Biomedical subjects

M Manchon

Publications and source records attributed to M Manchon.

At least 19 recordsLinked to original sources

PubMed2001

Remifentanil and controlled hypotension; comparison with nitroprusside or esmolol during tympanoplasty.

PURPOSE: To determine whether remifentanil, combined with propofol, could induce controlled hypotension, reduce middle ear blood flow (MEBF) measured by laser-Doppler flowmetry, provide a "dry" operative field, and could be compared with nitroprusside or esmolol combined with alfentanil and propofol. METHODS: Thirty patients undergoing tympanoplasty and anesthetized with 2.5 mg x kg(-1) propofol iv followed by a constant infusion of 120 microg x kg(-1) x min(-1), were randomly assigned in three groups to receive either 1 microg x kg(-1) remifentanil iv followed by a continuous infusion of 0.25 to 0.50 microg x kg(-1) x min(-1), or nitroprusside iv, or esmolol iv combined for the latter two groups with alfentanil iv. RESULTS: Controlled hypotension was achieved at the target pressure of 80 mmHg within 107 +/- 16, 69 +/- 4.4, 53.3 +/- 4.4 sec for remifentanil, nitroprusside and esmolol respectively. MEBF decreased by 24 +/- 0.3, 22 +/- 3.3, 37 +/- 3% and preceded the decrease in SABP, within 30 +/- 6.1, 11.2 +/- 3.1, 15 +/- 2.8 sec for remifentanil, nitroprusside and esmolol respectively. Remifentanil, and nitroprusside decreased MEBF autoregulation less than esmolol (0.36 +/- 0.1, 0.19 +/- 0.2, -0.5 +/- 0.2). Controlled hypotension was sustained in all three groups throughout surgery, and the surgical field rating decreased in a range of 80% in all three groups. Nitroprusside decreased pH and increased PaCO2. There were no postoperative complications in any of the groups. CONCLUSIONS: Remifentanil combined with propofol enabled controlled hypotension, reduced middle ear blood flow and provided good surgical conditions for tympanoplasty with no need for additional use of a potent hypotensive agent.

Adjuvants, Anesthesia↗

PubMed1996

Comparison between gas chromatography-atomic emission detection and gas chromatography-mass spectrometry for the assay of propofol.

Quantitation by gas chromatography-atomic emission detection (GC-AED) is based on the intensity of the signal measured at a wavelength characteristic of an element, after atomisation by the plasma. This response depends only on the number of atoms of this element present in the molecule under investigation, and is independent of the structure of the molecule. This technique was used for the assay of propofol, and the estimation of its two metabolites, after calibration with standard solutions of pure propofol. The results were compared with those obtained by gas chromatography-mass spectrometry (GC-MS). Propofol was quantified with higher precision and accuracy by GC-AED than by GC-MS which exhibited larger residual values. Concentration assessment for two metabolites showed a better agreement with the theoretical value by GC-AED since the response depends only on the number of carbon atoms in each molecule.

Calibration↗

PubMed1996

Serum and erythrocyte magnesium in critically ill patients.

OBJECTIVES: To evaluate the prevalence of serum and erythrocyte magnesium (Mg) abnormalities in patients on admission to the intensive care unit (ICU) and to test the hypothesis that low levels of Mg are associated with a higher mortality. DESIGN: Prospective study. SETTING: 14-bed ICU in a 1000-bed teaching hospital. PATIENTS: 179 consecutive patients admitted over a 4-month period. MEASUREMENTS: Total serum Mg (Mgs) and erythrocyte Mg (Mge) were determined on admission by atomic absorption spectrophotometry. Severity of illness was assessed by Acute Physiology and Chronic Health Evaluation (APACHE) II and the number of organ system failures (OSF) during the first 24 h. The patients were followed up until discharge from hospital. MAIN RESULTS: On admission, 79 patients (44%) were hypomagnesemic and 10 (6%) were hypermagnesemic. A low level of Mge was observed in 119 patients (66%). In patients with similar APACHE II scores and OSF numbers, more of those with hyperMgs died during their ICU stay. However, the Mge value on admission did not correlate with patient outcome. CONCLUSIONS: We confirm the high prevalence of Mgs abnormalities as well as Mg deficiency on admission to a medical ICU. Low levels of Mgs and Mge are not associated with higher fatality. HyperMgs was associated with patient death.

