxyethylstarch 10% (HES; n = 10) or the HBOC hemoglobin glutamer-200 (HBOC-200; n = 10) via a central venous infusion. Additionally, both groups received iNO. Monitoring of the right ventricular pressure (RVP) and mean arterial pressure (MAP) was performed with microtip transducers. Arterial oxygenation was measured via arterial blood gas analyses. RESULTS: Application of HBOC-200 led to a significant increase of MAP and RVP when compared to baseline and to the HES group. This effect was reversed by iNO. The application of HBOC and iNO had no effect on the arterial oxygenation over time. No difference in arterial oxygenation was found between the groups. CONCLUSION: Application of HBOC led to an increase of systemic and pulmonary vascular resistance in this animal model of ARDS. The increase in RVP was reversed by iNO. Pulmonary vasoconstriction by hemoglobin glutamer-200 in combination with iNO did not improve arterial oxygenation in ARDS.

Microparticles in red cell concentrates prime polymorphonuclear neutrophils and cause acute lung injury in a two-event mouse model.

Red cell-derived microparticles (RMPs) are potential mediators of transfusion-related acute lung injury (TRALI). The aim of this study was to investigate the effects of microparticles present in red cell concentrates (RCC) on polymorphonuclear neutrophil (PMN) respiratory burst and acute lung injury (ALI) in mice. Microparticles (MPs) in RCC supernatant were quantified using flow cytometry. The priming activity of either isolated MPs or RCC supernatant toward human PMN was measured in vitro. Mice were injected with lipopolysaccharide (LPS), followed by an infusion of either isolated MPs or heat-treated RCC supernatant. The lungs were harvested to assess myeloperoxidase (MPO) activity, histology and pulmonary edema. Protein content in bronchoalveolar lavage fluid (BALF) was measured. The number of RMPs increased significantly during storage. Both isolated MPs and the supernatants from RCCs that had been stored for 28 and 35days effectively primed the PMN respiratory burst. The infusion of isolated MPs or supernatants that had been stored for >28days into LPS-treated mice caused ALI. The filtered supernatant resulted in significantly ameliorated mouse ALI. MPs that accumulate during RCC storage prime the PMN respiratory burst and cause ALI in a two-event mouse model.

Effect of 0.9% Saline or Plasma-Lyte 148 as Crystalloid Fluid Therapy in the Intensive Care Unit on Blood Product Use and Postoperative Bleeding After Cardiac Surgery.

OBJECTIVE: To evaluate the effect of Plasma-Lyte 148 (PL-148) compared with 0.9% saline (saline) on blood product use and postoperative bleeding in patients admitted to the intensive care unit (ICU) following cardiac surgery. DESIGN: A post hoc subgroup analysis conducted within a multicenter, double-blind, cluster-randomized, double-crossover study (study 1) and a prospective, single-center nested-cohort study (study 2). SETTING: Tertiary-care hospitals. PARTICIPANTS: Adults admitted to the ICU after cardiac surgery requiring crystalloid fluid therapy as part of the 0.9% saline vs. PL-148 for ICU fluid therapy (SPLIT) trial. INTERVENTIONS: Blinded saline or PL-148 for 4 alternating 7-week blocks. MEASUREMENTS AND MAIN RESULTS: 954 patients were included in study 1; 475 patients received PL-148, and 479 received saline. 128 of 475 patients (26.9%) in the PL-148 group received blood or a blood product compared with 94 of 479 patients (19.6%) in the saline group (OR [95% confidence interval], 1.51 [1.11-2.05]; p = 0.008). In study 2, 131 patients were allocated to PL-148 and 120 patients were allocated to saline. There were no differences between groups in chest drain output from the time of arrival in the ICU until 12 hours postoperatively (geometric mean, 566 mL for the PL-148 group v 547 mL in the saline group; p = 0.60). CONCLUSIONS: The findings did not support the hypothesis that using PL-148 for fluid therapy in ICU following cardiac surgery reduces transfusion requirements compared to saline. The significantly increased proportion of patients receiving blood or blood product with allocation to PL-148 compared to saline was unexpected and requires verification through further research.

Abnormal Calcium Levels During Trauma Resuscitation Are Associated With Increased Mortality, Increased Blood Product Use, and Greater Hospital Resource Consumption: A Pilot Investigation.

