PubMed Health⌕ Search

Biomedical subjects

R Chioléro

Publications and source records attributed to R Chioléro.

At least 55 records · Page 3Linked to original sources
PubMed1995

Relations between copper, zinc and selenium intakes and malondialdehyde excretion after major burns.

Copper, zinc and selenium are involved in free radical scavenging. As trace element status is altered after major burns, related free radical scavenging may be decreased: consequently lipid peroxidation, reflected by increased urinary malondialdehyde excretion (MDA), is considerably increased. This preliminary study aimed to investigate the relationship between trace elements and MDA excretion. Sixteen patients aged 34 +/- 9 years (mean +/- s.d.) burned over 37 +/- 11 per cent of body surface, were studied prospectively. Trace element balance studies from days 1 to 7 and serum and urine concentrations on days 10, 15, 20 and 25 were measured. The first 11 patients (groups 1--SBU < 80, and 2--SBU > or = 80) were given standard supplements and the five next patients increased supplements (group 3, SBU > or = 80). The MDA excretion from days 1 to 3 was correlated with burn severity (r = 0.59). The correlations between serum trace element levels after day 3 and MDA were negative: Cu, r = -0.065; Zn, r = -0.52; Se, r = -0.53. In Group 3, MDA excretion after day 3 decreased with increasing cumulative Zn (r = -0.46) and Se intakes (r = -0.57). It can be concluded that the MDA decrease after day 3 was not clearly attributable to the trace element supplements, but the negative trend observed between Zn and Se supplements and decreased MDA excretion requires further studies.

Adult↗
PubMed1995

[Consequences of surgery on nutritional status].

Trauma and surgery induce extensive physiological changes, commonly denominated the acute phase reaction (APR). This APR is activated by various kinds of stimuli, namely nociceptive stimulations, tissue injury, tissue ischaemia and reperfusion as well as by haemodynamic disturbances which occur commonly in such patients. APR is mainly characterised by the release of counter-regulatory hormones, complex metabolic changes and by the hepatic synthesis of numerous acute phase factors (C-reactive protein, haptoglobin, complement protein, etc). In addition, fever is typically present and there is a resistance to the nutritional support. The intensity of APR is variable, according to the extent of surgery, the subsequent course, occurrence of complications and to various factors related to the patient and its treatment. In patients with non complicated surgery and low or moderate severity trauma, the metabolic changes are minor and self-limited. In such a condition, there is no need for nutritional support. Conservely, in patients with complicated surgery or major trauma, there is an extensive APR, which can be very prolonged. This results in important and sustained metabolic changes, leading to extensive catabolism and progressive loss of body cell mass. The latter is amplified by the decreased body ability to adapt to starvation and by the resistance to the nutritional support that typically occur in complicated postoperative and trauma patients. Total parenteral nutrition does not prevent from metabolic changes occurring in surgical patients. By contrast, several experimental and human studies have shown that early enteral nutrition may alleviate both the endocrine and metabolic responses in such conditions. Regional anaesthesia, particularly by the epidural route, may also decrease but not abolish the extent of APR.

Acute-Phase Proteins↗
PubMed1995

Effect of epinephrine on oxygen consumption and delivery during progressive hemorrhage.

OBJECTIVE: To determine whether, during hemorrhagic shock, the effect of epinephrine on energy metabolism could be deleterious, by enhancing the oxygen requirement at a given level of oxygen delivery (DO2). DESIGN: Prospective, randomized, control trial. SETTING: Experimental laboratory. SUBJECTS: Two groups of seven mongrel dogs were studied. The epinephrine group received a continuous infusion of epinephrine (1 microgram/min/kg) while the control group received saline. INTERVENTION: Dogs were anesthetized with pentobarbital, and shock was produced by stepwise hemorrhage. MEASUREMENTS AND MAIN RESULTS: Oxygen consumption (VO2) was continuously measured by the gas exchange technique, while DO2 was independently calculated from cardiac output (measured by thermodilution) and blood oxygen content. A dual-lines regression fit was applied to the DO2 vs. VO2 plot. The intersection of the two regression lines defined the critical value of DO2. Values above critical DO2 belonged to phase 1, while phase 2 occurred below critical DO2. In the control group, VO2 was independent of DO2 during phase 1; VO2 was dependent on DO2 during phase 2. In the epinephrine group, the expected increase in VO2 (+19%) and DO2 (+50%) occurred under normovolemic conditions. During hemorrhage, VO2 immediately decreased, and the slope of phase 1 was significantly (p < .01) different from zero, and was significantly (p < .05) steeper than in the control group (0.025 +/- 0.005 vs. 0.005 +/- 0.010). However, the critical DO2 (8.7 +/- 1.7 vs. 9.7 +/- 2.4 mL/min/kg), the critical VO2 (5.6 +/- 0.5 vs. 5.5 +/- 0.9 mL/min/kg), and the slope of phase 2 (0.487 +/- 0.080 vs. 0.441 +/- 0.130) were not different from control values. CONCLUSIONS: The administration of pharmacologic doses of epinephrine significantly increased VO2 under normovolemic conditions due to the epinephrine-induced thermogenic effect. This effect progressively decreased during hemorrhage. The critical DO2 and the relationship between DO2 and VO2 in the supply-dependent phase of shock were unaffected by epinephrine infusion. These results suggest that during hemorrhagic shock, epinephrine administration did not exert a detrimental effect on the relationship between DO2 and VO2.

