Low-volume resuscitation with a hemoglobin-based oxygen carrier after hemorrhage improves gut microvascular oxygenation in swine

Using palladium-porphyrin quenching of phosphorescence, we investigated the influence of diaspirin cross-linked hemoglobin (DCLHb) on gut microvascular oxygen pressure (microPO2) in anesthetized pigs. Values of gut microPO2 were studied in correlation with regional intestinal as well as global metabolic and circulatory parameters. A controlled hemorrhagic shock (blood withdrawal of 40 mL/kg) was followed by resuscitation with either a combination of lactated Ringer's solution (75 mL/kg) and modified gelatin (15 mL/kg)(lactR/Gel) or 10% DCLHb (5 mL/kg). After resuscitation, gut microPO2 was similarly improved in the lactR/Gel group (from 25 +/- 10 mm Hg to 53 +/- 8 mm Hg) and the DCLHb group (from 23 +/- 9 mm Hg to 46 +/- 6 mm Hg), which was associated with increased gut oxygen delivery. However, the improvement after resuscitation with DCLHb was sustained for longer periods of time (75 vs 30 min). Mesenteric venous PO2 was increased after resuscitation with lactated Ringer's solution and modified gelatin but not with DCLHb, which was associated with an increased gut oxygen consumption in the latter group. We conclude that measurement of microPO2 by the palladium-porphyrin phosphorescence technique revealed DCLHb to be an effective carrier of oxygen to the microcirculation of the gut. Also, this effect can be achieved with a lower volume than is currently used in resuscitation procedures.     

Diaspirin cross-linked hemoglobin resuscitation improves cerebral perfusion after head injury and shock

BACKGROUND: Shock associated with traumatic brain injury (TBI) doubles the mortality of TBI alone by inducing a secondary ischemic injury. Rapid correction of cerebral perfusion pressure (CPP) is thought to be essential to improving outcome. Diaspirin cross-linked hemoglobin (DCLHb) has been shown to improve cerebral blood flow, increase mean arterial pressure (MAP), and reduce lesion size in models of occlusive cerebral ischemia but has not been evaluated in a model of TBI combined with hemorrhagic shock. METHODS: We studied the effects of DCLHb resuscitation in a porcine model of cryogenic TBI and hemorrhagic shock (MAP = 50 mmHg). After combined insults, animals were randomized to receive a bolus of 4 mliters/kg of either lactated Ringer's solution (n = 5) or DCLHb (n = 6). Lactated Ringer's solution was then infused in both groups to maintain MAP at baseline. Shed blood was returned 1 hour after the initiation of resuscitation (R1). Animals were studied for 24 hours. RESULTS: DCLHb infusion resulted in a significantly greater MAP at R1 and R24 (95 +/- 4 vs. 82 +/- 2 and 99 +/- 3 vs. 85 +/- 3 mm Hg, respectively) and a significantly greater CPP at R1 and R24 (83 +/- 10 vs. 68 +/- 5 and 89 +/- 6 vs. 71 +/- 11 mm Hg, respectively). Intracranial pressure was lower in the DCLHb group, but this difference was not significant. There was no significant difference between the groups in cerebral oxygen delivery. DCLHb animals required less fluid to maintain MAP (12,094 +/- 552 vs. 15,542 +/- 1094 mliters, p < 0.05). CONCLUSION: These data suggest that DCLHb is beneficial in the early resuscitation of head injury and shock and that further investigation is warranted. Key Words: Diaspirin cross-linked hemoglobin, Head injury, Shock, Cerebral perfusion pressure.     

Prognostic value of blood lactate, base deficit, and oxygen-derived variables in an LD50 model of penetrating trauma

