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Biomedical subjects

C Lefrançois

Publications and source records attributed to C Lefrançois.

At least 19 recordsLinked to original sources
PubMed1999

Anaphylactoid and anaphylactic reactions to iodinated contrast material.

Some adverse reactions to iodinated contrast material (ICM) are considered allergy-like, with cutaneous, cardiovascular, respiratory, and digestive symptoms. Allergy-like reactions are usually unpredictable. Reactions are more frequent with ionic than with nonionic material, but the frequency of deaths is almost identical. In a recent study, 20 severe unexpected reactions to ICM, including 10 life-threatening reactions and one death, were investigated by measuring mediators in blood, within the first minutes or hours of reaction. The responsible ICMs were mostly ionic materials. Histamine and tryptase release correlated with the severity of the reaction. Specific IgE against the responsible ICM was significantly higher in reactors than in controls. A few patients had positive skin tests to the administered ICM, suggesting type-I allergic reaction. Only 2.4% and 3.1% of the cases yielded a positive IgE-RIA, in a second retrospective study which included 165 patients recruited during a 4-year period. In conclusion, IgE-mediated anaphylaxis is rare, but it may be one of the possible mechanisms of severe adverse reactions to ICM.

Anaphylaxis↗
PubMed1997

[Digestive hemorrhage disclosing an angiodysplasia and von Willebrand disease type 2].

The authors report a case of a 76-year-old man, with not past history of abnormal bleeding, who suffered an acute, recurrent, intestinal haemorrhage from extensive angiodysplasia of the colon. Intestinal bleeding and angiodysplasia were associated with a von Willebrand's disease. Genetic analysis showed a point mutation in arginine 611 of the mature von Willebrand's factor subunit (A1 loop) confirming a von Willebrand's disease type 2.

Aged↗
PubMed1996

Screening of health risk factors prior to exercise or a fitness evaluation of adults with traumatic brain injury: a consensus by rehabilitation professionals.

A modified Delphi technique was used to obtain group consensus among 31 rehabilitation professionals (RPs) from nine rehabilitation centres throughout the province of Québec (Canada) to ascertain their expert opinion on the health risk factors (HRF) to be verified prior to beginning an exercise programme or evaluation for patients with traumatic brain injury (TBI). From the initial survey 87 items were generated, which were later regrouped into 27 HRFs. The relative importance of each HRF in regard to being screened before exercise in a population with TBI was then assessed by each RP using a five-point ordinal scale (1 = not important to 5 = extremely important). HRFs that were considered extremely important by at least 50% of HPs include: angina pectoris, aortic stenosis, exertional syncope, musculoskeletal sequelae which are exacerbated by exercise, outward aggressivity, pulmonary embolism, uncontrolled epilepsy (seizures), and ventricular arrhythmias. Professionals involved in exercising patients with TBI may find these factors useful to the efficient conduct of their rehabilitation programme.

Adult↗
PubMed1995

Radioimmunoassay for plasma histamine: a study of false positive and false negative values.

In order to achieve a correct diagnosis of drug anaphylaxis using a radioimmunoassay devoid of interferences, we have studied factors leading to false positive or false negative values of plasma histamine. Different steps in sample collection were studied systematically in 30 normal volunteers. False positive values were found in haemolysed samples, with histamine concentrations being correlated with haemoglobin concentrations, and where plasma was aspirated from the white-cell layer. There was no significant increase when a tourniquet or vacuum tubes were used, or when blood tubes were left at 4 degrees C overnight. In 12 patients who experienced an anaphylactic reaction, histamine disappeared from blood 10 times more slowly than expected. False negative values were found in two pregnant women and one heparinized patient. Histamine was remarkably stable in vitro in blood or plasma samples, whereas it disappeared rapidly when plasma from a pregnant woman or a heparinized patient was added to the sample. We conclude that false positive and false negative values are rare when using this radioimmunoassay.

Adolescent↗
PubMed1994

[Mesentric venous thrombosis. Risk factors, treatment and outcome. An analysis of 18 cases].