Animals↗
PubMed1995

Effects of lactate on glucose metabolism in healthy subjects and in severely injured hyperglycemic patients.

Hepatic glucose production is autoregulated during infusion of gluconeogenic precursors. In hyperglycemic patients with multiple trauma, hepatic glucose production and gluconeogenesis are increased, suggesting that autoregulation of hepatic glucose production may be defective. To better understand the mechanisms of autoregulation and its possible alterations in metabolic stress, lactate was coinfused with glucose in healthy volunteers and in hyperglycemic patients with multiple trauma or critical illness. In healthy volunteers, infusion of glucose alone nearly abolished endogenous glucose production. Lactate increased gluconeogenesis (as indicated by a decrease in net carbohydrate oxidation with no change in total [13C]carbohydrate oxidation) but did not increase endogenous glucose production. In patients with metabolic stress, endogenous glucose production was not suppressed by exogenous glucose, but lactate did not further increase hepatic glucose production. It is concluded that 1) in healthy humans, autoregulation of hepatic glucose production during infusion of lactate is still present when glycogenolysis is suppressed by exogenous glucose and 2) autoregulation of hepatic glucose production is not abolished in hyperglycemic patients with metabolic stress.

Adolescent↗
PubMed1995

Systemic and hemodynamic effects of recombinant tumor necrosis factor alpha in isolation perfusion of the limbs.

OBJECTIVE: To describe the systemic effects of high-dose recombinant tumor necrosis factor alpha (rTNF-alpha), recombinant interferon gamma (rIFN-gamma), and melphalan administered through hyperthermic isolation perfusion of the limbs (IPL) in patients with melanoma and malignant soft-tissue tumors. DESIGN: The clinical, hemodynamic, and biologic parameters were recorded after IPL during the postoperative period. SETTING: Surgical intensive care service of a 1,000-bed tertiary university medical center. PATIENTS: Nineteen patients referred to a pluridisciplinary Center for Oncology after relapse of regionally advanced melanoma or soft-tissues tumors, included in a phase 2 therapeutic study. RESULTS: Major systemic and hemodynamic changes were observed after IPL in all patients. Ninety-four percent (17/18) of the evaluable patients presented a shock unresponsive to fluid challenge, requiring the continuous perfusion of vasopressors, inotropic agents, or both. Analysis of hemodynamic data showed two distinctive patterns: a pure distributive shock in nine patients requiring norepinephrine, and a mixed distributive and cardiogenic shock in eight patients requiring vasopressor and inotropic agents. The oxygen parameters were characterized by an increase in both the delivery and the uptake of oxygen, with a prolonged reduced oxygen extraction ratio for most patients. The other observed effects were as follows: transient bilateral or mixed pulmonary infiltrates in all patients; some hematologic disturbances in 83% of patients; infection requiring a modification of the antibiotic prophylaxis in 61% of patients; and some liver toxic reactions in 50% of patients. Very high systemic TNF-alpha serum bioactivity was found in 12 patients for whom serum samples were available, indicating an early and important rTNF-alpha leakage from the IPL. No correlations could be found between the levels of TNF-alpha and the observed systemic effects. Despite the severity of the hemodynamic disturbance, no patient died. CONCLUSION: Major systemic effects, consisting mainly in cardiovascular, respiratory, and hematologic disturbances, were observed in patients after IPL with high-dose of rTNF-alpha. The likely explanation for these observations is an early rTNF-alpha leakage related to inadequate IPL technique. These data show that the iatrogenic administration of high circulating TNF levels lead to a "septic shock-like" syndrome without resulting in lethal organ dysfunction.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

Failure in measuring gas exchange in the ICU.