APACHE↗

PubMed1995

Quantitation of propofol in whole blood by gas chromatography-mass spectrometry.

A gas chromatographic-mass spectrometric assay, using selected-ion monitoring (GC-MS-SIM) with thymol as internal standard, was developed for quantitating propofol, an intravenous anaesthetic. The method described is rapid and sensitive for the determination of propofol in whole blood. The sensitivity of the present method is 10 ng/ml. The recovery of propofol added to human whole blood in the concentration range 10-10,000 ng/ml ranged between 95 and 100%. A single extraction procedure was used with chloroform-ethyl acetate. The assay allowed the detection of two metabolites formed during propofol metabolism: 2,6-diisopropyl-1,4-quinone and 2,6-diisopropyl-1,4-quinol.

Anesthetics, Intravenous↗

PubMed1995

The influence of bilirubin, haemolysis and turbidity on 20 analytical tests performed on automatic analysers. Results of an interlaboratory study.

The director of a laboratory has to be sure to give out reliable results for routine tests on automatic analysers regardless of the clinical context. However, he may find hyperbilirubinaemia in some circumstances, parenteral nutrition causing turbidity in others, and haemolysis occurring if sampling is difficult. For this reason, the Commission for Instrumentation of the Société Française de Biologie Clinique (SFBC) (president Alain Feuillu) decided to look into "visible" interferences--bilirubin, haemolysis and turbidity--and their effect on 20 major tests: 13 substrates/chemistries: albumin, calcium, cholesterol, creatinine, glucose, iron, magnesium, phosphorus, total bilirubin, total proteins, triacylglycerols, uric acid, urea, and 7 enzymatic activities: alkaline phosphatase, alanine aminotransferase, alpha-amylase, aspartate aminotransferase, creatine kinase, gamma-glutamyl transferase and lactate dehydrogenase measured on 15 automatic analysers representative of those found on the French market (Astra 8, AU 510, AU 5010, AU 5000, Chem 1, CX 7, Dax 72, Dimension, Ektachem, Hitachi 717, Hitachi 737, Hitachi 747, Monarch, Open 30, Paramax, Wako 30 R) and to see how much they affect the accuracy of results under routine conditions in the laboratory. The study was carried out following the SFBC protocol for the validation of techniques using spiked plasma pools with bilirubin, ditauro-bilirubin, haemoglobin (from haemolysate) and Intralipid (turbidity). Overall, the following results were obtained: haemolysis affects tests the most often (34.5% of cases); total bilirubin interferes in 21.7% of cases; direct bilirubin and turbidity seem to interfere less at around 17%. The different tests are not affected to the same extent; enzyme activity is hardly affected at all; on the other hand certain major tests are extremely sensitive, increasingly so as we go through the following: creatinine (interference of bilirubin), triacylglycerols (interference of bilirubin and haemoglobin), glucose (interference of bilirubin), cholesterol (interference of bilirubin), phosphorus (interference of bilirubin and haemoglobin), uric acid (interference of turbidity), iron (interference of haemoglobin and turbidity), total proteins (interference of bilirubin, haemoglobin and turbidity) and bilirubin (interference of haemoglobin and turbidity). Three categories of interferences can be found: interference by addition, chemical interference and spectral interference, and the results show that not only the choice of a method is important on the analyser, but also how this has been adapted. By looking into these conditions carefully, it is sometimes possible to find a reason for the problem and thereby a simple solution to correct it.(ABSTRACT TRUNCATED AT 400 WORDS)

Autoanalysis↗

PubMed1995

[Compared diagnostic performances of CKMB measurements by immuno-inhibition and three immunoenzyme methods for the early diagnosis of myocardial infarction].