OBJECTIVE: To determine whether blood lactate, base deficit, or oxygen-derived hemodynamic variables correlate with morbidity and mortality rates in a clinically-relevant LD50 model of penetrating trauma. DESIGN: Prospective, controlled study. SETTING: University research laboratory. SUBJECTS: Anesthetized, mechanically-ventilated mongrel pigs (30+/-2 kg, n = 29). INTERVENTIONS: A captive bolt gun delivered a penetrating injury to the thigh, followed immediately by a 40% to 60% hemorrhage. After 1 hr, shed blood and supplemental crystalloid were administered for resuscitation. MEASUREMENTS AND MAIN RESULTS: After penetrating injury, 50.7+/-0.3% hemorrhage (range 50% to 52.5%), and a 1-hr shock period, seven of 14 animals died, compared with six of six animals after 55% to 60% hemorrhage, and 0 of nine animals after < or =47.5% hemorrhage. Only two of 13 deaths occurred during fluid resuscitation. At the LD50 hemorrhage, peak lactate concentration and base deficit were 11.2+/-0.8 mM and 9.3+/-1.5 mmol/L, respectively, and minimum mixed venous oxygen saturation, systemic oxygen delivery, and systemic oxygen consumption were 33+/-5%, 380+/-83 mL/min/kg, and 177+/-35 mL/min/kg, respectively. For comparison, baseline preinjury values were 1.6+/-0.1 mM, -6.7+/-0.6 mmol/L, 71+/-3%, 2189+/-198 mL/min/kg, and 628+/-102 mL/min/kg, respectively. Of all the variables, only lactate was significantly related to blood loss before and after fluid resuscitation in the 16 survivors. However, r2 values were relatively low (.20 to .50), which indicates that only a small fraction of the hyperiactacidemia was directly related to tissue hypoperfusion. In the whole population of survivors and nonsurvivors, both lactate and base deficit (but none of the oxygen-derived variables) correlated with blood loss. CONCLUSIONS: Arterial lactate is a stronger index of blood loss after penetrating trauma than base deficit or oxygen-derived hemodynamic variables. The reliability of arterial lactate depends on several factors, such as the time after injury, the proportion of survivors and nonsurvivors in the study population, and on factors other than tissue hypoxia.     

Characterization of the hemodynamic response to intravenous diaspirin crosslinked hemoglobin solution in rats

Diaspirin crosslinked hemoglobin solution (DCLHB) has potential for clinical use as an oxygen-carrying solution because of its excellent oxygen transport properties and biochemical stability. The present study characterizes the effects of intravenous infusions of 0.625-40 mL/kg (62.5-4000 mg/kg) DCLHb on mean blood pressure (MAP) and heart rate (HR) in conscious rats. DCLHb at all doses tested except 62.5 mg/kg was associated with an immediate increase in MAP (25-30% above baseline) that peaked between 20-30 minutes after infusion and returned to baseline within 120-300 minutes in a dose-dependent manner. Maximum MAP achieved was in the range of 129 +/- 7 to 140 +/- 7 mm Hg and there was no statistically significant difference in the response between doses. HR responded in a reciprocal manner to changes in MAP. Volume- and oncotic-matched infusions of LR and albumin did not alter MAP or HR. Slow infusion (0.34 mL/min) of DCLHb appeared to blunt the magnitude of the pressor response when compared to bolus injection (< 10 sec). DCLHb administration is associated with a pressor response that is not due to volume load, oncotic pressure, or rate of infusion, suggesting that it is intrinsic to the modified hemoglobin molecule and pharmacologic in nature.     

The efficacy of diaspirin crosslinked hemoglobin solution resuscitation in a model of uncontrolled hemorrhage

Controversy exists whether early aggressive fluid therapy in the setting of uncontrolled hemorrhage worsens outcome by increasing blood loss from injured vessels. Since diaspirin crosslinked hemoglobin (DCLHb) is a vasoactive, oxygen-carrying solution, we compared the effects of DCLHb with other resuscitative fluids on blood loss, hemodynamics, and tissue oxygen delivery in a model of uncontrolled hemorrhage. Anesthetized rats (250-350 g) were subjected to a 50% tail transection and resuscitated 15 minutes later with 1:1 DCLHb, 3:1 lactated Ringer's solution (LR), 1:1 hypertonic saline (7.5% HTS), or 1:1 human serum albumin (8.3% HSA) based on initial volume of blood loss (average 4.7 +/- 0.3 mL/kg). An unresuscitated group served as a control. Cumulative blood loss was measured at 5 hours postresuscitation. By 15 minutes after tail transection, mean arterial pressure (MAP) decreased 19.2 +/- 3.8 mm Hg from the baseline value (102 +/- 5 mm Hg). The DCLHb solution restored and maintained MAP and subcutaneous tissue oxygen tension at baseline values better than all other resuscitative fluids. Although blood loss in DCLHb-treated animals was greater than in unresuscitated animals, it was no different from other resuscitative fluids and less than with HSA. There was no difference in 24-hour survival between all treatment groups. In conclusion, DCLHb elevates MAP but does not exacerbate blood loss or compromise tissue oxygen delivery compared with other resuscitative fluids in this model of uncontrolled hemorrhage.     

Uncontrolled hemorrhage from parenchymal injury: is resuscitation helpful?

