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Biomedical subjects

Y Bouffard

Publications and source records attributed to Y Bouffard.

At least 37 records · Page 2Linked to original sources

Effects of protein intake on pulmonary gas exchange and ventilatory drive in postoperative patients.

The effects of different protein regimens on pulmonary gas exchange and ventilatory drive were examined in eight postoperative patients receiving inspiratory pressure support ventilation. They were studied during 60 consecutive hours, which included two 12-h periods of high protein intake (33%) of total caloric intake provided as protein), each of them being preceded and followed by a 12-h period of standard protein intake (14% of total caloric intake provided as protein). Throughout the study, total caloric intake was 1.5 times the predicted resting energy expenditure. Nitrogen was provided as a 24% branched chain amino acid (BCAA) solution during the period of standard protein intake. During the periods of high protein intake, it was provided as a 24% and a 41% BCAA solution. Pulmonary gas exchange was continuously measured during the second half of each period, with the use of a mass spectrometer system. Measurements of the ventilatory response to CO2 (FICO2 0, 1.5, and 3%) were achieved at the end of each dietary regimen. O2 consumption, CO2 production, respiratory quotient, minute ventilation, and PaCO2 were the same for the three protein regimens. Changing protein intake failed to affect the ventilatory response to CO2. The authors conclude that, in postoperative patients having inspiratory pressure support ventilation, the administration of a high protein intake does not affect the ventilatory drive and the pulmonary gas exchange.

Carbon Dioxide↗

A case of sotalol poisoning with fatal outcome.

The case of a 58 year old woman who died after ingestion of 14.4 g of sotalol and 50 mg of triazolam is described. Despite medical treatment, intracardiac pacing and hemodialysis, cardiovascular failure persisted and became irreversible. High sotalol concentrations were observed in plasma (65 micrograms/ml) and in post mortem tissues samples. Tissue to plasma ratios ranged from 2.5 to 6. The high drug concentration found in heart tissue (104.4 micrograms/g) explains the difficulties experienced in the sotalol poisoning.

Chromatography, High Pressure Liquid↗

Energy expenditure in the acute renal failure patient mechanically ventilated.

Twenty mechanically ventilated patients with acute renal failure were studied on 31 occasions to determine their energy expenditure (EE) during a 2 h period before a hemodialysis. Oxygen consumption and CO2 elimination were measured continuously with a mass spectrometer system. EE (1660 +/- 48 kcal day-1) was close to the total caloric intake (1682 +/- 83 kcal day-1) and represented 1.19 +/- 0.03 times the predicted resting energy expenditure (PREE) with large inter-individual variations (0.7-1.7 PREE). EE/PREE was higher when sepsis was present (1.31 +/- 0.03 versus 1.14 +/- 0.02; p less than 0.05). Glucose oxidation rate (4.35 mg kg-1 min-1) exceeded glucose intake (2.6 mg kg-1 min-1). Respiratory quotient was 1.02 +/- 0.01. Nitrogen loss was 17.3 +/- 1.7 g day-1 and nitrogen balance -11.9 +/- 1.9 g day-1. In conclusion, EE values were scattered but never exceeded 1.7 times the PREE. Sepsis increased EE. With a nutritional support covering EE, nitrogen balance remained markedly negative and a preferential utilisation of glucose and lipogenesis occurred.

Acute Kidney Injury↗

[Methanol poisoning].

The neurological signs, the cerebral CAT scan aspects and the ocular problems seen in five cases of acute methanol poisoning are reported; these were, respectively, coma requiring assisted ventilation, convulsions, hypotonicity, hypodensity of the putamen, and amaurosis and papillary oedema. The simplified acute physiologic score varied from 11 to 26; the value of 26 was observed in the only death of the series. Pathogenesis of the metabolic acidosis, as well as the different parts played by formic acid, lactic acid and ketone bodies are discussed. A normal or lowered serum potassium in a case of unexplained metabolic acidosis associated with an osmotic gap should make one think of the diagnosis. Macrocytosis, an indirect sign of folic acid deficiency, was in favour of a poor prognosis. The treatment included early gastric lavage, alkalinization, blocking of the metabolism of methanol by ethanol and haemodialysis with a bicarbonate dialysate enriched in ethanol; this corrected the acidosis and permitted the elimination of the toxic metabolites (clearance of methanol: 159 ml X min-1; half-life of methanol during purification: 3.46 +/- 1.32 h; quantity extracted: 246 g). The possible advantages of 4-methyl-pyrazol and alkyldiol derivatives need further confirmation.

