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Biomedical subjects

B Delafosse

Publications and source records attributed to B Delafosse.

At least 19 recordsLinked to original sources
PubMed2000

Time course of oxidative stress after major burns.

OBJECTIVE: To evaluate oxidative stress resulting from major burns in humans. DESIGN: Prospective clinical study with control group. SETTING: Mechanically ventilated adult patients admitted with more than 30% total burn surface area. PATIENTS AND PARTICIPANTS: 20 patients with a mean body surface burned area of 54%. MEASUREMENTS AND RESULTS: The oxidative stress evaluation was based on measurements of trace elements, vitamins, antioxidant enzymatic activity and end-products of lipid peroxidation. During the first 5 days after injury burn patients exhibit a decrease in selenium and antioxidant vitamins (C, beta-carotene, lycopene) and an increase in lipid peroxidation products (TBARS). CONCLUSION: Our results suggest that major burn is associated with oxidative stress during the 5 days after the initial injury, as demonstrated by a simultaneous decrease in antioxidant vitamins and a large increase in TBARS.

Adult↗
PubMed2000

Successful treatment of hepatic hydrothorax with octreotide.

Hepatic hydrothorax is a rare complication of cirrhosis. Controlling ascites formation is the goal of therapy. We report the case of an adult patient presenting with alcoholic cirrhosis who developed first a symptomatic hydrothorax, refractory to diuretics and fluid and sodium restriction, and then an hepatorenal syndrome. Treatment consisted of chest tube insertion and 5 days' intravenous infusion of octreotide. Complete clinical and biological data were reviewed. Octreotide administration resulted in an increased urinary outflow and sodium output, concomitant with improved renal function. The patient has been free of symptoms after discharge from hospital for a follow-up period of 5 months. This observation raises interesting issues regarding the possible utility of splanchnic vasoconstrictors, reducing portal hypertension, in the treatment of refractory hepatic hydrothorax.

Drainage↗
PubMed1998

Time course evolution of ventilatory responses to inspiratory unloading in patients.

Inspiratory muscle unloading decreases ventilatory drive. In this study, we examined the time course of this effect in patients with chronic obstructive pulmonary disease receiving two modes of ventilatory support: pressure support ventilation (PSV), during which each cycle was assisted, and biphasic positive airway pressure (BIPAP), set up in such a manner that one spontaneous breath took place between two consecutive pressure-assisted breaths. The first breath following the switch from spontaneous breathing to PSV was associated with an increase in tidal volume (VT) and a drop in mean transdiaphragmatic pressure (mean Pdi) and inspiratory work (WI) performed per liter but with unchanged values of esophageal occlusion pressure at 100 ms (Pes 0.1), diaphragmatic electrical activity (EMGdi), and WI performed by breath. The same phenomena were observed for the assisted breath of BIPAP as compared with the preceding spontaneous breath. During the subsequent breaths of PSV, Pes 0.1, EMGdi, and WI performed per breath decreased progressively up to the sixth to eighth breaths, and VT returned to pre-PSV values. We conclude that in patients with chronic obstructive pulmonary disease the decrease in ventilatory drive associated with PSV takes place from the first breath onwards but requires six to eight breaths to be fully achieved. During BIPAP, as a consequence of the kinetics of the PSV-induced downregulation of ventilatory drive, assisted breaths following spontaneous breaths are characterized by an enhanced inspiratory efficiency.

Aged↗
PubMed1997

Long- and medium-chain triglycerides during parenteral nutrition in critically ill patients.

Due to their special metabolic pathway, medium-chain triglycerides (MCT) have been claimed to be oxidized more extensively, compared with long-chain triglycerides (LCT), when administered as a parenteral nutritional support. This enhanced lipid oxidation rate of MCT emulsions could be particularly disclosed in hyperglycemic and hyperinsulinemic conditions. In an attempt to further elucidate this question, we measured substrate oxidation rates in critically ill patients liable to experience such metabolic conditions, that is to say postoperative patients after esophageal resection receiving 1.5 times their measured energy expenditure (n = 12) or after liver transplantation (n = 8). These patients received either LCT or MCT-LCT emulsions. The metabolic measurements were performed simultaneously by two methods, namely indirect calorimetry and isotopic methods based on natural abundance of nutrients. Although both groups of patients were hyperglycemic and hyperinsulinemic, the measured carbohydrate and lipid oxidation rates were not different with whatever type of lipid was administered. The MCT-LCT emulsions did not offer clear-cut advantages over LCT emulsions in critically ill patients when lipid energetic fate was considered.