Fluid resuscitation increases blood pressure and may increase hemorrhage. We tested this hypothesis in a model of liver injury. After standardized injury, rats were randomized into four groups: no resuscitation (NR, n = 30), small volume lactated Ringer's solution (SVLR, 4 mL/kg, n = 30), large volume lactated Ringer's solution (LVLR, 24 mL/kg, n = 30), and hypertonic saline (HS, 4 mL/kg, n = 30). Terminal circulating volume was estimated using controlled hemorrhage experiments. Survival times and mortality rates were significantly lower in HS animals (10%) than in NR (50%) or SVLR (47%) animals. Blood pressure was significantly higher after HS, and this difference was sustained. Intraperitoneal blood volume was significantly higher with HS (26.0 +/- 0.7 mL/kg) and LVLR (26.9 +/- 0.6 mL/kg) compared with NR (21.5 +/- 0.7 mL/kg) and SVLR (22.5 +/- 0.7 mL/kg). Estimated terminal blood volume was significantly decreased in LVLR (29.3 +/- 0.6 mL/kg) compared with NR (33.3 +/- 0.7 mL/kg), SVLR (33.7 +/- 0.8 mL/kg), and HS (31.7 +/- 0.7 mL/kg). CONCLUSION: Vigorous resuscitation increases bleeding from solid viscus injury. Small volume HS improves blood pressure and survival compared with no resuscitation. Results of large vessel hemorrhage models may not apply to parenchymal viscus injury.     

Isolyte S, a physiologic multielectrolyte solution, is preferable to normal saline to wash cell saver salvaged blood: conclusions from a prospective, randomized study in a canine model

OBJECTIVES: The purpose of this study is to compare normal saline with Isolyte S as the wash solutions during high-volume cell saver autologous blood transfusion. Normal saline, the standard wash solution in cell saver autologous blood transfusion, is associated with acid-base and electrolyte derangements. Isolyte S is a physiologic, balanced multielectrolyte crystalloid solution that approximates the electrolyte content of plasma. DESIGN: Open-label, prospective, randomized study. SETTING: Research laboratory in a Department of Veterans Affairs medical center. SUBJECTS: Fourteen mongrel dogs, weighing 22 to 23 kg each. INTERVENTIONS: Fourteen mongrel dogs were prospectively randomized to receive normal saline (n = 7) or Isolyte S (n = 7). Animals were anesthetized, received heparin for anticoagulation, and underwent 18 cycles of cell saver autotransfusion. In each cycle, 125 mL of blood was arterially withdrawn, and washed with either normal saline (mEq/L) (sodium 154, chloride 154) or Isolyte S (mEq/L) (sodium 141, potassium 5, magnesium 3, chloride 98, phosphate 1, acetate 28, and gluconate 23). The washed blood was retransfused. MEASUREMENTS AND MAIN RESULTS: Acid-base and electrolyte analyses were performed throughout the study on the systemic blood of each group and compared. By the end of the study, the Isolyte S group had a normal pH and an increased bicarbonate concentration (mEq/L: normal values 24 to 32; normal saline 9.0 +/- 1.9 vs. Isolyte S 13.2 +/- 3.0 [p < .01]) and an increased magnesium concentration (mg/dL: normal values 1.6 to 2.4; normal saline 1.6 +/- 0.2 vs. Isolyte S 2.2 +/- 0.2 [p < .0001]). Additionally, the Isolyte S group had a lower chloride concentration (mEq/L: normal values 95 to 110; normal saline 130 +/- 9 vs. Isolyte S 117 +/- 7 [p < .02]) and a lower potassium concentration (mEq/L: normal values 3.5 to 5.0; normal saline 4.4 +/- 0.5 vs. Isolyte S 3.7 +/- 0.3 [p < .01]). There were no significant differences between normal saline or Isolyte S in the values of PCO2, lactic acid, sodium, total and ionized calcium, inorganic phosphorus, total protein, albumin, hemoglobin, and hematocrit. CONCLUSIONS: Fewer systemic acid-base and electrolyte derangements were observed when blood was washed with Isolyte S. Differences between the normal saline and Isolyte S groups are ascribed primarily to the constituents of the wash solution. We conclude that Isolyte S, a physiologic, balanced, multielectrolyte solution, should be considered as the wash solution in high-volume autologous cell saver blood processing and transfusion.     

