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Biomedical subjects

B Grenier

Publications and source records attributed to B Grenier.

At least 37 records · Page 2Linked to original sources
PubMed1997

[What should medical decision be based on?].

Medical decision making is basically related to three criteria: 1) estimated effectiveness in terms of objective and subjective results: 2) equity related to the concept of justice in the societal context; 3) legitimacy according to the willingness to pay of the society, its resource availability and the fraction of its income that is allowed to be spent for health care. A worsening dilemma is unescapable between a utilitarian medical project, and the traditional hippocratic rule of rescue no matter what the cost may be. Every care taker should be involved to give a clear account of medical decision in order to generate and adopt some acceptable view for a reliable implementation with respect to equity and justice.

Decision Making↗
PubMed1997

Noninvasive determination of cardiac output in a model of acute lung injury.

OBJECTIVE: To examine the utility of single breath CO2 analysis as a noninvasive measure of cardiac output in a model of acute lung injury. SETTING: An animal laboratory in a university-affiliated medical center. DESIGN: A prospective, animal cohort study comparing 21 parameters derived from single breath CO2 analysis with cardiac output determined by an ultrasonic flow probe. SUBJECTS: Six adult sheep with saline lavage-induced acute lung injury. INTERVENTIONS: Animals were treated with repetitive saline lavage to achieve a uniform degree of acute lung injury (PaO2 of < 100 torr [< 13.32 kPa] on an FIO2 of 1.0). Cardiac output was manipulated by successive injections of an hydraulic constrictor placed around the inferior vena cava and measured using an ultrasonic flow probe. Twenty-one derived components of the CO2 expirogram were evaluated as predictors of cardiac output. MEASUREMENTS AND MAIN RESULTS: Thirty-eight measurements of cardiac output were available for comparison with derived variables from the CO2 expirogam. Stepwise linear regression identified four variables for the equation predicting cardiac output: a) PaO2/FIO2 ratio; b) the angle between the slope lines for phases II and III divided by the tidal volume; c) mixed expired CO2 tension; and d) physiologic deadspace to tidal volume ratio. The multivariate equation was highly statistically significant and explained 80% of the variance (adjusted R2 = .80, p < .0001). The blas and precision of the calculated cardiac output were .00 and .38, respectively. The mean percent difference for the cardiac output estimates derived from the single breath CO2 analysis station was -0.01%. CONCLUSIONS: Our results indicate that changes in cardiac output can be determined using components of the CO2 expirogram with a high degree of reliability in animals with induced acute lung injury. Specifically, the use of four parameters derived from a plot of expired CO2 concentration vs. expired volume predict changes in cardiac output in adult sheep with induced lung injury with an adjusted coefficient of determination of .80. Prospective application of this technology in the clinical setting with the rapidly changing physiology that is characteristic of the acutely ill patient will be essential in determining the clinical usefulness of single breath CO2 analysis as a noninvasive measure of cardiac output.

Acute Disease↗
PubMed1996

[Severe hyperthermia caused by sudden withdrawal of continuous intrathecal administration of baclofen].

Baclofen is used for the treatment of post-traumatic spasticity. It carries a risk of overdose as well as of an acute withdrawal syndrome. We report two cases of severe hypertonia and hyperthermia (> 42 degrees C), occurring after accidental discontinuation of intrathecal infusion of baclofen. Both hypertonia and hyperthermia ceased when administration of baclofen was resumed. In parallel, the patients developed transient life-threatening alterations of hepatic (cytolysis), haematologic (coagulopathy) and cardiorespiratory functions for some days. It is concluded that the occurrence of such a withdrawal syndrome should be prevented, especially in patients with chronic intrathecal administration and first symptoms should be recognized without delay. Relationships with other malignant hyperthermias are discussed.

Adult↗
PubMed1996

High-frequency oscillatory ventilation in pediatric patients.

