Interpretation of hemolysis tests following administration of a second-generation hemoglobin-based oxygen carrier

Hemoglobin released into the circulation during hemolysis or therapy with chemically modified hemoglobins, exert oxidative and NO-scavenging toxic effects. Pyridoxalated hemoglobin polyoxyethylene conjugate (PHP) is one of the second-generation hemoglobin-based oxygen carriers (HBOCs). We wanted to investigate the metabolism of PHP with a special focus on its consequences for interpreting hemolysis-related diagnostic parameters in PHP-treated patients. Clinical samples were analyzed from 3 patients, who received PHP (as part of the PHOENIX phase III trial) for treatment of catecholamine-resistant distributive shock. In contrast to expectations, clearance of PHP by hemopexin, instead of haptoglobin was documented by increased hemolysis indices, absence of decreased haptoglobin values, presence of free PHP-hemoglobin and exhausted hemopexin concentrations. The present case report is important for both clinicians and laboratorians since it nicely illustrates that a hemolytic aspect of plasma is not necessarely synonymous with hemolysis. A hemolytic aspect of plasma or serum (high hemolysis index) in combination with normal or increased haptoglobin values should draw the attention; additional determination of lactate dehydrogenase and hemopexin may then be useful to distinguish the condition from in vitro hemolysis and to monitor the in vivo elimination of the heme compounds.

[Clinical study on hematocrit used as a predictor for evaluation of resuscitation effect in the early shock stage after burn]

OBJECTIVE

To explore the clinical significance of hematocrit used as a predictor for diagnosis and evaluation of resuscitation effect in the early shock stage after burn.

METHODS

Clinical data of 131 severely burned patients admitted to our burn unit from January 2000 to December 2011 were retrospectively analyzed. The burn patients were divided into group A (n = 80) and group B (n = 51) based on the hematocrit level at post burn hour (PBH) 24. The hematocrit levels in group A were less than or equal to 0.50, which in group B were higher than 0.50. There were no statistically significant differences between two groups in age, gender, body weight, admission time after burn, total burn area, full-thickness burn area, and degree of inhalation injury (P values all above 0.05). Hematocrit levels in the shock stage were recorded. Total urine output, base excess, and the volume of fluid infused per kg per %TBSA at PBH 24 were recorded. Rates of complication and mortality were recorded. Data were processed with t test, chi-square test, and Wilcoxon rank sum test.

RESULTS

Hematocrit level of group A at PBH 24 was decreased to about 0.45, while that of group B was decreased to about 0.55. The urine output in group A at PBH 24 [(61 ± 22) mL/h] was higher than that in group B [(53 ± 20) mL/h, t = 2.212, P < 0.05]. Base excess in group A at PBH 24 [(-6.1 ± 2.9) mmol/L] was significantly higher than that in group B [(-9.0 ± 3.8) mmol/L, t = 4.888, P < 0.01]. The volume infused per kg per %TBSA was higher in group A [(1.9 ± 0.4) mL·kg(-1)·%TBSA(-1)] than in group B [(1.7 ± 0.4) mL·kg(-1)·%TBSA(-1), t = 2.472, P < 0.05]. The rates of complication and mortality in group A [11.3%(9/80), 8.8%(7/80), respectively] were significantly lower than those in group B [27.5%(14/51), 21.6%(11/51), with χ(2) values respectively 5.648 and 4.318, P values all below 0.05].

CONCLUSIONS

Hematocrit can indirectly reflect resuscitation effect in the burn shock stage. Whether hematocrit level can be lowered to 0.45-0.50 during the first 24 hours after burn may be an important index for evaluation of fluid resuscitation effect in the early shock stage after severe burn.

Clinico-pathological particularities of the shock-related pancreatitis

Acute pancreatitis can develop in patients with shock due to the underlying diseases, surgical interventions or because of severe hypoperfusion. The aim of our work was to study the histological alterations of the pancreas in patients dying after cardiogenic, hypovolemic or septic shock, to demonstrate the presence and severity of pancreatic injury. We performed a retrospective study which included patients who died and who were autopsied after different types of shock, hospitalized between 2007-2009 in general and cardiac intensive care units. We excluded the patients with known pancreatic diseases. From 223 patients included in our study 39 presented necrotising hemorrhagic alteration of the pancreatic tissue. There were no differences in histological and immunohistochemical findings between the different etiopathogenetic types of shock. None of the patients had characteristic clinical signs for acute pancreatitis. The digestive symptoms, they presented, could be related to the underlying disease or to postoperative state. The common findings in these patients were prolonged and severe hypotension, associated renal dysfunction, leucocytosis, hyperglycemia and hypocalcemia. Pancreatitis can occur in patients with shock, due to prolonged hypoperfusion of the pancreas. It is difficult to diagnose it because clinical signs are altered due to severity of underlying disease or analgo-sedation commonly used in intensive care. We therefore recommend in patients with shock to consider the possible development of ischemic pancreatitis for prompt and efficient treatment.

