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Biomedical subjects

J L Vincent

Publications and source records attributed to J L Vincent.

At least 127 records · Page 7Linked to original sources
PubMed1999

Can cardioplegia management influence cytokine responses during clinical cardiopulmonary bypass?

BACKGROUND: Cytokines play an important role in the inflammatory response associated with cardiopulmonary bypass (CPB) and may contribute to postoperative complications. Although it has been shown that the production of tumor necrosis factor a (TNF-a) and interleukin (IL)-6 were higher following normothermic CPB than hypothermic CPB, whether different cardioplegic management could influence the release of cytokines remains unknown. METHODS: We compared the blood concentrations of four cytokines (TNF-a, IL-6, IL-8, and IL-10) in two groups of patients undergoing complete revascularization with CPB in the same study period. Seventeen patients received cold crystalloid cardioplegia at a Belgian center (group-CC), while 21 patients received warm blood cardioplegia at a center in Hong Kong (group-WB). Blood samples were collected before and after surgery in each patient. RESULTS: There were no differences between the 2 groups in terms of age, sex ratio, number of grafts, duration of CPB and aortic crossclamping. All patients survived their hospital stay. The levels of TNF-a, IL-6 and IL-8 after surgery were higher in group-CC than in group-WB. However, IL-10 levels were significantly lower at the end of surgery in group-CC than in group-WB. CONCLUSIONS: Our data suggest that the use of warm blood cardioplegia, rather than cold crystalloid cardioplegia, may reduce the inflammatory response to CPB. This observation warrants future randomized investigation to determine its clinical relevance.

Blood↗
PubMed1999

[Post-traumatic carotid-cavernous sinus fistula].

The authors report the case of a 51 year-old man who developed a carotid-cavernous sinus fistula after a blunt trauma. In view of an exophthalmia, an impressive chemosis, a pupillary dilatation due to parasympathetic paralysis and a bruit over the right orbit, a carotid-cavernous sinus fistula was diagnosed. The existence of the fistula was confirmed by a brain CT scan and a cerebral angiogram. Carotid-cavernous sinus fistulas are rare. They are spontaneous or posttraumatic. Cerebral angiography is the diagnostic procedure of choice. The authors review the signs and symptoms, diagnostic procedures, treatment, and prognosis of this complication.

Arteriovenous Fistula↗
PubMed1998

Genomic fluidity is a necessary event preceding the acquisition of tumorigenicity during spontaneous neoplastic transformation of WB-F344 rat liver epithelial cells.

The genomic evolution of a cohort of WB-F344 rat liver epithelial cell lineages undergoing spontaneous neoplastic transformation was followed to define the mechanistic relationship between genomic instability and progression to the neoplastic phenotype. Eighteen independent populations of WB-F344 cells (initiated from a single diploid-founding population) were subjected to 12 cycles of selective growth at confluent cell density, and cellular DNA contents were measured after each selection cycle. Flow cytometry demonstrated significant gains in the amount of G1 DNA after selection cycles 3, 6, and 7 in 44% (8 of 18), 89% (16 of 18), and 39% (7 of 18) of the cell populations, respectively. All populations subsequently lost DNA and returned to a diploid or pseudo-diploid DNA content within 1 to 2 selection cycles after the appearance of an increased DNA content. Additionally, appearance and subsequent disappearance of aneuploid or tetraploid subpopulations was observed in 11% (2 of 18) and 83% (15 of 18) of the experimental lineages, respectively. Although perturbations of G1 DNA content were apparent as early as selection cycle 3, at least 8 cycles of selective growth were required for the acquisition of tumorigenicity. While the independent lineages demonstrated significant fluctuations in G1 DNA content between selection cycles 3 and 8, the majority (11 of 13) of the populations contained a diploid or pseudo-diploid DNA content at the time tumorigenicity was expressed. Genomic instability preceded the acquisition of tumorigenic potential in rat liver epithelial cells subjected to selective growth conditions of maintenance at confluence, and may be required for its expression.

Aneuploidy↗
PubMed1998

Oxygen supply dependency can characterize septic shock.

