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Introduction Genetic variation in the Protein C gene (PROC) is associated with altered risk of adverse outcome for a number of diseases. Common single nucleotide polymorphisms (SNPs) in the promoter region and the adjacent 5’ region of PROC are associated with Protein C expression. We tested the hypothesis that common SNPs (minor allele frequency > 10%) between the frequently studied promoter SNPs -1654 (rs1799808) and -1641 (rs1799809), and the end of PROC intron 2 alter nuclear transcription factor binding. Materials and Methods We used electrophoretic mobility shift assays with 25-mer oligonucleotides centered on each of the 10 SNPs assessed in this potential regulatory region of the Protein C gene to test for differential binding to nuclear factors isolated from Hep-G2 cells. Results We found that the G-allele oligo of the intron 2 SNP rs2069915[G/A] bound nuclear factors more avidly than the A-allele (p = 1.9 × 10 -9 , n = 24). Similarly, we found that the C-allele oligo of the intron 2 SNP rs2069916[C/T] bound nuclear factors more avidly than the T-allele, (p = 3.7 × 10 -6 , n = 19). Cold competition and supershift assays suggested that the protein differentially binding to the C-allele of rs2069916 was USF1. Notably, we observed minimal nuclear factor binding to oligos containing haplotypes of the previously reported -1654 and -1641 SNPs. Luciferase reporter assays that showed the A-T haplotype of rs2069915 and rs2069916 drives transcription significantly more than the C-G haplotype (t-test, P = 0.015, n = 12). Conclusion Differential transcription factor binding occurs for common SNPs in the 5’ intronic regions of PROC which may contribute to PROC regulation and reported PROC SNP – phenotype associations.

Stimulation of toll-like receptor 9 (TLR9) by CpG-C containing oligonucleotides attenuates ischemic injury in the brain and liver. In this study, we investigate whether any of the three classes of CpG (A, B, or C) mitigate ischemia-induced cardiac dysfunction. We measured left ventricular ejection fraction (LVEF) in C57BL/6 mice using transthoracic echocardiography. Using LPS as an inflammatory stimulus, CpG-C was uniquely able to prevent cardiac dysfunction; its activity was confirmed through nuclear factor κB transcriptional activity assay in HL-1 cardiomyocytes. We went on to investigate CpG-C's efficacy and mechanism in the treatment of ischemia-reperfusion. Compared with baseline, no class of CpG significantly altered LVEF at 6 or 24 h; 40 mg/kg LPS induced a rapid, profound suppression of LVEF compared with baseline (26% ± 1.4% vs. 65% ± 1.4%), whereas pretreatment with CpG demonstrated that of the three classes, only CpG-C prevented the LPS -induced decrease in LVEF (51% ± 5.8%). In separate mice, 1-h ischemia followed by reperfusion of the left anterior descending artery resulted in a 7-day suppression of the LVEF (66% ± 5.2% at baseline; 46% ± 4.7% at day 1, and 46% ± 4.0% at day 7), whereas mice either pretreated with or begun on an infusion of CpG-C during the ischemia had no significant decline in LVEF. Gene expression microarray of CpG-C-stimulated cells revealed upregulation of the nuclear factor κB pathway inhibitors TNFAIP3, NFKBIA, TRIM30, and TNIP1. These may play a role in attenuation of cardiac inflammation. The TLR9 ligand CpG-C attenuates the acute inflammatory cardiac dysfunction induced by both LPS and ischemia-reperfusion of the left anterior descending artery.

The reliability of electrocardiogram interpretation to diagnose myocardial ischemia in critically ill patients is unclear. In adults with septic shock, we assessed intra- and inter-rater agreement of electrocardiogram interpretation, and the effect of knowledge of troponin values on these interpretations.Prospective substudy of a randomized trial of vasopressin vs. norepinephrine in septic shock.Nine Canadian intensive care units.Adults with septic shock requiring at least 5 μg/min of norepinephrine for 6 hrs.Twelve-lead electrocardiograms were recorded before study drug, and 6 hrs, 2 days, and 4 days after study drug initiation.Two physician readers, blinded to patient data and group, independently interpreted electrocardiograms on three occasions (first two readings were blinded to patient data; third reading was unblinded to troponin). To calibrate and refine definitions, both readers initially reviewed 25 trial electrocardiograms representing normal to abnormal. Cohen's Kappa and the φ statistic were used to analyze intra- and inter-rater agreement.One hundred twenty-one patients (62.2 ± 16.5 yrs, Acute Physiology and Chronic Health Evaluation II 28.6 ± 7.7) had 373 electrocardiograms. Blinded to troponin, readers 1 and 2 interpreted 46.4% and 30.0% of electrocardiograms as normal, and 15.3% and 12.3% as ischemic, respectively. Intrarater agreement was moderate for overall ischemia (κ 0.54 and 0.58), moderate/good for "normal" (κ 0.69 and 0.55), fair to good for specific signs of ischemia (ST elevation, T inversion, and Q waves, reader 1 κ 0.40 to 0.69; reader 2 κ 0.56 to 0.70); and good/very good for atrial arrhythmias (κ 0.84 and 0.79) and bundle branch block (κ 0.88 and 0.79). Inter-rater agreement was fair for ischemia (κ 0.29), moderate for ST elevation (κ 0.48), T inversion (κ 0.52), and Q waves (κ 0.44), good for bundle branch block (κ 0.78), and very good for atrial arrhythmias (κ 0.83). Inter-rater agreement for ischemia improved from fair to moderate (κ 0.52, p = .028) when unblinded to troponin.In patients with septic shock, inter-rater agreement of electrocardiogram interpretation for myocardial ischemia was fair, and improved with troponin knowledge.

Acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) are common disorders estimated to affect nearly 200,000 people per year in the United States alone (1). Despite improvements in supportive care, the overall mortality rate for these patients continues to hover near 40% (2). In King County, Washington, Rubenfeld and coworkers reported that the incidence of ARDS was twice as high in patients over 74 compared with patients between 60 and 64 years of age, and that older patients who developed the syndrome were significantly more likely to die (1). Therefore, the incidence of ALI/ARDS and its associated mortality are likely to rise as the population ages, particularly in the developed world. Novel therapies identified through bench and clinical research and translated to clinical practice have led to substantial improvements in ICU care in the past decade. Advances in imaging and laboratory diagnostics have dramatically improved our ability to identify and treat primary causes of critical illness, reducing diagnostic procedure–related morbidity and mortality. New antimicrobials and vasoactive agents, more effective therapies to prevent stress ulcer and venous thromboembolism, and a variety of new agents to treat other complications of critical illness effectively reduce the risk of ICU-related complications. In addition, we have learned to better use the resources available to us in the ICU. Positive pressure ventilation strategies designed to prevent ventilator-induced lung injury, interruptions in sedation, improved fluid management, limitation of empiric antibiotic usage, strategies to prevent ventilator-associated pneumonia, and the use of protocols and checklists to ensure consistent patient care delivery have all improved the supportive care of patients with ALI/ARDS (3–8). Given these and other research-driven improvements in supportive care, it is surprising that the crude mortality in most studies conducted in patients with ARDS remains relatively constant (2). One possible explanation is that the lack of change represents a true success as our ICUs fill with older patients with more co-morbidities. Even if this is true, it is clear that for a significant proportion of patients with ALI/ARDS, even the best supportive therapy is not enough. For these patients, novel therapies designed to interrupt ongoing lung injury or promote healing lung that investigators have identified as effective in preclinical or phase II trials may improve outcomes (9). Therefore, when testing potentially toxic new therapies investigators need biomarkers to identify subsets patients with ARDS at a higher risk of death, as the risk-to-benefit profile in these patients is more likely to be favorable. Investigators have frequently examined bronchoalveolar lavage fluid to identify predictive biomarkers, as the procedure can be done safely, is often performed as part of routine clinical care, and can reveal valuable insight into the severity of damage to the alveolar membrane (5, 10). The low-density lipoprotein receptor–related protein (LRP-1) is a large endocytic receptor that is expressed in many tissues, including the lung (11). LRP-1 recognizes more than 30 different ligands with varying affinity, facilitating their cellular uptake via endocytosis (11). In the low pH of the endosome, a conformational change in the structure in LRP-1 causes it to release the ligand, which can be recycled or degraded in the lysosome (12). In this issue of the Journal, Wygrecka and colleagues (pp. 438) found that the levels of soluble LRP-1 (sLRP-1) were increased in patients with ARDS compared with a control group of spontaneously breathing subjects or mechanically ventilated patients with cardiogenic pulmonary edema (13). The BAL levels of sLRP-1 were positively correlated with APACHE II scores and were significantly higher in patients who died from ARDS compared with those who survived. BAL fluid from patients with ARDS induced sLRP release from lung fibroblasts (but not epithelial cells or macrophages) through a mechanism that required TNF-α and membrane type-1 matrix metalloproteinase. The investigators went on to show that sLRP-1 inhibited the uptake of matrix metalloproteinases-2 and -9, which might enhance tissue injury. In support of this hypothesis they found that BAL fluid levels of MMP-2 and -9, and the basement membrane protein laminin, were positively correlated with the levels of sLRP-1 in the patients with ARDS. Wygrecka and coworkers have identified one important mechanism by which LRP-1 might contribute to the pathophysiology of ARDS. In addition, LRP-1 has been shown to regulate the activity of platelet-derived growth factor and transforming growth factor-β1, promote the clearance of Factor VIII, modulate the activity of the fibrinolytic system by binding with the urokinase-type plasminogen activator, contribute to the tPA-mediated increase in blood–brain barrier permeability after stroke, promote focal adhesion disassembly, and enhance cell migration, all of which may be important in the development and resolution of ALI (11). In addition, LRP-1 plays an important role in the phagocytosis of apoptotic cells and foreign particles. For example, Gardai and colleagues reported that in the lung LRP-1 interacts with surfactant proteins-A and -D to promote phagocytosis and induce inflammation in response to foreign particles or damaged cells (14). Further study will be required to determine the predominant mechanism(s) by which LRP-1 might contribute to the pathogenesis of ALI/ARDS. Before it can be used to direct treatment, a biomarker must be shown to have a high sensitivity, specificity, and positive and negative predictive value for the predicted outcome; be reproducible outside of the institution or laboratory in which it was developed; demonstrate biological plausibility; and be validated in a cohort of patients independent from the original cohort (15). Substantial further investigation is required before bronchoalveolar lavage fluid levels of sLRP-1 can be used as a biomarker to identify patients at risk of death from ARDS. However, the findings of Wygreka and coworkers add to those conducted by other investigators who collectively have identified an array of physiologic and laboratory parameters to improve our ability to identify patients at high risk of death earlier in their clinical course (16). Rigorous prospective examination of their utility as clinical prediction tools may open the door for the use of active pharmacologic or biological interventions to prevent ALI/ARDS-associated mortality.

Objective We sought to determine the role of respiratory assessment by cardiorespiratory symptoms and/or oxygen saturation by pulse oximetry (SpO 2 ) in predicting adverse maternal outcomes in women admitted to hospital with preeclampsia. Methods These data derive from an international, prospective multicentre cohort study, PIERS (Pre-eclampsia Integrated Estimate of RiSk), which assesses predictors of adverse outcomes in women admitted to tertiary perinatal units with preeclampsia. Univariate and multivariate analyses of cardiorespiratory symptoms and pulse oximetry were performed to assess their ability to predict a combined adverse maternal outcome developed through international Delphi consensus. Results SpO 2 successfully predicted adverse maternal outcomes; the area under the receiver-operator characteristic curve (AUC ROC) was 0.71 (95% CI 0.65 to 0.77). Combining the symptoms of chest pain and/or dyspnea with pulse oximetry improved this predictive ability (AUC ROC 0.73; 95% CI 0.67 to 0.78). When SpO 2 was stratified into risk groups using inflection points on the ROC curve, the highest risk group (SpO 2 90% to 93%) had an odds ratio of 18.1 (95% CI 8.2 to 40.2) for all outcomes within 48 hours when compared with the baseline group (SpO 2 98% to 100%). Conclusion Assessing SpO 2 aids in the assessment of maternal risk in women admitted to hospital with preeclampsia. An SpO 2 value of ≤ 93% confers particular risk. The symptom complex of chest pain and/or dyspnea adds to the association.

In cancer, therapies are targeted at 6 important pathways. In sepsis, there is ongoing controversy regarding the number and relative roles of pathways that are activated or repressed and which are important in the progression from health to death. Adding to complexity, there is interaction of pathways, there are differences in temporal pattern of up and down-regulation of pathways and there are different responses of pathways to therapies of sepsis. In this review, we define four key pathways of sepsis: (1) inflammation and immunity, (2) coagulation and fibrinolysis, (3) apoptosis, and (4) endocrine. Each of these pathways can impair endothelial function, a unifying aspect of the pathophysiology of sepsis. There are few studies of interactions of pathways except for the interacttion of inflammation/immunity with coagulation/fibrinolysis. Successful treatment of cancer requires that cancer therapies interrupt several key pathways of cancer. Accordingly, we suggest that successful treatment of sepsis will require therapies that interrupt several key pathways of sepsis. Perhaps the paucity of approved therapies for sepsis is related in part to the underevaluation of novel pathways, to lack of understanding of interactions of pathways and to lack of interruption of key pathways of sepsis.