Erythrocyte damage of crucian carp (Carassius auratus) caused by microcystin-LR: in vitro study

Fish suffer from anemia and hypovolemic hypotensive shock after in vivo exposure with microcystins.However, except for in vivo causes for anemia and hypotension, an in vitro study of fish erythrocytes exposed to MC is necessary. For a better understanding of hematology toxicity of MC, the main aim of the present study was to investigate the toxic effects of microcystin on fish erythrocytes in vitro. Crucian carp erythrocytes were incubated in vitro with microcystin-LR (MC-LR) at doses of 0, 1, 10, 100 and 1,000 nM.The level of lipid peroxidate significantly increased in MC-LR treatment groups. Glutathione decreased after exposure to MC-LR. The activities of antioxidative enzymes, including superoxide dismutase, catalase,glutathione peroxidase and glutathione-S-transferase,were significantly increased after exposure with MC-LR.The hemolysis was significantly increased, while the activities of acetylcholinesterase, Na?–K?-ATPase and Ca2?–Mg2?-ATPase were significantly decreased. In addition, pathological alterations in agglomerated and jagged erythrocytes were observed in blood smears. The findings indicate that damages to erythrocytes should also be responsible for anemia and hypotensive shock or even death.

High sCD40L levels early after trauma are associated with enhanced shock, sympathoadrenal activation, tissue and endothelial damage, coagulopathy and mortality

BACKGROUND

Severe injury activates the sympathoadrenal, hemostatic and inflammatory systems, but a maladapted response may contribute to a poor outcome. Soluble CD40L is a platelet-derived mediator that links inflammation, hemostasis and vascular dysfunction.

OBJECTIVES

To investigate the association between the sCD40L level and tissue injury, shock, coagulopathy and mortality in trauma patients.

METHODS

A prospective, observational study of 80 trauma patients admitted to a Level I Trauma Center. Data on demography, biochemistry, Injury Severity Score (ISS) and 30-day mortality were recorded and admission plasma/serum analyzed for sCD40L and biomarkers reflecting sympathoadrenal activation (adrenaline, noradrenaline), tissue/endothelial cell/glycocalyx damage (histone-complexed DNA fragments [hcDNA], Annexin V, thrombomodulin and syndecan-1), coagulation activation/inhibition (PF1.2, TAT-complex, antithrombin, protein C, activated protein C, sEPCR, TFPI, von Willebrand factor [VWF], fibrinogen and factor [F] XIII), fibrinolysis (D-dimer, tissue plasminogen activator [tPA] and plasminogen activator inhibitor-1 [PAI-1]) and inflammation (interleukin-6 [IL-6] and sC5b-9). We compared patients stratified by median sCD40L level and investigated predictive values of sCD40L for mortality.

RESULTS

High circulating sCD40L was associated with enhanced tissue and endothelial damage (ISS, hcDNA, Annexin V, syndecan-1 and sTM), shock (pH, standard base excess), sympathoadrenal activation (adrenaline) and coagulopathy evidenced by reduced thrombin generation (PF1.2), hyperfibrinolysis (D-dimer), increased activated partial thromboplastin time (APTT) and inflammation (IL-6) (all P < 0.05). A higher ISS (P = 0.017), adrenaline (P = 0.049) and platelet count (P = 0.012) and lower pH (P =0.002) were associated with higher sCD40L by multivariate linear regression analysis. High circulating sCD40L (odds ratio [OR] 1.84 [95% CI 1.05-3.23], P = 0.034), high age (P = 0.002) and low Glasgow Coma Score (GCS) pre-hospital (P = 0.002) were independent predictors of increased mortality.

CONCLUSIONS

High early sCD40L levels in trauma patients reflect tissue injury, shock, coagulopathy and sympathoadrenal activation and predict mortality. As sCD40L has pro-inflammatory activity and activates the endothelium, sCD40L may be involved in trauma-induced endothelial damage and coagulopathy.

[Primary study on changes of serum proteomics in rabbit superior mesenteric artery occlusion shock]

OBJECTIVE

To explor the changes of serum proteomics in rabbits superior mesenteric artery occlusion (SMAO) shock as well as its possible effect in SMAO shock.

METHODS

SMAO shock model in rabbits were induced by occlusion of the superior mesenteric artery, serum samples were obtained from rabbits before and after SMAO shock, proteins in samples were separated by two-dimensional electrophoresis(2-DE), spots in the 2-DE map were detected and evaluated by PDQuest software 8.0. The spots with different expression level were subjected to matrix assisted laser desorption/ionization-time of flight-time of flight-mass spectrometry (MALDI-TOF-TOF-MS) for identification, the protein database was searched to further characterized the differential proteins.

RESULTS

19 differential protein spots were screened out in the 2-DE maps, 11 proteins were up-regulated and 8 proteins were down-regulated in SMAO shock rabbits' s serum. 4 of the 19 differential protein spots were selected for MALDI-TOF-TOF-MS study, and 2 of the 4 differential protein spots were identified satisfactoryly as paraoxonase and haptoglobin, which content were increased in rabbits' s serum after SMAO shock.