Eighteen patients with an acute thrombosis of the splanchnic veins were reviewed. Most of apparently idiopathic cases of splanchnic vein thrombosis are related to an increased coagulation related to a congenital or acquired defect of haemostasis. The aim of this study was to assess the effects of a new and effective treatment. Nine male and 9 female patients (range of age: 19 to 81 years) experienced a mesenteric venous thrombosis. There were 14 mesenteric vein thromboses with infarction, two transient mesenteric venous ischaemias without bowel infarction and two acute thromboses of the splanchnic veins without bowel ischaemia. A coagulopathy was detected in seven patients: oral contraception, protein C (PC) or antithrombin III (AT III) congenital deficiencies, acquired deficiency of AT III, PC and protein S (PS), polycythaemia in the post-partum period and primary myeloproliferative disorder. No coagulopathy was associated with thrombosis in eight cases: mesenteric haematoma, splenomegaly, cirrhosis, appendicectomy, cholescytectomy, chronic heart failure, treatment with beta-adrenergic receptor antagonist and digitalis, stenosis of the portal anastomosis after liver transplantation. Twelve patients required surgery: eight intestinal bowel resections with immediate anastomosis, four resections without immediate anastomosis. Only one patient underwent a second look for a repeat bowel resection. No death occurred in the early postoperative period and 17 out of 18 patients were alive after 12 years. An oral anticoagulant therapy was undertaken from two months to seven years. However, three patients suffered a recurrent thrombosis. Two of them required a long-term anticoagulation. Six patients experienced a portal hypertension and oral anticoagulants were discontinued in three of them because of bleeding oesophageal varices. Six patients were treated only by unfractionated heparin (UFH) or low molecular weight heparin (LMWH) followed by oral anticoagulants. After laparotomy, two were only treated with UFH without any bowel resection, as mesenteric venous ischaemia was too extensive. These observations suggest that the choice between an appropriate medical or surgical treatment is important and must be discussed. Since 1989, the therapeutic choice has been modified by ultrasonography and contrast enhanced computed tomographic scan which confirms diagnosis, allows to follow up and check the effects of anticoagulation and to choose the time for surgery. When the diagnosis is established and the patient's risk is low, the IU . kg(-1) . d(-1) to obtain an antifactor Xa activity between 0.3 and 0.6 antiXa IU mL(-1). When the diagnosis is uncertain and the patient's risk if high a laparotomy is required.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1994

[Antibiotic prophylaxis in surgery of the esophagus].

Surgery of oesophagus carcinoma is a long and major procedure. Perioperative radiochemotherapy is often required. Therefore many factors favour the occurrence of local and general postoperative infection, justifying an antibiotic prophylaxis directed against oesophageal and gastric flora. In case of oesophageal stenosis, the oesophageal floral often switches to the fecal type. Antimicrobial agents diffuse to the surgical site and reach there high concentrations for the time of surgery. We recommend, just prior the induction of anaesthesia the intravenous administration of a single dose of a third generation cephalosporin (ceftriaxone 2 g) and nitroimidazole (ornidazole 1 g). The long half-life of these agents allows sufficient concentrations at surgical site to be obtained and the efficacy of this regimen has been demonstrated. Selective decontamination of the digestive tract with systemic antibiotherapy is another approach for the prevention of postoperative complications of surgery of oesophagus carcinoma.

Anti-Bacterial Agents↗
PubMed1994

[Doppler echocardiography in the evaluation of volume expansion effects in newborn infants].

BACKGROUND: The effects of volume expansion on the cardiac output (CO) of newborns have not been studied, so that the indications for colloid infusion are not well standardized. POPULATION AND METHODS: Twenty one newborns (14 preterm and seven term babies) were studied before the 7th day of life. Thirteen had patent ductus arteriosus (PDA) and six had ischemic cardiopathy. Hemodynamic data indicated that these babies should be given 20 ml/kg of a 10% albumin solution. Pulsed-wave Doppler echocardiography was performed before and after infusion. RESULTS: Only 11 newborns had initial low Co (less than 260 ml/kg/min in patients with PDA; less than 200 ml/kg/min in the others). The increases in CO (31 +/- 25% vs 7 +/- 11%, P < 0.01) and of mean aortic flow velocity (MAFV) (34.6 +/- 19.5% vs 7.2 +/- 6.1%, P < 0.01) were significantly greater in this group. The increases in mean arterial pressure (+4 +/- 5 mmHg) and CO (+20 +/- 18%) were significant (P < 0.01) for all patients, both premature and term (with or without PDA and ischemic cardiopathy). The increase in CO was correlated with the initial CO and the cutaneous refilling time but was not correlated with the increase in arterial pressure. The sizes of the ventricles and left atrium grew significantly but that of the right atrium did not. Analysis of the increase in stroke volume in terms of the end diastolic diameter of the left ventricle indicated that the cardiac reserves varied according to the Starling relation. CONCLUSION: Evaluation of MAFV and CO plus diagnosis of PDA are all needed in order to assess whether volume expansion is accurate or not, since, clinical data obtained during the neonatal period are insufficient to do this.

Albumins↗
PubMed1993

Doppler ultrasound assessment of the effects of ketamine on neonatal cerebral circulation.

The effects of a single dose of 5 mg.kg-1 of ketamine administered intravenously to 10 critically ill preterm infants prior to epicutaneo-caval catheterization were analyzed using pulsed-wave Doppler ultrasound. The infants weighed between 670 and 1,885 g and their gestational ages ranged from 26 to 33 weeks. Arterial pressure (MAP), cardiac output (CO), transcutaneous oxygen pressure (TcPO2), transcutaneous carbon dioxide pressure (TcPCO2), end-diastolic velocity (EDV), peak systolic velocity (PSV), mean arterial velocity (MAV) of the cerebral anterior artery as well as Pourcelot's resistance index (PRI) were measured before and after injection of the drug. We observed a significant decrease in arterial pressure at 2 min after injection while heart rate and CO did not vary significantly. TcPO2 and TcPCO2, also remained unchanged throughout the period of measurement. EDV, PSV, and MAV did not vary significantly nor did PRI. As this drug provides major comfort to the baby during painful procedures and considerably facilitates difficult thin vessel catheterization, we believe that it may be used in such conditions.