Mutations in IRAK4 have been associated with recurrent Gram-positive infections in children. Given the central role of IRAK4 in innate immunity signaling, we hypothesized that common genetic variants of IRAK4 may be associated with prevalence of Gram-positive infection in critically ill adults. Haplotype clade tag single nucleotide polymorphisms (SNPs) of the IRAK4 gene were selected and genotyped in a cohort of 1,029 critically ill patients with systemic inflammatory response syndrome (SIRS). We found that a haplotype clade tagged by the A allele of the htSNP G29429A (Ala428Thr) was associated with increased relative risk of Gram-positive infection at admission to ICU (RR = 1.2, p < 0.05). Furthermore, the 29429A allele was associated with decreased lymphoblastoid cell response to CpG (as measured by IL-6 production) (raw values ± 95% CI 40.3 ± 32.3 vs. 85.8 ± 29.4 pg/ml; log-transformed values ± 95% CI 1.13 ± 0.37 vs. 1.55 ± 0.18, p < 0.04). We also found that IRAK4-deficient fibroblasts transfected with an IRAK4 expression plasmid containing the 29429A allele produced less IL-6 in response to lipopolysaccharide (p = 0.07). Our data suggest that the IRAK4 haplotype clade marked by 29429A (428Thr) alters susceptibility to Gram-positive bacteria, by decreasing cellular response to TLR ligands.

Background Vasopressin is an essential peptide hormone regulating cardiovascular homeostasis and an adjunctive vasopressor therapy for septic shock. Methods We tested for association between single nucleotide polymorphisms (SNPs) in vasopressin pathway genes and altered outcome in derivation (n = 589) and replication (n = 616) cohorts of patients with septic shock. The primary outcome was 28-day mortality and the secondary outcome was vasopressin clearance. In a third cardiac surgical cohort (n = 977), we tested for locus-specific heritability of serum sodium concentrations. Results Of 17 tested tag SNPs in five vasopressin pathway genes (arginine vasopressin [ AVP ], arginine vasopressin receptor 1A and 1B [ AVPR1A, AVPR1B ], leucyl/cystinyl aminopeptidase [ LNPEP ], and oxytocin receptor [ OXTR ]), rs18059 in LNPEP (also known as vasopressinase) was associated with 28-day mortality in the derivation cohort ( P = .037). Therefore, we resequenced the 160-kb haplotype block encompassing the LNPEP gene, including rs18059, and genotyped the 230 identified SNPs in the derivation cohort. The strongest signal was found for LNPEP rs4869317 (adjusted P = .044). The rs4869317 TT genotype was associated with increased 28-day mortality in the derivation cohort (51.0% [TT] vs 34.5% [AA/AT]; adjusted hazard ratio [HR], 1.58; 95% CI, 1.21-2.06; P = .00073) and the replication cohort (38.6% vs 29.6%; HR, 1.36; 95% CI, 1.03-1.80; P = .030). We found that the TT genotype was associated with increased plasma vasopressin clearance ( P = .028), and the rs4869317 genotype accounted for 80% of the variance of serum sodium concentrations (locus-specific heritability) in cardiac surgical patients. Conclusions The genetic variation in LNPEP (vasopressinase) is associated with 28-day mortality in septic shock and is associated with biologic effects on vasopressin clearance and serum sodium regulation. Further confirmation in additional cohorts is required.

In cancer, therapies are targeted at 6 important pathways. In sepsis, there is ongoing controversy regarding the number and relative roles of pathways that are activated or repressed and which are important in the progression from health to death. Adding to complexity, there is interaction of pathways, there are differences in temporal pattern of up and down-regulation of pathways and there are different responses of pathways to therapies of sepsis. In this review, we define four key pathways of sepsis: (1) inflammation and immunity, (2) coagulation and fibrinolysis, (3) apoptosis, and (4) endocrine. Each of these pathways can impair endothelial function, a unifying aspect of the pathophysiology of sepsis. There are few studies of interactions of pathways except for the interacttion of inflammation/immunity with coagulation/fibrinolysis. Successful treatment of cancer requires that cancer therapies interrupt several key pathways of cancer. Accordingly, we suggest that successful treatment of sepsis will require therapies that interrupt several key pathways of sepsis. Perhaps the paucity of approved therapies for sepsis is related in part to the underevaluation of novel pathways, to lack of understanding of interactions of pathways and to lack of interruption of key pathways of sepsis.

Hemodynamic monitoring plays a fundamental role in the management of acutely ill patients. With increased concerns about the use of invasive techniques, notably the pulmonary artery catheter, to measure cardiac output, recent years have seen an influx of new, less-invasive means of measuring hemodynamic variables, leaving the clinician somewhat bewildered as to which technique, if any, is best and which he/she should use. In this consensus paper, we try to provide some clarification, offering an objective review of the available monitoring systems, including their specific advantages and limitations, and highlighting some key principles underlying hemodynamic monitoring in critically ill patients., Journal Article, Research Support, Non-U.S. Gov't, Review, SCOPUS: re.j, info:eu-repo/semantics/published

The use of pulmonary artery catheters has diminished, so that other technologies are emerging. Central venous oxygen saturation measurement (ScvO₂) as a surrogate for mixed venous oxygen saturation measurement (SvO₂) is simple and clinically accessible. To maximize the clinical utility of ScvO₂ (or SvO₂) measurement, it is useful to review what the measurement means in a physiologic context,how the measurement is made, important limitations, and how this measurement may be helpful in common clinical scenarios. Compared with cardiac output measurement, SvO₂ is more directly related to tissue oxygenation. Furthermore,when tissue oxygenation is a clinical concern, SvO₂ is less prone to error compared with cardiac output, where small measurement errors may lead to larger errors in interpreting adequacy of oxygen delivery. ScvO₂ should be measured from the tip of a central venous catheter placed close to, or within, the right atrium to reduce measurement error. Correct clinical interpretation of SvO₂, or its properly measured ScvO₂ surrogate, can be used to (1) estimate cardiac output using the Fick equation, (2) better understand whether a patient's oxygen delivery is adequate to meet their oxygen demands, (3) help guide clinical practice, particularly when resuscitating patients using validated early goal directed therapy treatment protocols, (4) understand and treat arterial hypoxemia, and (5) rapidly estimate shunt fraction (venous admixture).

