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Biomedical subjects

J L Vincent

Publications and source records attributed to J L Vincent.

At least 145 records · Page 8Linked to original sources
PubMed1998

Is the pulmonary artery catheter misused? A European view.

OBJECTIVES: To review the problems associated with pulmonary artery catheter use in the intensive care unit; to discuss the need for clinical trials to assess its benefits; and to present original data on the use of the pulmonary artery catheter in European countries. DATA SOURCES: Selected relevant articles from the literature and data from a recent multicenter European study. DATA EXTRACTION AND SYNTHESIS: It has recently been suggested that pulmonary artery catheter use increases mortality. As a result, some have recommended placing a moratorium on pulmonary catheter use or suggested conducting large multicenter trials to assess the positive and negative effects of pulmonary catheter use. Although there is limited evidence showing an improved outcome with pulmonary artery catheter use, many leaders in intensive care medicine feel that the pulmonary catheter is a useful tool, when used correctly. We believe that misuse of the pulmonary artery catheter is common. The incidence of complications is low and, with improved training of insertion techniques, the frequency of complication would decrease further. The pulmonary artery catheter is a monitoring tool and, as such, is only as good as the interpretation of the data it generates. Clinical trials on such an accepted technique are difficult to conduct and their cost/benefit ratio is debatable. CONCLUSIONS: A moratorium on pulmonary artery catheter use is not necessary and clinical trials in heterogeneous ICU populations are not warranted. Improved training in the insertion, interpretation, and implementation of the pulmonary artery catheter and the data it generates is required. As an alternative to expensive clinical trials on the pulmonary artery catheter, we propose that our limited financial resources for clinical investigation be invested in the development of innovative techniques that may reduce the need for pulmonary artery catheter in the future.

APACHE↗
PubMed1998

Effects of vasoactive drugs on gastric intramucosal pH.

OBJECTIVE: To review current knowledge about the effects of vasoactive agents on gastric intramucosal pH (pHi). DATA SOURCES: All studies involving pHi and vasoactive agents were retrieved from a computerized MEDLINE search from 1980 to 1997. We also reviewed the reference lists of all available review articles and primary studies to identify references not found in the computerized searches. STUDY SELECTION: Clinical and experimental studies using dopamine, dopexamine, dobutamine, norepinephrine, epinephrine, nitric oxide, N-acetylcysteine, prostaglandins, or pentoxifylline were considered if splanchnic perfusion and/or pHi measurements were utilized. DATA EXTRACTION: From the selected studies, information was obtained regarding patient population, dosing regimen, duration of study, and effects on splanchnic blood flow (SBF), splanchnic oxygenation, and pHi. DATA SYNTHESIS: Although dopaminergic effects increase SBF, dopamine does not generally increase pHi. Data on the effects of dopexamine on pHi are scarce and inconsistent. Dobutamine can significantly increase SBF and usually increases pHi. In septic patients, norepinephrine seems to increase pHi. Epinephrine may have detrimental effects on gastric perfusion. Prostacyclin seems to increase pHi but data are limited. Insufficient evidence exists to support the beneficial effects of nitric oxide donors or blockers, pentoxifylline, or N-acetylcysteine on pHi. CONCLUSIONS: Overall, the effects of vasoactive agents on pHi are unpredictable. Among the catecholamines, dopamine is the least likely, and dobutamine the most likely, to increase pHi.

Acetylcysteine↗
PubMed1998

Use of the SOFA score to assess the incidence of organ dysfunction/failure in intensive care units: results of a multicenter, prospective study. Working group on "sepsis-related problems" of the European Society of Intensive Care Medicine.

