Changes of the hemostatic network in critically ill patients--is there a difference between sepsis, trauma, and neurosurgery patients?

Protein C activity as a potential prognostic factor for nursing home-acquired pneumonia

Introduction

Despite the poor prognosis for nursing home acquired pneumonia (NHAP), a useful prognostic factor is lacking. We evaluated protein C (PC) activity as a predictor of in-hospital death in patients with NHAP and community-acquired pneumonia (CAP).

Methods

This prospective, observational study included all patients hospitalized with pneumonia between July 2007 and December 2012 in a single hospital. We measured PC activity at admission and investigated whether it was different between survivors and non-survivors. We also examined whether PC activity < 55% was a predictor for in-hospital death of pneumonia by logistic regression analysis with CURB-65 items (confusion, blood urea >20 mg/dL, respiratory rate >30/min, and blood pressure <90/60 mmHg, age >65). When it was a useful prognostic factor for pneumonia, we combined PC activity with the existing prognostic scores, the pneumonia severity index (PSI) and CURB-65, and analyzed its additional effect by comparing the areas under the receiver operating characteristic curves (AUCs) of the modified and original scores.

Results

Participants comprised 75 NHAP and 315 CAP patients. PC activity was lower among non-survivors than among survivors in NHAP and all-pneumonia (CAP+NHAP). PC activity <55% was a useful prognostic predictor for NHAP (Odds ratio 7.39 (95% CI; 1.59–34.38), and when PSI or CURB-65 was combined with PC activity, the AUC improved (from 0.712 to 0.820 for PSI, and 0.657 to 0.734 for CURB-65).

Conclusions

PC activity was useful for predicting in-hospital death of pneumonia, especially in NHAP, and became more useful when combined with the PSI or CURB-65.

Gene Co-Expression Analysis Identified Preserved and Survival-Related Modules in Severe Blunt Trauma, Burns, Sepsis, and Systemic Inflammatory Response Syndrome

Background

Severe trauma and burns accompanied by sepsis are associated with high morbidity and mortality. Little is known about the transcriptional similarity between trauma, burns, sepsis, and systemic inflammatory response syndrome (SIRS). Uncovering key genes and molecular networks is critical to understanding the biology of disease. Conventional analysis of gene changes (fold change) analysis is difficult for time-serial data such as post-injury blood transcriptome.

Methods

Weighted gene co-expression network analysis (WGCNA) was applied to the trauma dataset to identify modules and hub genes. Module stability was tested by half sampling. Module preservations of burns, sepsis, and SIRS were calculated using trauma as reference. Module functional enrichment was analyzed in gProfiler server. Candidate drugs were screened using Connectivity Map based on hub genes. The modules were visualized in Cytoscape.

Results

Seventeen modules were identified. The modules were robust to the exclusion of half the sample. They were involved in lymphocyte and platelet activation, erythrocyte differentiation, cell cycle, translation, and interferon signaling. In addition, highly connected hub genes were identified in each module, such as GUCY1B1, BCL11B, HMMR, and CEACAM6. High BCL11B (M13) or low CEACAM6 (M27) expression indicates better survival prognosis in sepsis patients regardless of endotype class and age. Network preservation in burns, sepsis, and SIRS showed a general similarity between trauma and burns. M4, M5, M13, M16, M20, and M27 were significantly associated with injury time in trauma and burns. High M13 (T cell activation), low M15 (cell cycle), and low M27 (neutrophil activation) indicate better survival of sepsis patients, regardless of endotype class and age. Moreover, the modules can efficiently separate patients with different diseases. Some modules and hub genes have good prognostic performance in sepsis. Based on the hub genes of each module, six candidate drugs were screened.

Conclusion

This study first compared the gene co-expression modules in trauma, burns, sepsis, and SIRS. The identified modules are useful for disease prognosis and drug discovery. BCL11B and CEACAM6 may be promising biomarkers for sepsis risk assessment.

Early Tranexamic Acid Administration After Traumatic Brain Injury Is Associated With Reduced Syndecan-1 and Angiopoietin-2 in Patients With Traumatic Intracranial Hemorrhage

OBJECTIVE

To evaluate the effect of early tranexamic acid (TXA) administration on circulating markers of endotheliopathy.

SETTING

Twenty trauma centers in the United States and Canada.

PARTICIPANTS

Patients with moderate-to-severe traumatic brain injury (TBI) (MS-TBI) and intracranial hemorrhage who were not in shock (systolic blood pressure ≥90 mm Hg).

DESIGN

TXA (2 g) or placebo administered prior to hospital arrival, less than 2 hours postinjury. Blood samples and head computed tomographic scan collected upon arrival. Plasma markers measured using Luminex analyte platform. Differences in median marker levels evaluated using t tests performed on log-transformed variables. Comparison groups were TXA versus placebo and less than 45 minutes versus 45 minutes or more from time of injury to treatment administration.

MAIN MEASURES

Plasma levels of angiopoietin-1, angiopoietin-2, syndecan-1, thrombomodulin, thrombospondin-2, intercellular adhesion molecule 1, vascular adhesion molecule 1.

RESULTS

Demographics and Injury Severity Score were similar between the placebo (n = 129) and TXA (n = 158) groups. Levels of syndecan-1 were lower in the TXA group (median [interquartile range or IQR] = 254.6 pg/mL [200.7-322.0] vs 272.4 pg/mL [219.7-373.1], P = .05. Patients who received TXA less than 45 minutes postinjury had significantly lower levels of angiopoietin-2 (median [IQR] = 144.3 pg/mL [94.0-174.3] vs 154.6 pg/mL [110.4-209.8], P = .05). No differences were observed in remaining markers.

CONCLUSIONS

TXA may inhibit early upregulation of syndecan-1 and angiopoietin-2 in patients with MS-TBI, suggesting attenuation of protease-mediated vascular glycocalyx breakdown. The findings of this exploratory analysis should be considered preliminary and require confirmation in future studies.

Clinical, laboratory, and hemostatic findings in cats with naturally occurring sepsis

OBJECTIVE To characterize clinical and laboratory findings in cats with naturally occurring sepsis, emphasizing hemostasis-related findings, and evaluate these variables for associations with patient outcomes. DESIGN Prospective, observational, clinical study. ANIMALS 31 cats with sepsis and 33 healthy control cats. PROCEDURES Data collected included history; clinical signs; results of hematologic, serum biochemical, and hemostatic tests; diagnosis; and outcome (survival vs death during hospitalization or ≤ 30 days after hospital discharge). Differences between cats with and without sepsis and associations between variables of interest and death were analyzed statistically. RESULTS The sepsis group included cats with pyothorax (n = 10), septic peritonitis (7), panleukopenia virus infection (5), bite wounds (5), abscesses and diffuse cellulitis (3), and pyometra (1). Common clinical abnormalities included dehydration (21 cats), lethargy (21), anorexia (18), pale mucous membranes (15), and dullness (15). Numerous clinicopathologic abnormalities were identified in cats with sepsis; novel findings included metarubricytosis, hypertriglyceridemia, and high circulating muscle enzyme activities. Median activated partial thromboplastin time and plasma D-dimer concentrations were significantly higher, and total protein C and antithrombin activities were significantly lower, in the sepsis group than in healthy control cats. Disseminated intravascular coagulopathy was uncommon (4/22 [18%] cats with sepsis). None of the clinicopathologic abnormalities were significantly associated with death on multivariate analysis. CONCLUSIONS AND CLINICAL RELEVANCE Cats with sepsis had multiple hematologic, biochemical, and hemostatic abnormalities on hospital admission, including several findings suggestive of hemostatic derangement. Additional research including larger numbers of cats is needed to further investigate these findings and explore associations with outcome.