OBJECTIVE: This study was performed on patients after coronary artery bypass surgery, and in healthy volunteers to assess discrepant oxygen consumption (VO2) measurement between indirect calorimetry and Fick methods. Further evaluations were performed to point out the technical failure. METHODS: In this prospective study, the VO2 was assessed in the patients using a commercial indirect calorimeter and the reverse Fick method. This calorimeter does not directly measure gas flow, but it assumes a constant preset flow. Bench testing of the calorimeter was performed in spontaneous and respirator mode using a reference calorimeter in healthy volunteers. RESULTS: An important overestimation of VO2 and carbon dioxide production (VCO2) of approximately 30% was found in both groups. The actual flow was lower than the preprogrammed value. This lead to spuriously high fractions of carbon dioxide and low fraction of oxygen. VCO2 and VO2, calculated with the overestimated gas flow value were overestimated, while respiratory quotient remained unchanged. Technical check-up revealed leaks in the mixing chamber and in the sampling lines. CONCLUSION: Indirect calorimetry is a useful clinical tool, but the investigator has to be very attentive to all potentially interfering factors and hazards.

Blood Flow Velocity↗
PubMed1994

Thermogenic effect of amrinone in healthy men.

OBJECTIVES: The thermogenic effect of amrinone is unknown and its utilization in patients with severe cardiac failure could potentially increase oxygen requirements and therefore aggravate oxygen debt. Consequently, the present study was undertaken to assess the thermogenic response to amrinone at three different plasma concentrations under controlled conditions and to analyze amrinone's effects on various biochemical variables. DESIGN: A prospective, unblinded, controlled study. The initial control period was followed by three sequential, experimental treatments. SUBJECTS: Ten young, healthy, male volunteers with normal body weight. INTERVENTIONS: Three experimental periods. Amrinone was administered intravenously in progressive doses: a) 0.5 mg/kg followed by 5 micrograms/kg/min; b) 0.5 mg/kg followed by 10 micrograms/kg/min; and c) 1.0 mg/kg followed by 10 micrograms/kg/min. MEASUREMENTS AND MAIN RESULTS: Oxygen consumption (VO2) and CO2 production were continuously measured by means of a computerized indirect calorimeter. At the highest dose, amrinone produced a slight and significant (p < .01) increase in VO2 and in resting metabolic rate (+4.5% and +3.7%, respectively), while no change in CO2 production or in respiratory quotient occurred throughout the study. At the medium and high doses, amrinone increased plasma free fatty acid concentrations by 38% and 53%, respectively (p < .05). No variation in plasma glucose, lactate, insulin, norepinephrine, or epinephrine concentrations was observed during the study. CONCLUSIONS: Amrinone administered intravenously at therapeutic doses has minimal thermogenic and metabolic effects in humans without cardiac failure.

Adult↗
PubMed1994

O2 consumption by the fick method. Methodologic factors.

This study aimed to compare O2 consumption (VO2) determination by the gas-exchange (VO2GE) and Fick (VO2F) methods in cardiac surgical patients. A total of 10 mechanically ventilated postoperative patients were studied prospectively. Thermodilution was performed using three randomly applied techniques: room temperature saline injected at end expiration, room temperature saline randomly injected in the respiratory cycle, and iced saline injected at end expiration. The influence of the number of thermodilution determinations was assessed by comparing results from 2 and 10 injections. The variability of VO2F was greater than that of VO2GE. There was no bias between VO2GE and VO2F values using injectate at room temperature. Accuracy and precision were not improved by increasing the number of cardiac output determinations from 2 to 10. A significant bias was observed using ice-cold injectate, VO2F being 18.0 +/- 15.4 ml/min/m2 lower than VO2GE (p = 0.001). Published results when comparing VO2F and VO2GE are discrepant. However, a significant bias was found in all studies using cold injectate, with lower VO2F values. We conclude that iced injectate should not be used to assess VO2 in critically ill patients.

Adult↗
PubMed1994

Endocrine response to brain injury.