OBJECTIVE: To evaluate the use of the Sequential Organ Failure Assessment (SOFA) score in assessing the incidence and severity of organ dysfunction in critically ill patients. DESIGN: Prospective, multicenter study. SETTING: Forty intensive care units (ICUs) in 16 countries. PATIENTS: Patients admitted to the ICU in May 1995 (n = 1,449), excluding patients who underwent uncomplicated elective surgery with an ICU length of stay <48 hrs. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The main outcome measures included incidence of dysfunction/failure of different organs and the relationship of this dysfunction with outcome. In this cohort of patients, the median length of ICU stay was 5 days, and the ICU mortality rate was 22%. Multiple organ dysfunction and high SOFA scores for any individual organ were associated with increased mortality. The presence of infection on admission (28.7% of patients) was associated with higher SOFA scores for each organ. The evaluation of a subgroup of 544 patients who stayed in the ICU for at least 1 wk showed that survivors and nonsurvivors followed a different course. This subgroup had greater respiratory, cardiovascular, and neurologic scores than the other patients. In this subgroup, the total SOFA score increased in 44% of the nonsurvivors but in only 20% of the survivors (p < .001). Conversely, the total SOFA score decreased in 33% of the survivors compared with 21% of the nonsurvivors (p < .001). CONCLUSIONS: The SOFA score is a simple, but effective method to describe organ dysfunction/failure in critically ill patients. Regular, repeated scoring enables patient condition and disease development to be monitored and better understood. The SOFA score may enable comparison between patients that would benefit clinical trials.

Adult↗
PubMed1998

Has the mortality of septic shock changed with time.

OBJECTIVES: To determine whether a systematic review of the literature could identify changes in the mortality of septic shock over time. DATA SOURCES: A review of all relevant papers from 1958 to August 1997, identified through a MEDLINE search and from the bibliographies of articles identified. DATA SYNTHESIS: The search identified 131 studies (99 prospective and 32 retrospective) involving a total of 10,694 patients. The patients' mean age was 57 yrs with no change over time. The overall mortality rate in the 131 studies was 49.7%. There was an overall significant trend of decreased mortality over the period studied (r=.49, p < .05). The mortality rate in those patients with bacteremia as an entry criterion was greater than that rate in patients whose entry criterion was sepsis without definite bacteremia (52.1% vs. 49.1%; chi2=6.1 and p< .05). The site of infection altered noticeably over the years. Chest-related infections increased over time, with Gram-negative infections becoming proportionately less common. If all other organisms and mixed infections are included with the Gram-positives, the result is more dramatic, with these organisms being causative in just 10% of infections between 1958 and 1979 but in 31% of infections between 1980 and 1997. CONCLUSIONS: The present review showed a slight reduction in mortality from septic shock over the years, although this result should be approached with caution. The heterogeneity of the articles and absence of a severity score for most of the studies limited our analysis. Furthermore, there was an increasing prevalence of Gram-positive causative organisms, and a change of the predominant origin of sepsis from the abdomen to the chest.

APACHE↗
PubMed1998

Comparison of hypertonic with isotonic saline hydroxyethyl starch solution on oxygen extraction capabilities during endotoxic shock.

Hypertonic colloid solutions reportedly exert protective effects on the microcirculation. The present study investigated the effects of a hypertonic saline hydroxyethyl starch (HES) solution on the oxygen extraction capabilities in an endotoxic shock model in the dog. Fourteen anesthetized and mechanically ventilated dogs received 2 mg/kg of Escherichia coli endotoxin before being randomly divided into two groups to receive a 4 mLkg infusion in 10 min of either hypertonic (7.5%, n = 7), or isotonic (.9%, n = 7) HES solution. Thereafter, each animal received isotonic HES titrated to restore cardiac index to baseline levels, followed by a constant infusion of normal saline at 20 mLkg throughout the study. The amount of fluid required to restore cardiac index to baseline levels was approximately one-half in the hypertonic saline HES group as compared with the isotonic group (123+/-12 vs. 291+/-62 mLkg, p < .05). The two groups of dogs had similar mean arterial pressure and cardiac index values. Hypertonic saline HES-treated animals had a higher sodium concentration than the control group (144.4+/-4.0 vs. 138.7+/-3.1 mM/L, p < .05). There were no significant differences in blood gases or lactate concentrations between the groups. When cardiac tamponade was induced to study the tissue oxygen extraction capabilities, hypertonic saline HES-treated dogs had a slightly lower critical oxygen delivery (11.1+/-1.6 vs. 14.2+/-3.3 mL/kg x min, p = NS), and a significantly higher critical oxygen extraction ratio (61.9+/-17.1 vs. 44.0+/-11.5%, p < .05) than the isotonic group. We conclude that during endotoxic shock in dogs, hypertonic saline HES solution can increase whole body oxygen extraction capabilities, probably by an improvement in microvascular perfusion in septic conditions.