OBJECTIVE: To demonstrate that oxygen consumption (VO2) can be dependent on oxygen delivery (DO2) during hemodynamic instability and independent of DO2 following stabilization. DESIGN: We retrospectively reviewed hemodynamic and blood gas data collected from ten patients in whom DO2 was acutely altered during an episode of septic shock (phase A) and after recovery from this episode (phase B). SETTING: General intensive care unit of a university hospital. PATIENTS: 10 critically ill adult patients (aged 55 +/- 19 years). INTERVENTIONS: DO2 was altered by fluid challenge, administration of vasoactive agents, or application of positive end-expiratory pressure. RESULTS: In phase A, changes in VO2 (121 +/- 32 vs 165 +/- 36 ml/min.m2; p < 0.001) paralleled changes in DO2 (415 +/- 153 vs 607 +/- 217 ml/min.m2; p < 0.001), but oxygen extraction (O2ER) remained stable (31.9 +/- 11.2 vs. 30.2 +/- 8.9%; NS). In phase B, changes in DO2 (412 +/- 118 vs 526 +/- 152 ml/min.m2; p < 0.001) were associated with opposite changes in O2ER (36.1 +/- 4.2 vs 28.9 +/- 4.9%; p < 0.001), and VO2 was unchanged (147 +/- 35 vs 149 +/- 33 ml/min.m2; NS). The mean VO2/DO2 slope was greater in phase A than in phase B (0.26 +/- 0.09 vs. 0.08 +/- 0.08; p < 0.004). Blood lactate levels were higher in phase A than in phase B (3.3 +/- 1.8 vs 1.6 +/- 0.6 mEq/l; p < 0.05). CONCLUSIONS: Oxygen supply independency and dependency can be found at different times in the same critically ill patient. Our findings are consistent with the concept that VO2/DO2 dependency is a marker of septic shock. Interventions to increase DO2 are probably justified when this phenomenon is present.

Adult↗
PubMed1998

Epidemiology, diagnosis and treatment of systemic Candida infection in surgical patients under intensive care.

The incidence of systemic Candida infections in patients requiring intensive care has increased substantially in recent years as a result of a combination of factors. More patients with severe underlying disease or immunosuppression from anti-neoplastic or anti-rejection chemotherapy and at risk from fungal infection are now admitted to the ICU. Improvements in supportive medical and surgical care have led to many patients who would previously have died as a result of trauma or disease surviving to receive intensive care. Moreover, some therapeutic interventions used in the ICU, most notably broad-spectrum antibiotics and intravascular catheters, are also associated with increased risks of candidiasis. Systemic Candida infections are associated with a high morbidity and mortality, but remain difficult to diagnose and ICU staff need to be acutely aware of this often insidious pathogen. A number of studies have identified risk factors for systemic Candida infection which may be used to identify those at highest risk. Such patients may be potential candidates for early, presumptive therapy. Here we review the epidemiology, pathogenesis, morbidity and mortality of systemic Candida infections in the ICU setting, and examine predisposing risk factors. Antifungal treatment, including the use of amphotericin B, flucytosine and fluconazole, and the roles of early presumptive therapy and prophylaxis, is also reviewed.

Antifungal Agents↗
PubMed1998

A profile of European ICU nursing.

OBJECTIVE: To evaluate major similarities and major differences between Western European countries in intensive care unit (ICU) nurse staffing, education, training, responsibilities, and initiative. DESIGN: A questionnaire was sent to Western European doctor members of the European Society of Intensive Care Medicine, to be passed on to the nurse-in-charge of their ICU. RESULTS: 156 completed questionnaires were analyzed: 49% were from university hospitals, 26% from university-affiliated hospitals, and 25% from community hospitals; 42% of the hospitals had more than 700 beds, 67% of the ICUs had between 6 and 12 beds, and 54% were mixed medical-surgical units. Among British units, 79% had more than three full-time nursing equivalents (FTE) per ICU bed, while in Sweden 75% of units had less than two FTE/ICU bed. University hospitals had more nursing staff per bed than community hospitals. As regards training, 33% of nurses followed a training course before starting work on the ICU and 64% after starting on the unit, and 85% had easy access to continuing education, particularly in the university hospitals. In an emergency, more than 70% of nurses regularly initiated oxygen administration, mask ventilation, or cardiac massage. In Sweden 100% of nurses and in Switzerland 91% of nurses regularly inserted peripheral intravenous catheters, but only 7% of German nurses did. No German nurses and only 12% of British nurses regularly performed arterial puncture, but in Sweden 75% of nurses regularly did. CONCLUSION: Even though the number of participants were limited, our questionnaire revealed variations in nurse staffing patterns among European countries and in their systems of training and education. Nurse autonomy also varies widely between countries.

Clinical Competence↗
PubMed1998

Information in the ICU: are we being honest with our patients? The results of a European questionnaire.