Arthur Guyton's concepts of the determinative role of right heart filling in cardiac output continue to be controversial. This paper reviews his seminal experiments in detail and clarifies the often confusing concepts underpinning his model. One primary criticism of Guyton's model is that the parameters describing venous return had not been measured in a functioning cardiovascular system in humans. Thus, concerns have been expressed in regard to the ability of Guyton's simplistic model, with few parameters, to model the complex human circulation. Further concerns have been raised in regard to the artificial experimental preparations that Guyton used. Recently reported measurements in humans support Guyton's theoretical and animal work.

Since the publication of the Surviving Sepsis Campaign guidelines, a number of additional and highly relevant studies have been published addressing the issue of vasopressor use during septic shock. While these new results are provocative, none of the studies are definitive. In sum, they suggest that maybe we should not be thinking of one vasopressor versus another in a winner-takes-all sense. Rather, we should be looking for the best balance of vasopressor agents and, further, the choice likely depends on clinical context. Clinical context may drive the choice of adrenergic agonist; for example, norepinephrine may be superior to dopamine when the potential for arrhythmias is of concern. Norepinephrine may be superior to epinephrine if elevated lactate associated with epinephrine use confounds the clinical picture. The Vasopressin and Septic Shock Trial (VASST) identified an effective dose of arginine vasopressin (AVP) when adrenergic agonist doses are low, but higher doses of AVP may be appropriate in the context of very high adrenergic agonist doses. The effect may be a direct beneficial AVP effect or indirect sparing of adrenergic agonist use. The choice to add AVP may also be influenced by the clinical context, including renal function or the concomitant use of corticosteroids. These interim conclusions, in truth, are hypotheses warranting randomized controlled trials adequately powered to test for survival differences in these severely ill patients.

Vasopressin is a stress hormone. However, vasopressin levels are inappropriately low in septic shock. Vasopressin stimulates AVPR1a, AVPR1b, AVPR2 and purinergic receptors. Vasopressin increases blood pressure by occupying AVPR1a receptors on vascular smooth muscle. An increase in ventricular afterload due to vasopressor administration limits ventricular systolic ejection, an effect that becomes increasingly important as systolic contractility is decreased. Stimulation of AVPR1a receptors may also decrease edemagenesis. Stimulation of AVPR1b by vasopressin releases ACTH and cortisol. AVPR2 stimulation increases retention of water by increasing cyclic AMP. Yet, vasopressin infusion may increase urine output, creatinine clearance and improve renal function in septic shock. Vasopressin has many effects on immune function such as altering cytokines, neuroimmunity, prostaglandins, humoral immunity and immune cells. For example, vasopressin decreases sepsis-induced pulmonary inflammation, could have renal anti-inflammatory effects and may decrease prostaglandin levels in a dose-dependent manner. Vasopressin may also modulate responses to stress by expression and release from immune cells. Interestingly, there are vasopressin receptors on immune cells. Many small clinical studies of vasopressin infusion in septic shock have shown that vasopressin infusion increases blood pressure, decreases requirements for norepinephrine and improves renal function. However, vasopressin could decrease coronary, cerebral and mesenteric perfusion. A multicenter trial of vasopressin versus norepinephrine in septic shock found no overall difference in mortality. Vasopressin may decrease mortality in patients with less severe septic shock. Vasopressin plus corticosteroid treatment may decrease mortality compared to corticosteroids plus norepinephrine. Potential mechanisms are that vasopressin plus corticosteroids beneficially alter immunity in septic shock.

To compare the effects of vasopressin versus norepinephrine infusion on the outcome of kidney injury in septic shock. Post-hoc analysis of the multi-center double-blind randomized controlled trial of vasopressin versus norepinephrine in adult patients who had septic shock (VASST). Seven hundred seventy-eight patients were randomized to receive a blinded infusion of either low-dose vasopressin (0.01–0.03 U/min) or norepinephrine infusion (5–15 μg/min) in addition to open-label vasopressors and were included in the outcome analysis. All vasopressors were titrated and weaned to maintain a target blood pressure. RIFLE criteria for acute kidney injury were used to compare the effects of vasopressin versus norepinephrine. In view of multiple simultaneous comparisons, a p value of 0.01 was considered statistically significant. Kidney injury was present in 464 patients (59.6%) at study entry. In patients in the RIFLE “Risk” category (n = 106), vasopressin as compared with norepinephrine was associated with a trend to a lower rate of progression to renal “Failure” or “Loss” categories (20.8 vs. 39.6%, respectively, p = 0.03), and a lower rate of use of renal replacement therapy (17.0 vs. 37.7%, p = 0.02). Mortality rates in the “Risk” category patients treated with vasopressin compared to norepinephrine were 30.8 versus 54.7%, p = 0.01, but this did not reach significance in a multiple logistic regression analysis (OR = 0.33, 99% CI 0.10–1.09, p = 0.02). The interaction of treatment group and RIFLE category was significant in predicting mortality. Vasopressin may reduce progression to renal failure and mortality in patients at risk of kidney injury who have septic shock.

Endothelial dysfunction is a major cause of organ dysfunction in diseases involving systemic inflammation. The disease with the highest attributable mortality and morbidity due to explosive systemic inflammation is septic shock. In this chapter we use septic shock to illustrate how traditional approaches to therapy have fallen short, and how targeting the microcirculation might be of benefit. Specific therapies are discussed, divided into sections according to their molecular target and mode of action.

Lactic acidosis due to tissue hypoperfusion during hypovolemic shock may depress left ventricular contractility and further reduce the inadequate cardiac output. Bicarbonate has been used to correct the acidemia, yet the effect of this therapy on left ventricular contractility during resuscitation from hypovolemic shock is unknown. Therefore, in 12 anesthetized, mechanically ventilated pigs we measured left ventricular pressure using a Millar catheter and left ventricular volume using three pairs of ultrasonic crystals. Left ventricular contractility was assessed using the endsystolic pressure-volume relationship determined from left ventricular pressure-volume trajectories. Following phlebotomy (40% of the circulating blood volume removed for 4 ± 1 hours) and then reinfusion of all shed blood, six pigs were randomized to receive an infusion of bicarbonate (6 mEq/kg of 1 mol/L NaHCO3) and six control pigs received an equivalent infusion of saline (6 mEq/kg of 1 mol/L NaCl). During hypovolemic shock severe lactic acidosis developed (pH 7.08 ± 0.7, lactate 9.3 ± 4.0 mmol/L) but contractility increased slightly (P ≤ .005). Our main finding is that following reinfusion of all shed blood, bicarbonate (which increased arterial pH to 7.45 ± 0.07; P ≤ .0001) did not improve left ventricular contractility. We conclude that during resuscitation from hypovolemic shock, correction of acidemia using bicarbonate does not increase left ventricular contractility.