CONCLUSION

Serum proteomics of rabbit change remarkablely before and after SMAO shock, paraoxonase and haptoglobin may be associated with the compensation after SMAO shock.

[Prognostic value of platelet aggreagation capacity and lymphocyte-platelet adhesion in patients suffering acute poisoning with acetic acid]

The patients experiencing severe acute poisoning with acetic acid were divided into 2 groups with and without exotoxic shock to study platelet aggregation capacity and lymphocyte-platelet adhesion. The data obtained were used to develop exotoxic shock probability coefficient for patients with acute poisoning.

[Change in plasma brain natriuretic peptide and its clinical significance in burn patients after delayed fluid resuscitation of shock]

OBJECTIVE

To observe the early change in plasma brain natriuretic peptide (BNP) level in burn patients with long delayed fluid resuscitation of burn shock and its clinical significance.

METHODS

Thirty-six burn patients with second and third degree of burn covering 32%-92% total body surface area were enrolled for the study, among them 10 patients were complicated with serious heart failure (heart failure group), and 26 patients rallied from shock after delayed fluid resuscitation without heart failure (stable group). The level of plasma BNP, lactate dehydrogenase (LDH), MB isoenzyme of creatine kinase (CK-MB), and left ventricle ejection fraction (LVEF) were determined at admission and 3 hours after hospitalization, and 24, 48, 72, 168 hours after the injury in both groups with electrochemiluminescence (ECL).

RESULTS

Compared with stable group, the plasma BNP level (ng/L) of heart failure group at 3 hours after hospitalization, and 24, 48, 72 hours after the burn injury increased significantly (3 hours after hospitalization: 1 521.38+/-121.11 vs. 391.36+/-63.27, 24 hours after burn: 2 516.86+/-193.25 vs. 360.79+/-146.56, 48 hours after burn: 1 587.76+/-169.23 vs. 398.92+/-77.46, 72 hours after burn: 974.45+/-166.33 vs. 283.43+/-68.15, all P<0.01), the level of LVEF lowered significantly (3 hours after hospitalization : 0.33+/-0.03 vs. 0.58+/-0.09, 24 hours after burn: 0.36+/-0.09 vs. 0.60+/-0.10, 48 hours after burn: 0.35+/-0.08 vs. 0.62+/-0.11, 72 hours after burn: 0.39+/-0.10 vs. 0.64+/-0.10, all P<0.05). The levels of LDH (micromolxs(-1) xL(-1)) in stable group were 2.87+/-0.50 at admission, 3.02+/-0.43 3 hours after hospitalization, 4.02+/-0.87 24 hours after burn, 6.90+/-0.87 48 hours after burn, 3.64+/-0.75 72 hours after burn, 2.67+/-0.45 168 hours after burn while in heart failure group, they were 2.97+/-1.40, 3.84+/-0.37, 4.29+/-0.45, 8.50+/-0.38, 3.84+/-0.62, 2.30+/-0.38, respectively; and CK-MB (U/L) in stable group were 59.12+/-13.75 at admission, 70.39+/-10.72 3 hours after hospitalization, 79.29+/-17.27 24 hours after burn, 67.44+/-12.77 48 hours after burn, 30.28+/-7.13 72 hours after burn, 21.44+/-3.15 168 hours after burn while in heart failure group, they were 65.76+/-16.38, 81.46+/-7.92, 86.43+/-14.19, 72.53+/-11.27, 36.39+/-6.18, 22.85+/-7.26, respectively. No statistically significant difference was found in changes in both LDH and CK-MB between two groups (all P>0.05).

CONCLUSION

Determination of the plasma BNP is a simple and useful method in detecting heart failure during resuscitation of shock after a serious burn injury.

Comparison of lactate, base excess, bicarbonate, and pH as predictors of mortality after severe trauma in rhesus macaques (Macaca mulatta)

Social group housing of rhesus macaques at biomedical facilities is advocated to improve the psychologic wellbeing of these intelligent and social animals. An unintended outcome of social housing in this species is increased intraspecific aggression resulting in cases of severe multiple trauma and posttraumatic shock. The metabolic correlates of oxygen debt are likely important quantifiers of the severity of posttraumatic shock and may serve as useful guides in the treatment of these cases. The purpose of this retrospective study was to evaluate venous blood lactate, base excess, bicarbonate, and pH as predictors of mortality. These 4 variables were assessed in 84 monkeys with severe traumatic injury and shock. Data were available from blood samples collected prior to resuscitation therapy and the day after resuscitation therapy. The pre- and postresuscitation therapy levels of the variables then were tested for association with 6-d survival. When measured prior to resuscitation therapy, all variables were strongly correlated with each other and had a statistically significant association with survival. No single variable had both strong specificity and high sensitivity when measured prior to resuscitation therapy. Survival analysis showed that as the number of categorical indicators of acidosis increased, 6-d survival decreased. Analysis of the 4 variables after resuscitation therapy indicated that lactate was the only variable significantly associated with survival in our study.