BACKGROUND: We were interested in determining the current practices and views of European intensive care doctors regarding communication with patients and informed consent for interventions. METHODS: A questionnaire was sent to the 1272 western European doctor members of the European Society of Intensive Care Medicine. All questionnaires were anonymous. Five hundred four completed questionnaires from 16 western European countries were analyzed. RESULTS: Of the respondents, 25 % said they would always give complete information to a patient, although 35 % felt they should. Thirty-two percent would give complete details of an iatrogenic incident, but 70% felt they should. There were significant differences in these attitudes between doctors from different countries, with doctors from the Netherlands more likely to give complete information, and doctors from Greece, Spain and Italy less likely. Fifty percent of the respondents required written consent for surgery, but for insertion of an arterial catheter oral consent was more widely accepted. The Netherlands and Scandinavia generally accepted oral requests for procedures, while Germany and the United Kingdom preferred written requests. Doctors of all countries were generally happy with their current practice concerning informed consent. Seventy-five percent would accept the right of a patient to refuse treatment, but 19% would carry out the procedure against the patient's wishes. CONCLUSIONS: Doctors are often not completely honest with their patients regarding their diagnosis or prognosis, or in the event of an iatrogenic incident. However, most doctors will respect a patient's right to refuse treatment. Informed consent practices vary substantially and are largely determined by locally accepted policy and accepted by doctors working in those areas.

Adult↗
PubMed1998

Fatal outcome after polytrauma: multiple organ failure or cerebral damage?

To assess the relative importance of multiple organ failure (MOF) and cerebral damage on the mortality rate following trauma we analyzed retrospectively the records from 99 polytrauma patients admitted to a multidisciplinary European intensive care unit in a 2 year period. In all, 93% of the trauma was non-penetrating and 73% was the result of road accidents. 28 patients died giving an overall mortality of 28.3%. The cause of death was cerebral lesions in 19 patients, hemorrhagic shock in eight and multiple organ failure in one patient who had an injury severity score (ISS) of 13. Most deaths (78%) occurred within 24 h of admission, 15 of these were due to extensive cerebral lesions and seven due to hemorrhagic shock. A total of six deaths occurred after 24 h, four due to extensive cerebral lesions, one due to hemorrhagic shock and one due to multiple organ failure. In our experience, cerebral damage was a more common cause of death than MOF following multiple non-penetrating trauma.

Adolescent↗
PubMed1998

An evidence-based approach to round tables and consensus conferences.

In current clinical practice, it is important to be able to evaluate the evidence supporting each of our actions. Physicians can no longer rely on tradition or habit; however, with the increasing number of journals available, it is impossible for the practicing clinician to keep abreast of all the relevant literature. One valuable method of gathering and summarizing the latest information and opinions is the use of round tables and consensus conferences. Published reports of round table and consensus conference findings can be invaluable in guiding the clinician.

Consensus Statements as Topic↗
PubMed1998

The platelet-activating factor antagonist BB-882 does not improve tissue oxygen extraction in endotoxic shock.

PURPOSE: We investigated whether BB-882, a novel potent PAF antagonist, could influence systemic and pulmonary hemodynamics and oxygen extraction capabilities during an acute reduction in blood flow induced by cardiac tamponade after endotoxin challenge. MATERIALS AND METHODS: Twenty-one anesthetized, ventilated, and endotoxin-shocked (2 mg/kg i.v. Escherichia coli endotoxin) dogs were randomly divided in three groups. One group (N = 7) served as control. A second group (N = 7) received BB-882 as a single bolus dose of 5 mg/kg, 30 minutes before endotoxin administration. A third group (N = 7) received BB-882 as a continuous infusion of 5 mg/kg x h, started 30 minutes after endotoxin. Hemodynamic and gazometric measurements were obtained in all dogs 30 minutes after endotoxin injection and repeated 30 minutes after cardiac filling pressures were restored to baseline by generous saline infusion. Saline infusion rate was then set at 20 mL/kg x h and tamponade was induced by repeated bolus injections of warm saline into the pericardial sac. RESULTS: Compared with controls, pretreatment with BB-882 attenuated the early endotoxin-induced decrease in arterial pressure (70 +/- 17 v 51 +/- 14 mm Hg, P < .05), cardiac index (118 +/- 29 v 91 +/- 15 mL/ kg x min, P < .05), stroke index (1.0 +/- 0.2 v 0.7 +/- 0.3 mL/kg, P < .05), and left ventricular stroke work index (0.9 +/- 0.3 v 0.4 +/- 0.2 g x m/kg, P < .05), but these effects were not sustained after fluid resuscitation. In contrast, BB-882 post-treatment maintained arterial pressure and improved cardiac performance at lower filling pressures in the later phase of endotoxic shock. BB-882 did not influence pulmonary hemodynamics. Treatment with BB-882 did not influence oxygen extraction at critical oxygen delivery (51.5 +/- 9.9% and 52.8 +/- 13.9% v 46.6 +/- 9.0%, respectively BB-882 pretreatment and post-treatment v control). CONCLUSIONS: We conclude that in this model of endotoxic shock the administration of BB-882, either before or after endotoxin challenge, has time-related beneficial hemodynamic and cardiac effects but does not improve global oxygen extraction capabilities. The potential benefit of adjunctive treatment with a platelet-activating factor antagonist in sepsis remains doubtful.