High-frequency oscillatory ventilation (HFOV) offers the potential to maintain adequate gas exchange without imposing the large pressure swings and tidal volumes associated with ventilatory-induced lung injury. This article reviews the studies evaluating the use of HFOV to treat pediatric respiratory failure, discusses the complications associated with HFOV, and details an approach to the practical application of HFOV in the non-neonatal pediatric population.

Adolescent↗
PubMed1995

[Chronic cervico-brachial neuralgia treated by cervical epidural injection of corticosteroids. Long-term results].

OBJECTIVE: To assess long-term results of a single cervical epidural corticosteroid injection (CECI) in patients suffering from chronic cervicobrachial neuralgia (CCBN). STUDY DESIGN: Open prospective study. PATIENTS: A CECI was performed in 29 patients suffering for more than 12 months from a non-compressive and non-surgical CCBN with permanent pain for at least three months non relieved by an adequately conducted medical treatment. METHODS: The cervical epidural space was injected (C7-T1, 18 G needle) with an increasing volume (maximum 10 mL) of isotonic saline solution to exacerbate patient's cervicobrachial pain. The patients then received an equivalent volume of 0.5% lidocaine plus triamcinolone acetonide (10 mg.mL-1). The pain decrease was estimated on a visual analogic scale (VAS), in comparison to intensity of pain rated at 100 mm before CECI. RESULTS: The mean volume injected into the epidural space was 6 +/- 2 mL. It increased pain in 26 out of 29 patients. After 3 months, a success rate of 83% was obtained, with a pain rate of 12 mm on VAS. Concerning mid- and long-term results, pain relief remained stable for at least 24 months (mean follow-up: 48 +/- 18 months). Simultaneously, the need for analgesics decreased significantly. CONCLUSION: A single CECI in patients suffering from non-compressive and non-surgical CCBN results in long-lasting pain relief.

Administration, Topical↗
PubMed1994

Effect of timolol vs. acetazolamide on sodium hyaluronate-induced rise in intraocular pressure after cataract surgery.

This prospective study was done to compare the efficacy of timolol and acetazolamide in lowering the intraocular pressure (IOP) secondary to the use of sodium hyaluronate (Healon) in cataract surgery. Fifty patients undergoing extracapsular cataract extraction and implantation of a posterior chamber lens were randomly assigned to one of four treatment groups: no viscoelastic (10 patients), Healon with 0.5% timolol drops postoperatively (12 patients), Healon with acetazolamide postoperatively (16 patients), or Healon only (12 patients). The IOP was measured during the first 24 hours after surgery. Sodium hyaluronate caused a marked increase in IOP in the early (6 to 12 hours) postoperative period. Timolol proved to be more effective than acetazolamide in controlling this pressure increase.

Acetazolamide↗
PubMed1991

Suction blisters technique in amikacin diffusion through interstitial fluid in cystic fibrosis.

Modifications in the pharmacokinetics of aminoglycosides have been reported among patients with cystic fibrosis. We obtained suction blister fluid (SBF) to study the tissue diffusion of amikacin in cystic fibrosis in 2 children (a 9-year-old boy and a 7-year-old girl) over the course of bronchopulmonary infection. Amikacin was administered intravenously using a single dose of 5 mg/kg. The peak plasma concentrations were 24.5 and 11.2 mg/l, and the peak SBF concentrations were 8.3 and 3.2 mg/l. The ratio of the area under the curve in SBF and plasma was 58 and 60%, respectively. These results suggest a good penetration of amikacin through SBF and a good tissue diffusion of amikacin. The preliminary data suggest that the suction blister method may be useful to assess the tissue diffusion of drugs.

Amikacin↗
PubMed1991

[Tools for the evaluation of diagnostic techniques].

