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Jean-Charles Preiser

Publications and source records attributed to Jean-Charles Preiser.

28 records · Page 2Linked to original sources
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

Antioxidant therapy in intensive care.

PURPOSE OF REVIEW: This review intends to summarize the recent findings regarding the presence of increased oxidative stress in critically ill patients and its potential pathophysiologic role, as well as the results of recent clinical trials of antioxidant therapies. RECENT FINDINGS: Several lines of evidence confirm the increase in oxidative stress during critical illness. The oxidative damage to cells and tissues eventually contributes to organ failure. Prophylactic administration of antioxidant vitamins or glutamine, incorporated in the nutritional support or given as separate medications, efficiently attenuates the oxidative stress and in some studies improves the outcome of critically ill patients. Few data on the effects of N-acetylcysteine or trace elements have been published during the last two years. SUMMARY: Patients at risk of organ failure could benefit from the early adjunction of antioxidant treatment, including vitamins and glutamine.

Antioxidants↗
PubMed2003

Differential effects of a selective inhibitor of soluble guanylyl cyclase on global and regional hemodynamics during canine endotoxic shock.

Activation of soluble guanylyl cyclase (sGC) might occur early during septic shock and play a role in the regulation of vascular tone and the redistribution of blood flow. The aim of this study was to assess the effects of sGC inhibition with oxadiazoloquinoxalinone (ODQ) on global and regional hemodynamic parameters in a clinically relevant model of septic shock. Fifteen anesthetized adult mongrel dogs were equipped with femoral and pulmonary artery catheters and ultrasonic flow probes around the mesenteric, femoral and renal arteries. The animals were randomized to receive Escherichia coli endotoxin (2 mg/kg, i.v.) alone, endotoxin followed by ODQ (1 mg/kg i.v.), or ODQ alone. Endotoxin administration was followed by decreases in mean arterial pressure, cardiac index, mesenteric, renal and femoral blood flows (MBF, RBF and FBF), and increases in systemic and pulmonary vascular resistances. Fluid resuscitation restored cardiac index, systemic vascular resistance, pulmonary vascular resistance, MBF, RBF and FBF to pre-endotoxin levels. In the presence of endotoxin, ODQ administration increased MBF and prevented the restoration of FBF. Hence, selective inhibition of sGC may increase splanchnic blood flow in septic shock.

Animals↗
PubMed2002

Nutritional papers in ICU patients: what lies between the lines?

The abundance of literature related to nutritional support reflects its recently recognised role in preventing metabolic complications and gut dysfunction during critical illness. However, some published studies lack relevance to critically ill patients, as a result of the selection of subjects and outcome variables, or flaws in the study design, as well as in the type, composition, timing, route of administration and amount of nutritional support given. This review will highlight these confounding factors by describing two imaginary (but typical) clinical trials and by analysing some studies published. The point at issue is that basic quality requirements, such as the formulation of a prospective hypothesis and the delineation of the effects of the reference treatment, are often lacking in many studies published. Data analysis was often found to be biased by the absence of statistical power calculation and intention-to-treat analysis. Globally, studies designed to assess the effects of nutritional support on the outcome of critically ill patients, rarely fulfil basic quality requirements and should therefore be interpreted cautiously. We suggest simple strategies or study design that will allow important questions to be answered by future clinical trials.

Clinical Trials as Topic↗
PubMed2002

Position paper of the ESICM Working Group on Nutrition and Metabolism. Metabolic basis of nutrition in intensive care unit patients: ten critical questions.

The metabolic changes associated with critical illness involve several pathways acting at different steps of the utilization of nutritive substrates. The understanding of the role of these pathways and of their complex regulation has led to the development of new strategies for the metabolic and nutritional management of critically ill patients, including the development of new products for nutritional support. The rationale for changing the profile of nutritional support solutions by adding novel substrates is also discussed. This review focuses on the metabolic specificities of critically ill patients and also includes an analysis of the adequacy of tools to monitor the metabolic status and the adequacy of the nutritional support.

Critical Care↗
PubMed2002

Microvascular blood flow is altered in patients with sepsis.