Aged↗
PubMed1996

Gas embolism during laparoscopy: a report of seven cases in patients with previous abdominal surgical history.

The use of laparoscopic surgery has grown considerably, and the occurrence of some accidents, albeit rare, is now reported. Among them, gas embolism can induce a bad postoperative outcome. We report seven cases of carbon dioxide embolism (CO2) during laparoscopic surgery. In the seven cases gas embolism occurred during insufflation or a few minutes later. All the patients had a previous abdominal or pelvic surgical history. Five patients presented cardiac bradycardia or arrhythmia. Cardiovascular collapse or cyanosis was the first manifestation in three cases. Sudden bilateral mydriasis was the earliest neurologic sign, present in five cases. Finally, the gas embolism complication was lethal in two cases. In summary, this study strongly stresses the need for precise rules of prevention of gas embolism, and close monitoring of cardiac rhythm during insufflation of carbon dioxide. The patients who had previous surgery should be considered as a risk population.

Adult↗
PubMed1995

Clinical validation of the Deltatrac monitoring system in mechanically ventilated patients.

OBJECTIVE: To evaluate a monitor of pulmonary gas exchange (Deltatrac, Datex) in a clinical setting. DESIGN: After in vitro evaluation, comparison over 2 min between VO2 and VCO2 values measured by the Deltatrac and the Douglas bag technique. Comparisons were also achieved over 8 h periods between the Deltatrac and a system using a mass-spectrometer. SETTING: Polyvalent intensive care unit (ICU 15 beds) in a 1200 bed general hospital. PATIENTS: Comparison with the Douglas bag technique in 10 patients undergoing controlled ventilation. Comparison with the mass-spectrometer system in 25 other patients undergoing controlled or pressure support ventilation. MEASUREMENTS AND RESULTS: Compared to the results obtained by the Douglas bag technique, the bias (+/- 2 SD) for VO2 and VCO2 was -3.5 +/- 26.6 and 6.1 +/- 12.7 ml.min-1, respectively. By comparison with the mass-spectrometer system, the bias for VO2 and RQ was -5.8 +/- 16.0 ml.min-1 and 0.018 +/- 0.048, respectively. No drift between the two systems was observed over time. CONCLUSIONS: The Deltatrac appears suitable for VO2 and VCO2 measurements in ventilated patients and equivalent to a mass-spectrometer system for long term measurements.

Analysis of Variance↗
PubMed1995

[How to assess and monitor postoperative artificial nutrition?].

Quantitative and qualitative nutritional requirements depend on the level of energetic expenses. Various formulas, especially the tables by Harris and Benedict allow the estimation of the level of energetic expenses with an approximation of 14%. Corrective factors permit an adjustment of the figures, according to the level of body aggression. In complex cases, indirect calorimetry allows a more accurate appraisal of energetic expenses. This technique provides also indications on the utilisation of each substrate and allows therefore to determine the optimal carbohydrate-lipid ratio for each patient. The assessment of the direct benefit of artificial nutritional support relies on anthropometric techniques and at present on body composition appraisal by determination of its impedance. The changes in muscular strength are difficult to assess. Moreover the time course of body weight is not specific for nutritional status. Therefore other biological indicators such as the nitrogen balance, the concentration of plasma proteins and albumin are more often assessed; proteins with a short half-life depend on the body aggression level. The potassium balance, which is easy to obtain in clinical practice, is a relevant indicator for nitrogen balance and protein synthesis. Clinical monitoring includes the checking of hydratation and its impact on the circulatory, respiratory and renal functions. The tolerance of enteral nutrition is appraised by the quality of gastrointestinal function. Biological monitoring includes the electrolyte balance and various variables of carbohydrate, lipidic and proteic metabolisms. It allows to check the absence of hyperglycaemia, hyperlipidaemia and cholestasis. The daily checking of catheters is part of the monitoring of nutritional support.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1995

Effects of a continuous lipid infusion on glucose metabolism in critically ill patients.

The effects of lipid administration on carbohydrate oxidation rate remain controversial, particularly in critically ill patients. The aim of this study was to determine the effects of these patients of a continuous lipid infusion on glucose metabolism using indirect calorimetry and stable isotopes. We studied seven patients, mechanically ventilated, during two consecutive 24-h periods. Throughout the first period they received a continuous infusion of glucose (2 mg.kg-1.min-1) and amino acids. During the second period, in addition to the glucose, they received a continuous infusion of 1 mg.kg-1.min-1 of long-chain triglycerides emulsion. Substrate oxidation rates were calculated from pulmonary gas exchange and nitrogen excretion measurements. Glucose kinetic parameters were measured using primed constant infusions of [6,6-2H2]glucose and [1-13C]glucose. The lipid infusion did not modify the glucose metabolism parameters; 45% of the lipid supply was stored.