Animals↗
PubMed1998

Does hepato-splanchnic VO2/DO2 dependency exist in critically ill septic patients?

Since the gradient between the mixed venous and hepatic vein oxygen saturation (DSO2) is often increased in septic patients, we suspected these patients may have an imbalance between oxygen supply and demand in the hepato-splanchnic area. In 42 septic patients, hepato-splanchnic blood flow was determined by the indocyanine green clearance method with hepatic vein catheterization. The relationships between hepato-splanchnic oxygen delivery (DO2spla) and consumption (VO2spla) were analyzed during an increase in blood flow induced by a dobutamine infusion at doses up to 10 microg/kg x min. In 14 patients, positive end-expiratory pressure (PEEP) was also increased up to 20 cm H2O. The patients were separated according to their DSO2 (Group I: DSO2 < 10%, n = 13; and Group II: DSO2 > 10%, n = 29). Although DO2spla increased similarly in both groups, VO2spla only increased in Group II (from 45+/-22 to 59+/-39 ml/min x M2, p < 0.01). The slope of the VO2spla/DO2spla relationship was higher in Group II than in Group I (31.2+/-16.7 versus 10.4+/-5.1%, p < 0.001) and was similar during dobutamine and PEEP (21.9+/-14.2 versus 21.9+/-14.0%, p = NS). In conclusion, VO2spla increased only in septic patients with an increased DSO2 indicating splanchnic dysoxia. The similar slope observed with dobutamine and PEEP suggests that a thermogenic effect was unlikely.

Arteries↗
PubMed1998

Does N-acetyl-L-cysteine influence cytokine response during early human septic shock?

STUDY OBJECTIVE: To assess the effects of adjunctive treatment with N-acetyl-L-cysteine (NAC) on hemodynamics, oxygen transport variables, and plasma levels of cytokines in patients with septic shock. DESIGN: Prospective, randomized, double-blind, placebo-controlled study. SETTING: A 24-bed medicosurgical ICU in a university hospital. PATIENTS: Twenty-two patients included within 4 h of diagnosis of septic shock. INTERVENTIONS: Patients were randomly allocated to receive either NAC (150 mg/kg bolus, followed by a continuous infusion of 50 mg/kg over 4 h; n= 12) or placebo (n=10) in addition to standard therapy. MEASUREMENTS: Plasma concentrations of tumor necrosis factor-alpha (TNF), interleukin (IL)-6, IL-8, IL-10, and soluble tumor necrosis factor-alpha receptor-p55 (sTNFR-p55) were measured by sensitive immunoassays at 0, 2, 4, 6 and 24 h. Pulmonary artery catheter-derived hemodynamics, blood gases, hemoglobin, and arterial lactate were measured at baseline, after infusion (4 h), and at 24 h. RESULTS: NAC improved oxygenation (PaO2/FIO2 ratio, 214+/-97 vs 123+/-86; p<0.05) and static lung compliance (44+/-11 vs 31+/-6 L/cm H2O; p<0.05) at 24 h. NAC had no significant effects on plasma TNF, IL-6, or IL-10 levels, but acutely decreased IL-8 and sTNFR-p55 levels. The administration of NAC had no significant effect on systemic and pulmonary hemodynamics, oxygen delivery, and oxygen consumption. Mortality was similar in both groups (control, 40%; NAC, 42%) but survivors who received NAC had shorter ventilator requirement (7+/-2 days vs 20+/-7 days; p<0.05) and were discharged earlier from the ICU (13+/-2 days vs 32+/-9 days; p<0.05). CONCLUSION: In this small cohort of patients with early septic shock, short-term IV infusion of NAC was well-tolerated, improved respiratory function, and shortened ICU stay in survivors. The attenuated production of IL-8, a potential mediator of septic lung injury, may have contributed to the lung-protective effects of NAC.