Acidosis↗

[Myocardial infarction during postoperative peridural analgesia with opiates].

A case of postoperative myocardial infarction is reported. It occurred seven days after intra-abdominal surgery (left hemicolectomy), in a patient with coronary heart disease. Diagnosis was delayed because of lack of pain; it was suggested by cardiogenic shock occurring 48 h after the initial phase. The patient had been receiving postoperative epidural analgesia with an opioid (pethidine); this may explain the pain was missing, so delaying the diagnosis.

Analgesia↗

Pulmonary gas exchange during hemodialysis.

UNLABELLED: Pulmonary gas exchange was continuously measured in 13 mechanically ventilated patients during 24 hemodialyses for acute renal failure. Minute-ventilation was maintained constant by controlled ventilation and gas exchange was continuously measured by a mass-spectrometer system. Three groups were compared: a cuprophan membrane with an acetate dialysate; a polyacrilonitrile membrane (PAN) with an acetate dialysate; and PAN with a bicarbonate dialysate. Arterial PO2 and the O2 alveolar-arterial gradient were the same regardless of the membrane used. [H+] mildly decreased with all dialysates used. Arterial PCO2 decreased only with the acetate dialysate. O2 consumption increased, up to 20 +/- 5% of the initial values during hemodialysis, and remained increased during the two hours following the hemodialysis. Respiratory exchange ratio was lower after than before the hemodialysis. IN CONCLUSION: the maintenance of a constant minute ventilation prevented hemodialysis induced hypoxemia. VO2 increased during hemodialysis.

Acute Kidney Injury↗

[Acute water intoxication induced by oxytocin].

A new case of oxytocin-induced water intoxication is reported in a 30 year old gravid woman. The severe symptoms of this uncommon complication are principally neurological; biological signs are a hyponatraemia with low plasma osmolality. Usually, biological and clinical signs are rapidly cleared up by treatment, but maternal death or neonatal water intoxication may occur. Such accidents must be prevented by clinical monitoring, watching out for alarm signals (oliguria is always found, resulting from the effect of oxytocin on the kidney), minimum fluid and proportional salt intakes, careful monitoring of oxytocin infusion rates, facilitated by the use of a constant flow-rate pump.

Abortion, Eugenic↗

Alfentanil pharmacokinetics in patients with cirrhosis.

The pharmacokinetics of alfentanil were studied in 11 patients with alcoholic cirrhosis and 10 control patients during general anesthesia. All patients received 50 micrograms . kg-1 alfentanil as an intravenous bolus injection. Plasma concentrations were measured at intervals up to 10 h, using a specific radioimmunoassay technique. Protein binding was measured by equilibrium dialysis. Patients with cirrhosis had a significantly lower (P less than 0.01) plasma clearance of alfentanil of 1.6 +/- 1.0 ml . min-1 . kg-1 (mean +/- SD) instead of 3.1 +/- 1.6 ml . min-1 . kg-1 in the controls. The total apparent volume of distribution was similar in the two groups. The elimination half-life was prolonged from 90 +/- 18 min in the controls to 219 +/- 128 min in the cirrhotics (P less than 0.01). Patients with cirrhosis had a higher (P less than 0.01) alfentanil plasma-free fraction (18.6 +/- 9.4%) compared with the control patients (11.5 +/- 3.9%). When kinetic parameters were corrected for protein binding, the unbound volume of distribution and the free drug clearance were decreased significantly in patients with cirrhosis. Since the concentration alpha 1-glycoprotein to which alfentanil mainly is bound in plasma did not differ in the two groups, it is suggested that the increase in the free fraction is caused by an alteration of binding sites of this protein in patients with cirrhosis. Owing to its delayed elimination and increased free fraction, alfentanil will exert a prolonged and pronounced effect in patients with cirrhosis.

Adult↗

[Acute amiodarone poisoning. Clinical and pharmacokinetic study].

A 73 years old patient, treated with Amiodarone for ventricular tachycardia, ingested 6 000 mg of Amiodarone. This did not induce hemodynamic troubles or aggravation of ventricular arrhythmia. Treatment included a gastric lavage and purging at the third hour. Plasma assay revealed a concentration of 3.69 mg/l at the fourth hour. Their evolution can be described as the sum of two exponentials. The half-life of the first exponential is 4.9 hours ; the half-life of the second one is 544 hours. Amiodarone is an antiarrhythmic agent of high safety.

Aged↗