Soluble fibrin causes an acquired platelet glycoprotein VI signaling defect: implications for coagulopathy

Essentials Collagen and thrombin when used simultaneously generate highly activated platelets. The effect of thrombin stimulation on subsequent glycoprotein VI (GPVI) function was observed. Soluble fibrin, but not protease activated receptor (PAR) activation, prevented GPVI activation. Circulating soluble fibrin in coagulopathic blood may cause an acquired GPVI signaling defect.

SUMMARY

Background In coagulopathic blood, circulating thrombin may drive platelet dysfunction. Methods/Results Using calcium dye-loaded platelets, the effect of thrombin exposure and soluble fibrin generation on subsequent platelet GPVI function was investigated. Exposure of apixaban-treated platelet-rich plasma (12% PRP) to thrombin (1-10 nm), but not ADP or thromboxane mimetic U46619 exposure, dramatically blocked subsequent GPVI activation by convulxin, collagen-related peptide or fibrillar collagen. Consistent with soluble fibrin multimerizing and binding GPVI, the onset of convulxin insensitivity required 200-500 s of thrombin exposure, was not mimicked by exposure to PAR-1/4 activating peptides, was not observed with washed platelets, and was blocked by fibrin polymerization inhibitor (GPRP) or factor XIIIa inhibitor (T101). PAR-1 signaling through Gαq was not required because vorapaxar blocked thrombin-induced calcium mobilization but had no effect on the ability of thrombin to impair GPVI-signaling. Convulxin insensitivity was unaffected by the metalloprotease inhibitor GM6001 or the αIIb β3 antagonist GR144053, indicating negligible roles for GPVI shedding or αIIb β3 binding of fibrin. Thrombin treatment of washed platelets resuspended in purified fibrinogen also produced convulxin insensitivity that was prevented by GPRP. Exposure of apixaban/PPACK-treated whole blood to thrombin-treated fibrinogen resulted in > 50% decrease in platelet deposition in a collagen microfluidic assay that required soluble fibrin assembly. Conclusions Conversion of only 1% plasma fibrinogen in coagulopathic blood would generate 90 nm soluble fibrin, far exceeding ~1 nmGPVI in blood. Soluble fibrin, rather than thrombin-induced platelet activation throuh PAR-1 and PAR-4, downregulated GPVI-signaling in response to stimuli, and may lead to subsequent hypofunction of endogenous or transfused platelets.

Activated Protein C Drives the Hyperfibrinolysis of Acute Traumatic Coagulopathy

BACKGROUND

Major trauma is a leading cause of morbidity and mortality worldwide with hemorrhage accounting for 40% of deaths. Acute traumatic coagulopathy exacerbates bleeding, but controversy remains over the degree to which inhibition of procoagulant pathways (anticoagulation), fibrinogen loss, and fibrinolysis drive the pathologic process. Through a combination of experimental study in a murine model of trauma hemorrhage and human observation, the authors' objective was to determine the predominant pathophysiology of acute traumatic coagulopathy.

METHODS

First, a prospective cohort study of 300 trauma patients admitted to a single level 1 trauma center with blood samples collected on arrival was performed. Second, a murine model of acute traumatic coagulopathy with suppressed protein C activation via genetic mutation of thrombomodulin was used. In both studies, analysis for coagulation screen, activated protein C levels, and rotational thromboelastometry (ROTEM) was performed.

RESULTS

In patients with acute traumatic coagulopathy, the authors have demonstrated elevated activated protein C levels with profound fibrinolytic activity and early depletion of fibrinogen. Procoagulant pathways were only minimally inhibited with preservation of capacity to generate thrombin. Compared to factors V and VIII, proteases that do not undergo activated protein C-mediated cleavage were reduced but maintained within normal levels. In transgenic mice with reduced capacity to activate protein C, both fibrinolysis and fibrinogen depletion were significantly attenuated. Other recognized drivers of coagulopathy were associated with less significant perturbations of coagulation.

CONCLUSIONS

Activated protein C-associated fibrinolysis and fibrinogenolysis, rather than inhibition of procoagulant pathways, predominate in acute traumatic coagulopathy. In combination, these findings suggest a central role for the protein C pathway in acute traumatic coagulopathy and provide new translational opportunities for management of major trauma hemorrhage.

Preoperative Platelet Count Predicts Lower Extremity Free Flap Thrombosis: A Multi-Institutional Experience

BACKGROUND

Thrombocytosis in patients undergoing lower extremity free tissue transfer may be associated with increased risk of microvascular complications. This study assessed whether preoperative platelet counts predict lower extremity free flap thrombosis.

METHODS

All patients undergoing lower extremity free tissue transfer at Duke University from 1997 to 2013 and at the University of Pennsylvania from 2002 to 2013 were retrospectively identified. Logistic regression was used to assess whether preoperative platelet counts independently predict flap thrombosis, controlling for baseline and operative factors.

RESULTS

A total of 565 patients underwent lower extremity free tissue transfer, with an overall flap thrombosis rate of 16 percent (n = 91). Elevated preoperative platelet counts were independently associated with both intraoperative thrombosis (500 ± 120 versus 316 ± 144 × 10/liter; p < 0.001) and postoperative thrombosis (410 ± 183 versus 320 ± 143 × 10/liter; p = 0.040) in 215 patients who sustained acute lower extremity trauma within 30 days before reconstruction. In acute trauma patients, preoperative platelet counts predicted a four-fold increased risk of intraoperative thrombosis (cutoff value, 403 × 10/liter; OR, 4.08; p < 0.001) and a two-fold increased risk of postoperative thrombosis (cutoff value, 361 × 10/liter; OR, 2.16; p = 0.005). In patients who did not sustain acute trauma, preoperative platelet counts predicted a four-fold increased risk of intraoperative thrombosis (cutoff value, 352 × 10/liter; OR, 3.82; p = 0.002).

CONCLUSIONS

Acute trauma patients with elevated preoperative platelet counts are at increased risk for lower extremity free flap complications. Prospective evaluation is warranted for guiding risk stratification and targeted treatment strategies.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

[Posttraumatic thromboembolic complications: Incidence, risk factors, pathophysiology and prevention]

Venous thromboembolism (VTE) remains a major challenge in critically ill patients. Subjects admitted in intensive care unit (ICU), in particular trauma patients, are at high-risk for both deep vein thrombosis (DVT) and pulmonary embolism (PE). The rate of symptomatic PE in injured patients has been reported previously ranging from 1 to 6%. The high incidence of posttraumatic venous thromboembolic events is well known. In fact, major trauma is a hypercoagulable state. Several factors placing the individual patient at a higher risk for the development of DVT and PE have been suggested: high ISS score, meningeal hemorrhage and spinal cord injuries have frequently been reported as a significant risk factor for VTEs after trauma. Posttraumatic pulmonary embolism traditionally occurs after a period of at least 5 days from trauma. The prevention can reduce the incidence and mortality associated with the pulmonary embolism if it is effective. There is no consensus is now available about the prevention of venous thromboembolism in trauma patients.

