Biomedical subjects

Jean-Louis Vincent

Publications and source records attributed to Jean-Louis Vincent.

At least 145 records · Page 8Linked to original sources

PubMed2003

Does aprotinin influence the inflammatory response to cardiopulmonary bypass in patients?

OBJECTIVES: Aprotinin has been shown to have anti-inflammatory properties, but its effects on the inflammatory reaction to cardiopulmonary bypass remain controversial. This prospective, randomized, double-blind study evaluated the influence of aprotinin on various blood markers of inflammation during and after cardiopulmonary bypass. METHODS: Sixty male patients underwent coronary artery bypass grafting. The patients were randomized into 3 groups: a placebo group, a second group receiving 2,000,000 KIU of aprotinin followed by an infusion of 500,000 KIU/h and 2,000,000 KIU in the pump prime, and a third group receiving half this dosage. Measurements of tumor necrosis factor, interleukin 6, interleukin 8, interleukin 10, endotoxin, histamine, complement factors, prekallikrein, and prostaglandin D(2) were obtained at baseline, 30 minutes after study drug loading, 10 minutes after the beginning of cardiopulmonary bypass, before the end of bypass, 4 hours after bypass, and on the first and second postoperative days. RESULTS: Aprotinin had no significant effect on any of these parameters. As expected, aprotinin reduced early blood loss in both treated groups. CONCLUSIONS: These results indicate that aprotinin at doses currently used to reduce blood loss has no significant influence on the systemic inflammatory response during moderate hypothermic cardiopulmonary bypass in human subjects, as assessed by the mediators measured in this study.

Aprotinin↗

PubMed2003

Acute barium intoxication and hemodiafiltration.

We report a case of severe hypokalemia and flaccid muscle paralysis following a suicide attempt associating the calcium channel blocker amlodipine, the antidepressant fluoxetine and barium carbonate. Despite rapid correction of severe, life-threatening hypokalemia, areflexic quadriplegia persisted, suggesting a direct effect of barium on muscle cells. Continuous veno-venous hemodiafiltration (CVVHDF) was initiated. We determined barium concentration in the urine, plasma, and hemodiafiltrate during CVVHDF. We subsequently calculated the amounts of barium eliminated both by the CVVHDF and the kidneys. CVVHDF triples the measured barium elimination, reduced serum barium half-life by a factor of three, stabilized serum potassium levels, and rapidly improved motor strength, with complete neurological recovery within 24 h. Presentation and treatment of barium intoxication are discussed.

Amlodipine↗

PubMed2003

Optimal adrenergic support in septic shock due to peritonitis.

BACKGROUND: The authors evaluated optimal adrenergic support using norepinephrine, dopamine, and dobutamine in a clinically relevant model of septic shock. METHODS: Twenty-eight mature, female, anesthetized sheep (weight, 30.5 +/- 3.6 kg) underwent cecal ligation and perforation and were randomized into four groups of seven animals to be treated with norepinephrine, dopamine-norepinephrine, dobutamine-norepinephrine, or no adrenergic agent. In all groups, lactated Ringer's solution was administered to restore cardiac filling pressures to baseline. In the norepinephrine group, norepinephrine (0.5-5 microg. kg(-1). min(-1)) was titrated to maintain mean arterial pressure between 75-85 mmHg. In the dopamine-norepinephrine group, dopamine was given first, and norepinephrine was added only when mean arterial pressure remained below 75 mmHg despite the infusion of 20 microg. kg(-1). min(-1) dopamine. In the dobutamine-norepinephrine group, dobutamine was started at the same time as norepinephrine and titrated up to 20 microg. kg(-1). min(-1) to get a 15% increase in cardiac output. RESULTS: The dobutamine-norepinephrine group had greater cardiac output; superior mesenteric blood flow, oxygen delivery (Do(2)), and oxygen consumption ([OV0312]o(2)); and lower blood lactate concentration and partial pressure of carbon dioxide (Pco(2)) gap than the controls did. Cumulative urine output was significantly higher in the dobutamine-norepinephrine group than in the other groups. Survival time was significantly longer in the dobutamine-norepinephrine (24 +/- 4 h), dopamine- norepinephrine (24 +/- 6 h), and norepinephrine (20 +/- 1 h) groups than the control group (17 +/- 2 h; P < 0.05 vs. other groups), and significantly longer in the combined dopamine-norepinephrine and dobutamine-norepinephrine groups (24 +/- 5 h) than in the norepinephrine alone group (P < 0.05). Histologic examination of lung biopsies revealed less severe lesions in the dobutamine-norepinephrine group than in the control and norepinephrine alone groups. Anatomic alterations in the lung, liver, and small intestine were less severe in the dobutamine-norepinephrine group than in the other groups. CONCLUSIONS: In this prolonged septic shock model, association of norepinephrine with either dopamine or dobutamine resulted in the longest survival and the least severe pulmonary lesions. The combination of dobutamine with norepinephrine was associated with a better myocardial performance, greater Do(2) and [OV0312]o(2), lower blood lactate concentration and Pco(2) gap, and less anatomic injury.