Aged↗
PubMed1994

Effects of glucose-to-lipid ratio and type of lipid on substrate oxidation rate in patients.

This study is an investigation into the effects of different carbohydrate-to-lipid ratios on CO2 production in postoperative patients and the determination of the substrate oxidation rates induced by long-chain triglycerides (LCT) or a mixture of long- and medium-chain triglycerides (MCT/LCT) at various carbohydrate-to-lipid ratios. Two groups of eight patients randomly received either LCT or MCT/LCT emulsions. Total caloric intake was set at the measured energy expenditure provided at three different glucose-to-lipid ratios (70:30, 50:50, 30:70). We used long-term indirect calorimetry with a mass spectrometer system and measurement of natural enrichment in 13C of expired CO2 and plasma glucose. The carbon dioxide production and minute ventilation were not different among the different glucose-to-lipid ratios, whatever the type of lipid. Increasing the lipid supply up to 70% of nonprotein caloric intake led to an only minor increase in lipid oxidation rate and thus to a net fat deposit. We conclude that large amounts of lipid (LCT or MCT/LCT) were not of interest in such patients.

Aged↗
PubMed1993

Metabolic effects of hemodialysis with and without glucose in the dialysate.

This study was conducted in eight acute renal failure patients undergoing mechanical ventilation to test if the addition of glucose in the dialysate prevents metabolic and hormonal changes induced by hemodialysis. Hemodialysis was performed with a bicarbonate dialysate, a polyacrilonitrile membrane and a continuous heparinization. Two four-hour hemodialysis sessions were performed in each patient: one without glucose (GFD) and one with glucose (GD) in the dialysate at a concentration close to each patient's initial plasma glucose concentration. Oxygen consumption and carbon dioxide elimination, glucose insulin, aceto-acetate and free fatty acids were measured before, during and after the sessions. Oxygen consumption and carbon dioxide elimination were measured with a system using a mass spectrometer. Hemodynamic state and temperature remained constant. Before hemodialysis, respiratory quotient (RQ) values were the same in both groups. There was no change in RQ during GD. There was a decrease in RQ during GFD. Glucose and insulin concentrations decreased during GFD and remained unchanged during GD. Aceto-acetate concentration remained constant under both conditions. Free fatty acids concentration increased to the same extent during GD and GFD. The authors conclude that the addition of glucose in the dialysate prevents the decrease in RQ induced by hemodialysis. This effect is most likely related to a decreased mobilization of non-glucidic fuels.

Acute Kidney Injury↗
PubMed1993

Recovery of [13C]bicarbonate as respiratory 13CO2 in mechanically ventilated patients.

Measurement of the nutrient oxidation rate with 13C as a tracer requires knowledge of the value of its coefficient of fractional recovery in the expired gas (FR). We measured FR in nine intensive care patients who were mechanically ventilated and received total parenteral nutrition. NaH13CO3 was administered at a priming dose (3.75 mumol.kg-1.min-1) followed by a continuous infusion (0.05 mumol.kg-1.min-1). Metabolic rate and pulmonary carbon dioxide elimination (VCO2) were measured by using a mass-spectrometer system. The 13C-12C ratio was measured in the expired gas with an isotopic-ratio mass spectrometer and FR was calculated by using standard equations. The average value of FR was 0.899 +/- 0.026 (means +/- SE) and remained stable for each patient on 2 consecutive days. Between patients, the coefficient of variation of FR was 8.6%. Metabolic rate was the only physiological factor found to affect the FR value.

Adolescent↗
PubMed1991

[Orthotopic liver transplantation for severe amanita phalloides poisoning].

Forty-eight hours after a women was poisoned by ingesting Amanita phalloides mushrooms, she developed fulminant hepatic failure with collapse, pH 7.24, lactic acidosis 7.6 mmol/l, hypoglycaemia 3.5 mmol/l, anuria and stage IV coma requiring tracheal intubation and mechanical ventilation. Transaminase level was up to 8,000 UI/l. Prothrombin and factor V levels were below 10 percent, with an APT time of 86 s versus a 29 s control time. Twenty-four hours after her admission, the patient underwent orthotopic liver transplantation. The postoperative period was uneventful, with return to consciousness and rapid normalization of hepatic biochemistry values, without signs of acute rejection. This 10th published case of orthotopic liver transplantation for Amanita phalloides poisoning with acute hepatic necrosis confirms that this type of treatment must be systematically envisaged in all such cases.

Amanita↗