Comparing two different arginine vasopressin doses in advanced vasodilatory shock: a randomized, controlled, open-label trial

PURPOSE

To compare the effects of two arginine vasopressin (AVP) dose regimens on the hemodynamic response, catecholamine requirements, AVP plasma concentrations, organ function and adverse events in advanced vasodilatory shock.

METHODS

In this prospective, controlled, open-label trial, patients with vasodilatory shock due to sepsis, systemic inflammatory response syndrome or after cardiac surgery requiring norepinephrine >0.6 microg/kg/min were randomized to receive a supplementary AVP infusion either at 0.033 IU/min (n = 25) or 0.067 IU/min (n = 25). The hemodynamic response, catecholamine doses, laboratory and organ function variables as well as adverse events (decrease in cardiac index or platelet count, increase in liver enzymes or bilirubin) were recorded before, 1, 12, 24 and 48 h after randomization. A linear mixed effects model was used for statistical analysis in order to account for drop-outs during the observation period.

RESULTS

Heart rate and norepinephrine requirements decreased while MAP increased in both groups. Patients receiving AVP at 0.067 IU/min required less norepinephrine (P = 0.006) than those infused with AVP at 0.033 IU/min. Arterial lactate and base deficit decreased while arterial pH increased in both groups. During the observation period, AVP plasma levels increased in both groups (both P < 0.001), but were higher in the 0.067 IU/min group (P < 0.001) and in patients on concomitant hydrocortisone. The rate of adverse events and intensive care unit mortality was comparable between groups (0.033 IU/min, 52%; 0.067 IU/min, 52%; P = 1).

CONCLUSIONS

A supplementary AVP infusion of 0.067 IU/min restores cardiovascular function in patients with advanced vasodilatory shock more effectively than AVP at 0.033 IU/min.

[Changes in B-type natriuretic peptide in plasma and its clinical significance in patients with severe burn during shock stage]

OBJECTIVE

To study the plasma content of B-type natriuretic peptide (BNP) in patients with severe burn during shock stage and probe its clinical significance.

METHODS

Forty-two patients aged 18-60 years, with total burn surface area 30% TBSA or full-thickness burn area > or = 10% TBSA, hospitalized within 4 hours after burn, were divided into A group (with total burn surface area 30%-50% TBSA or full-thickness burn area 10%-20% TBSA, n = 21), and B group (with total burn surface area > 50% TBSA or full-thickness burn area > 20% TBSA, n = 21). Twenty patients admitted during the same time for plastic surgery were enrolled as control group. The plasma levels of BNP, creatine kinase (CK), CK-MB, troponin I (TnI) of all patients were determined on admission. The levels of BNP, TnI and fluid resuscitation volume were examined at 8, 16, 24, 48 post burn hour (PBH) in A and B groups. Analysis of correlation between BNP and fluid resuscitation volume was performed.

RESULTS

On admission: BNP level in A group (68 +/- 19 ng/L) and B group (99 +/- 38 ng/L), respectively, was increased as compared with that in control group (17 +/- 7 ng/L, P < 0.01). TnI level in A group (2.13 +/- 0.67 microg/L) and B group (2.98 +/- 0.58 microg/L), respectively, was increased as compared with that in control group (0.12 +/- 0.03 microg/L, P < 0.01). There was no obvious difference in CK, CK-MB levels among A, B, and control groups (P > 0.05). BNP levels in A, B groups continuously rose during 8-48 PBH, and they were positively correlated with fluid resuscitation volume. TnI level peaked at 24 PBH, and decreased at 48 PBH.

CONCLUSIONS

The plasma level of BNP is sensitive to reflect changes in myocardial ischemia and hypoxia as a rise in level of TnI in shock stage of severe burn, and it was positively correlated with fluid resuscitation volume. BNP can be used to guide fluid resuscitation during shock stage.

[Improved detection of the pulse oximeter signal with a digital nerve block in patients in poor health status]

OBJECTIVE

To demonstrate the efficacy of a digital nerve block for improving pulse oximetry in conditions of low tissue perfusion.

METHOD

A randomized single-blind study of adult patients undergoing surgery under general anesthesia for conditions characterized by hypoperfusion. Patients were assigned to a control group or an experimental group. The experimental group received a digital nerve block in the middle finger of the left hand; a sensor was then placed on the finger for between 120 and 300 minutes. Age, sex, diagnosis, total observation time (TOT), percentage of time with no pulse oximeter signal (NoPO), and percentage of time with an unstable pulse oximeter signal (UnstPO) were recorded. Each patient was questioned between 16 and 24 hours after surgery and was examined for flushing, paresthesia, hypoesthesia, pain, and ecchymosis. The chi2 test was used to compare dichotomized or nominal variables and the t test was used to compare age, TOT, NoPO, and UnstPO. Values of P<.05 were considered statistically significant in both cases.

RESULTS

Fifty patients were randomized to each group. A total of 82 patients remained in the study (control group=42, experimental group=40). There were no significant between-group differences in diagnoses or TOT. The mean values for NoPO and UnstPO were higher in the control group than in the experimental group (11.1% vs 4.4% and 35.9% vs 15.7%, respectively; P<.001).