Adrenergic Agents↗

PubMed2003

Tolerance to acute isovolemic hemodilution. Effect of anesthetic depth.

BACKGROUND: Acceptance of a lower transfusion trigger in the perioperative period requires study of the effects of anesthetic depth on the tolerance to acute isovolemic anemia. Anesthetic agents with negative effects on the cardiovascular system may exert proportionately greater depressant effects on cardiac output response than on tissue oxygen demand, reducing tolerance to acute isovolemic anemia. METHODS: In the first study, animals were anesthetized with halothane (n = 14; 23.8 +/- 4.8 kg, mean +/- SD). In a second study, animals were anesthetized with ketamine (n = 14; 24.3 +/- 4.7 kg). In each study, dogs were randomly allocated to receive either low or high concentrations of anesthetic. Oxygen delivery and oxygen consumption were determined from independent measurements during a stepwise isovolemic hemodilution protocol. In each dog, critical oxygen delivery was determined from a plot of oxygen consumption versus oxygen delivery using a least-sum-of-squares technique. Critical hemoglobin (hemoglobin) was determined from a plot of hemoglobin versus oxygen consumption using the same method. RESULTS: With both agents, the higher anesthetic concentration was associated with decreased oxygen consumption, resulting in a lower critical oxygen delivery. However, critical hemoglobin was significantly higher in the animals receiving the higher anesthetic dosage (1.5 vs. 1.0 minimum alveolar concentration of halothane: 4.1 +/- 1.3 vs. 2.3 +/- 0.5 g/dl, P < 0.05; high- vs. low-dose ketamine: 3.7 +/- 1.4 vs. 2.5 +/- 0.6 g/dl, P < 0.05). This was related to a marked blunting of the cardiac output response to hemodilution in the animals receiving the higher anesthetic dosage. CONCLUSIONS: Increased anesthetic depth with halothane or ketamine resulted in a decreased tolerance to acute anemia, as reflected by a significant increase in critical hemoglobin concentration.

Anemia↗

PubMed2003

Infection in critically ill patients: clinical impact and management.

PURPOSE OF REVIEW: The aim of this review is to summarize recent developments in the epidemiology, diagnosis and management of infection in critically ill patients. RECENT FINDINGS: New definitions of sepsis, including a grading system, similar to the tumor, node, metastasis system for cancer, have been suggested and are being developed. In terms of epidemiology, sepsis remains an important cause of morbidity and mortality among the critically ill, but the last couple of years have seen the development and licensing of a new immunomodulatory agent, drotrecogin-alpha (activated) that reduces mortality. Moderate doses of steroids have also been shown to improve outcomes for patients with septic shock. SUMMARY: Improved characterization of septic patients will help target and monitor new therapies. Newly developed immunomodulatory strategies and others currently undergoing clinical testing will help reduce the high mortality rates seen in this disease

Anti-Infective Agents↗

PubMed2003

Cost-effectiveness of drotrecogin alfa (activated) in the treatment of severe sepsis.