Filtration of diaspirin crosslinked hemoglobin into lung and soft tissue lymph

Diaspirin crosslinked hemoglobin (DCHb) is a new blood substitute manufactured from human blood. To evaluate its microvascular filtration properties, we infused DCLHb into unanesthetized sheep (10%, 20 ml/kg) and measured the flow and composition of lung and soft tissue lymph. For comparison, we also infused human serum albumin (HSA; 10%, 20 ml/kg). DCLHb raised systemic and pulmonary arterial pressures from baseline values of 83 +/- 7 and 13 +/- 2 mm Hg, respectively, to peak values of 113 +/- 9 and 26 +/- 3 mm Hg (p < 0.05 versus baseline). These increases were significantly greater than those associated with HSA, which raised systemic and pulmonary arterial pressures from baseline values of 86 +/- 4 and 13 +/- 2 mm Hg, respectively, to peak values of 97 +/- 3 and 21 +/- 7 mm Hg (p <= 0.05 versus baseline and versus DCLHb). These differences reflect the known pressor properties of DCLHb. Accordingly, DCLHb raised lung and soft tissue lymph flows to peak values of 12.2 +/- 3.8 and 1.6 +/- 0.7 ml/30 min, respectively, while HSA raised lung and soft tissue lymph flows to peak values of 7.5 +/- 4.8 and 4.6 +/- 1.9 ml/30 min, respectively (p <= 0.05 versus DCLHb). The half-times of DCLHb equilibration from plasma into lung and soft tissue lymph of 1. 0 +/- 0.3 and 2.1 +/- 1.1 h, respectively, were significantly faster than HSA equilibration half-times of 3.1 +/- 0.2 and 3.8 +/- 0.9 h. Filtration differences between DCLHb and HSA appear to be due to the pressor properties DCLHb.     

Experimental subarachnoid hemorrhage in rats: effect of intravenous alpha-alpha diaspirin crosslinked hemoglobin on hypoperfusion and neuronal death

BACKGROUND: Hemodilution with diaspirin crosslinked hemoglobin (DCLHb) ameliorates occlusive cerebral ischemia. However, subarachnoid hemoglobin has been implicated as a cause of cerebral hypoperfusion. The effect of intravenous DCLHb on cerebral perfusion and neuronal death after experimental subarachnoid hemorrhage was evaluated. METHODS: Rats (n = 48) were anesthetized with isoflurane and subarachnoid hemorrhage was induced by injecting 0.3 ml of autologous blood into the cistema magna. Each animal received one of the following regimens: Control, no hematocrit manipulation; DCLHb, hematocrit concentration decreased to 30% with DCLHb; or Alb, hematocrit concentration decreased to 30% with human serum albumin. The experiments had two parts, A and B. In part A, after 20 min, cerebral blood flow (CBF) was assessed with 14C-iodoantipyrine autoradiography. In part B, after 96 h, in separate animals, the number of dead neurons was determined in predetermined coronal sections by hematoxylin and eosin staining. RESULTS: Cerebral blood flow was greater for the DCLHb group than for the control group; and CBF was greater for the Alb group than the other two groups (P < 0.05). In one section, CBF was 45.5 +/- 10.9 ml x 100 g(-1) x min(-1) (mean +/- SD) for the control group, 95.3 +/- 16.6 ml x 100 g(-1) x min(-1) for the DCLHb group, and 138.1 +/- 18.7 ml x 100 g(-1) x min(-1) for the Alb group. The number of dead neurons was less in the Alb group (611 +/- 84) than in the control group (1,097 +/- 211), and was less in the DCLHb group (305 +/- 38) than in the other two groups (P < 0.05). CONCLUSIONS: These data support a hypothesis that hemodilution decreases hypoperfusion and neuronal death after subarachnoid hemorrhage. The data do not support the notion that intravascular molecular hemoglobin has an adverse effect on brain injury after subarachnoid hemorrhage.     

Matrix metalloproteinase expression during experimental autoimmune encephalomyelitis and effects of a combined matrix metalloproteinase and tumour necrosis factor-alpha inhibitor

Diaspirin crosslinked hemoglobin (DCLHb Baxter Healthcare Corp., Round Lake, IL, USA), a hemoglobin-based blood substitute has been found to be an effective resuscitative agent following hemorrhage in animals. The present study was undertaken to determine the effect of DCLHb on microvascular perfusion in the brain and kidney following hemorrhage in anaesthetized, male Sprague Dawley rats using laser Doppler flowmetry. Hemorrhage was induced by withdrawal of arterial blood at a rate of 0.5 to 1.0 ml/min until blood pressure of 35-40 mmHg was achieved. This was maintained for up to 30 min. The arterial blood pH, pO2, pCO2 and total hemoglobin (THb) were monitored. Hemorrhage significantly decreased pH, pCO2 and THb and increased pO. Hemorrhage significantly decreased (26%) brain blood perfusion due to a decrease (17%) in the concentration of moving red blood cells (CMBC). In the kidney there was a greater decrease (65%) in blood perfusion due to a significant decrease in both CMBC (28%) and red blood cell velocity (49%). Resuscitation with vehicle (Ringer's lactate, 4 ml/kg, i.v.) did not produce any improvement in cerebral and renal blood perfusion. Resuscitation with DCLHb (400 mg/kg, i.v.) improved perfusion in the brain (112%) due to an increase in the CMBC (69%) and the velocity of red blood cells (33%). Similarly, in the kidney, DCLHb increased perfusion (178%) by increasing CMBC (55%) and red blood cell velocity (89%) of hemorrhaged rats. The increase in renal blood perfusion was more marked (p < 0.001) than the changes in cerebral blood perfusion following resuscitation with DCLHb in hemorrhaged rats. It is concluded that DCLHb can significantly increase cerebral and renal blood perfusion of hemorrhaged rats and this effect may contribute to its efficacy as a resuscitative solution.     