CONCLUSION

A digital nerve block can be used to prevent pulse oximetry failures in conditions of low peripheral perfusion.

Severe hyperlactatemia with normal base excess: a quantitative analysis using conventional and Stewart approaches

INTRODUCTION

Critically ill patients might present complex acid-base disorders, even when the pH, PCO2, [HCO3-], and base excess ([BE]) levels are normal. Our hypothesis was that the acidifying effect of severe hyperlactatemia is frequently masked by alkalinizing processes that normalize the [BE]. The goal of the present study was therefore to quantify these disorders using both Stewart and conventional approaches.

METHODS

A total of 1,592 consecutive patients were prospectively evaluated on intensive care unit admission. Patients with severe hyperlactatemia (lactate level > or = 4.0 mmol/l) were grouped according to low or normal [BE] values (<-3 mmol/l or >-3 mmol/l).

RESULTS

Severe hyperlactatemia was present in 168 of the patients (11%). One hundred and thirty-four (80%) patients had low [BE] levels while 34 (20%) patients did not. Shock was more frequently present in the low [BE] group (46% versus 24%, P = 0.02) and chronic obstructive pulmonary disease in the normal [BE] group (38% versus 4%, P < 0.0001). Levels of lactate were slightly higher in patients with low [BE] (6.4 +/- 2.4 mmol/l versus 5.6 +/- 2.1 mmol/l, P = 0.08). According to our study design, the pH, [HCO3-], and strong-ion difference values were lower in patients with low [BE]. Patients with normal [BE] had lower plasma [Cl-] (100 +/- 6 mmol/l versus 107 +/- 5 mmol/l, P < 0.0001) and higher differences between the changes in anion gap and [HCO3-] (5 +/- 6 mmol/l versus 1 +/- 4 mmol/l, P < 0.0001).

CONCLUSION

Critically ill patients may present severe hyperlactatemia with normal values of pH, [HCO3-], and [BE] as a result of associated hypochloremic alkalosis.

THE IMPACT OF ARTERIAL OXYGEN TENSION ON VENOUS OXYGEN SATURATION IN CIRCULATORY FAILURE

Central and mixed venous oxygen saturations have been used to guide resuscitation in circulatory failure, but the impact of arterial oxygen tension on venous oxygen saturation has not been thoroughly evaluated. This observational study investigated the impact of arterial oxygen tension on venous oxygen saturation in circulatory failure. Twenty critically ill patients with circulatory failure requiring mechanical ventilation and a pulmonary artery catheter in an intensive care unit in a tertiary hospital in Western Australia were recruited. Samples of arterial blood, central venous blood, and mixed venous blood were simultaneously and slowly drawn from the arterial, central venous, and pulmonary artery catheter, respectively, at baseline and after the patient was ventilated with 100% inspired oxygen for 5 min. The blood samples were redrawn after a significant change in cardiac index (>or =10%) from the baseline, occurring within 24 h of study enrollment while the patient was ventilated with the same baseline inspired oxygen concentration, was detected. An increase in inspired oxygen concentration significantly increased the arterial oxygen tension from 12.5 to 38.4 kPa (93.8-288 mmHg) (mean difference, 25.9 kPa; 95% confidence interval [CI], 7.5-31.9 kPa; P < 0.001) and the venous oxygen saturation from 69.9% to 76.5% (mean difference, 6.6%; 95% CI, 5.3% - 7.9%; P < 0.001). The effect of arterial oxygen tension on venous oxygen saturation was more significant than the effect associated with changes in cardiac index (mean difference, 2.8%; 95% CI, -0.2% to 5.8%; P = 0.063). In conclusion, arterial oxygen tension has a significant effect on venous oxygen saturation, and this effect is more significant and consistent than the effect associated with changes in cardiac index.

Fibrinolysis in patients with an abdominal aortic aneurysm with special emphasis on rupture and shock

BACKGROUND

A ruptured abdominal aortic aneurysm (AAA) is associated with high mortality. Postoperative complications such as hemorrhage, multiple organ failure, myocardial infarction, and thromboembolism are common. An active and balanced hemostatic system is essential to avoid bleeding as well as thrombosis. When these activities are not properly regulated the patient is at risk of developing either excessive bleeding or thrombosis-related complications. Previous studies have shown a state of activated coagulation in patients with ruptured AAA. However, there are conflicting results regarding the fibrinolytic response.

OBJECTIVES

The aim of the present study was to investigate the fibrinolytic state pre-operatively in patients with ruptured and non-ruptured AAA in relation to the clinical outcome with special regard to the influence of shock.

METHODS

A prospective study was performed on 95 patients who underwent surgery for a ruptured AAA with shock (n = 43), a ruptured AAA without shock (n = 12), and a non-ruptured AAA (n = 40). Forty-one controls without an aneurysm were matched to the AAA patients according to age, gender and smoking habits. Plasma levels of tissue plasminogen activator antigen (tPAag), and plasminogen activator inhibitor type-1 (PAI-1) were measured as markers of fibrinolytic activity. D-dimer, a marker of fibrin turnover, was also measured.