OBJECTIVE: To assess the cost-effectiveness of drotrecogin alfa (activated) therapy, which was recently shown to reduce mortality in severe sepsis. DESIGN: Estimates of effectiveness and resource use were based on data collected prospectively as part of a multicenter international trial. Estimates of hospital costs were based on a subset of the patients treated in the United States (33% of all enrolled patients). Lifetime projections were modeled from published sources and tested in sensitivity analyses. Analyses were conducted from the United States societal perspective, limited to healthcare costs, and using a 3% annual discount rate. SETTING: A total of 164 medical institutions in 11 countries. PATIENTS: Adults > or = 18 yrs of age with severe sepsis INTERVENTIONS: Eligible patients were randomly assigned to receive a 96-hr intravenous infusion of drotrecogin alfa (activated) at 24 microg/kg/hr (n = 850) or placebo (n = 840). MEASUREMENTS AND MAIN RESULTS: Base Case: incremental short-term (days 1-28) healthcare costs per day-28 survivor; Panel on Cost-Effectiveness in Health and Medicine Reference Case: incremental lifetime healthcare costs per quality-adjusted life-year. Over the first 28 days (short-term Base Case), drotrecogin alfa (activated) increased the costs of care by $9,800 and survival by 0.061 lives saved per treated patient. Thus, drotrecogin alfa (activated) cost $160,000 per life saved (with 84.7% probability that ratio is <$250,000 per life saved). Projected to lifetime (lifetime Reference Case), drotrecogin alfa (activated) increased the costs of care by $16,000 and quality-adjusted survival by 0.33 quality-adjusted life-years per treated patient. Thus, drotrecogin alfa (activated) cost $48,800 per quality-adjusted life-year (with 82% probability that ratio is <$100,000 per quality-adjusted life-year). Estimates were generally robust to sensitivity analyses, although cost-effectiveness deteriorated to >$100,000 per quality-adjusted life-year if survivors lived <4.6 yrs on average. Drotrecogin alfa (activated) cost $27,400 per quality-adjusted life-year when limited to patients with an Acute Physiology and Chronic Health Evaluation II score > or = 25 and was cost-ineffective when limited to patients with a score <25. CONCLUSIONS: Drotrecogin alfa has a cost-effectiveness profile similar to that of many well-accepted healthcare strategies and below commonly quoted thresholds.

Adult↗

PubMed2003

Drotrecogin alfa (activated) administration across clinically important subgroups of patients with severe sepsis.

OBJECTIVE: To assess the effects of drotrecogin alfa (activated) therapy, a recombinant human activated protein C, across clinically relevant subpopulations in a randomized, phase 3, placebo-controlled study of patients with severe sepsis (recombinant human activated protein C worldwide evaluation in severe sepsis [PROWESS]). DESIGN: Univariate and multivariable analysis of prospectively defined subgroups from the PROWESS study. SETTING: A total of 164 medical centers in 11 countries. PATIENTS: A total of 1,690 patients with severe sepsis. MEASUREMENTS AND MAIN RESULTS: We report observed 28-day mortality rates for drotrecogin alfa (activated) and placebo patients for subgroups prospectively defined by demographic data, surgical status, type and site of infection, and clinical and biochemical measures of disease severity. We performed subgroup analyses to explore the consistency of the mortality benefit observed in the overall population and performed tests for both quantitative and qualitative interactions. To examine the magnitude of the treatment benefit with drotrecogin alfa (activated) across the underlying predicted risk of mortality spectrum, we used stepwise logistic regression on PROWESS placebo patients to generate a predicted risk of mortality model that simultaneously included many clinical and biochemical markers of mortality risk. Because drotrecogin alfa (activated) has anticoagulant properties, we also present analyses of bleeding and thrombotic events. Actual mortality rates were lower with drotrecogin alfa (activated) compared with placebo for nearly all prospectively defined subgroups. Both univariate and multivariable regression analyses showed a consistent relative risk reduction in 28-day mortality rates for drotrecogin alfa (activated). Larger absolute risk reductions were found with drotrecogin alfa (activated) in patients with a higher baseline predicted risk of mortality, and actual mortality rates were lower with drotrecogin alfa (activated) in all subgroups defined by disease severity measures where a > or = 20% placebo mortality was observed. Although discriminatory power was limited by few observed events, the increased absolute risk of experiencing a serious bleeding event with treatment did not seem to vary according to the baseline predicted risk of mortality. CONCLUSIONS: The administration of drotrecogin alfa (activated) to patients with severe sepsis was associated with a significant survival benefit that tended to increase with higher baseline likelihood of death. Current data suggest that the increased risk of bleeding does not vary according to likelihood of death.

APACHE↗

PubMed2003

Monocyte CD40 expression in severe sepsis.