Feasibility Analysis for Treatment of Giant Intracranial Benign Tumor by Delayed Operation in Infancy

OBJECTIVE

The survival rate and prognosis in infants with giant intracranial tumors are significantly worse than in older children. This study aimed to analyze the feasibility of delayed operation for infants with giant intracranial benign tumor by evaluating the initial clinical presentations, expectant treatment measures, perioperative vital signs, and recuperation after surgery.

PATIENTS AND DATA

We reviewed 3 infant patients (average age, 9.33 months; range, 5-12 months) with giant intracranial benign tumors during January 2015 and April 2016. The maximum sections of tumors were 38 × 50 mm, 57 × 39 mm, and 55 × 67 mm, respectively. All clinical presentations, neuroimaging, and laboratory examinations were recorded.

RESULTS

Obstructive hydrocephalus was observed in 2 infants; ventriculoperitoneal shunts were placed in both before the delayed tumor resection. The disease progressed rapidly in the infant with teratoma and surgery was performed 4 months after placement of the ventriculoperitoneal shunt. The other 2 patients had experienced a 12-month growth and developmental phase and later underwent operations. Gross total resection was achieved in all patients. The pathologic results were consistent with the preoperative diagnosis. During a period of high-quality postoperative care, they remained stable and were discharged without any complications or neurologic deficits, and continued to improve toward their baseline.

CONCLUSIONS

Delayed operation enabled infant patients to gain a better physical state, with a stage of full preoperative preparation that may reduce intraoperative/postoperative morbidity and mortality.

Drotrecogin Alfa (Activated) in an Infant with Gram-Negative Septic Shock

The authors observed the effect of drotrecogin alfa (activated) in a case of pediatric severe sepsis. A 4-month-old male infant with Serratia marcescens septic shock, multiple organ dysfunction syndrome (MODS), and consumptive coagulopathy was admitted. The safety and efficacy of drotrecogin alfa (activated) has not yet been established for patients younger than 18 years of age. This is the first published report of the use of drotrecogin alfa (activated) in an infant with severe sepsis. Within 6 hours of starting therapy, there was a significant improvement in hemodynamics, which was not maintained after the drotrecogin alfa (activated) infusion was temporarily discontinued. No significant bleeding complications occurred during the infusion. A brain MRI on day 22 after drotrecogin alfa (activated) infusion showed bilateral small occipital hemorrhages. Drotrecogin alfa (activated) in this infant was temporally related to significant improvement. It is unknown whether the MRI brain lesions are related to severe sepsis with disseminated intravascular coagulation or drotrecogin alfa (activated) infusion. The authors believe that drotrecogin alfa (activated) should be considered in select children with life-threatening severe sepsis.

Host response biomarkers in the diagnosis of sepsis: a general overview

Critically ill patients who display a systemic inflammatory response syndrome (SIRS) are prone to develop nosocomial infections. The challenge remains to distinguish as early as possible among SIRS patients those who are developing sepsis. Following a sterile insult, damage-associated molecular patterns (DAMPs) released by damaged tissues and necrotic cells initiate an inflammatory response close to that observed during sepsis. During sepsis, pathogen-associated molecular patterns (PAMPs) trigger the release of host mediators involved in innate immunity and inflammation through identical receptors as DAMPs. In both clinical settings, a compensatory anti-inflammatory response syndrome (CARS) is concomitantly initiated. The exacerbated production of pro- or anti-inflammatory mediators allows their detection in biological fluids and particularly within the bloodstream. Some of these mediators can be used as biomarkers to decipher among the patients those who developed sepsis, and eventually they can be used as prognosis markers. In addition to plasma biomarkers, the analysis of some surface markers on circulating leukocytes or the study of mRNA and miRNA can be helpful. While there is no magic marker, a combination of few biomarkers might offer a high accuracy for diagnosis.

Purification of protein C from canine plasma

Background

In order to characterize the functional properties of canine protein C (CnPC), the zymogen needs to be purified from plasma. The goals of this study were (1) to purify protein C from fresh frozen canine plasma by barium chloride and ammonium sulphate precipitation, followed by immunoaffinity chromatography using a monoclonal mouse antibody against human protein C (HPC4) and (2) to characterize this protein’s structure.

Results

The purified protein contained three glycosylated forms of a heavy chain (~49 kDa) and a glycosylated light chain (~25 kDa). Tandem mass spectra of the peptides obtained following trypsin digestion and liquid chromatography identified this protein to be protein C (vitamin K-dependent protein C precursor, gi|62078422) with 100% probability. Three glycosylation sites (Asn139, Asn202, and Asn350) were identified by detection of peptides containing an N-linked glycosylation consensus sequon with a 3-dalton increase in mass following incubation of the protein with PNGase F in ¹⁸O-labeled water. Following incubation with Protac (a specific activator of protein C), the heavy chain showed a slight decrease in molecular size and amidolytic activity measured by a synthetic chromogenic substrate containing an amide bond [H-D-(γ-carbobenzoxyl)-lysyl-prolyl-arginine-paranitroanilide diacetate salt]. The amidolytic activity was increased by ~303-fold in the final protein preparation compared to that in plasma. The purified protein showed concentration-dependent anti-factor V and anti-factor VIII activities in canine plasma in coagulometric factor assays.

Conclusions

These studies showed that CnPC could be purified from plasma using HPC4 and that this protein showed amidolytic and anti-coagulant properties upon activation with Protac.

Risks associated with obese patient handling in emergency prehospital care

The number of ambulance crewmembers may affect the quality of cardiopulmonary resuscitation in particular situations. However, few studies have investigated how the number of emergency care providers affects the quality of CPR. Nonetheless, problems in the initial handling of patients due to small ambulance crew sizes may have significant consequences. These difficulties may be more frequent in an obese population than in a non-obese population. Hence such problems may be frequently encountered because obesity is epidemic in developed countries. In this report, we illustrate the fatal consequences of initial problems in patient handling due to a small ambulance crew size in an obese patient who suffered an out-of-hospital cardiac arrest. Following successful resuscitation, this patient presented humeral fractures that may have promoted a disorder of hemostasis. The patient eventually died. This case highlights the requirement for specific instructions for paramedics to manage obese patients in these emergency conditions. This case also highlights the need to take into account body mass index when deciding on appropriate pre-hospital care, especially regarding the number of ambulance crewmembers.

The specific characteristics of DIC syndrome vary with different clinical settings in the newborn

Abstract Two hundred fourteen newborns with serious perinatal pathology (posthypoxic syndrome, sepsis, surgical intervention, etc.) were examined in progress, according to 27 parameters including coagulative, trombocitic, anti-coagulative and fibrinolitic parts of hemostasis system. It was proved, that neonatal disseminated intravascular coagulation (DIC) syndrome had different hemostasiological patterns, which were connected with the genesis: sepsis, surgical intervention or posthypoxic syndrome. Precise periods of DIC syndrome are not always presented in newborns. DIC syndrome with neonatal sepsis has two different patterns (overcompensated and decompensated). The manifestation of trombo-hemorrhagic disorders and their characteristics depend on the genesis of DIC syndrome (e.g. an infection process and hyperbilirubinemia can provide the appearance of hemorrhagic syndrome).