Microvascular blood flow alterations are frequent in animal models of sepsis and may impair tissue oxygenation. We hypothesized that alterations of the microcirculation are present in patients with sepsis. We used an orthogonal polarization spectral imaging technique to investigate the sublingual microcirculation in 10 healthy volunteers, 16 patients before cardiac surgery, 10 acutely ill patients without sepsis (intensive care unit control subjects), and 50 patients with severe sepsis. The effects of topical application of acetylcholine (10(-2) M) were tested in 11 patients with sepsis. In each subject, five to seven sublingual areas were recorded and analyzed semiquantitatively. Data were analyzed with nonparametric tests and are presented as medians (25th-75th percentiles). No significant difference in microvascular blood flow was observed between healthy volunteers and patients before cardiac surgery or intensive care unit control subjects. The density of all vessels was significantly reduced in patients with severe sepsis (4.5 [4.2-5.2] versus 5.4 [5.4-6.3]/mm in volunteers, p < 0.01). The proportion of perfused small (< 20 microm) vessels was reduced in patients with sepsis (48 [33-61] versus 90 [89-92]% in volunteers, p < 0.001). These alterations were more severe in nonsurvivors. The topical application of acetylcholine totally reversed these alterations. In conclusion, microvascular blood flow alterations are frequent in patients with sepsis and are more severe in patients with a worse outcome.

Acetylcholine↗
PubMed2002

Does methylene blue administration to septic shock patients affect vascular permeability and blood volume?

OBJECTIVE: To assess the effects of the inhibition of guanylate cyclase, an enzyme involved in sepsis-related vascular and myocardial dysfunctions, on hemodynamic variables including blood volume and pulmonary vascular permeability during septic shock. DESIGN: Prospective, open study with repeated measurements. SETTING: A medicosurgical intensive care unit of a university hospital. PATIENTS: Fifteen patients with septic shock associated with persisting hypotension despite conventional treatment including fluid loading, vasopressors, and inotropes. INTERVENTIONS: A fiberoptic catheter was inserted for the determination of blood and extravascular volumes by the thermal-dye double indicator technique, using indocyanine green (COLD system). A bolus dose of methylene blue (3 mg/kg) was infused intravenously over 10 mins. COLD-derived variables were recorded before methylene blue and 20 mins, 1 hr, and 2 hrs after the end of methylene blue infusion. MEASUREMENTS AND MAIN RESULTS: Standard hemodynamic and oxygen-derived variables; total, intrathoracic, systolic, and diastolic cardiac blood volumes; extravascular lung water; plasma osmolarity; and lactate and protein concentrations were recorded. Mean arterial and pulmonary artery pressures, systemic and pulmonary vascular resistances, and left ventricular stroke work index increased, and blood lactate transiently decreased after methylene blue (p <.05). The other variables recorded were unchanged during the 2-hr period following methylene blue infusion. CONCLUSIONS: This study confirmed the acute vasoconstrictive and positive inotropic effects of methylene blue during septic shock. These effects were not associated with changes in blood volume, myocardial diastolic function, or pulmonary vascular permeability assessed by extravascular lung water.

Adult↗
PubMed2002

Tight control of glycaemia in critically ill patients.

PURPOSE OF REVIEW: This manuscript attempts to review the effects associated with hyperglycaemia in critically ill patients and the effects of various insulin regimens. The available clinical findings and pertinent experimental data are examined. RECENT FINDINGS: Intensive insulin therapy titrated to maintain blood glucose level between 4.4 and 6.1 mmol/l during intensive care unit stay has recently been shown to significantly decrease mortality, septic morbidity, sepsis-related organ failure, transfusion requirements and polyneuropathies. Prior studies have already documented that hyperglycaemia on admission is related to susceptibility to infections and worse outcomes following myocardial and cerebral ischaemic events. Additional effects of insulin, unrelated to the control of glycaemia, have also been reported. SUMMARY: Intensive insulin therapy is probably warranted in most categories of critically ill patients, although some of the underlying mechanisms of its beneficial effects still need to be elucidated.

Blood Glucose↗
PubMed2002

Management and knowledge of enteral nutrition in intensive care units in a city in Belgium.

The administration of enteral nutrition in intensive care unit (ICU) patients is largely managed by nurses. However, the degree of knowledge, interest, and training in this field can differ considerably among nurses and among ICUs. Such differences may lead to variations in the way in which enteral nutrition is used. To investigate these issues, a questionnaire survey was sent to the nursing staffs of 5 ICUs in Belgium. The response rate was 68%. Although theoretical knowledge of enteral nutrition was globally poor, its advantages over parenteral nutrition were usually known. Responses to questions related to practical issues associated with enteral feeding showed more institution-specific answers than interindividual differences.

Journal Article↗