The ferredoxin:sulphite reductase gene from Synechococcus PCC7942

Conventional therapies with recombinant human erythropoietin (rHuEPO) to sustain preoperative autologous blood collection entail high doses of the drug at short intervals. To evaluate the efficacy of a single weekly dose of rHuEPO for autologous blood collection, we randomly assigned 24 male patients scheduled for coronary artery bypass surgery to receive 400 IU/kg rHuEPO subcutaneously once a week or iron only. Patients were examined weekly and a total of up to 4 units of autologous blood were obtained if the hemoglobin level exceeded 12 g/dL. Patients receiving rHuEPO had consistently higher hemoglobin values than those receiving iron only (P < 0.001). Consequently, more autologous red cells were obtained from this group (776 +/- 49 mL vs 682 +/- 91 mL; P < 0.05). One patient receiving rHuEPO and eight in the control group required homologous blood at surgery (P < 0.01). These results suggest that 400 IU/kg rHuEPO administered subcutaneously once a week efficiently stimulates erythropoiesis and compensates the hemoglobin decrease after autologous blood donation.     

Diaspirin cross-linked hemoglobin improves neurological outcome following reversible but not irreversible CNS ischemia in rabbits

BACKGROUND AND PURPOSE: Hemodilution using modified hemoglobin solutions may reduce ischemic central nervous system injury. Purified diaspirin cross-linked hemoglobin (DCLHb) is a cell-free hemoglobin that is intramolecularly cross-linked between the two alpha subunits, resulting in enhanced oxygen offloading to tissues and increased half-life. In the present experiments, we evaluated the ability of DCLHb to reduce neurological damage in two rabbit stroke models. METHODS: In a reversible spinal cord ischemia model, ischemia of the caudal lumbar spinal cord was produced by temporary occlusion of the abdominal aorta. In an irreversible model of cerebral ischemia, plastic microspheres (50 microns) were injected into the internal carotid artery and lodged in the cerebral microvasculature. DCLHb was administered 5 minutes after initiation of ischemia as either a 10-mL/kg infusion, 10-mL/kg exchange transfusion, or a 20-mL/kg infusion. Control animals received human serum albumin that was oncotically matched to the DCLHb. RESULTS: In the spinal cord model, DCLHb significantly increased the duration of ischemia required to produce permanent paralysis from 27.33 +/- 8.71 minutes (mean +/- SD) in controls to 42.59 +/- 10.10 minutes in the 10-mL/kg exchange transfusion group and to 40.82 +/- 18.16 minutes in the 20-mL/kg infusion condition (P < .05). DCLHb did not significantly reduce neurological damage in the microsphere embolization model. CONCLUSIONS: These data suggest that cross-linked hemoglobin reduces neurological damage after reversible central nervous system ischemia and that this is not attributable to hemodilution or hypervolemia only.     

Elevated arterial base deficit in trauma patients: a marker of impaired oxygen utilization

BACKGROUND: In trauma patients, the admission value of arterial base deficit stratifies injury severity, predicts complications, and is correlated with arterial lactate concentration. In theory, elevated base deficit and lactate concentrations after shock are related to oxygen transport imbalance at the cellular level. The purpose of this study was to test the hypothesis that an elevated base deficit in trauma patients is indicative of impaired systemic oxygen utilization and portends poor outcomes. METHODS: This study was a retrospective analysis of a prospectively collected database. The study population included all patients admitted to the trauma intensive care unit at a Level 1 trauma center during a 12-month period who were monitored with a pulmonary artery catheter and serial measurements of lactate and base deficit, and who achieved a normal arterial lactate concentration (< 2.2 mmol/L) with resuscitation. The patients were divided into those who maintained a persistently high base deficit (> or = 4 mmol/L) and those who achieved a low base deficit (< 4 mmol/L) during resuscitation. RESULTS: One-hundred patients (mortality 20%) were monitored with a pulmonary artery catheter and achieved a normal arterial lactate concentration. The mean age+/-SD (SEM) of the group was 37+/-17 years and the Injury Severity Score was 25+/-11. Subgroup analysis revealed that patients with a persistently high base deficit (n=26) had higher rates of multiple organ failure (35% versus 5%, p < 0.001) and death (50% versus 9%, p < 0.00001) compared with patients who achieved a low base deficit. Patients with a persistently high base deficit also had lower oxygen consumption (126+/-40 mL/m2 versus 156+/-30 mL/m2, p=0.01 at 48 hours) and a lower oxygen utilization coefficient (0.20+/-0.05 versus 0.24+/-0.03, p=0.01 at 48 hours) compared with patients with a low base deficit. At 48 hours, both oxygen consumption (r=-0.44, [r, correlation coefficient] p=0.002) and oxygen utilization (r=-0.46, p=0.001) had a significant negative correlation with base deficit. CONCLUSIONS: In trauma patients, a persistently high arterial base deficit is associated with altered oxygen utilization and an increased risk of multiple organ failure and mortality. Serial monitoring of base deficit may be useful in assessing the adequacy of oxygen transport and resuscitation.     