Animals↗
PubMed1998

The metabolic fate of long-term inhaled nitric oxide.

PURPOSE: The fate of inhaled nitric oxide (NO) has not been precisely defined in critically ill patients. This study aimed at defining the effects of long-term NO inhalation on circulating NO byproduct levels. MATERIAL AND METHODS: During NO therapy, plasma and urine from 13 critically ill patients were sampled daily for determination of the stable byproducts of NO (nitrite [NO2-] and nitrate [NO3-]. Routine monitoring data included inhaled NO concentration, hemodynamic parameters, arterial blood gases, creatinine clearance, and C-reactive protein. RESULTS: For the first 24 hours of NO inhalation (6.3+/-1.1 ppm), NO3- plasma concentration increased (from 13.3+/-5.4 to 52.3+/-17.6 micromol/L), but NO2- plasma concentration was not affected. The NO3- plasma concentration was correlated with the C-reactive protein level, the inhaled NO concentration. Renal excretion of NO metabolites was unaltered by NO inhalation. The NO3 concentrations returned to baseline when NO therapy was discontinued. CONCLUSION: Long-term NO inhalation was associated with a consistent increase in the NO3- plasma concentration. NO byproducts may be implicated in the systemic effects associated with this treatment.

Administration, Inhalation↗
PubMed1998

Critical haemoglobin concentration in anaesthetized dogs: comparison of two plasma substitutes.

We have explored systemic and regional tolerance to haemodilution during anaesthesia with two different synthetic colloids. Eighteen dogs undergoing mechanical ventilation during anaesthesia with ketamine were submitted to progressive normovolaemic haemodilution with either gelatin (GEL; n = 9) or hydroxyethylstarch (HES; n = 9) administered on a 1:1 ratio. Systemic oxygen delivery was calculated from measurement of thermodilution cardiac output and arterial oxygen content, while systemic oxygen consumption was determined from expired gas analysis. Mesenteric oxygen delivery and consumption were determined using ultrasonic flow measurements, and arterial and mesenteric venous oxygen contents. The critical haemoglobin concentration (i.e. the haemoglobin value below which oxygen consumption becomes oxygen delivery dependent) was mean 3.6 (SD 0.8) g dl-1 in the GEL and 3.5 (1.5) g dl-1 in the HES group. The mesenteric critical oxygen extraction ratio (O2ER) (GEL 50.1 (12.1)%; HES 48.5 (13.4)%) was significant lower than the systemic critical O2ER (GEL 66.1 (8.4)%; HES 67.7 (7.1)%). There were no significant differences between the GEL and HES groups for any of these variables, or in the amount of colloid administered. During the study, oxygen delivery decreased almost linearly with reduction in haemoglobin, indicating a lack of cardiac output response to anaemia during ketamine anaesthesia.

Anesthesia, Intravenous↗
PubMed1998

Cardiovascular alterations in septic shock.

Cardiovascular alterations in sepsis include a decrease in vascular tone and an impairment in myocardial contractility, and occur largely as the result of the release and action of mediators of the sepsis cascade. Many mediators are involved including cytokines, particularly tumour necrosis factor and interleukin-1, and secondary mediators such as nitric oxide and oxygen free radicals. The degree of reduced vascular tone and myocardial depression have both been related to the severity of sepsis. In this article we will review current knowledge on the factors involved in the cardiovascular alterations of sepsis, the clinical implications of these alterations, and the possibilities for future treatments.

Blood Pressure↗
PubMed1998

Pharmacologic strategies in acute respiratory distress syndrome.

Treatment of the acute respiratory distress syndrome includes both supportive measures and correction of the underlying cause. Various pharmacological interventions have been proposed to limit the severity of lung injury and enhance the healing process, including exogenous surfactant, inhaled vasodilators (mainly nitric oxide), corticosteroids, prostaglandin E1, antioxidants (N-acetylcysteine), ketoconazole and other substances. Some of these interventions are administered via the airways, for example inhaled nitric oxide or liquid ventilation with perfluorocarbons. Some have beneficial effects on surrogate end-points such as pulmonary gas exchange. However, in large prospective trials none of these pharmacological approaches have resulted in significantly improved survival in acute respiratory distress syndrome patients.

Journal Article↗