Cerebrovascular Circulation↗
PubMed1993

[Value and limits of autopsy in perinatal medicine. A plea for complete perimortem evaluation].

The dead newborns and stillborns of a French department (Ille et Vilaine, préfecture: Rennes) were studied during a 3 year period by a multidisciplinary physician group. There were 128 newborns and 207 stillborns among whom autopsies were carried out in 90 (72%) and 107 (52%) respectively. The contribution of the autopsies to diagnosis was highly different in the two groups: 92% in newborns and 34% in the stillborns. In the stillborns, autopsy was only contributive when congenital malformations were observed, whereas it was not when the cause of the death was obstetrical. We conclude that an autopsy must be performed in all dead newborns and stillborns; however for stillborns complementary investigations must be added, particularly on the placenta.

Autopsy↗
PubMed1992

[Early biological markers of anaphylactoid reactions occurring during anesthesia].

Three markers of in vivo histamine release, i.e. plasma histamine and tryptase, and urinary methylhistamine, were assessed using sensitive radioimmunoassays in 18 patients who had experienced an adverse reaction to an anaesthetic agent. Controls were obtained from 35 patients following a general anaesthetic, which included a muscle relaxant, and who remained free from any adverse reaction. A first blood sample was obtained from all 18 patients a mean 25 +/- 26 min after the reaction, and a second one in thirteen a mean 120 +/- 65 min after the reaction. Ten patients had had a life-threatening reaction. Plasma histamine levels were increased in all these cases, and tryptase concentrations in 9 out of 10. Urinary methylhistamine rarely reached pathological levels (4 out of 10). Skin tests were positive in the four tested patients. Plasma histamine concentration was still high in 8 cases thirty minutes after the reaction, and remained increased for more than 2 h in two patients. Among the other eight patients with a moderate reaction, 3 had high histamine levels, with normal or weakly increased tryptase concentrations, and normal urinary methylhistamine. Two of these patients had positive skin tests. There were no abnormal findings in any of the investigations carried out in the other five patients, except for a slightly positive skin test to atracurium in one patient. Plasma histamine had a higher sensitivity than tryptase levels. Methylhistamine concentrations were only rarely of interest. There were no false positives with the three investigated markers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Early diagnosis of anaphylactic reactions to neuromuscular blocking drugs.

Neuromuscular blocking drugs (NMB) are involved in most of the anaphylactic reactions occurring during anaesthesia. Patients are evaluated usually 6 weeks after the reaction, by skin testing. In order to obtain an earlier diagnosis, we have measured plasma concentrations of histamine, tryptase and NMB-specific IgE antibodies in 14 patients after an anaphylactoid reaction. We have compared the results with those of skin tests and specific IgE obtained 8 weeks later. Good agreement was observed in all subjects between the results of skin tests and the values for histamine and tryptase, provided that both markers were measured simultaneously. Furthermore, there was no significant difference between the concentrations of NMB-specific IgE antibodies observed at the time of the reaction and 8 weeks later. Thus anaphylaxis to neuromuscular blocking drugs can be demonstrated at the time of the reaction by measuring plasma concentrations of histamine, tryptase and specific IgE. In the event of the patient's death, such measurements may be useful in identifying the likely cause.

Adolescent↗
PubMed1992

[Acquired tracheobronchial stenosis of the premature infant under artificial respiration. Value of bronchography and endoscopic balloon dilatation. Apropos of 7 cases].

The authors report about a series of 7 cases of acquired tracheobronchial stenosis in premature infants who were intubated as soon as they were born and ventilated. Two important points can be pointed out: the merits of bedside bronchography, which allows diagnosing the lesions, the merits of balloon dilatation during tracheobronchoscopy on the ENT operating theatre to treat the stenosis. This technique allowed improving ventilation and removing the tube in 6 of 7 cases.

Bronchography↗
PubMed1991

[Post-vaccinal hemi-convulsion hemiplegia syndrome].

An 18-month-old infant developed hemiseizure-hemiplegia syndrome following a booster dose of vaccine against diphtheria, pertussis, tetanus, and poliomyelitis. Clinical, CT scan, and electroencephalographic findings during the two-and-a-half-year follow-up are described. The timing of events and data from the literature suggest that hemiseizure-hemiplegia syndrome is related to post-immunization hyperthermia rather than to direct neurologic toxicity of the vaccine.

Child, Preschool↗
PubMed1991

[Spontaneous and instrumental perforations of the thoracic esophagus (non-neoplastic, non-caustic). Apropos of 20 cases].

The authors present twenty cases of spontaneous or instrumental perforation of the thoracic esophagus (neoplastic and caustic perforations excluded). The delay before treatment was less than 24 hours in only one case. Mortality rate was 15%, concerning three patients (three cases of Boerhaave's syndrome) treated by T tube drainage. The contribution of exclusion using stapling technique should increase the indications of direct suture, which remains elective treatment. Esophagectomy retains its indications for perforations with pathologic esophagus or late diagnosis.

Adult↗