D40 is a cell surface protein belonging to the tumor necrosis factor (TNF) receptor family. Ligation of monocyte CD40 by the T cell-derived CD40 ligand can trigger the production of various mediators, the transcription and activation of enzymes, and the upregulation of costimulatory molecules involved in the pathogenesis of sepsis. To test the hypothesis that CD40 is expressed on the surface of monocytes during sepsis, we measured CD40 expression by flow cytometry on freshly sampled monocytes from 40 patients with severe sepsis, including 15 patients with bacteremia, and from eight healthy volunteers. Plasma concentrations of interleukin (IL) 6, IL-10, and IL-13 were also measured. We detected CD40 only on monocytes from patients with sepsis (mean 6.5 +/- 0.4 median channel fluorescence). There was an inverse correlation between peak CD40 expression and survival (P = 0.05), particularly in the patients with bacteremia (P = 0.019). In the bacteremic group, there was an inverse correlation between CD40 expression and bilirubin levels (r2 = 0.52, P = 0.004) and plasma IL-6 concentrations (r2 = 0.30, P = 0.04). Our results showed that upregulation of CD40 expression on peripheral blood monocytes is a protective phenomenon during severe sepsis. Monocyte deactivation reflected by low CD40 expression may represent impairment of immune function associated with severity of illness and poor outcome. Further studies on monocyte phenotype and function may help to assess the immune status of patients with sepsis and perhaps be useful to guide immunomodulatory strategy in the future.

Adult↗

PubMed2003

Impairment of beta-adrenergic signaling in healthy peripheral blood mononuclear cells exposed to serum from patients with septic shock: involvement of the inhibitory pathway of adenylyl cyclase stimulation.

The objective of this study was to determine whether the serum of patients with sepsis could alter the capability of healthy human peripheral blood mononuclear cells (PBMC) to synthesize cAMP in response to beta-adrenergic stimulation and to evaluate the involvement of the inhibitory pathway (Gi) of adenylyl cyclase in the sepsis-induced alteration of beta-adrenergic signaling. First, PBMC from a healthy donor were incubated for 24 h in serum-containing medium according to three culture conditions: serum alone, serum with pertussis toxin, and serum with propranolol. Second, PBMC were stimulated with 10(-5) M isoproterenol or 10(-6) M forskolin, and measurement of cyclic adenosine monophosphate (cAMP) intracellular accumulation was performed. Serum samples were obtained from three groups of subjects: 14 patients with severe sepsis, 21 patients with septic shock, and 10 healthy control subjects. Basal and forskolin-stimulated cAMP levels were similar in PBMC cultured in control or in septic serum. Isoproterenol-stimulated accumulation was reduced in PBMC preincubated in septic serum. The lowest cAMP levels were found after exposure to serum from patients with septic shock. The addition of pertussis toxin in the incubation medium constantly increased cAMP response to isoproterenol, but more significantly in PBMC exposed to septic serum. Incubation in the presence of propranolol had no significant effect. The serum of patients with sepsis contained soluble depressant substances that inhibited adenylyl cyclase activation by beta-adrenergic agonists. Septic shock serum exhibited the most potent inhibitory effect. Hyperactivation of the Gi pathway of adenylyl cyclase was mainly responsible for the altered transmembrane beta-adrenergic signaling.

Adenylyl Cyclases↗

PubMed2003

Hemodynamic effects of glibenclamide during endotoxemia: contrasting findings in vitro versus in vivo.

The final common pathway involved in the cardiovascular alterations of septic shock is incompletely defined. The opening of KATP channels is associated with vasorelaxation and alterations in cardiac contractility. This event may be triggered during septic shock by increased nitric oxide (NO) production, by a decreased intracellular content of ATP, or by a change in the transmembrane electrical potential. In the present study, we assessed the effects of glibenclamide, an agent that blocks the opening of KATP channels in vitro, on the contractile response of rat aortic rings to norepinephrine, and in vivo in anesthetized dogs, with or without exposure to Escherichia coli endotoxin. In vitro, glibenclamide decreased the contractile response to norepinephrine in the presence of endotoxin, provided that the endothelium was intact. In vivo, administration of 0.15 mg/kg increased systemic vascular resistance (SVR) in the absence of endotoxin only, and increased myocardial performance. A higher dose of 1 mg/kg increased SVR and decreased myocardial performance, both during endotoxic shock and in control conditions. Renal and mesenteric blood flows decreased, but the respective fractional flows were unchanged. Oxygen delivery decreased in both experimental conditions, but oxygen consumption decreased only in control conditions. The in vitro observations suggest that the opening of KATP channels is involved in the regulation of vascular tone during endotoxemia, via an endothelium-dependent mechanism. As different effects of glibenclamide were observed in vivo, the importance of the opening of KATP channels in endotoxic shock may be limited.