A new salutary resuscitative fluid: liposome encapsulated hemoglobin/hypertonic saline solution

Low-volume resuscitation with hypertonic (7.5%) saline (HTS) is an evolving therapeutic modality for patients with hemorrhagic shock. This solution has been shown to exert protective hemodynamic effects in models of controlled hemorrhagic shock and in several clinical trials. However, HTS has no oxygen-carrying capacity and therefore does not improve oxygen delivery directly. One of the leading strategies in developing an oxygen-carrying resuscitative fluid is the encapsulation of hemoglobin within phospholipid vesicles (LEH). This preparation has the advantage of being blood type and antigen free, easily adaptable to scale-up production, and remarkably stable with a long shelf life. We therefore tested the hypothesis that lyophilized LEH reconstituted with HTS will improve tissue oxygenation and survival in rats exposed to a lethal controlled hemorrhagic shock. Shock was induced by withdrawal of 70% of blood volume and therapy (n = 10-16) with HTS (5 mL/kg), LEH (5 mL/kg), lactated Ringer's solution (vol:vol = 1:3), LEH-HTS (5 mL/kg), or oxygen (100%) was initiated 15 minutes later. The LEH-HTS improved skeletal muscle oxygen tension directly measured using a thin-film chamber oxygen sensor (PO2 87 +/- 13 mm Hg vs. 40-50 mm Hg in other groups, p < 0.05). This was associated with improved blood pressure, reduced acidosis, and increased survival at 24 hours (75% vs. 6%-25% in other groups, p < 0.05). In conclusion, the study demonstrates a remarkably salutary effect of LEH reconstituted with HTS as a blood substitute in the treatment of hemorrhagic shock.     

Effect of diaspirin cross-linked hemoglobin on endothelin-1 and blood pressure in acute ischemic stroke in man

OBJECTIVE: For almost 50 years it has been known that hemolysed blood can increase blood pressure. Although preclinical studies suggest that this pressor response is due to an interaction of hemoglobin with endothelium-derived vasoactive substances, its mechanism in humans is unknown. We investigated the involvement of endothelin-1 in the blood pressure response to the oxygen carrier diaspirin cross-linked hemoglobin (DCLHb) in stroke patients. DESIGN: In a randomized phase II study, increasing doses of DCLHb (25, 50 and 100 mg/kg, n=8, 8 and 11, respectively) or placebo (n=26) were infused intravenously every 6 h for 72 h to patients with an acute ischemic stroke. Blood pressure and heart rate were measured every 15 min and plasma concentrations of endothelin-1, catecholamines, renin, vasopressin and atrial natriuretic peptide were measured before and 24 and 66 h after the start of the infusions. RESULTS: In the placebo group, mean arterial pressure (MAP) was 112 (109-115) mmHg (mean and 95% confidence interval) at baseline and decreased spontaneously by 11.4 (5.4-17.5) and 12.5 (5.4-19.5) mmHg after 24 and 66 h, respectively. This decrease in MAP was attenuated in patients treated with DCLHb, reaching statistical significance in the highest dose group. The plasma endothelin-1 concentration decreased slightly in the placebo group, from 4.2 (3.1-5.3) pg/ml (median and range) at baseline to 2.4 (1.9-3.7) pg/ml after 24 h (P=0.0044) and 2.8 (1.9-3.7) pg/ml after 66 h (P=0.0042), but increased dose-dependently in response to DCLHb infusion. With the highest dose of DCLHb, the plasma endothelin-1 concentration rose from 4.8 (0.1-7.8) pg/ml at baseline to 21.2 (13.4-53.2) pg/ml after 24 h (P< 0.001) and to 27.6 (11.9-47.8) pg/ml after 66 h (P< 0.001). The increases in the plasma endothelin-1 concentration and in MAP were correlated (r=0.30, P=0.02). Other vasoactive hormones were not affected by the DCLHb infusion. CONCLUSIONS: Infusion of DCLHb in patients with acute ischemic stroke was associated with a dose-dependent increase in plasma endothelin-1 concentration. This may underlie the attenuation by DCLHb of the natural decrease in blood pressure that we observed in these patients.     