In 98 patients consecutively admitted in a medical intensive care unit, an aliquot taken from the blood sample withdrawn for the cardiac enzyme admission request has been frozen. After thawing of these 98 aliquots total CK and the creatine kinase MB isoenzyme were measured on the same day. For this last determination, four methods were used and compared: an immunoinhibition method (Merck) and three immunoenzymatic assays (Abbott on IMX; Baxter on Stratus II; Hybritech on single use Icon cylinder). In 19 out of the 98 patients studied the diagnosis of myocardial infarction was made retrospectively by a cardiologist. This diagnosis was established according to the criteria defined by the WHO. The clinical performances (sensitivity, specificity, positive predictive value, negative predictive value) have been calculated for each test according to the following criteria: on the one hand, a cut-off of 8% (reference range of our laboratory) for the immunoinhibition technique; on the other hand, a cut-off defined by the manufacturer together with a cut-off obtained from the ROC curves for the three immunoenzymatic assays. Our results clearly demonstrate that the clinical performances of the three immunoenzymatic CKMB assays are very comparable and appear to be much better than the immunoinhibition method which should be abandoned.

Adult↗

PubMed1994

Effects of posture, hypotension and locally applied vasoconstriction on the middle ear microcirculation in anaesthetized humans.

Studies by laser-Doppler flowmetry of middle ear microcirculation changes induced by physical and chemical stimuli in the animal have only recently been made. This prospective study, performed in humans, was designed to compare the effects of a postural manoeuvre (headup tilt 30 degrees), hypotension and locally applied vasoconstriction on middle ear blood flow during anaesthesia. Circulatory changes provoked by a headup tilt of 30 degrees, and successive intravenous boluses of potent vasodilators, were compared with circulatory changes provoked by locally applied adrenaline, in ten healthy patients in good physical states undergoing middle ear surgical repair. Heart rate and direct arterial pressure were continuously recorded via a radial artery cannula. Middle ear blood flow was continuously recorded via a laser-Doppler probe placed on the promontorium cavi tympani. Metabolic parameters (partial pressure of O2 and CO2 in arterial blood, pH, arterial lactate concentrations) and arterial concentrations of propofol were measured just before and just after the experiment. Headup tilt did not modify heart rate, mean arterial pressure or middle ear blood flow. Vasodilators (nicardipine, nitroprusside, nitroglycerin) provoked a fall in arterial pressure (P < 0.0001, P < 0.0001, P < 0.019, respectively), but did not induce any significant variations in heart rate; variations occurred in middle ear blood flow (P > 0.05, not significant) which were different according to patients and agents. Locally applied adrenaline provoked a fall in the middle ear blood flow (P < 0.0012), with no effect on heart rate and arterial pressure. There were no significant changes in metabolic values, or propofol serum concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1994

Development of a solid/liquid extraction method for analysis of toxic drugs in serum using an automated liquid chromatograph: the Remedi.

The aim of this work was to develop a procedure for analysis of drugs in serum using a chromatographic apparatus marketed by the Bio-Rad company. This automated apparatus, the Remedi, can identify nearly 200 substances and metabolites in biological fluids. The method for pretreatment of serum recommended by the manufacturer is inefficient. We thus decided to develop and validate an extraction method for analysis of serum. Our method extends column life and improves the sensitivity of the Remedi for the detection of drugs. For psychotropic drugs, a study was carried out that enables a semi-quantitative evaluation of blood levels to be made. In addition, the sera of patients admitted to hospital for intentional drug overdosage were studied to compare the results obtained using the Remedi and Emit techniques, and also to compare these results with toxicological data obtained by questioning the patient and his immediate circle.