The role of soluble thrombomodulin in the risk stratification and prognosis evaluation of septic patients in the emergency department

INTRODUCTION

Soluble thrombomodulin (sTM) is a sensitive marker of endothelial damage. In this study we investigated the role of sTM in the evaluation of the severity and prognosis of septic patients in the emergency department (ED).

MATERIALS AND METHODS

A prospective, observational cohort study was performed in the ED of an urban, university hospital. Patients who had suspected infection with two or more criteria of systemic inflammatory response syndrome were consecutively enrolled. sTM, D-Dimer and procalcitonin levels were measured on enrollment, and the Mortality in Emergency Department Sepsis (MEDS) score was calculated. A 30-day follow-up was performed for all patients.

RESULTS

A total of 372 patients with sepsis, 210 patients with severe sepsis and 98 patients with septic shock were enrolled in this study. According to the disease severity, patients were divided into sepsis subgroup and severe sepsis subgroup (including septic shock). In addition, patients were divided into survivors subgroup and non-survivors subgroup according to the 30-day mortality. Plasma sTM levels in patients with severe sepsis were higher than those with sepsis (P<0.001). Compared with survivors, non-survivors has higher plasma sTM levels (P<0.001). Multivariate logistic regression analysis showed that sTM was an independent predictor of severe sepsis (odds ratio 1.11) and 30-day mortality (odds ratio 1.059). Receiver operating characteristic curve analysis showed that sTM was a useful parameter in prediction of severe sepsis (0.859) and 30-day mortality (0.78). Compared with the MEDS score alone, combination of sTM and the MEDS score can improve the accuracy in prediction of severe sepsis and 30-day mortality.

CONCLUSIONS

sTM is a valuable biomarker in the risk stratification and prognosis evaluation of ED sepsis. Furthermore, sTM can enhance the ability of the MEDS score in prediction of severe sepsis and 30-day mortality.

Early complementopathy after multiple injuries in humans

After severe tissue injury, innate immunity mounts a robust systemic inflammatory response. However, little is known about the immediate impact of multiple trauma on early complement function in humans. In the present study, we hypothesized that multiple trauma results in immediate activation, consumption, and dysfunction of the complement cascade and that the resulting severe "complementopathy" may be associated with morbidity and mortality. Therefore, a prospective multicenter study with 25 healthy volunteers and 40 polytrauma patients (mean injury severity score = 30.3 ± 2.9) was performed. After polytrauma, serum was collected as early as possible at the scene, on admission to the emergency room (ER), and 4, 12, 24, 120, and 240 h post-trauma and analyzed for the complement profile. Complement hemolytic activity (CH-50) was massively reduced within the first 24 h after injury, recovered only 5 days after trauma, and discriminated between lethal and nonlethal 28-day outcome. Serum levels of the complement activation products C3a and C5a were significantly elevated throughout the entire observation period and correlated with the severity of traumatic brain injury and survival. The soluble terminal complement complex SC5b-9 and mannose-binding lectin showed a biphasic response after trauma. Key fluid-phase inhibitors of complement, such as C4b-binding protein and factor I, were significantly diminished early after trauma. The present data indicate an almost synchronical rapid activation and dysfunction of complement, suggesting a trauma-induced complementopathy early after injury. These events may participate in the impairment of the innate immune response observed after severe trauma.

Activated protein C improves pial microcirculation in experimental endotoxemia in rats

INTRODUCTION

The brain is one of the first organs affected clinically in sepsis. Microcirculatory alterations are suggested to be a critical component in the pathophysiology of sepsis. The aim of this study was to investigate the effects of recombinant human activated protein C (rhAPC) on the pial microcirculation in experimental endotoxemia using intravital microscopy. Our hypothesis is rhAPC protects pial microcirculation in endotoxemia.

METHODS

Endotoxemia was generated in Lewis rats with intravenous injection of lipopolysaccharide (LPS, 5 mg/kg i.v.). Dura mater was removed through a cranial window to expose pial vessels on the brain surface. The microcirculation, including leukocyte-endothelial interaction, functional capillary density (FCD) and plasma extravasation of pial vessels was examined by fluorescent intravital microscopy (IVM) 2 h after administration of LPS, LPS and rhAPC or equivalent amount of saline (used as Control group). Plasma cytokine levels of interleukin 1 alpha (IL1-α), tumor necrosis factor-α (TNF-α), interferon γ (IFN-γ), Monocyte chemotactic protein-1 (MCP-1) and Granulocyte-macrophage colony-stimulating factor (GM-CSF) were evaluated after IVM.

RESULTS

LPS challenge significantly increased leukocyte adhesion (773±190 vs. 592±152 n/mm(2) Control), decreased FCD (218±54 vs. 418±74 cm/cm(2) Control) and increased proinflammatory cytokine levels (IL-1α: 5032±1502 vs. 8±21 pg/ml; TNF-α: 1823±1007 vs. 168±228 pg/ml; IFN-γ: 785±434 vs. 0 pg/ml; GM-CSF: 54±52 vs. 1±3 pg/ml) compared to control animals. rhAPC treatment significantly reduced leukocyte adhesion (599±111 n/mm(2)), increased FCD (516±118 cm/cm(2)) and reduced IL-1α levels (2134±937 pg/ml) in the endotoxemic rats.

CONCLUSION

APC treatment significantly improves pial microcirculation by reducing leukocyte adhesion and increasing FCD.

Guidance on patient identification and administration of recombinant human activated protein C for the treatment of severe sepsis

Approximately one-third of cases of severe sepsis result in death. Endogenous activated protein C (APC) plays a key role in the regulation of the inflammation, fibrinolysis and coagulation associated with severe sepsis. In a recently published phase III trial, Protein C Worldwide Evaluation in Severe Sepsis (PROWESS), intravenous administration of recombinant human APC (rhAPC) 24 mug/kg/h for 96 h to patients with severe sepsis resulted in a 6.1% reduction in absolute mortality and a 19.4% reduction in the relative risk of death from any cause within 28 days (number needed to treat = 16). This dose is now being applied in clinical practice.rhAPC is recommended for the treatment of severe sepsis (sepsis associated with acute organ dysfunction) occurring as a result of all types of infection (Gram-negative bacterial, Gram-positive bacterial and fungal). A panel of Canadian clinicians experienced in the treatment of severe sepsis and the management of critical care patients has developed this consensus document to assist clinicians in appropriate patient selection and management of potential challenges associated with rhAPC therapy.

Coagulation and inflammation. Molecular insights and diagnostic implications

Overwhelming evidence has linked inflammatory disorders to a hypercoagulable state. In fact, thromboembolic complications are among the leading causes of disability and death in many acute and chronic inflammatory diseases. Despite this clinical knowledge, coagulation and immunity were long regarded as separate entities. Recent studies have unveiled molecular underpinnings of the intimate interconnection between both systems. The studies have clearly shown that distinct pro-inflammatory stimuli also activate the clotting cascade and that coagulation in turn modulates inflammatory signaling pathways. In this review, we use evidence from sepsis and inflammatory bowel diseases as a paradigm for acute and chronic inflammatory states in general and rise hypotheses how a systematic molecular understanding of the "inflammation-coagulation" crosstalk may result in novel diagnostic and therapeutic strategies that target the inflammation-induced hypercoagulable state.