The effects of diaspirin-crosslinked hemoglobin on the assessment of immunohematology profiles

BACKGROUND: Extensive studies have been conducted on the in vitro effects of diaspirin-crosslinked hemoglobin (DCLHb) in biochemical, hematologic, hemostatic, and blood banking (immunohematologic) methods. The absence of red cell antigens or plasma and/or serum antibodies allows DCLHb to be used as "universal-donor" material. This study evaluates the effects of DCLHb on the accurate assessment of the immunohematologic profile (ABO and Rh blood grouping, antibody screen, and crossmatching). STUDY DESIGN AND METHODS: DCLHb, 7.4 g per dL in an electrolyte solution, was mixed in vitro with human whole blood, representing the blood types A Rh-positive. A Rh-negative, B Rh-positive, B Rh-negative, O Rh-positive, O Rh-negative, and AB Rh-positive. Two concentrations of DCLHb were tested: 10-percent (0.74 g/dL) and 30-percent (2.22 g/dL). Controls were prepared by adding a 5-percent albumin solution to aliquots of whole blood in volumes equivalent to those used in preparing the DCLHb dilutions. Serum and/or red cell suspensions from these admixed samples were analyzed for their ABO and Rh blood groups, the presence of unexpected antibodies (antibody screen), and compatibility in crossmatch testing. RESULTS: DCLHb added to whole blood in vitro had no effect on the accurate interpretation of the immunohematologic profile. CONCLUSION: DCLHb does not appear to inhibit the true response or crossreact in the analysis of blood grouping, antibody screening, or crossmatching. In addition, the red color of DCLHb (up to 2.22 g/dL) did not obscure the visual reading for agglutination.     

Hypertonic saline dextran prime reduces increased intracranial pressure during cardiopulmonary bypass in pigs

Children and adults who develop neurologic deficits after cardiac surgery may experience cerebral ischemia during cardiopulmonary bypass. Increased intracranial pressure (ICP) may contribute to cerebral ischemia during bypass. Hypertonic saline dextran (HSD), a hyperosmotic, hyperoncotic resuscitation solution, decreases ICP in trauma resuscitation. We hypothesized that HSD would decrease ICP, reduce brain water, and reduce intravascular fluid requirements during bypass. Twelve swine were divided into two bypass groups: Group 1 (ISO = isotonic) received as prime 1 L of lactated Ringer's solution and 500 mL of 6% hydroxyethyl starch. Group 2 (HSD = hypertonic saline/dextran) received as prime 1 L of lactated Ringer's solution, 500 mL of 6% hydroxyethyl starch, and 1 mL/kg of 24% hypertonic saline/25% dextran. Normothermic bypass was instituted at 100 mL.kg-1.min-1. ICP increased significantly during bypass with ISO prime but not with HSD. Brain water in the cerebrum did not differ between groups but was reduced in the cerebellum to 75.9% +/- 1.4%. We conclude that HSD prevented any significant increase in ICP during normothermic bypass, and substantially improved fluid balance during bypass. In cardiac surgery patients in whom maintaining decreased ICP and reducing isotonic fluid administration is important, HSD may be a useful addition to the bypass prime solution.     

The promoter of the plant defensin gene PDF1.2 from Arabidopsis is systemically activated by fungal pathogens and responds to methyl jasmonate but not to salicylic acid