Animals↗

PubMed2003

Time course of hemoglobin concentrations in nonbleeding intensive care unit patients.

OBJECTIVES: To evaluate the time course of hemoglobin concentrations in nonbleeding intensive care unit patients. DESIGN: Prospective, observational study. SETTING: Multidisciplinary (medicosurgical) department of intensive care. PATIENTS: Ninety-one patients with no evidence of recent or active blood loss, no history of hematologic disease or chronic renal failure, and no need for extracorporeal epuration techniques. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Data collection included primary diagnoses, Acute Physiology and Chronic Health Evaluation II and sepsis-related organ failure assessment scores, signs of sepsis, 24-hr fluid balance, and hemoglobin concentrations. For the entire intensive care unit stay, the fall in hemoglobin concentrations (calculated from the mean of individual slopes of hemoglobin concentrations over time) averaged 0.52 +/- 0.69 g/dL/day. For the 33 patients who stayed in the intensive care unit for >3 days, this decline was larger for the first 3 days than for subsequent days (0.66 +/- 0.84 g/dL/day vs. 0.12 +/- 0.29 g/dL/day; p<.01). After the third intensive care unit day, the change in hemoglobin concentrations was inversely related to the severity of the disease, as reflected by the Acute Physiology and Chronic Health Evaluation II and the sepsis-related organ failure assessment scores. Hemoglobin concentrations decreased by 0.44 +/- 0.70 g/dL/day in the nonseptic and 0.68 +/- 0.66 g/dL/day in the septic patients (p =.13). After the third intensive care unit day, hemoglobin concentrations continued to decrease in the septic patients but not in the nonseptic patients (-0.29 +/- 0.19 vs. 0.006 +/- 0.3 g/dL/day; p=.0016). The fall in hemoglobin concentrations was not significantly related to the fluid balance. The volume of blood drawn daily for laboratory studies was 40.3 +/- 15.4 mL: 49.0 +/- 11.3 mL in the septic patients and 36.7 +/- 14.9 mL in the nonseptic patients (p =.04). CONCLUSIONS: Hemoglobin concentrations typically decline by >0.5 g/dL/day during the first days of intensive care unit stay in nonbleeding patients. Beyond the third day, hemoglobin concentrations can remain relatively constant in nonseptic patients but continue to decrease in septic patients, as well as patients with high sepsis-related organ failure assessment or Acute Physiology and Chronic Health Evaluation II scores. These observations may help in the interpretation of hemoglobin concentrations in critically ill patients.

Critical Care↗

PubMed2003

Multicenter, double-blind, placebo-controlled study of the use of filgrastim in patients hospitalized with pneumonia and severe sepsis.

OBJECTIVE: To determine the safety and efficacy of filgrastim (r-metHuG-CSF) in combination with intravenous antibiotics to reduce the rate of mortality in patients with pneumonia and sepsis. DESIGN: This study was multicenter, double-blind, and randomized. SETTING: Intensive care units PATIENTS Adult patients with bacterial pneumonia, either acquired or nosocomial, as confirmed by chest radiograph and positive culture or Gram-negative stain, and severe sepsis, defined as sepsis-induced hypotension or organ dysfunction. INTERVENTIONS: Standard antibiotic therapy with or without filgrastim (300 microg/day) or placebo administered as a 30-min intravenous infusion. The study drug was started within 24 hrs of enrollment and was continued for 5 days or until the white blood cell count reached >75.0 x 10(9) cells/L. MEASUREMENTS AND MAIN RESULTS: The primary end point was the occurrence of mortality through day 29; secondary end points included occurrence of subsequent organ dysfunction, time to discharge from intensive care unit, number of days on mechanical ventilatory support, and time to death. Study-related observations were recorded through day 10 and included vital signs, onset of organ dysfunction, clinical laboratory variables, and adverse events. Filgrastim increased the white blood cell count to a median peak of 31.7 x 10(9) cells/L from a baseline of 12.3 x 10(9) cells/L. The two groups were well matched and did not differ significantly with regard to severe adverse events, time to death, occurrence of end-organ dysfunction, days of intensive care unit hospitalization, or days on mechanical ventilatory support. Mortality was low in both treatment groups; the mortality rate in patients with adult respiratory distress syndrome was similar between the two groups. CONCLUSIONS: The addition of filgrastim to the antibiotic and supportive care treatment of patients with pneumonia complicated by severe sepsis appeared to be safe, but not efficacious in reducing mortality rates or complications from this infection.