The CysGlyGln haplotype of the beta(2)-adrenergic receptor gene (ADRB2) is functional and associated with altered responses to adrenergic agonists in patients with asthma. Whether this functional haplotype alters outcome in patients receiving adrenergic agonists in septic shock is unknown.To determine whether genetic variation of ADRB2 influences outcome in septic shock.Two cohorts of patients with septic shock were studied: a single center (St. Paul's Hospital [SPH]) cohort (n = 589) and the Vasopressin and Septic Shock Trial (VASST) cohort (n = 616). The A allele of the rs1042717 G/A polymorphism is in complete linkage disequilibrium with the CysGlyGln haplotype of ADRB2; therefore, rs1042717 was genotyped. Modulation by norepinephrine and salbutamol of IL-6 production by stimulated in vitro lymphoblastoid cells was measured by genotype.Patients who had the AA genotype of rs1042717 displayed increased 28-day mortality in SPH (adjusted hazard ratio, 2.23; 95% confidence interval, 1.33-3.72; P = 0.0022), and this result was replicated in VASST (adjusted hazard ratio 2.82; 95% confidence interval, 1.56-5.09; P = 0.0006). This genotypic effect was eliminated in patients treated with acute low-dose corticosteroids. In all patients, the AA genotype was associated with more organ dysfunction. Patients with the AA genotype had a higher heart rate (SPH; P0.05; VASST; P0.05) and required a higher norepinephrine dose over Days 1 through 3 (VASST; P0.05). The AA genotype was associated with decreased norepinephrine and salbutamol inhibition of IL-6 production by stimulated lymphoblastoid cells in vitro (P0.05).The AA genotype of ADRB2 rs1042717, identifying homozygotes for the CysGlyGln haplotype, was associated with increased mortality and more organ dysfunction in septic shock.

Vasoactive drugs are the mainstay of hemodynamic management of vasodilatory shock when fluids fail to restore adequate tissue perfusion. In this review, studies published during the past year that increase our understanding of the use of vasoactive drugs in the ICU are discussed.The Vasopressin and Septic Shock Trial did not find a difference between low-dose vasopressin and norepinephrine vs. norepinephrine alone in the hemodynamic support of septic shock, suggesting that either approach is reasonable. However, vasopressin may be beneficial in the less severe septic shock subgroup. In this study, patients who were also treated with corticosteroids, vasopressin, compared with norepinephrine, were associated with significantly decreased mortality. Epinephrine, phenylephrine and terlipressin can be used safely in the ICU setting as first-line therapy for septic shock. The incidence of global left ventricular hypokinesia in patients with septic shock is 60%, much higher than previously described. Although dobutamine remains the gold standard therapy for septic myocardial depression, combined milrinone and metoprolol therapy may be an effective alternative therapy.Current evidence does not support a clear recommendation of one vasopressor over another; indeed norepinephrine, vasopressin, terlipressin, phenylephrine and epinephrine may be used safely with similar survival outcomes.

Preeclampsia is characterized by a systemic inflammatory response involving cytokines, chemokines, and anti-angiogenic factors such as sFLT-1. In many other inflammatory diseases related responses are triggered by toll-like receptor (TLR) stimulation. Therefore, we tested the hypothesis that TLR stimulation of a trophoblast cell line induces inflammatory mediator production and, in particular, production of the preeclampsia-related anti-angiogenic factor sFLT-1.We stimulated human first trimester extravillous trophoblast cells (HTR-8/SV neo cell line) with a variety of TLR ligands and measured downstream NF-kappaB and IRF signaling, inflammatory mediator (RANTES), and sFLT-1 mRNA expression and protein production.Of all TLR ligands, we found that TLR3 ligation with polyI:C resulted in the biggest response with 5.6-fold increased signaling via NF-kappaB and 5.8-fold increased signaling via IRF. RANTES mRNA expression increased 2900 fold and protein production increased 1600 fold in response to TLR3 ligation. sFLT-1 mRNA expression increased 1.7-fold and protein production increased 3.1-fold in response to TLR3 ligation. Inhibitors of the NF-kappaB and IRF signaling pathway decreased TLR3 ligation-induced sFLT-1 protein production by 31.8% and 24.9%, respectively.We conclude that trophoblast cells respond to TLR3 ligation by signaling through both NF-kappaB and IRF pathways resulting in expression of inflammatory mediators and, in particular, the preeclampsia-related anti-angiogenic factor sFLT-1.

For patients undergoing cardiac surgical procedures, there are multiple sources of potential end-organ injury including microgaseous and microparticulate emboli, hypoperfusion, and local and systemic inflammatory processes. These factors are independent of, but potentially synergistic with, further inherent susceptibilities resulting from patient specific co-morbidities. It is also apparent that some patients are more prone to suffer adverse outcomes than others, despite apparently similar risk profiles, giving rise to consideration of genetic susceptibilities. This review will provide a brief overview of genetic studies and the interaction between phenotype and individual patient susceptibilities with a focus on cardiac surgical procedures.

Purpose of review Echocardiography has become more widely available to noncardiologists because of the technological advances in smaller, multipurpose ultrasound units with basic cardiac capabilities. In this review, we discuss the type of clinical information a trained intensivist can hope to obtain from bedside echocardiography and suggest the ways in which this complements traditional hemodynamic monitoring. Recent findings Following a 10-h hands-on course, intensivists are able to perform and interpret a goal-oriented echocardiogram in approximately 10 min with good accuracy. Bedside echocardiography can aid in determining fluid status and qualitative cardiac ejection fraction, which can then be used immediately to guide therapy. Summary Intensivists can safely and accurately perform goal-oriented echocardiography. Although not yet proven to influence clinical outcome, we suggest that the major utility of echocardiography is for those with distributive or mixed shock in whom target central venous pressure has been achieved without evidence of adequate tissue perfusion. In this subset of patients, echocardiography can aid in selecting those most likely to benefit from further fluid or inotropic support.