Acetylcysteine↗
PubMed1997

Erythropoietin response is blunted in critically ill patients.

OBJECTIVES: Critically ill patients often develop anaemia which can be related to a number of factors. However, the exact causes of anaemia in many patients remain unexplained. We hypothesized that the relationship between erythropoietin (EPO) and haematocrit may be altered in critically ill patients. DESIGN: Serum concentrations of EPO were serially determined by the ELISA method in 36 critically ill, non-hypoxaemic patients who stayed more than 7 days in the Intensive Care Unit, including 22 patients with sepsis and 14 without. Eighteen ambulatory patients with iron-deficiency anaemia served as a control group. SETTING: Two University Hospital Intensive Care Departments. RESULTS: A significant inverse correlation between serum EPO and haematocrit levels was found in the control patients (r = -0.81, p < 0.001), but not in the critically ill patients (r = -0.09, NS), except in a subgroup of non-septic patients without renal failure (r = -0.61, p < 0.01). CONCLUSIONS: EPO levels can be inappropriately low in critically ill patients, so that EPO deficiency may contribute to the development of anaemia in these patients. This phenomenon is observed not only in the presence of acute renal failure, but also in the presence of sepsis.

Acute Kidney Injury↗
PubMed1997

Organization of intensive care units in Europe: lessons from the EPIC study.

OBJECTIVE: To study differences related to intensive care unit (ICU) structure and patient demography between the various countries of Western Europe. DESIGN: Application of data collected by the European Prevalence of Infection in Intensive Care (EPIC) study, a one-day prevalence study. SETTING: Voluntary participation of all Western European ICUs. A total of 1417 ICUs responded. PATIENTS: All patients, older than 10 years of age, occupying a bed in the participating ICUs over a 24-h period. 10,038 patient case reports were submitted. RESULTS: The study revealed important differences. In particular, there seems to be a north/south divide with fewer ICU beds and more severely ill patients in the south. The United Kingdom seemed more similar to southern European countries than to the north. CONCLUSION: While there are similarities between European countries, large differences still remain and are important to identify to enable us to work together to create a more uniform system of intensive care, which will in turn give more effective and efficient patient care.

APACHE↗
PubMed1997

Hepatic release of interleukin-10 during cardiopulmonary bypass in steroid-pretreated patients.

With its antiinflammatory properties, interleukin (IL)-10 may play an important role in limiting complications associated with cardiopulmonary bypass (CPB). We previously demonstrated that pretreatment with steroids can significantly increase IL-10 production during CPB, but neither the heart nor the lung was found to be its main source. To define whether the liver is the source of IL-10, hepatic venous cannulation was performed in 12 patients undergoing CPB. Each patient received 30 mg/kg of methylprednisolone before operation. Plasma levels of IL-10 were simultaneously measured in peripheral arterial blood and hepatic venous blood before heparin administration, before aortic cross-clamping, and 5, 30, 60, 90, and 120 minutes after aortic declamping. The duration of CPB and aortic cross-clamping was 113 +/- 7 minutes and 75 +/- 6 minutes (mean +/- SEM), respectively. IL-10 levels 30 minutes after declamping were significantly higher in hepatic venous blood than in arterial blood (1187 +/- 573 pg/ml vs 911 +/- 405 pg/ml, p < 0.01 by Wilcoxon's signed-rank test). To determine whether steroids can also induce the release of another antiinflammatory cytokine, IL-4, plasma IL-4 levels were measured simultaneously. IL-4 was detected in the arterial blood of only 4 of the 12 patients, transiently after aortic declamping. IL-4 was not detected in hepatic venous blood. In conclusion, the liver is a major source of IL-10 during CPB. However, steroid-treated patients do not show an increase in IL-4, and the liver is not the source of IL-4 during and after CPB.