Adolescent↗

PubMed2003

2001 SCCM/ESICM/ACCP/ATS/SIS International Sepsis Definitions Conference.

OBJECTIVE: In 1991, the American College of Chest Physicians (ACCP) and the Society of Critical Care Medicine (SCCM) convened a "Consensus Conference," the goals of which were "to provide a conceptual and a practical framework to define the systemic inflammatory response to infection, which is a progressive injurious process that falls under the generalized term 'sepsis' and includes sepsis-associated organ dysfunction as well." The general definitions introduced as a result of that conference have been widely used in practice and have served as the foundation for inclusion criteria for numerous clinical trials of therapeutic interventions. Nevertheless, there has been an impetus from experts in the field to modify these definitions to reflect our current understanding of the pathophysiology of these syndromes. DESIGN: Several North American and European intensive care societies agreed to revisit the definitions for sepsis and related conditions. This conference was sponsored by the SCCM, The European Society of Intensive Care Medicine (ESICM), The American College of Chest Physicians (ACCP), the American Thoracic Society (ATS), and the Surgical Infection Society (SIS). METHODS: The conference was attended by 29 participants from Europe and North America. In advance of the conference, five subgroups were formed to evaluate the following areas: signs and symptoms of sepsis, cell markers, cytokines, microbiologic data, and coagulation parameters. The subgroups corresponded electronically before the conference and met in person during the conference. A spokesperson for each group presented the deliberation of each group to all conference participants during a plenary session. A writing committee was formed at the conference and developed the current article based on executive summary documents generated by each group and the plenary group presentations. The present article serves as the final report of the 2001 International Sepsis Definitions Conference. CONCLUSION: This document reflects a process whereby a group of experts and opinion leaders revisited the 1992 sepsis guidelines and found that apart from expanding the list of signs and symptoms of sepsis to reflect clinical bedside experience, no evidence exists to support a change to the definitions. This lack of evidence serves to underscore the challenge still present in diagnosing sepsis in 2003 for clinicians and researchers and also provides the basis for introducing PIRO as a hypothesis-generating model for future research.

Humans↗

PubMed2003

Effects of drotrecogin alfa (activated) on organ dysfunction in the PROWESS trial.

OBJECTIVE: To assess morbidity in patients with severe sepsis managed with and without drotrecogin alfa (activated). DESIGN: Analysis of secondary end points in a prospective, randomized, double-blind, placebo-controlled, multicenter, phase 3 trial (PROWESS). SETTING: A total of 164 medical institutions in 11 countries. PATIENTS: A total of 1,690 consecutive adult patients with severe sepsis. INTERVENTIONS: A 96-hr infusion of drotrecogin alfa (activated) (human recombinant activated protein C) or placebo. MEASUREMENTS AND MAIN RESULTS: Sequential Organ Failure Assessment (SOFA) scores for cardiovascular, respiratory, renal, hematologic, and hepatic organ systems were measured for 28 days. Mean cardiovascular SOFA scores were significantly lower for patients treated with drotrecogin alfa (activated) compared with placebo patients over this time period (p = .022). Drotrecogin alfa (activated)-treated patients also showed significantly faster resolution of cardiovascular (p = .009) and respiratory (p = .009) dysfunction and significantly slower onset of hematologic organ dysfunction (p = .041) compared with placebo patients for days 1 to 7. No significant differences in morbidity were observed between treatment groups among 28-day survivors. CONCLUSION: Drotrecogin alfa (activated) demonstrated significant improvements in organ function compared with placebo in a large phase 3 clinical trial that has shown a mortality benefit in patients with severe sepsis.