Background: Cardiac troponins are sensitive and specific biomarkers of myocardial necrosis. Elevated troponin levels have been reported in patients with septic shock. We compared the effects of VP vs NE infusion on troponin, CK and CKMB in adults with septic shock (VASST, NEJM 2008;358:877). Results: 126 patients, mean age 62A?16, APACHE II 29.2A?7.9, 68% male, had troponin, CK and CKMB measured. 5 patients (1 VP, 4 NE) had a clinical diagnosis of myocardial infarction, based on ECG changes and cardiac biomarkers, over the 4 study days. At the 4 time points, 44, 52, 45, and 33% of patients had elevations in troponin, respectively.

Vasodilatory septic shock is characterized by profound vasodilation of the peripheral circulation, relative refractoriness to catecholamines and a relative deficiency of the posterior pituitary hormone, vasopressin. Arginine vasopressin is effective in restoring vascular tone in vasodilatory septic shock and may be associated with decreased mortality in less severe septic shock as well as improved mortality and decreased renal failure in septic shock patients at risk for renal failure.

Rationale: Polymorphisms affecting Toll-like receptor (TLR)–mediated responses could predispose to excessive inflammation during an infection and contribute to an increased risk for poor outcomes in patients with sepsis. Objectives: To identify hypermorphic polymorphisms causing elevated TLR-mediated innate immune cytokine and chemokine responses and to test whether these polymorphisms are associated with increased susceptibility to death, organ dysfunction, and infections in patients with sepsis. Methods: We screened single-nucleotide polymorphisms (SNPs) in 43 TLR-related genes to identify variants affecting TLR-mediated inflammatory responses in blood from healthy volunteers ex vivo. The SNP associated most strongly with hypermorphic responses was tested for associations with death, organ dysfunction, and type of infection in two studies: a nested case–control study in a cohort of intensive care unit patients with sepsis, and a case–control study using patients with sepsis, patients with sepsis-related acute lung injury, and healthy control subjects. Measurements and Main Results: The SNP demonstrating the most hypermorphic effect was the G allele of TLR1−7202A/G (rs5743551), which associated with elevated TLR1-mediated cytokine production (P < 2 × 10−20). TLR1−7202G marked a coding SNP that causes higher TLR1-induced NF-κB activation and higher cell surface TLR1 expression. In the cohort of patients with sepsis TLR1−7202G predicted worse organ dysfunction and death (odds ratio, 1.82; 95% confidence interval, 1.07–3.09). In the case-control study TLR1−7202G was associated with sepsis-related acute lung injury (odds ratio, 3.40; 95% confidence interval, 1.59–7.27). TLR1−7202G also associated with a higher prevalence of gram-positive cultures in both clinical studies. Conclusions: Hypermorphic genetic variation in TLR1 is associated with increased susceptibility to organ dysfunction, death, and gram-positive infection in sepsis.

Bicarbonate therapy for severe lactic acidosis remains a controversial therapy.The most recent 2008 Surviving Sepsis guidelines strongly recommend against the use of bicarbonate in patients with pH at least 7.15, while deferring judgment in more severe acidemia. We review the mechanisms causing lactic acidosis in the critically ill and the scientific rationale behind treatment with bicarbonate.There is little rationale or evidence for the use of bicarbonate therapy for lactic acidosis due to shock. We agree with the Surviving Sepsis guidelines recommendation against the use of bicarbonate for lactic acidosis for pH at least 7.15 and we further recommend a lower target pH of 7.00 or less. If bicarbonate is used, consideration must be given to slow infusion and a plan for clearing the CO2 that is produced and measuring and correcting ionized calcium as the resultant 10% drop may decrease cardiac and vascular contractility and responsiveness to catecholamines. When continuous renal replacement therapy is used during severe acidosis, we recommend bicarbonate-based replacement fluid over citrate as citrate may increase the strong ion gap. Effective therapy of lactic acidosis due to shock is to reverse the cause.

Cardiovascular dysfunction as a result of sepsis is the leading cause of death in the critically ill. Cardiomyocytes respond to infectious pathogens with a Toll-like receptor–initiated proinflammatory response in conjunction with a decrease in contractility, although the downstream events linking Toll-like receptor activation and reduced cardiac contractility remain to be elucidated. Using microarray analysis of cardiac tissue exposed to systemic lipopolysaccharide (LPS), we discovered that 2 small calcium-regulating proteins (S100A8 and S100A9) are highly upregulated. HL-1 cardiomyocytes, isolated primary cardiomyocytes, and live mice were exposed to LPS, whereas beating HL-1 cells had S100A8 and S100A9 overexpressed and their calcium flux quantified. Using in vivo microbubble technology, we delivered S100A8 and S100A9 to normal mouse hearts; using the same technology, we inhibited S100A9 production in mouse hearts and subsequently exposed them to LPS. Coimmunoprecipitation of S100A8 and S100A9 identified interaction with RAGE (the receptor for advanced glycation end products), the cardiac function and postreceptor signaling of which were investigated. HL-1 cardiomyocytes, isolated primary cardiomyocytes, and whole hearts exposed to LPS have large increases in S100A8 and S100A9. Cardiac overexpression of S100A8 and S100A9 led to a RAGE-dependent decrease in calcium flux and, in the intact mouse, to a decreased cardiac ejection fraction, whereas knockdown of S100A9 attenuated LPS-induced cardiac dysfunction. Cardiomyocytes exposed to LPS express S100A8 and S100A9, leading to a RAGE-mediated decrease in cardiomyocyte contractility. This finding provides a novel mechanistic link between circulating pathogen-associated molecular products and subsequent cardiac dysfunction.

Chen et al. found that the CA haplotype of protein C -1654C/T and -1641G/A was associated with increased risk of death and organ dysfunction in Chinese Han patients with severe sepsis (Hum Genet 123:281–287, 2008). We similarly tested for association of the C allele of protein C 673 T/C (rs2069912) (linkage disequilibrium with the CA haplotype, D′ = 100%) in a cohort of 100 North American East Asians with severe sepsis. The C allele was associated with increased mortality and organ dysfunction, consistent with Chen et al.