Aged↗
PubMed1997

Cytokine responses to cardiopulmonary bypass: lessons learned from cardiac transplantation.

BACKGROUND: A growing body of evidence relates the release during cardiopulmonary bypass (CPB) of proinflammatory cytokines, such as tumor necrosis factor-alpha, interleukin (IL)-6, and IL-8, to the postoperative systemic inflammatory response syndrome. Antiinflammatory cytokines, such as IL-10, however, may also play an important role in limiting these complications. METHODS: The English-language literature was reviewed. Emphasis was placed on cytokine responses during clinical CPB for cardiac operations and, in particular, for heart and heart-lung transplantation. RESULTS: The recent data indicate that (1) although cytokine release can be triggered by many factors during CPB, ischemia-reperfusion may play the most important role; (2) the levels of tumor necrosis factor-alpha, IL-6, and IL-8 are correlated with the duration of cardiac ischemia and the myocardium is a major source of these three cytokines during CPB; (3) IL-10 levels are correlated with the duration of CPB and the liver is a major source of IL-10 during CPB; and (4) steroid pretreatment is an effective intervention to inhibit the release of proinflammatory cytokines and enhance IL-10 production. CONCLUSIONS: The improved knowledge of cytokine responses to CPB may help to develop interventions aimed at reducing postoperative morbidity and mortality.

Adrenal Cortex Hormones↗
PubMed1997

Thrombus formation on a calcific and severely stenotic bicuspid aortic valve.

We report on a case of thrombus formation on a native bicuspid aortic valve, which was found during an elective operation for aortic valve replacement. Although no apparent predisposing cause of thrombosis could be ascertained, severe calcific stenosis of the bicuspid valve and cardiac catheterization may have played a role. The patient is in excellent condition 9 months after the operation.

Aged↗
PubMed1997

Intrahepatocellular erythrocyte inclusions and increased calcium precipitation in canine endotoxic shock.

AIMS: To investigate the electron microscopic localization of membrane-bound and exchangeable calcium with specific calcium precipitation techniques during endotoxic shock in the dog. METHODS: Ten pentobarbital anesthetized, mechanically ventilated, and paralyzed dogs were studied. Six dogs received 2 mg/kg E. coli endotoxin i.v. followed by a continuous 0.9% saline infusion to restore and maintain baseline cardiac filling pressures. Four dogs served as time-matched controls. Each experiment lasted for 3 h. After the completion of study, the livers of four endotoxic and two control dogs were fixed by perfusion of 3% glutaraldehyde via the portal vein. Liver sections were then prepared for electron microscopy and calcium localization studies. RESULTS: Hepatocytes of endotoxic animals completely lost their plasma membrane-bound calcium. The most severely damaged cells showed extensive "blebbing" of the plasma membrane and contained numerous cytoplasmic erythrocyte inclusions. Endotoxin administration also caused excessive calcium precipitation inside hepatocytes in areas with pronounced sinusoidal damage. CONCLUSIONS: In this acute model of fluid-resuscitated endotoxic shock in dogs, the use of specific calcium localization techniques enables the demonstration of disturbances in hepatocellular calcium handling, which appear to be closely related to structural alterations of the hepatocyte cell membrane. Erythrocyte uptake by hepatocytes is a previously undescribed phenomenon in canine endotoxic shock and may serve as an additional histologic marker of ultrastructural cell (membrane) damage.

Animals↗
PubMed1997

Critical care in Europe.

Intensive care medicine developed in Europe following the polio epidemic in Denmark in 1952 and is now a specialty in its own right. Across Europe differences exist between countries regarding unit size, policy, staffing, and patient demographics. There is in particular a marked north/south divide, with smaller units dealing with sicker patients in the south than the north. The United Kingdom appears to be similar to the countries of Southern Europe. Guidelines for training and structure are being developed in an attempt to create more uniformity and improve communication between units.

Aged↗