RESULTS

D-dimer was significantly higher in patients with a non-ruptured AAA compared with controls without AAA. There were significantly higher levels of D-dimer, tPAag, and PAI-1 in patients operated for ruptured compared with non-ruptured AAA. tPAag was also significantly higher in ruptured AAA patients with shock compared with without shock. No deaths occurred in patients operated on for a non-ruptured AAA or ruptured AAA without shock. There were 12 deaths after repair of a ruptured AAA with shock, of which two patients died from bleeding and the remaining 10 from multiple organ failure and cardiac failure.

CONCLUSION

Our results indicate a state of activated coagulation in patients with a non-ruptured AAA, the state being intensified by rupture. The present data show normal fibrinolytic activities in patients with a non-ruptured AAA, but increased systemic fibrinolysis, as demonstrated by elevated tPAag level, in patients with a ruptured AAA. The elevated PAI-1 level indicates a simultaneous inhibition of the systemic fibrinolysis. Furthermore, the hyperfibrinolytic state was reinforced by shock in this study. However, the clinical outcome, with a relatively high incidence of thrombosis-related deaths, indicate a prothrombotic state instead of a hyperfibrinolytic state as a major point of attention in patients with shock as a result of a ruptured AAA.

NOREPINEPHRINE AND INTESTINAL MUCOSAL PERFUSION IN VASODILATORY SHOCK AFTER CARDIAC SURGERY

Patients with norepinephrine-dependent vasodilatory shock after cardiac surgery (n = 10) were compared with uncomplicated postcardiac surgery patients (n = 10) with respect to jejunal mucosal perfusion, gastric-arterial PCO2 gradient, and splanchnic oxygen demand/supply relationship. Furthermore, the effects of norepinephrine-induced variations in MAP on these variables were evaluated in vasodilatory shock. Norepinephrine infusion rate was randomly and sequentially titrated to target MAPs of 60, 75, and 90 mmHg (0.25 +/- 0.24, 0.37 +/- 0.21, and 0.55 +/- 0.39 microg/kg per minute, respectively). Data on jejunal mucosal perfusion, jejunal mucosal hematocrit, and red blood cell (RBC) velocity (laser Doppler flowmetry) as well as gastric-arterial PCO2 gradient (gastric tonometry) and splanchnic oxygen and lactate extraction (hepatic vein catheter) were obtained. Splanchnic oxygen extraction was 71 +/- 16% in the vasodilatory shock group and 41 +/- 9% in the control group (P < 0.001), whereas splanchnic lactate extraction did not differ between the two groups. Jejunal mucosal perfusion (61%; P < 0.001), RBC velocity (35%; P < 0.01), and gastric-arterial mucosal PCO2 gradient (150%; P < 0.001) were higher in the vasodilatory shock group compared with those of the control group. Jejunal mucosal perfusion, jejunal mucosal hematocrit, RBC velocity, gastric-arterial mucosal PCO2 gradient, splanchnic oxygen extraction, and splanchnic lactate extraction were not affected by increasing infusion rates of norepinephrine. In patients with norepinephrine-dependent vasodilatory shock after cardiac surgery, intestinal mucosal perfusion was higher, whereas splanchnic and gastric oxygen demand/supply relationships were impaired compared with postoperative controls, suggesting that intestinal mucosal perfusion is prioritized in vasodilatory shock. Increasing MAP from 60 to 90 mmHg with norepinephrine in clinical vasodilatory shock does not affect intestinal mucosal perfusion and gastric or global splanchnic oxygen demand/supply relationships.

Hormonally active women tolerate shock-trauma better than do men: a prospective study of over 4000 trauma patients

OBJECTIVE

To test the hypothesis that comparably injured women, especially those in the hormonally active age groups, would manifest a better preserved hemodynamic response and tissue perfusion after major trauma than do men.

SUMMARY BACKGROUND DATA

The notion that premenopausal women are more resistant than men to shock and trauma has been shown in numerous preclinical models. However, human studies on the effects of gender on outcome after shock-trauma are less clear, and none has examined the effect of gender on the immediate postinjury response to major trauma.

METHODS

Prospective series of all patients at a Level I trauma center from January 2000 to December 2005. Study patients were all patients arriving to the trauma area of the emergency department and having a serum lactate drawn within 30 minutes of arrival. Demographic data, injury severity indices, blood utilization, and lactate levels were recorded. Lactate was used as a marker of the hemodynamic response to injury, because it has been shown to be an excellent and accurate indicator of inadequate tissue perfusion.

RESULTS

: A total of 5192 patients were eligible for the study of which 4106 fulfilled the study requirements and were enrolled. Initial serum lactate levels were significantly lower in premenopausal (age 14-44) and perimenopausal (age 45-54) women than in men of the same age groups (P < 0.001), even though the Injury Severity Score of the women was significantly higher than that of the men (24 vs. 18; P < 0.1). When patients were stratified into major injury groups as well as groups receiving blood transfusions, the premenopausal women were also found to have lower initial serum lactate levels and receive less blood, while having a greater magnitude of injury as reflected in their Injury Severity Score.