Protein C in critical illness

PURPOSE

The role of protein C in critical illness is assessed.

SUMMARY

Conversion of protein C to activated protein C (APC) requires thrombin and thrombomodulin. When thrombin is not bound to thrombomodulin, it can convert fibrinogen to fibrin, factor V to factor Va, and factor VIII to factor VIIIa but will not convert protein C to APC. When thrombin is bound to thrombomodulin, it can convert protein C to APC but cannot convert fibrinogen, factor V, or factor VIII. Activation of protein C is accelerated by the presence of endothelial protein C receptors. In conjunction with protein S, APC limits coagulation by inactivating factors Va and VIIIa, which decreases thrombin-mediated inflammation. By inhibiting the formation of thrombin and the release of proinflammatory cytokines, APC reduces the inflammatory response to infection. By inducing cell signaling, APC directly modulates the cellular response to infection, resulting in antiinflammatory, cytoprotective, and barrier-protective activities. APC is metabolized by protease inhibitors and other proteins in the plasma. Conversion of protein C to APC is impaired in severe sepsis. During severe sepsis, endogenous levels of the inactive precursor protein C are reduced because of decreased production by the liver and degradation by enzymes. More than 85% of patients with severe sepsis have low levels of protein C. Absolute levels of protein C correlate with morbidity and mortality outcomes of the sepsis population, regardless of age, infecting microorganism, presence of shock, disseminated intravascular coagulation, degree of hypercoagulation, or severity of illness.

CONCLUSION

The protein C pathway is a natural homeostatic regulator with multiple mechanisms of action. Blood protein C concentration is inversely correlated with morbidity and mortality in sepsis and other critical illness.

Decreased activated protein C levels as a clinical predictor in patients with ST-elevation myocardial infarction

BACKGROUND

Circulating markers that indicate atherosclerotic plaque instability may have diagnostic and prognostic value in patients with acute coronary syndromes. We evaluated activated protein C (APC), which has antithrombotic, anti-inflammatory, and profibrinolytic properties, as a possible clinical predictor in ST-elevation myocardial infarction (STEMI), including return of spontaneous circulation after sudden cardiac arrest.

METHODS

Patients with STEMI whose APC level was measured upon arrival at the emergency room were enrolled in this study (n=335). The primary end point was inhospital death from any cause.

RESULTS

The APC level ranged from 29% to 142% with a median of 80%. The unadjusted death rate increased in a stepwise fashion with decreasing APC levels (33.7% in quartile 1, 12.7% in 2, 6.0% in 3, and 3.6% in 4, P<.001). This association remained significant in subgroups of patients with STEMI only (P=.04) or with return of spontaneous circulation (P=.01). After adjusting for independent predictors of inhospital death, the odds ratio for death among those in the first quartile of APC levels was 9.4 (95% CI 1.1-81.6, P=.04). A cutoff APC level of 65% had the highest combined sensitivity and specificity in predicting death.

CONCLUSIONS

Measuring APC levels provides predictive information for use in risk stratification across the STEMI spectrum. Decreased APC levels may be a unifying feature among patients at high risk for death after STEMI.

Advances in understanding sepsis

Sepsis, a systemic inflammatory response to infection, is a leading cause of death in intensive care units. Recent investigations into the pathogenesis of sepsis reveal a biphasic inflammatory process. An early phase is characterized by pro-inflammatory cytokines (e.g. tumour necrosis factor-alpha), whereas a late phase is mediated by an inflammatory high-mobility group box 1 and an anti-inflammatory interleukin-10. Inflammation aberrantly activates coagulation cascades as sepsis progresses. This dual inflammatory response concomitant with dysregulated coagulation partially accounts for unsuccessful anti-cytokine therapies that have solely targeted early pro-inflammatory mediators (e.g. tumour necrosis factor-alpha). In contrast, activated protein C, which modifies both inflammatory and coagulatory pathways, has improved survival in patients in severe sepsis. Inhibition of the late mediator high-mobility group box 1 improves survival in established sepsis in pre-clinical studies. In addition, recent advances in molecular medicine have shed light on two novel experimental interventions against sepsis. Accelerated apoptosis of lymphocytes has been shown to play an important role in organ dysfunction in sepsis and techniques to suppress apoptosis have improved survival rate in sepsis models. The vagus nerve system has also been shown to suppress innate immune response through endogenous release and exogenous administration of cholinergic agonists, ameliorating inflammation and lethality in sepsis models.

Acute coagulopathy of trauma: hypoperfusion induces systemic anticoagulation and hyperfibrinolysis

BACKGROUND

Coagulopathy is present at admission in 25% of trauma patients, is associated with shock and a 5-fold increase in mortality. The coagulopathy has recently been associated with systemic activation of the protein C pathway. This study was designed to characterize the thrombotic, coagulant and fibrinolytic derangements of trauma-induced shock.

METHODS

This was a prospective cohort study of major trauma patients admitted to a single trauma center. Blood was drawn within 10 minutes of arrival for analysis of partial thromboplastin and prothrombin times, prothrombin fragments 1 + 2 (PF1 + 2), fibrinogen, factor VII, thrombomodulin, protein C, plasminogen activator inhibitor-1 (PAI-1), thrombin activatable fibrinolysis inhibitor (TAFI), tissue plasminogen activator (tPA), and D-dimers. Base deficit was used as a measure of tissue hypoperfusion.

RESULTS

Two hundred eight patients were studied. Systemic hypoperfusion was associated with anticoagulation and hyperfibrinolysis. Coagulation was activated and thrombin generation was related to injury severity, but acidosis did not affect Factor VII or PF1 + 2 levels. Hypoperfusion-induced increase in soluble thrombomodulin levels was associated with reduced fibrinogen utilization, reduction in protein C and an increase in TAFI. Hypoperfusion also resulted in hyperfibrinolysis, with raised tPA and D-Dimers, associated with the observed reduction in PAI-1 and not alterations in TAFI.

CONCLUSIONS

Acute coagulopathy of trauma is associated with systemic hypoperfusion and is characterized by anticoagulation and hyperfibrinolysis. There was no evidence of coagulation factor loss or dysfunction at this time point. Soluble thrombomodulin levels correlate with thrombomodulin activity. Thrombin binding to thrombomodulin contributes to hyperfibrinolysis via activated protein C consumption of PAI-1.

Acute coagulopathy of trauma: mechanism, identification and effect

PURPOSE OF REVIEW

Acute coagulopathy of trauma has only been described relatively recently. Developing early in the postinjury phase, it is associated with increased transfusion requirements and poor outcomes. This review examines the possible initiators, mechanism and clinical importance of acute coagulopathy.

RECENT FINDINGS

Acute coagulopathy of trauma occurs in patients with shock and is characterized by a systemic anticoagulation and hyperfibrinolysis. Dilution, acidemia and consumption of coagulation proteases do not appear to be significant factors at this stage. There is evidence to implicate activation of the protein C pathway in this process. Diagnosis of acute coagulopathy currently relies on laboratory assessment of clotting times. These tests do not fully characterize the coagulopathy and have significant limitations, which reduce their clinical utility.