APACHE↗

PubMed2003

Comparison of polyacrylonitrile (AN69) and polysulphone membrane during hemofiltration in canine endotoxic shock.

OBJECTIVE: This study was designed to compare the effects of continuous venovenous hemofiltration (CVVH) with two different membranes, polysulphone and polyacrylonitrile (AN69), on global and regional hemodynamics, plasma lactate, tumor necrosis factor-alpha levels, and plasma nitrite/nitrate during endotoxic shock in dogs. METHODS: Fifteen pentobarbital anesthetized and mechanically ventilated dogs were randomized into three groups of five dogs each. One group served as an endotoxin alone, time matching group and, 1 hr after endotoxin administration, the two other groups received CVVH at 3 L/hr for 270 mins, with either a polysulphone membrane or an polyacrylonitrile membrane. RESULTS: At 90 mins after endotoxin administration, dogs receiving CVVH with polyacrylonitrile membranes had a higher cardiac output, stroke volume, and left-ventricular stroke work index than the endotoxin alone and the polysulphone groups. CVVH with either polyacrylonitrile or polysulphone membranes prevented the rise in pulmonary artery pressure and pulmonary vascular resistance compared with the endotoxin alone group. Plasma lactate levels were not significantly altered, but the fall in bicarbonate seen in the endotoxin alone group did not occur in the two CVVH groups. Tumor necrosis factor levels in the plasma were not significantly altered by CVVH and remained very low (<50 pg/mL) in the ultrafiltrate fluid. CONCLUSION: In this acute endotoxic shock model, CVVH with the polyacrylonitrile membrane improved cardiac performance when compared with the polysulphone membrane. These effects could be caused by a more effective adsorption of inflammatory mediators other than tumor necrosis factor. Whether the polyacrylonitrile membrane should be preferred over the polysulphone membrane for CVVH in severe sepsis warrants further experimental and clinical study.

Acrylic Resins↗

PubMed2003

Development of ionized hypomagnesemia is associated with higher mortality rates.

OBJECTIVE: Previous studies have shown a wide variation in the prevalence of total serum hypomagnesemia in intensive are unit (ICU) patients and in associated mortality rates. As the ionized part of magnesium is the active portion, we sought to define the prevalence of ionized hypomagnesemia in critically ill patients and to evaluate its relationship with organ dysfunction, length of stay, and mortality. DESIGN: Prospective observational study. SETTING: A 31-bed, medical-surgical, university hospital ICU. PATIENTS: A total of 446 consecutive patients admitted to the ICU over a 3-month period. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The ionized magnesium level (normal value, 0.42-0.59 mmol/L) was measured at admission and then every day until discharge from the ICU. At admission, 18% of patients had ionized hypomagnesemia, 68% had normal ionized magnesium levels, and 14% had ionized hypermagnesemia. There was no significant difference in the length of stay or in the mortality rate between these three groups of patients. Hypomagnesemic patients more frequently had total and ionized hypocalcemia, hypokalemia, and hypoproteinemia. A total of 23 patients developed ionized hypomagnesemia during their ICU stay; these patients had higher Acute Physiology And Chronic Health Evaluation II (14.9 +/- 5.4 vs. 11.0 +/- 6.2) and Sequential Organ Failure Assessment (SOFA; 7.1 +/- 5.4 vs. 3.9 +/- 2.8) scores at admission (p <.01 for both), a higher maximum SOFA score during their ICU stay (10.0 +/- 5.6 vs. 4.4 +/- 3.2, p <.01), a higher prevalence of severe sepsis and septic shock (57 vs. 11%, p <.01), a longer ICU stay (15.4 +/- 15.5 vs. 2.8 +/- 4.7 days, p <.01), and a higher mortality rate (35% vs. 12%, p <.01) than the other patients. The major risk factors for developing hypomagnesemia during the ICU stay were a prolonged ICU stay, treatment with diuretics, and sepsis. CONCLUSION: Development of ionized hypomagnesemia during an ICU stay is associated with a worse prognosis. It is often associated with the use of diuretics and the development of sepsis. Monitoring of ionized magnesium levels may have prognostic, and perhaps therapeutic, implications.