The management of heart failure has traditionally rested on a paradigm centering on reducing cardiac work load, and more recently on the antagonism of endogenous chronic pathogenic (over)stimulation with stress hormones such as angiotensin, catecholamines, and aldosterone. Depending on the individual patient, cardiac work load is decreased through a combination of modulating the heart rate, contractility, and perhaps most importantly afterload. As the pressure against which the left ventricle must eject is a main determinant of energy expended, afterload reduction has been a foundation of modern therapy. It is thus counterintuitive that in severe heart failure there is a role for agents whose main effect is to increase afterload. There are, however, clinical situations in which acute heart failure coexists with shock states requiring the use of pressor agents. This chapter discusses the pharmacology of the vasopressor agents approved for use and the clinical situations in which they are useful, and offers general recommendations for their use in acute severe heart failure.

Introduction Cardiomyocytes exposed to inflammatory processes express intracellular adhesion molecule-1 (ICAM-1). We investigated whether fibrinogen and fibrinogen degradation products, including D-dimer, could alter cardiomyocyte contractile function through interaction with ICAM-1 found on inflamed cardiomyocytes. Methods In vivo, rats were injected with endotoxin to model systemic inflammation, whereas isolated rat cardiomyocytes were treated with tumor necrosis factor-alpha to model the inflammatory environment seen following exposure to bacterial products such as lipopolysaccharide. Results In vivo, endotoxin administration profoundly decreased cardiac contractile function associated with a large increase in intracardiac ICAM-1 and perivascular fibrinogen. Confocal microscopy with double-staining of isolated rat cardiomyocytes demonstrated colocalization of ICAM-1 and fibrinogen. This interaction was disrupted through pre-treatment of the cells with an ICAM-1-blocking antibody. Functionally, isolated rat cardiomyocyte preparations exhibited decreased fractional shortening when incubated with fibrinogen, and through the use of synthetic peptides, we determined that residues 117–133 of the fibrinogen gamma chain are responsible for this interaction with ICAM-1. Despite having crosslinked gamma chains, D-dimer retained the ability to decrease cardiomyocyte contractility. Conclusion Site 117–133 of the fibrinogen gamma chain is able to depress cardiomyocyte contractility through binding ICAM-1.

OBJECTIVE Fluid resuscitation to improve delivery of oxygen to vital organs is a principal clinical intervention for septic patients. We previously reported that albumin resuscitation in rat endotoxemia improved contractility in isolated cardiomyocytes, but whether this effect occurs in vivo is unknown. We hypothesized that albumin resuscitation would improve decreased ventricular contractility and myocardial tissue oxygenation in vivo. DESIGN Randomized, controlled, prospective animal study. SETTING University animal laboratory. SUBJECTS Male Sprague-Dawley rats (250-350 g). INTERVENTIONS Rats were randomized into three groups: control with no lipopolysaccharide (n = 8), lipopolysaccharide (10 mg/kg) without albumin resuscitation (n = 8), and lipopolysaccharide with albumin resuscitation (n = 6). Five hours after lipopolysaccharide injection, animals were resuscitated with 10 mL/kg 5% rat albumin in 0.9% saline. Six hours after 10 mL/kg lipopolysaccharide, a pressure-volume conductance catheter (MIKRO-Tip 2.0-Fr, Millar Instruments, Houston, TX) was inserted into the left ventricle to quantify maximum elastance as an index of contractility. Myocardial tissue Po2 was measured using a fiberoptic oxygen probe. MEASUREMENTS AND MAIN RESULTS Maximum elastance decreased after lipopolysaccharide relative to control (47%, from 5.9 +/- 0.8 to 3.1 +/- 0.4 mm Hg/microL, p < .05). Albumin resuscitation prevented the lipopolysaccharide-induced decrease in maximum elastance (7.0 +/- 1.2 mm Hg/microL, p < .05 vs. lipopolysaccharide). Myocardial tissue Po2 was reduced in endotoxemia compared with control (53%, from 10.1 +/- 0.9 to 4.7 +/- 0.6 mm Hg, p < .05), and albumin resuscitation improved the lipopolysaccharide-induced tissue hypoxia toward the control value (9.0 +/- 1.4 mm Hg, p < .05). CONCLUSIONS Albumin resuscitation improved decreased ventricular contractility and myocardial oxygenation in endotoxemic rats. This result suggests that albumin resuscitation may improve ventricular dysfunction by improving myocardial hypoxia.

The systemic inflammatory response to infection is the leading cause of mortality in North American intensive-care units. Although much is known about inflammatory mediators, the relationships between microregional inflammation, microvascular heterogeneity, hypoxia, hypoxia-inducible gene expression, and myocardial dysfunction are unknown. Male Sprague-Dawley rats were injected intraperitoneally with LPS to test the hypothesis that sepsis-induced local inflammation and increased microvascular heterogeneity are spatially and temporally associated with hypoxia, hypoxia-inducible gene expression, and decreased left-ventricular contractility. Using a combination of three-dimensional microvascular imaging, tissue Po2, and pressure-volume conductance measurements, we found that 5 h after LPS, minimum oxygen-diffusion distances increased ( P < 0.05), whereas tissue oxygenation and contractility both decreased ( P < 0.05) in the left ventricle. Real-time RT-PCR analysis revealed that the hypoxia-inducible genes hypoxia-inducible factor (HIF)-1α, VEGF, and glucose transporter (GLUT) 1 were all upregulated ( P < 0.05) in the left ventricle. Tissue regions expressing ICAM-1, obtained by using laser-capture microdissection, had increased HIF-1α and GLUT1 ( P < 0.05) gene expression. VEGF gene expression was more diffuse. In LPS rats, GLUT1 gene expression correlated ( P < 0.05) with left-ventricular contractility. In 5-h hypoxic cardiomyocytes, we found strong transient HIF-1α, weak VEGF, and greater prolonged GLUT1 gene expression. By comparison, the HIF-1α-GLUT1 gene-induction pattern was reversed in the left ventricle of LPS rats. Together, these results show that LPS induces hypoxia in the left ventricle associated with increased microvascular heterogeneity and decreased contractility. HIF-1α and GLUT1 gene induction are related to a heterogeneous ICAM-1 expression and may be cardioprotective during the onset of septic injury.