CONCLUSION

The data firmly establishes a proof of principle that hormonally active human women have a better physiologic response to similar degrees of shock and trauma than do their male counterparts. These gender-based differences should be taken into account in designing studies evaluating the response to shock-trauma.

The guanylyl cyclase inhibition by MB as vasoplegic circulatory shock therapeutical target

There were strong evidences that NO has capital importance in the progressive vasodilatation that associates to the varied circulatory shock forms. The decreased systemic vascular resistance observed in irreversible hemorrhagic (hypovolemic) and septic shock may be due to the excess production of nitric oxide. Other forms of shock associated to anaphylaxis (anaphylactic shock, SIRS) and ischemia reperfusion injury (cardiogenic shock, organ transplants), may involve nitric oxide overproduction. In these situations, the nitric oxide-induced loss of vascular sensitivity to catecholamines and myocardial depression contributes to lethal hypotension. As NO vasodilatation is cyclic GMP-mediated, there were two therapeutical options: a) The unspecific NO synthesis inhibition by L-arginine analogs, iNOS-specific inhibition by corticoids and/or aminoguanidine and; b) Guanylyl cyclase inhibition by MB. As the NO synthesis inhibition is associated to tissue necrosis and adverse hemodynamic effects and its clinical use was associated with high mortality, the second option using MB is safer and more rational. The elaboration of this text was motivated to suggest the guanylyl cyclase inhibition by MB as vasoplegic circulatory shock therapeutical target.

Effects of early enteral arginine supplementation on resuscitation of severe burn patients

OBJECTIVES

To investigate the effects of dietary supplementation of l-arginine (l-Arg) on shock in severely burned patients.

METHODS

This was a prospective, randomized, single blind, controlled study. Forty-seven severely burned patients due to various causes with a total burn surface area (TBSA) more than 50% each admitted in early postburn phase (within 10h postburn) were included in this study. All patients were treated by the traditional resuscitation program of our institute. After the nasogastric feeding tube was placed, they were randomly divided into three groups-(1) group A400 (n = 16): giving gastrointestinal feeding with 500 ml 5% GNS, containing l-Arg (400 mg/ kgday) at equal pace with fluid resuscitation; (2) group A200 (n = 16): giving gastrointestinal feeding with 500 ml 5% GNS containing l-Arg (200 mg/ kgday); (3) group C (n = 15): giving gastrointestinal feeding with 500 ml 5% GNS without any supplementation. The feeding started within 12h after burn and lasted for 72 h, the feeding rate was controlled by an enteral feeding pump. The following parameters were observed on days (PBD) 1-4: serum nitric oxide content (NO), mean arterial blood pressure (MAP), oxygenation index (PO2/FiO2), and arterial blood content of lactic acid (LA). Gastric mucosal blood flow was measured by laser Doppler flow-metry on PBD1 and PBD2.

RESULTS

(1) Enteral feeding of l-Arg did not change MAP of severely burned patients, with no difference in MAP between the l-Arg supplemented and control groups. (2) There were significant changes of the l-Arg supplemented groups (A400 and A200), with an increased gastric mucosa blood flow, oxygenation index, and a decreased LA content in arterial blood, compared with the control group. (3) The serous NO content was significantly decreased in the A400 group on PBD2-4 (P < 0.01), and in the A200 group on PBD4 (P < 0.05) compared with the control group.

CONCLUSIONS

Enteral feeding with l-arginine supplementation on early stage of burn decreases NO production to a relatively normal level and exerts beneficial effects on the resuscitation of burned shock.

Natriuretic peptide testing for the evaluation of critically ill patients with shock in the intensive care unit: a prospective cohort study

Introduction

Amino-terminal pro-brain natriuretic peptide (NT-proBNP) is useful in evaluating heart failure, but its role in evaluating patients with shock in the intensive care unit (ICU) is not clear.

Method

Forty-nine consecutive patients in four different ICUs with shock of various types and with an indication for pulmonary artery catheter placement were evaluated. Analyses for NT-proBNP were performed on blood obtained at the time of catheter placement and results were correlated with pulmonary artery catheter findings. Logistic regression identified independent predictors of mortality.

Results

A wide range of NT-proBNP levels were observed (106 to >35,000 pg/ml). There was no difference in median NT-proBNP levels between patients with a cardiac and those with a noncardiac origin to their shock (3,046 pg/ml versus 2,959 pg/ml; P = 0.80), but an NT-proBNP value below 1,200 pg/ml had a negative predictive value of 92% for cardiogenic shock. NT-proBNP levels did not correlate with filling pressures or hemodynamics (findings not significant). NT-proBNP concentrations were higher in patients who died in the ICU (11,859 versus 2,534 pg/ml; P = 0.03), and the mortality rate of patients in the highest log-quartile of NT-proBNP (66.7%) was significantly higher than those in other log-quartiles (P < 0.001); NT-proBNP independently predicted ICU mortality (odds ratio 14.8, 95% confidence interval 1.8–125.2; P = 0.013), and was superior to Acute Physiology and Chronic Health Evaluation II score and brain natriuretic peptide in this regard.