OBJECTIVES: Hemoglobin-based oxygen carriers are designed to replace blood volume and to increase oxygen delivery to tissues after blood loss. The goals of the present study were two-fold: a) to determine the systemic and regional vascular effects of resuscitation with recombinant human hemoglobin (rHb1.1) in rats during controlled hemorrhage; and b) to determine whether nitric oxide (NO) or prostaglandins were involved in the observed responses. DESIGN: Paralyzed, ventilated rats were hemorrhaged (18 mL blood/kg body weight) during halothane anesthesia and allowed to stabilize for 30 mins. Systemic and regional hemodynamics and oxygen delivery were monitored at three time points, using the radioactive microsphere method. Microspheres were first infused at the end of the hemorrhage stabilization period (t=0 min). rHb1.1 (1 g/kg body weight) or rHb1.1 diluent (phosphate buffered saline, 36 mL/kg body weight) were infused over 20 mins and microspheres were administered again, 30 mins later (t=50 mins). Saline (0.5 mL), indomethacin (5 mg/kg to inhibit cyclooxygenase), or NG-monomethyl-L-arginine (L-NMMA, 100 mg/kg, to inhibit NO synthase) were then infused in rHb1.1-treated rats and microspheres injected once more (t=80 mins). SETTING: Research laboratory. SUBJECTS: Male Wistar rats (n=37). INTERVENTIONS: Recombinant human hemoglobin (rHb1.1), rHb1.1 diluent (phosphate buffered saline) resuscitation of hemorrhaged rats. Saline, L-NMMA, or indomethacin treatment after resuscitation. MEASUREMENTS AND MAIN RESULTS: Resuscitation with rHb1.1 increased mean arterial pressure (MAP), cardiac output, and systemic oxygen delivery significantly when compared with diluent. After rHb1.1 resuscitation, regional blood flows were significantly increased in skin, kidney, spleen, and heart compared with diluent resuscitation. Compared with saline treatment after rHb1.1 resuscitation, L-NMMA increased MAP and regional resistances in virtually all tissues; indomethacin did not alter MAP, but increased resistance in the brain. CONCLUSIONS: These data indicate that rHb1.1 resuscitation was more effective than diluent in improving systemic and regional hemodynamics and oxygen delivery, suggesting that rHb1.1 may be of benefit in the treatment of acute blood loss. Increased resistance after L-NMMA in the presence of rHb1.1 indicated that rHb1.1 resuscitation did not eliminate NO dependent circulatory control. Increased resistance after indomethacin in brain indicated that vasodilator prostanoids were important in regulating vascular resistance in these tissues after rHb1.1 resuscitation.     

Significant reduction of medical costs by differentiation therapy with all-trans retinoic acid during remission induction of newly diagnosed patients with acute promyelocytic leukemia. The Japan Adult Leukemia Study Group

OBJECTIVE: For resuscitation of hemorrhagic hypovolemia, we compared the effectiveness of (1) isotonic lactated Ringer's solution (LRS), (2) 2400 mOsm of 7.5% NaCl:6% dextran 70 (HSD), and (3) 2400 mOsm of 7.9% sodium acetate:1.9% NaCl:6% dextran 70 (HAD). DESIGN: In six randomized, blinded experiments for each solution, conscious instrumented adult sheep were hemorrhaged by removing approximately 1.8 L (42 +/- 3 mL/kg) of blood, while maintaining the mean arterial pressure (MAP) at 50 mm Hg for 2 hours. METHODS: Test solutions were infused as needed to restore the cardiac index to baseline. RESULTS: Volume requirements with HAD (236 +/- 29 mL) and HSD (244 +/- 39 mL) were significantly less (p < 0.05) than LRS (3463 +/- 234 mL). Mean arterial pressure was normalized with HSD and LRS, but not with HAD, which resulted in MAPs of 20 to 25 mm Hg less than baseline resulting from a reduced peripheral resistance. Oxygen delivery, however, was significantly higher with HAD during the resuscitation period. Acid-base balance (pH) and oxygen consumption were normalized within 5 minutes of infusion only with HAD. CONCLUSIONS: Small-volume infusion with HAD resulting in "high-flow-low-pressure" resuscitation may offer unique hemodynamic and metabolic advantages for the initial treatment of hemorrhage from trauma.     

Effects of hypertonic sodium lactate dextran resuscitation in severely burned dogs

12 dogs with 35% TBSA third degree burns received HLD resuscitation (HLD group, n = 6) or LR resuscitation (LR group, n = 6). Fluid resuscitation started one hour postburn. The amount of fluid infused with HLD resuscitation was calculated by that after giving HLD 19.6 ml/kg in 3 hours and 6 ml/kg/% TBSA lactate Ringer's solution followed. The amount of fluid infused with LR resuscitation was calculated by 8 ml/kg/% TBSA lactate Ringer's solution. Infusion of lactated Ringer's solution in both groups was adjusted by maintaining urinary output 0.5-1 ml/kg/h. The volume of fluid infused in HLD group (5.05 +/- 1.11 ml/kg/% TBSA) was much less than that of LR group (10.03 +/- 1.30 ml/kg/%TBSA) (P < 0.01). There was no significant difference in urinary output, serum Na+ and albumin, and plasmacrystalloid osmolarity between two groups. Plasma level of MDA decreased after resuscitation with HLD, which (0.81 +/- 0.20 mmol/g Hb) was much lower than that (1.39 +/- 0.44 mmol/g Hb) of LR group 4 hours postburn (P < 0.05). Plasma SOD activity (7.22 +/- 0.68 u/g Hb) of HLD group were much higher than that of LR group (4.86 +/- 0.53 u/g Hb) 4 hours postburn (P < 0.05). HLD resuscitation could significant reduce the amount of fluid infused comparing with lactate Ringer's solution. HLD resuscitation could attenuate postburn damage to tissue induced by lipid peroxide by elevating plasma SOD activity.