Protein C contains an A/G polymorphism at position -1641 and a C/T polymorphism at -1654 associated with risk of deep venous thrombosis. We tested the hypothesis that these polymorphisms are associated with altered outcome in patients having severe sepsis, in which protein C is a central molecule.Prospective cohorts, gene-association study.Tertiary care medical/surgical intensive care unit.We first recruited a derivation cohort of patients having severe sepsis (n = 62). A second replication cohort was similarly defined but larger (n = 402). We tested for biological plausibility in a third cohort of post-cardiopulmonary bypass patients (n = 61).Patients were genotyped at protein C -1641 and -1654.The primary outcome variable was survival in cohorts 1 and 2 and postoperative serum interleukin-6 concentration in cohort 3. Severity of individual organ dysfunctions and systemic inflammation were secondary outcome variables. In the first derivation cohort, the protein C -1641 AA genotype was associated with decreased 28-day survival (p.05). This finding was confirmed in the much larger replication cohort of patients having severe sepsis (p = .028). In addition, the protein C -1641 AA genotype was associated with significantly more organ dysfunction and more clinical evidence of systemic inflammation (p.05). Furthermore, the -1641 AA genotype was associated with increased serum interleukin-6 at 4 and 24 hrs after cardiopulmonary bypass (p = .024). There was no association of -1654 A/G with phenotype in any cohort.Protein C -1641 AA genotype is associated with decreased survival, more organ dysfunction, and more systemic inflammation in patients having severe sepsis and with increased interleukin-6 levels after cardiopulmonary bypass surgery.

Objective: The transmembrane receptor family of Toll-like receptors (TLRs) may play a role in initiating early inflammatory and functional responses to danger signals arising from ischemia-reperfusion and inflammatory stimuli. We determined whether Toll-like receptors are expressed in cardiac tissue and whether stimulation with cognate ligands would result in a pro-inflammatory response and decreased cardiomyocyte contractility. Methods and results: We observed mRNA expression of TLR2, TLR3, TLR4, TLR5, TLR7 and TLR9 in both whole heart tissue and a murine cardiomyocyte cell line (HL-1). Ligand activation of TLR2, TLR4 and TLR5, but not TLR3, TLR7 or TLR9, resulted in cardiomyocyte expression of the inflammatory cytokine IL-6, the chemokines KC and MIP-2, and the cell surface adhesion molecule ICAM-1. Activation of these Toll-like receptors was associated with decreased cardiomyocyte contractility. Using transfection of a nuclear factor kappa B (NF-κB)-Luciferase reporter plasmid, we found significantly increased NF-κB transcriptional activity in response to TLR2, TLR4 and TLR5 activation in cardiomyocytes. Further, a chemical inhibitor of NF-κB, pyrrolidine dithiocarbamate (PDTC), as well as transfection using a dominant negative form of IKKβ, resulted in profound reduction of the TLR-initiated pro-inflammatory response. Conclusions: Cardiomyocytes express most known Toll-like receptors. Of these, TLR2, TLR4 and TLR5 signal via NF-κB, resulting in decreased contractility and a concerted inflammatory response.

Summary Objectives Fibrinogen plays a key role in coagulation and inflammation. Transcription of the fibrinogen-beta gene ( FGB ) is the rate-limiting step in fibrinogen production. Our aim was to determine whether haplotypes of FGB are associated with mortality and organ dysfunction in a cohort of patients with sepsis. Methods A prospective cohort of 631 consecutive Caucasian patients with sepsis from a tertiary care medical–surgical ICU were enrolled in a gene association study. Patients were genotyped for three polymorphisms in FGB : −854 G/A, −455 G/A, and +9006 G/A. Haplotypes were inferred using PHASE. The primary outcome was mortality. Secondary outcomes were severity of organ dysfunction as measured by days alive and free (DAF) of organ dysfunction. Results Haplotype GAA was associated with a significantly lower 28-day mortality (28.9% vs. 36.9% for all other haplotypes, p =0.03). Carriers of two copies of haplotype GAA (vs. one and zero copies) had more DAF of organ dysfunction. In a multivariate analysis, haplotype GAA was an independent predictor for lower mortality (OR=0.66, 95% CI=0.46–0.94, p =0.02). Conclusions Haplotype GAA in FGB is associated with lower mortality and lower severity of organ dysfunction. Haplotype GAA encompasses a previously described haplotype −1420A/−854G/−455A/−249C/−148T/+1690G that is associated with higher fibrinogen levels.

Microvascular permeability is a serious complication of systemic inflammation in critically ill patients; yet, no direct techniques exist to quantify this in vivo. To overcome this limitation, we investigated the use of multiphoton microscopy to evaluate fluorescent macromolecular gradients in the eye. Following the induction of systemic inflammation in a CD1 mouse, a bolus of high (250 KD FITC-dextran) and low (70 KD rhodamine-dextran) molecular weight fluorescent macromolecules was injected via the tail vein. The anesthetized mouse was positioned in such a way that different microvessels in the eye could be imaged directly using an upright microscope. The fluorophores were simultaneously excited at 840nm and a series of images including a spectral scan (480 to 680nm), an xt line scan (96 lines) and an x,y,z image stack were collected from the iris, cornea and limbal plexus at one hour intervals for four hours. A simple fluorescent gradient across the vessel wall was used as an index of microvascular permeability. In all microvessels, the LMW dye was more permeable. We found that the fluorescent gradient increased dramatically in the limbal plexus up to three hours then declined. This may indicate that circulating fluid pooled near the limbal plexus. Consistent with the thick walls and tight junctions of the iris microvessels, no significant fluorescent gradients were detected in this area. The cornea, containing a collagen filled stroma layer, was found to have both lateral and perpendicular fluorescent gradients. This work demonstrates that inflammation causes differential microvascular permeability in the mouse eye.

Sepsis causes microvascular dysfunction. Increased heterogeneity of capillary blood flow results in local tissue hypoxia, which can cause local tissue inflammation, impaired oxygen extraction, and, ultimately, organ dysfunction. Microvascular dysfunction is clinically relevant because it is a marker for mortality: it improves rapidly in survivors of sepsis but fails to improve in nonsurvivors. This, along with the fact that resuscitation of mean arterial pressure and cardiac output alone fails to improve microvascular function, means that microvascular resuscitation is therefore a therapeutic goal. In animal studies of sepsis, volume resuscitation improves microvascular permeability and tissue oxygenation, and leads to improved organ function, including a reduction in myocardial dysfunction. Microvascular resuscitation strategies include hemodynamic resuscitation using the linked combination of volume resuscitation, judicious vasopressor use, and inotropes and vasodilators. Alternative vasoactive agents, such as vasopressin, may improve microcirculatory function to a greater degree than conventional vasopressors. Successful modulation of inflammation has a positive impact on endothelial function. Finally, targeted treatment of the endothelium, using activated protein C, also improves microvascular function and ultimately increases survival. Thus, attention must be paid to the microcirculation in patients with sepsis, and therapeutic strategies should be employed to resuscitate the microcirculation in order to avoid organ dysfunction and to reduce mortality.