This presentation focuses on evaluation of the diagnostic value of clinical findings, laboratory test results and data provided by diagnostic technologies including imaging techniques. A sign S or indicant of a disease D is a datum which is more frequent (more likely) in patients with the disease D than in subjects free of the disease D. The ratio of these two conditional probabilities is the likelihood ratio or Bayes factor of S for D. For a given test T, the number of likelihood ratios is equal to the number of different result patterns obtained with test T. The likelihood ratio reflects the role of the test result in the predictive value, i.e., the likelihood that the disease is present given the test result observed. The likelihood ratio is the tool of choice for evaluating the diagnostic value of a test. The method proposed by Spiegelhalter and Knill-Jones is based on the likelihood ratio. Evaluation of an imaging technique rests on the characteristics of the "image-physician" combination. The rating method can be used to analyze Receiver Operating Characteristic curves in view of assessing either the imaging technique or the physician's diagnostic skills.

Clinical Laboratory Techniques↗
PubMed1990

[Choice of antibiotic treatment in otitis media].

The choice of antibiotics to be prescribed in otitis media may be guided by microbiological culture of the middle ear exudate obtained by tympanocentesis, or by direct examination and culture of purulent material obtained by myringotomy after rupture of the tympanic membrane. Otherwise, routine antibiotic prescription is based on the epidemiological frequencies of bacteria such as Streptococcus pneumoniae, Hoemophilus influenza or Strepcococcus A. In children who have infrequently received beta-lactam antibiotics, amoxicillin 50-75 mg/kg/day for 10 days may be the first choice. Children who suffer from recurrent episodes of acute otitis media may benefit from one of the three following prescriptions: amoxicillin + clavulanate (Augmentin), or an oral cephalosporin, or the erythromycin + sulfisoxazole combination (Pediazole). If recurrences are frequent and at short intervals, antibiotic prophylaxis may be effective, using penicillin V (Oracillin) 250,000 IU daily throughout the entire cold period.

Acute Disease↗
PubMed1990

[Is the qualitative research of benzodiazepines by the EMIT method and diazocopulation in accidental poisoning in children relevant?].

A retrospective study was undertaken to evaluate the relevance of benzodiazepine detection in 42 children with accidental poisoning. Immunoenzymatic assay for benzodiazepine in serum and colorimetric method in urines were positive respectively in 3 and 4 patients only. Several reasons could explain these results: the high detection threshold, the different drug reactivity according to the molecular structure and the great delay between intoxication and toxicology analysis. An advised physician should not prescribe a toxicological analysis after a small quantity of benzodiazepine ingestion.

Benzodiazepines↗
PubMed1988

Distribution of cholesterol in milk fat fractions.

Milk fat was fractionated into liquid (m.p. congruent to 12 degrees C), intermediate (m.p. congruent to 21 degrees C) and solid (m.p. congruent to 39 degrees C) fractions by three different processes--melt crystallization, short-path distillation and supercritical CO2 extraction--and the cholesterol content of these fractions determined. Cholesterol was enriched in the liquid fractions from all three processes, in particular about 80% of the cholesterol being found in the liquid fraction obtained by short-path distillation. The basis of migration of cholesterol into various milk fat fractions was explained by its affinity to various triglycerides (melt crystallization) and by vapour pressure and molecular weight (short-path distillation). It was more complex in the supercritical CO2 extraction process; the interplay of cholesterol affinity toward CO2 and its molar volume, and its vapour pressure enhancement under applied pressure play a role.

Animals↗
PubMed1987

[Erythromelalgia, arterial hypertension and increased excretion of urinary catecholamines].

A 7 year-old girl was hospitalized with acute, severe and drug resistant erythromelalgia. During her stay in the hospital, she presented with an epileptic seizure associated with hypertension (220-120 mmHg). Catecholamine urinary excretion was markedly increased. Diagnoses of pheochromocytoma and acrodynia were excluded. Erythromelalgia and hypertension both disappeared in a few days without any relapse after a 2 year-follow-up. Catecholamine urinary excretion returned to normal levels in a few weeks. A skin biopsy which was performed in an affected site, showed a slight and questionable reduction of the density of autonomic adrenergic nerve terminals in the periarterial and glandular plexuses. The relevance of transitory excess catecholamine excretion and its link with erythromelalgia and hypertension are discussed. The hypothesis that the disorder could be explained by an abnormality of distal autonomic axons is likely.

Catecholamines↗