The neuroendocrine response (NER) is an essential component of the adaptive process to trauma, brain injury, and major surgery. While receiving additive humoral and neural afferent inputs, the brain nuclei responsible for the NER act mainly by efferent pathways to the hypothalamic-pituitary-adrenal (HPA) axis and the sympathoadrenal system, the activations of which induce subsequent circulatory and metabolic responses. The NER to brain injury is similar to the response observed in patients with extracerebral injury, even if the response after brain injury is extremely variable. Generally, there is a biphasic pattern, with a sympathoadrenal storm associated with variable and altered stimulation of the HPA during the ebb phase. The first phase is followed by a decrease in both responses while other endocrine changes develop, involving mainly the counter-regulatory, gonadal, and thyroid hormones. The outcome after brain injury is closely correlated with the intensity of these changes, particularly with catecholamine plasma levels and the severity of the low triiodothyronine syndrome. Alterations of the thyroid hormones are largely related to a reduction in peripheral deiodination of thyroxin. Recent research shows that increased free-radical production and decreased selenium (an antioxidant) serum levels play an important role in thyroid metabolism. Two major issues remain unsolved: a) the precise definition of cerebral death, since endocrine brain function is not abolished in the state currently defined as brain death; and b) the question of whether substitutive hormone therapy should be applied in severe brain injury.

Animals↗
PubMed1994

Cost containment: Europe. Switzerland.

Thanks to Switzerland's very favorable economic situation over the last 20 yrs, intensive care medicine in the country has reached a very satisfactory level. The country is covered by a dense network of ICUs certified by the Swiss Society of Intensive Care Medicine (SSICM). Bed allocation is generous, technological equipment plentiful, and nurses are well trained in a specialized certification program. Rules imposed on physician training by the SSICM have recently become more stringent. A large supply of money in Switzerland has made cost containment efforts a low priority; no well defined program to reduce intensive care costs is in effect. Due to an increasingly difficult economic situation in the future, Switerland's near optimal healthcare system may change; cost containment will probably have to be dealt with seriously in the near future.

Attitude to Health↗
PubMed1993

Effects of infused sodium acetate, sodium lactate, and sodium beta-hydroxybutyrate on energy expenditure and substrate oxidation rates in lean humans.

Infusion of sodium acetate in lean humans results in a decrease in respiratory exchange ratio, which may be advantageous in patients with respiratory failure. However, this potential decrease in respiratory work was observed to be offset by significant thermogenesis. The metabolic effects of sodium acetate, sodium lactate, and sodium beta-hydroxybutyrate, infused at a rate of 20 mumol.kg-1.min-1 for 3 h, was monitored in six healthy human volunteers. Respiratory exchange ratio decreased from 0.85 +/- 0.02 at baseline to 0.75 +/- 0.02, 0.75 +/- 0.02, and 0.80 +/- 0.02, after acetate, lactate, or beta-hydroxybutyrate, respectively (P < 0.05 for each). Acetate produced a larger thermic effect (22.7% of energy infused) than did lactate (16.3%) or beta-hydroxybutyrate (13.6%). Thus, sodium salts of organic acids may potentially decrease the respiratory requirements by decreasing the respiratory exchange ratio. However, this effect is partially offset by the thermic effect of these substrates. The maximal doses and safety of these anions during larger infusion periods remain to be determined.

3-Hydroxybutyric Acid↗
PubMed1992

Cutaneous copper and zinc losses in burns.

To measure the exudative cutaneous copper (Cu) and zinc (Zn) losses in burns, 10 patients, aged 36 +/- 9 years (mean +/- s.d.) with burns covering 33 +/- 10 per cent of the total body surface area, were studied from the first postburn day (D1) until D7. All intakes and losses were analysed for Cu, Zn and nitrogen (N) content. Cutaneous losses were extracted from textiles surrounding the patients. Urinary excretions were 0.12 +/- 0.06mg/24h for Cu, 0.9 +/- 0.6mg/24h for Zn, and 14.1 +/- 4.4g/24h for N. Mean daily exudative losses through wound seepage from D1 to D7 were 4.7 +/- 2.1mg/24h for Cu, 27.1 +/- 14.4mg/24h for Zn, and 8.7 +/- 3.8g/24h for N. The cumulated mean losses over 7 days were 37mg for Cu, and 212mg for Zn, representing respectively 20-40 per cent and 5-10 per cent of normal body content. Serum Cu and Zn levels were strongly depressed. The urinary Cu/N ratios correlated with clinical improvement. We conclude that the exudative Cu and Zn losses during the first week postburn contribute significantly to the increased nutrient requirements in burns.