APACHE↗

PubMed2003

Effects of dopamine, norepinephrine, and epinephrine on the splanchnic circulation in septic shock: which is best?

OBJECTIVE: To assess the effects of different doses of dopamine, norepinephrine, and epinephrine on the splanchnic circulation in patients with septic shock. DESIGN: Prospective, randomized, open-label study. SETTING: A 31-bed, medicosurgical intensive care unit of a university hospital. PATIENTS: Convenience sample of 20 patients with septic shock, separated into two groups according to whether (moderate shock group, n = 10) or not (severe shock, n = 10) dopamine alone was able maintain mean arterial pressure >65 mm Hg. INTERVENTIONS: Dopamine was progressively withdrawn and replaced successively by norepinephrine and then epinephrine (the order of the two agents was randomly determined) to maintain mean arterial pressure constant (moderate shock) or to increase mean arterial pressure above 65 mm Hg (severe shock). MEASUREMENTS AND MAIN RESULTS: Systemic circulation (pulmonary artery catheter) and splanchnic circulation (indocyanine green dilution and hepatic vein catheter) and gastric mucosal Pco(2) (gas tonometry) were measured during dopamine (moderate shock only), norepinephrine, and epinephrine administration (both groups). Data were analyzed with nonparametric tests and are presented as median [percentiles 25-75]. In moderate shock, cardiac index was similar to dopamine and norepinephrine (3.1 [2.7-3.8] vs. 2.9 [2.7-4.1] L/min.m2, p = nonsignificant) but greater with epinephrine (4.1 [3.5-4.4] p <.01 vs. dopamine and norepinephrine). Splanchnic blood flow was similar with the three agents (732 [413-1483] vs. 746 [470-1401] vs. 653 [476-1832] mL/min.m, p = nonsignificant). The gradient between mixed-venous and hepatic venous oxygen saturations was lower with dopamine than with norepinephrine and epinephrine, but the Pco(2) gap was similar with the three agents. In severe shock, cardiac index was higher, but splanchnic blood flow was lower, with epinephrine than with norepinephrine (4.6 [3.7-5.3] vs. 3.4 [3.0-4.1] L/min.m2, p <.01 and 860 [684-1334] vs. 977 [806-1802] mL/min.m2, p <.05, respectively). Epinephrine increased the mixed-venous and hepatic venous oxygen saturation gradient but did not alter Pco(2) gap. CONCLUSIONS: Dopamine and norepinephrine have similar hemodynamic effects, but epinephrine can impair splanchnic circulation in severe septic shock.

Aged↗

PubMed2003

Measures, markers, and mediators: toward a staging system for clinical sepsis. A report of the Fifth Toronto Sepsis Roundtable, Toronto, Ontario, Canada, October 25-26, 2000.

BACKGROUND: Sepsis is not a single disease but a complex and heterogeneous process. Its expression is variable, and its severity is influenced by the nature of the infection, the genetic background of the patient, the time to clinical intervention, the supportive care provided by the clinician, and a number of factors as yet unknown. The evaluation of effective therapies has been hampered by limitations in our ability to characterize the process and to stratify patients into more homogeneous groups with respect to pathogenesis. OBJECTIVES: To develop a taxonomy of markers relevant to clinical research in sepsis and to propose a testable candidate system for stratifying patients into more therapeutically homogeneous groups. DATA SOURCE: An expert roundtable discussion and a MEDLINE review using search terms "marker" and "sepsis." RESULTS: Markers provide information in one or more of three domains: diagnosis, prognosis, and response to therapy. More than 80 putative markers of sepsis have been described. All correlate with the risk of mortality (prognosis), yet none has shown utility in stratifying patients with respect to therapy (diagnosis) or in titrating that therapy (response). Their limitations arise from the challenges of establishing causality in a complex disease process such as sepsis and of stratifying patients into more homogeneous populations. The former limitation may be addressed through a modification of Koch's postulates to differentiate causality from simple association. The latter suggests the need for a staging system analogous to those used in other complex disease processes such as cancer. A candidate framework for such a system, based on the infection, the host response, and the extent of organ dysfunction (the IRO system) is described. CONCLUSIONS: Advances in the understanding and management of patients with sepsis will necessitate more rigorous approaches to disease description and stratification. Models should be developed, tested, and modified through clinical studies rather than through consensus.

Biomarkers↗