BACKGROUND: Admission hypocalcemia predicts both massive transfusion and mortality in severely injured patients. However, the effect of calcium derangements during resuscitation remains unexplored. We hypothesize that any hypocalcemia or hypercalcemia (either primary or from overcorrection) in the first 24 hours after severe injury is associated with increased mortality. METHODS: All patients at our institution with massive transfusion protocol activation from January 2013 through December 2014 were identified. Patients transferred from another hospital, those not transfused, those with no ionized calcium (Ca) measured, and those who expired in the trauma bay were excluded. Hypocalcemia and hypercalcemia were defined as any level outside the normal range of Ca at our institution (1-1.25 mmol/L). Receiver operator curve analysis was also used to further examine significant thresholds for both hypocalcemia and hypercalcemia. Hospital mortality was compared between groups. Secondary outcomes included advanced cardiovascular life support, damage control surgery, ventilator days, and intensive care unit days. RESULTS: The massive transfusion protocol was activated for 77 patients of whom 36 were excluded leaving 41 for analysis. Hypocalcemia occurred in 35 (85%) patients and hypercalcemia occurred in 9 (22%). Mortality was no different in hypocalcemia versus no hypocalcemia (29% vs 0%; P = .13) but was greater in hypercalcemia versus no hypercalcemia (78% vs 9%; P < .01). Receiver operator curve analysis identified inflection points in mortality outside a Ca range of 0.84 to 1.30 mmol/L. Using these extreme values, 15 (37%) had hypocalcemia with a 60% mortality (vs 4%; P < .01) and 9 (22%) had hypercalcemia with a 78% mortality (vs 9%; P < .01). Patients with extreme hypocalcemia and hypercalcemia also received more red blood cells, plasma, platelets, and calcium repletion. CONCLUSIONS: Hypocalcemia and hypercalcemia occur commonly during the initial resuscitation of severely injured patients. Mild hypocalcemia may be tolerable, but more extreme hypocalcemia and any hypercalcemia should be avoided. Further assessment to define best practice for calcium management during resuscitation is warranted.

SANGUINATE™ (PEGylated Carboxyhemoglobin Bovine) Improves Cerebral Blood Flow to Vulnerable Brain Regions at Risk of Delayed Cerebral Ischemia After Subarachnoid Hemorrhage.

BACKGROUND: Delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH) has been linked to focal reductions in cerebral blood flow (CBF) and microvascular impairments in oxygen delivery. Effective therapies that restore flow and oxygen transport to vulnerable brain regions are currently lacking. SANGUINATE is a dual-action carbon monoxide-releasing and hemoglobin-based oxygen transfer agent with efficacy in animal models of focal brain ischemia and tolerability in patients with sickle cell disease. METHODS: We performed a safety and proof-of-principle study in 12 SAH patients at risk of DCI across three escalating doses (160, 240, and 320 mg/kg). We used 15O-PET (performed at baseline, after SANGUINATE and at 24 h) to evaluate efficacy for improving CBF and restoring flow-metabolism balance (assessed by oxygen extraction fraction [OEF]) to vulnerable regions (defined as baseline OEF ≥ 0.50). RESULTS: SANGUINATE resulted in a transient rise in mean arterial pressure (116 ± 15-127 ± 13 mm Hg, p = 0.001) that normalized by 24 h and allowed three patients with DCI to be weaned off vasopressors. No adverse events were noted during infusion. Global CBF did not rise (43 ± 8-46 ± 9 ml/100 g/min) although a trend was seen at the highest dose (45 ± 7-51 ± 9, p = 0.044). However, a significant 16% rise in regional CBF associated with reduction in OEF was seen in vulnerable regions, but did not persist at 24 h. CONCLUSIONS: We demonstrated that this novel agent can improve regional CBF and may improve oxygen supply-demand balance. Clinical studies (likely with repeat dosing) are required to evaluate whether this effect can prevent DCI or cerebral infarction.

Optimising Intravenous Volume Resuscitation of the Newborn in the Delivery Room: Practical Considerations and Gaps in Knowledge.

Volume resuscitation (VR) for the treatment of newborn shock is a rare but potentially lifesaving intervention. Conducting clinical studies to assess the effectiveness of VR in the delivery room during newborn stabilization is challenging. We review the available literature and current management guidelines to determine which infants will benefit from VR, the frequency of VR, and the choice of agents used. In addition, the potential role for placental transfusion in the prevention of newborn shock is explored.

[Management of Massive Intraoperative Blood Loss Using a Case Study]. / Management des massiven intraoperativen Blutverlusts anhand eines Fallbeispiels.

Massive intraoperative bleeding is a major and potentially life-threatening complication during surgical procedures. The lethal triade of hemorrhagic shock with metabolic acidosis, hypothermia and coagulopathy enhances bleeding tendency. Avoiding this vitious circle requires a well-structured and standardized procedure. Primary goals include the maintenance of adequate tissue oxygenation, restauration of proper coagulatory function, normothermia and homeostasis of acid-base and electrolyte balance. In the present article, these therapeutic goals and their pathophysiological background are illustrated with a clinical case example.