SUMMARY

Acute coagulopathy results in increased transfusion requirements, incidence of organ dysfunction, critical care stay and mortality. Recognition of an early coagulopathic state has implications for the care of shocked patients and the management of massive transfusion. Identification of novel mechanisms for traumatic coagulopathy may lead to new avenues for drug discovery and therapeutic intervention.

Levels of protein C activity and clinical factors in early phase of pediatric septic shock may be associated with the risk of death

Severe sepsis and septic shock are major causes of morbidity and mortality among children in pediatric intensive care units (PICUs) worldwide. Activated protein C (PC) is a critical endogenous regulator of coagulation and inflammation in patients with sepsis. However, the role of PC in pediatric sepsis is still obscure. We prospectively recruited infants and children aged between 1 month and 15 years old who were admitted to PICU with a clinical diagnosis of systemic inflammatory response syndrome, sepsis, or septic shock. Clinical data were recorded and blood samples kept for further analysis. We then measured the levels of PC activity. Of the approximately 1,100 pediatric patients admitted to PICU from January 1, 2004 to December 31, 2005, 75 were diagnosed with septic shock (6.8%), and 67 samples were available for analysis. Out of these, 41 (61%) were survivors, and 26 (39%) were nonsurvivors. The average plasma PC activity (%) was at 37.8 +/- 4.4. Plasma PC activity (%) was significantly lower in the nonsurvivors compared with the survivors at 23.6 +/- 4.3 and 46.8 +/- 6.3 (P = 0.002), respectively. D-Dimer levels were not significantly different between the survivors (1,461 +/- 266 ng/mL) and the nonsurvivors (1,989 +/- 489 ng/mL) (P = 0.68). Also, there was no correlation between plasma PC activity and D-dimer levels (r = -0.07; P = 0.6). Importantly, the odds of dying were significantly higher in patients whose level of PC activity was less than 25% (odds ratio = 5.6; P = 0.02). Pediatric patients with septic shock demonstrate very low levels of PC activity, and this may be associated with an increased risk of death.

A comparative study of the protein C pathway in septic and nonseptic patients with organ failure

RATIONALE

Severe sepsis is associated with an exacerbated procoagulant state with protein C (PC) system impairment. In contrast, the inflammatory and coagulation status of nonseptic patients with organ failure (OF) is less documented.

OBJECTIVES

To compare coagulation activation, focusing on the PC system, and inflammatory status in septic and nonseptic patients with OF.

METHODS

Thirty patients with severe sepsis and 30 nonseptic patients were recruited at the onset of OF and compared with 30 matched healthy subjects. We performed an extensive analysis of the PC pathway, including plasma protein measurements and quantification of leukocyte expression of PC system receptors. In addition, we analyzed the inflammatory status, based on inflammation-related gene leukocyte expression.

MEASUREMENTS AND MAIN RESULTS

We observed coagulation activation, reflected by a similar increase in tissue factor mRNA expression, in the two patient groups when compared with the healthy subjects. Soluble thrombomodulin levels were higher in septic patients than in healthy control subjects, whereas PC, protein S, and soluble endothelial cell PC receptor levels were lower. Similar results were obtained in nonseptic patients with OF. Monocyte thrombomodulin overexpression, together with increased circulating levels of activated PC, suggests that the capacity for PC activation is at least partly preserved in both settings. No difference in the inflammatory profile was found between septic and nonseptic patients.

CONCLUSIONS

The pathogenesis of OF in critical care patients is characterized by an overwhelming systemic inflammatory response and by exacerbated coagulation activation, independently of whether or not infection is the triggering event. Clinical trial registered with www.clinicaltrials.gov (NCT 00361725).

Antithrombin levels, morbidity, and mortality in a surgical intensive care unit

BACKGROUND

Antithrombin (AT) levels have been suggested as being predictive of outcome in intensive care unit (ICU) patients with septic shock. We investigated the time course of AT levels in a surgical ICU and tested the hypothesis that AT levels may be associated with morbidity and increased mortality rates in a cohort of surgical ICU patients.

METHODS

Three-hundred-twenty-seven consecutive patients admitted to the ICU with an estimated length of stay more than 48 h were included. AT levels were measured daily.

RESULTS

On admission to the ICU, AT levels were below the lower limit of normal in 84.1% (n = 275) of patients and increased significantly by 48 h after admission to reach normal values by the 7th ICU day in patients who never had sepsis (n = 208). This increase in AT levels was delayed in patients with sepsis. Patients with severe sepsis (n = 55) had consistently lower AT levels compared with other patients. Patients with lower AT levels were more likely to need blood products and had a greater maximum degree of organ dysfunction in the ICU than did other patients. The ICU length of stay was similar, regardless of the AT level on admission. Admission AT levels were not associated with increased ICU mortality in a multivariable analysis.

CONCLUSIONS

AT levels are low on admission to the ICU, regardless of the presence of sepsis. Although associated with the degree of organ dysfunction and the severity of sepsis, AT levels were not independently associated with worse outcome in this group of surgical ICU patients.

Protein C concentrations correlate with organ dysfunction and predict outcome independent of the presence of sepsis

BACKGROUND

Characterizing the evolution of protein C concentrations in critically ill patients may help in identifying high risk groups and potential therapeutic targets. The authors investigated the time courses of protein C concentrations and their relation to the presence of sepsis, organ dysfunction/failure, and outcome.

METHODS

This observational cohort study, in a university hospital surgical intensive care unit (ICU), included 312 consecutive patients with an estimated ICU length of stay more than 48 h. Plasma protein C concentrations and parameters of organ dysfunction were measured daily until discharge or death.

RESULTS

Protein C concentrations were below the lower limit of normal in 50.6% of patients (n = 158) on admission and decreased to a nadir within 3-4 days after admission before almost normalizing by 2 weeks thereafter, irrespective of the presence of sepsis, sex, source and type of admission, and type of surgery. The minimum protein C concentration was lower in patients with severe sepsis/septic shock (n = 54) than in those with sepsis (n = 63) and those who never had sepsis (n = 195), and was negatively correlated to the maximum Sequential Organ Failure Assessment score (R = 0.345, P < 0.001). Protein C levels were lower in nonsurvivors (n = 46; 14.7%) than in survivors, especially in the first 4 days after admission. In a multivariable analysis with ICU mortality as the dependent variable, a minimum protein C concentration less than 45% was an independent risk factor for ICU death.

CONCLUSIONS

In critically ill surgical patients, protein C concentrations were generally low, associated with organ dysfunction/failure, and independently associated with a higher risk of ICU mortality.

Low plasma protein C values predict mortality in low birth weight neonates with septicemia

BACKGROUND

Septicemia activates coagulation and decreases activated protein C (APC). Low APC in adults is associated with multiorgan dysfunction and mortality, but such data in neonates are lacking. Being deficient in APC, neonates may be especially vulnerable to the effects of low APC.

METHODS

This cohort study was conducted on 40 neonates with severe bacterial septicemia to determine the relationship between plasma APC values and mortality, time to mortality, and hazard of dying. Low birth weight neonates with sepsis, organ dysfunction, and systemic inflammatory response syndrome were enrolled after parental consent. Plasma APC was assayed at enrollment and subjects were followed for 14 days from enrollment. Low birth weight neonates, who had major malformations, severe birth asphyxia, or received blood products before APC assay, were excluded.