Conclusion

Elevated levels of NT-proBNP do not necessarily correlate with high filling pressures among patients with ICU shock, but marked elevation in NT-proBNP is strongly associated with ICU death. Low NT-proBNP values in patients with ICU shock identifed those at lower risk for death, and may be useful in excluding the need for pulmonary artery catheter placement in such patients.

New horizons: NT-proBNP for risk stratification of patients with shock in the intensive care unit

B-type natriuretic peptide (BNP) and amino-terminal pro-BNP (NT-proBNP) are promising cardiac biomarkers that have recently been shown to be of diagnostic value in decompensated heart failure, acute coronary syndromes and other conditions resulting in myocardial stretch and volume overload. In view of the high prevalence of cardiac disorders in the intensive care unit, the experience of elevated natriuretic peptide levels in the critically ill might be of enormous diagnostic and therapeutic value. BNP and NT-proBNP levels rise to different degrees in critical illness and may also serve as markers of severity and prognosis in diseases beyond acute or chronic heart failure. The diagnostic and prognostic use of natriuretic peptides in the intensive care setting for patients with various forms of shock could be an attractive alternative as noninvasive markers of cardiac dysfunction that could obviate the need for pulmonary artery catheterization in some patients.

Effects of post-treatment with direct hemoperfusion using a CTR column on mortality and inflammatory responses to endotoxin-induced shock in rats

BACKGROUND

To clarify the effects of post-treatment with direct hemoperfusion using a CTR column on the mortality and inflammatory responses to endotoxin-induced shock in rats.

METHODS

Thirty-six male rats were randomly assigned to 1 of 3 groups (n = 12/group): the endotoxemic group, receiving intravenous Escherichia coli endotoxin (15 mg/kg over 2 min); the control column group, treated without CTR for 120 min at 2 h after endotoxin injection, and CTR-post-treatment group, treated with CTR for 120 min at 2 h after endotoxin injection. Hemodynamics, arterial blood gases, and mortality were recorded for the 8-hour observation period, and plasma cytokine concentrations were measured every 4 h.

RESULTS

The mortality rates were 83, 83 and 33% for the endotoxemic, control column, and CTR post-treatment groups, respectively. The increases in IL-6 concentrations were less for the CTR post-treatment group than the other 2 groups.

CONCLUSION

The present study shows that CTR post-treatment inhibited hypotension and elevations in IL-6 concentrations, reducing the mortality rate of rats with endotoxin-induced shock.

Meaning of arterio-venous PCO2 difference in circulatory shock

The arterovenous difference in carbon dioxide tension (DeltaPCO2) can be calculated after simultaneous sampling of arterial blood (PaCO2) and of mixed venous blood from the distal of a pulmonary artery catheter (PvCO2). Under physiological conditions, DeltaPCO2 ranges from 2 to 5 mmHg. The DeltaPCO2 depends on carbon dioxide and cardiac output by a complex fashion. In this article, we detail the influence of these factors on DeltaPCO2 in normoxic conditions and in hypoxic conditions. We bring evidence that DeltaPCO2 cannot serve as a marker of tissue hypoxia contrary to what was initially thought. However, DeltaPCO2 can be considered as a marker of the adequacy of venous blood flow (i.e. cardiac output) to remove the total CO2 produced by the peripheral tissues. In this regard, the knowledge of DeltaPCO2 should help the clinicians for the decision of giving therapy aimed at increasing cardiac output.

[B-natriuretic peptide and cardiological emergencies in childhood]

The increase in B-natiuretic peptide (BNP) is well correlated with cardiovascular symptoms in adults. Its use in children is recent and only partially evaluated. The authors undertook a prospective study of BNP concentrations and its kinetics in 54 children with an average age of 15 months (5 days to 11 years) admitted as paediatric emergencies. The symptoms were dyspnoea (60%), shock (15%), suspicion of Kawasaki disease (15%) and other (10%). Twenty children had BNP levels of more than 100 pg/ml related to decompensation of known congenital heart disease in 7 patients (average BNP 462 +/- 323 pg/ml), due to neonatal coarctation in 2 patients (BNP > 3000 pg/ml), due to cardiomyopathy in 6 patients (BNP= 2576 +/- 1215 pg/ml), due to an arrhythmia in 1 patient (BNP= 3754 pg/ml) and to Kawasaki disease in 4 patients (BNP= 521 +/- 448 pg/ml). Thirty-four children had BNP values of less than 100 pg/ml; 29 had no cardiac disease and 5 had known congenital heart disease with other symptoms. Measuring BNP is quick and economical and is a valuable aid in the diagnosis of cardiac dysfunction in symptomatic children in the emergency room. High BNP values seem to be correlated with the severity of the cardiac disease. Low BNP values seem to have a good negative predictive value in children without underlying cardiac disease. The interpretation of intermediary values, especially when there is previous cardiac disease, is more difficult in view of the absence of known threshold values for different haemodynamic situations. Further studies are required to determine the value of this test for the follow-up and setting up of prognostic values in children with congenital heart disease.