Adult↗
PubMed1992

Current concepts in pediatric burn care: management of burn wounds with cultured epidermal autografts.

Our experience with CEA is based on 21 patients operated on from 1986 to 1991. The areas covered with CEA measured 500 cm2 to 3160 cm2. At one setting no more than 40 sheets of 40 cm2 CEA have been transplanted. The take of CEA is over 75% when applied to dermis. The same holds true when covering "deepithelialised" skin homografts on immunosuppressed patients. Scar formation has not been a problem, and the overall results have been good.

Adolescent↗
PubMed1992

Evaluation of the consistency of Acute Physiology and Chronic Health Evaluation (APACHE II) scoring in a surgical intensive care unit.

OBJECTIVES: To determine the applicability of the Acute Physiology and Chronic Health Evaluation (APACHE II) scoring system in a Swiss ICU, and to evaluate its utility in evaluating data from 2 yrs of consecutive admissions to show that the predictability of outcome is similar to that predictability observed by Knaus et al. in 1985 (in 5,815 patients), with the provision that large numbers of patients are studied. DESIGN: Prospective clinical trial over 2 yrs, with statistical analysis of the Swiss patients, and between the Swiss patients and the patients studied by Knaus et al. Receiver operating characteristic curves were calculated. SETTING: Surgical ICU in a Swiss university hospital. PATIENTS: A total of 2,061 consecutive patients admitted to the surgical ICU who were classified as postoperative (elective or emergency) and nonoperative. Hospital mortality rate was considered. RESULTS: Patients were 53 +/- 16 yrs of age. Mean APACHE II score was 10.5 +/- 7.0. The mean APACHE II score was significantly (p < .001) lower in the 1,813 survivors (9.0 +/- 5.2) than in the 248 nonsurvivors (21.5 +/- 8.5). The mortality rate was higher among the Swiss patients when compared with the patients studied by Knaus et al. who had postoperative scores of 20 to 29 and nonoperative scores of > 24. The distribution of the scores and mortality rates were stable during the two study periods, as were the differences in mortality rates between the Swiss population and that population studied by Knaus et al. Sensitivity and specificity of the scores were highest in the emergency surgery group (87% and 78%), and lowest in the elective surgery group (76% and 73%). The APACHE equation underestimated the risk of death. CONCLUSIONS: The APACHE II score, because of its consistency over time and the stability of the mortality rates, can be used in our surgical ICU without modification. The calculated risk of death gives no additional information.

Adolescent↗
PubMed1992

Metabolic and respiratory effects of infused sodium acetate in healthy human subjects.

The metabolic and respiratory effects of intravenous 0.5 M sodium acetate (at a rate of 2.5 mmol/min during 120 min) were studied in nine normal human subjects. O2 consumption (VO2) and CO2 production (VCO2) were measured continuously by open-circuit indirect calorimetry. VO2 increased from 251 +/- 9 to 281 +/- 9 ml/min (P < 0.001), energy expenditure increased from 4.95 +/- 0.17 kJ/min baseline to 5.58 +/- 0.16 kJ/min (P < 0.001), and VCO2 decreased nonsignificantly (211 +/- 7 ml/min vs. 202 +/- 7 ml/min, NS). The extrapulmonary CO2 loss (i.e., bicarbonate generation and excretion) was estimated at 48 +/- 5 ml/min. This observation is consistent with 1 mol of bicarbonate generated from 1 mol of acetate metabolized. Alveolar ventilation decreased from 3.5 +/- 0.2 l/min basal to 3.1 +/- 0.2 l/min (P < 0.001). The minute ventilation (VE) to VO2 ratio decreased from 22.9 +/- 1.3 to 17.6 +/- 0.9 l/l (P < 0.005), arterial PO2 decreased from 93.2 +/- 1.9 to 78.7 +/- 1.6 mmHg (P < 0.0001), arterial PCO2 increased from 39.2 +/- 0.7 to 42.1 +/- 1.1 mmHg (P < 0.0001), pH from 7.40 +/- 0.005 to 7.50 +/- 0.007 (P < 0.005), and arterial bicarbonate concentration from 24.2 +/- 0.7 to 32.9 +/- 1.1 (P < 0.0001). These observations indicate that sodium acetate infusion results in substantial extrapulmonary CO2 loss, which leads to a relative decrease of total and alveolar ventilation.

Acetates↗