PRIMARY OUTCOME

comparison of APC level between survivors and nonsurvivors.

SECONDARY OUTCOMES

survival with low versus normal APC; and hazard ratio of APC, adjusted for birth weight, Score for Neonatal Acute Physiology and number of affected organs.

RESULTS

Forty of 74 eligible neonates were included. Twenty-five of the enrolled neonates died within 14 days. APC levels in nonsurvivors were lower than in survivors [median (interquartile range) %, 15 (4.5-21) versus 33 (18-55); P < 0.001]. Ten nonsurvivors versus 1 survivor had low APC (P = 0.03). Positive predictive value (PPV) of low APC values for mortality was 90.9%. Survival in the low APC group (n = 11) was shorter than in normal APC group [median (95% confidence interval) days, 3 (2.3-3.7) versus 10, P value <0.001]. APC value was independently associated with hazard of dying [adjusted risk 0.95 (95% confidence interval 0.92-0.99), P = 0.02]. Each 1% rise in APC decreased the hazard of dying by 5%.

CONCLUSIONS

Mortality was higher and duration of survival shorter in septic neonates with lower plasma ACP. The latter was an independent predictor of the hazard of dying.

Acute traumatic coagulopathy: initiated by hypoperfusion: modulated through the protein C pathway?

OBJECTIVES

Coagulopathy following major trauma is conventionally attributed to activation and consumption of coagulation factors. Recent studies have identified an acute coagulopathy present on admission that is independent of injury severity. We hypothesized that early coagulopathy is due to tissue hypoperfusion, and investigated derangements in coagulation associated with this.

METHODS

This was a prospective cohort study of major trauma patients admitted to a single trauma center. Blood was drawn within 10 minutes of arrival for analysis of partial thromboplastin and prothrombin times, prothrombin fragments 1+2, fibrinogen, thrombomodulin, protein C, plasminogen activator inhibitor-1, and D-dimers. Base deficit (BD) was used as a measure of tissue hypoperfusion.

RESULTS

A total of 208 patients were enrolled. Patients without tissue hypoperfusion were not coagulopathic, irrespective of the amount of thrombin generated. Prolongation of the partial thromboplastin and prothrombin times was only observed with an increased BD. An increasing BD was associated with high soluble thrombomodulin and low protein C levels. Low protein C levels were associated with prolongation of the partial thromboplastin and prothrombin times and hyperfibrinolysis with low levels of plasminogen activator inhibitor-1 and high D-dimer levels. High thrombomodulin and low protein C levels were significantly associated with increased mortality, blood transfusion requirements, acute renal injury, and reduced ventilator-free days.

CONCLUSIONS

Early traumatic coagulopathy occurs only in the presence of tissue hypoperfusion and appears to occur without significant consumption of coagulation factors. Alterations in the thrombomodulin-protein C pathway are consistent with activated protein C activation and systemic anticoagulation. Admission plasma thrombomodulin and protein C levels are predictive of clinical outcomes following major trauma.

Making sense of multiple organ dysfunction syndrome

Despite recent advances in critical care medicine, caring for patients with MODS remains one of the most challenging experience a critical care can encounter. New therapies that current exist and continue to be developed contribute to successful outcomes for patients with MODS, but there is no substitute for prevention and early intervention for persons at risk for developing MODS. Early and subtle changes in the patient who is at risk and has endured an initial insult can make a great difference in the patient's outcome and chances of mortality. Goal-directed therapy, supportive management, as well as an understanding of the inflammatory process are key to decreasing the mortality rate among patients with MODS.

The use of drotrecogin alfa (activated) in a patient with recent orthotopic liver transplant

Drotrecogin alfa has been shown to reduce mortality in severe sepsis. However, it remains unlicensed for use in patients with previous liver transplantation. We report its use in such a case. Prior to administration a risk benefit analysis was performed in line with General Medical Council recommendations. This included being satisfied that no appropriately licensed alternative would better serve the patient's needs and that sufficient evidence existed to demonstrate the safety and efficacy of the drug. Responsibility was taken for prescription, monitoring and follow up. The process was carefully documented and the patient recovered fully with no adverse effects. To date the only published data on the use of drotrecogin alpha in transplant recipients is a case series of three patients. Further published data may encourage review of the licence.

[Activated proteine C]

Recombinant human activated protein C (APC) might be the first pharmacological intervention which decreases mortality in the course of severe sepsis. Surviving Sepsis Campaign guidelines have recommended the use of APC with grade B level of proof. During sepsis, the APC pathway serves as a major system for controlling thrombosis inhibiting thrombin formation, limiting inflammatory responses, and potentially decreasing endothelial cell apoptosis. APC use was assessed in the course of severe sepsis 24 microg/kg/h for 96 hours with the aim of inhibiting coagulopathy and inflammation. The PROWESS trial included 1,690 patients and demonstrated a significantly decreased mortality in the treated group. Additional publications have clarified the characteristics of the included patients and tried to outline the potential benefits of APC. The results of ENHANCE, a multicenter open trial, have confirmed the trends reported in the PROWESS trial. Evidence supporting the efficacy of APC in the management of severe sepsis is clearly assessed. However, several issues remain unsolved and require to be addressed as the appropriate use of the drug and its place with other adjunctive therapies directed the sepsis process.

Low plasma vasopressin/norepinephrine ratio predicts septic shock

To evaluate if low plasma vasopressin and high norepinephrine concentrations predict grave prognosis of sepsis, a prospective sample of consecutive patients visiting the emergency department of a university teaching hospital who met the American College of Chest Physicians criteria of sepsis or severe sepsis was enrolled. Besides septic workup, we measured serum vasopressin and norepinephrine concentrations to correlate the impending outcome. One hundred eighty-two patients aged 27 to 99 years met the inclusive criteria and were classified as those with septic shock (n = 72), severe sepsis (n = 56), and those with sepsis only (n = 54) according to the outcome within 6 hours. Thirty healthy subjects were included as control. The plasma vasopressin level at baseline was significantly lower for those who finally developed septic shock (septic shock group, 3.6 +/- 2.5 pg/mL; 95% confidence interval [CI], 3.0-4.2 pg/mL; severe sepsis group, 21.8 +/- 4.1 pg/mL, 95% CI, 20.7-22.9 pg/mL; sepsis group, 10.6 +/- 6.5 pg/mL, 95% CI, 8.8-12.4 pg/mL, P < .001), whereas the norepinephrine level was highest for the same group (septic shock group, 3650 +/- 980 pg/mL, 95% CI, 3420-3880 pg/mL; severe sepsis group, 3600 +/- 1000 pg/mL, 95% CI, 3330-3870 pg/mL; sepsis group, 1720 +/- 320 pg/mL, 95% CI, 1630-1810 pg/mL). The vasopressin/norepinephrine ratio was significantly lower for the patients with final diagnosis of septic shock (P < .001). The mean interval between the time of samples drawn and the time of the most severe occurring sequelae was 2.4 +/- 0.8 hours. Receiver operating characteristic analysis revealed that the vasopressin/norepinephrine ratio 1 x 10(-3) had a sensitivity of 97% (95% CI, 90%-99%) and a specificity of 85% (95% CI, 78%-91%) for detecting impending septic shock. Low serum vasopressin/norepinephrine ratio can predict impending septic shock.

Activated protein C for the treatment of fulminant meningococcal septicaemia

We report two cases of meningococcal septic shock with multiple organ failure treated with prompt administration of activated protein C. This was associated with a rapid clinical improvement and early cessation of organ support. Both patients survived to hospital discharge with no long-term sequelae.

Recombinant human activated protein C resets thrombin generation in patients with severe sepsis - a case control study

Introduction

Recombinant human activated protein C (rhAPC) is the first drug for which a reduction of mortality in severe sepsis has been demonstrated. However, the mechanism by which this reduction in mortality is achieved is still not clearly defined. The aim of the present study was to evaluate the dynamics of the anticoagulant, anti-inflammatory and pro-fibrinolytic action of rhAPC in patients with severe sepsis, by comparing rhAPC-treated patients with case controls.

Methods

In this prospectively designed multicenter case control study, 12 patients who were participating in the ENHANCE study, an open-label study of rhAPC in severe sepsis, were treated intravenously with rhAPC at a constant rate of 24 μg/kg/h for a total of 96 h. Twelve controls with severe sepsis matching the inclusion criteria received standard therapy. The treatment was started within 48 h after the onset of organ failure. Blood samples were taken before the start of the infusion and at 4, 8, 24, 48, 96 and 168 h, for determination of parameters of coagulation and inflammation.

Results

Sepsis-induced thrombin generation as measured by thrombin-antithrombin complexes and prothrombin fragment F1+2, was reset by rhAPC within the first 8 h of infusion. The administration of rhAPC did not influence parameters of fibrinolysis and inflammation. There was no difference in outcome or occurrence of serious adverse events between the treatment group and the control group.

Conclusion

Sepsis-induced thrombin generation in severely septic patients is reset by rhAPC within the first 8 h of infusion without influencing parameters of fibrinolysis and inflammation.

Protein C levels can be forecasted by global haemostatic tests in critically ill patients and predict long-term survival

INTRODUCTION

We have shown the usefulness of global haemostatic tests International Normalized Ratio (INR) and Activated Partial Thromboplastin Time (APTT) for predicting survival in critically ill patients. Ability to analyse inhibitors protein C and antithrombin is limited to a small number of laboratories and often only during office hours. We therefore studied the usefulness of global haemostatic tests to predict levels of protein C and antithrombin and investigated value of these latter tests in predicting outcome.

PATIENTS/METHODS

Blood samples were collected within 6 h of admission to intensive care unit (ICU) and tested regarding platelet count, INR, and APTT. If platelet count was <100x10(9) L(-1), INR >1.36 and/or APTT >45 s, a second sampling was done within 6 h after the first one for analysis of protein C and antithrombin. Ninety-two patients were included; length of stay at ICU and hospital, survival when leaving ICU and hospital and up to 5 years were recorded.

RESULTS

Using univariate analysis of variance, INR and APTT separately predicted levels of protein C and to some extent antithrombin. Neither platelet count nor any combinations of global haemostatic tests were predictive. Utilising Cox regression, decreased protein C, but not antithrombin, predicted lower survival rate.

CONCLUSIONS

Global haemostatic tests INR and APTT can predict levels of protein C and, though less so, antithrombin. A low protein C level indicated a sinister prognosis in the ICU setting, at the hospital, and after up to 5 years.

Mycotic intracavernous carotid aneurysm

Intracavernous carotid mycotic aneurysms are rare and management is dictated by clinical presentation. This case involved a patient presenting with a symptomatic expanding proximal internal carotid artery aneurysm treated with antibiotics and balloon occlusion but with thromboembolic complications resulting in a fatal outcome. Points of discussion include difficulties faced in reaching a diagnosis, management options for mycotic aneurysms and the rationale in this case for choosing endovascular rather than surgical treatment. The use and limitations of trial balloon occlusion are discussed as well as complications of vessel occlusion, in particular thromboembolism. Also discussed is the importance of surveillance imaging and the impact of sepsis on overall management.

Optimum treatment of severe sepsis and septic shock: evidence in support of the recommendations

Severe sepsis and septic shock are among the most common causes of death in noncoronary intensive care units. The incidence of sepsis has been increasing over the past two decades, and is predicted to continue to rise over the next 20 years. While our understanding of the complex pathophysiologic alterations that occur in severe sepsis and septic shock has increased greatly asa result of recent clinical and preclinical studies, mortality associated with the disorder remains unacceptably high. Despite these new insights, the cornerstone of therapy continues to be early recognition, prompt initiation of effective antibiotic therapy, and source control, and goal-directed hemodynamic, ventilatory,and metabolic support as necessary. To date, attempts to reduce mortality with innovative, predominantly anti-inflammatory therapeutic strategies have been extremely disappointing. Observations of improved outcomes with physiologic doses of corticosteroid replacement therapy and activated protein C (drotrecogin alfa[activated]) have provided new adjuvant therapies for severe sepsis and septic shock in selected patients. This article reviews the components of sepsis management and discusses the available evidence in support of these recommendations. In addition, there is a discussion of some promising new strategies.

Activated protein C in sepsis: emerging insights regarding its mechanism of action and clinical effectiveness

PURPOSE OF REVIEW

Dysregulation of endogenous coagulant and anticoagulant systems is now believed to play an important role in the pathogenesis of sepsis and septic shock. Reductions in host activated protein C levels and resultant microvascular thrombosis provided a basis for the use of recombinant human activated protein C in sepsis. Although controversial, the findings from an initial phase III trial testing this agent resulted in its approval for use in patients with severe sepsis and high risk of death. This review highlights emerging insights into the biology of protein C and activated protein C in sepsis, summarizes additional analysis growing out of the phase III trial testing recombinant human activated protein C, and assesses the cost-effectiveness that the clinical use of the agent has had thus far.

RECENT FINDINGS

Binding of activated protein C to the endothelial cell protein C receptor is recognized to result in a growing number of actions including increased activity of activated protein C itself and inhibition of both nuclear factor-kappaB, a central regulator in the host inflammatory response, and apoptosis. Additional analysis of the original phase III trial testing recombinant human activated protein C appears to emphasize one of the US Food and Drug Administration's original concerns regarding an association between severity of sepsis and this agent's effects. Postmarketing analysis and growing experience with other anticoagulant agents and corticosteroids in sepsis raise questions regarding the ultimate cost-effectiveness of activated protein C.

SUMMARY

The protein C pathway is important both to coagulant and inflammatory pathways during sepsis. Based on emerging investigations, its actions appear to be increasingly complex ones. Despite potentially promising results in an initial phase III trial, the role of recombinant human activated protein C in the treatment of septic patients must continue to be evaluated.

New approaches to the treatment of sepsis

The clinical spectrum of sepsis, severe sepsis, and septic shock is responsible for a growing number of deaths and excessive health care expenditures. Until recently, despite multiple clinical trials, no intervention provided a beneficial outcome in septic patients. Within the last 2 years, studies that involved drotrecogin alfa (activated), corticosteroid therapy, and early goal-directed therapy showed efficacy in those with severe sepsis and septic shock. These results have provided optimism for reducing sepsis-related mortality.