Blood Chemical Analysis↗

PubMed1993

[Evaluation of an automated liquid chromatograph permitting toxicologic screening of biological fluids].

This study evaluated an automated high performance liquid chromatography algorithm that allows identification of 330 substances and metabolites in biological fluids. We assessed its ability to detect in urine and gastric lavage fluids the main psychotropic drugs ingested with suicidal intent. Antidepressants and most of the phenothiazines were recognised; identification of benzodiazepines was more uncertain. Compared to EMIT techniques, chromatography is less sensitive, but allows precise identification of the offending poison, quantifies the amount, and allows broad toxicological screening of pharmacological classes inaccessible to the EMIT technique.

Antidepressive Agents↗

PubMed1992

Treatment of malignant peritoneal effusion in digestive and ovarian cancer.

Intra Peritoneal Chemo Hyperthermia (IPCH) with Mitomycin C (MMC) or Cisplatinum (CP) was used to treat 32 patients with far advanced digestive or ovarian cancers and peritoneal carcinomatosis. Surgical resection of the primary tumor has been possible in 18 cases. After closure of the abdominal wall, a 90 minutes IPCH as performed under general anaesthesia and 32 degrees C general hypothermia, through 3 intraperitoneal drainages realizing a closed circuit, using 10 mg/l of MMC or 15 to 25 mg/l of CP in 6 l of peritoneal dialysate heated at the inflow temperature of 46 to 49 degrees C. The mortality rate was 3% and the morbidity rate was 3%. In 11 out of 12 patients with preoperative malignant ascites, no more ascites could be found after IPCH. For peritoneal carcinomatosis from digestive origin, median survival was 11.2 months and 1 year survival rate was 46.9%. These encouraging preliminary results show that IPCH is a safe and reliable treatment for peritoneal carcinomatosis in far advanced digestive or ovarian cancers.

Adenocarcinoma↗

PubMed1992

[Local analgesic action by direct effect of pethidine on the nervous trunks].

The aim of this paper is to study the analgesic effects of meperidine (pethidine) on nervous trunks. First we compared the analgesic effect of pethidine in surgery of knee and femur. Meperidine was randomly administered either by femoral block or intravenously. The onset of analgesia was shorter with femoral block (5 minutes against 146 minutes). In the surgery of shoulder, nerve block with meperidine was performed using intersclalenic block. Plasma concentrations ar lower (maximum of 0.29 mg per liter) than intravenous therapeutic concentrations (between 0.5 and 0.7 mg per liter). So we can conclude as do other papers, there is a direct effect of meperidine on nervous trunks. This effect is probably mediated by receptors located on nervous trunks.

Female↗

PubMed1990

Isolation-induced changes in radioligand binding to benzodiazepine binding sites.

Binding of [3H]flunitrazepam was studied in brain tissues of isolated Wistar rats and compared to group-reared animals. Modifications were observed in hippocampus and cortex (Kd increased) and in cerebellum (Bmax decreased) and when brain sections of control rats were incubated in the bath fluid that had served to incubate sections from isolated rats, a flattening of the saturation curve was observed. Results are discussed in terms of possible modulators of benzodiazepine binding sites, mainly tissue GABA concentrations.

Animals↗

PubMed1990

[Voluntary drug poisoning: epidemiology, performance and limits of the emergency laboratory].

The aim of this study is to determine the efficiency ot toxicologic screening (detection of barbiturates, benzodiazepines, tricyclic antidepressants, salicylates, phenothiazines, meprobamate and ethanol assay), during acute drug poisoning. In 1988, 898 patients are enclose in this study. Screenings are negative in 17% of cases; benzodiazepines, alcohol and antidepressants are often found. The recovery is very good for barbiturates and salicylates but it's not perfect for benzodiazepines, particularly flunitrazepam triazolam, loflazepate, oxazepam, and non tricyclic antidepressants. This failure probably depends on these emergency methods.

Clinical Laboratory Techniques↗

PubMed1989

Intraoperative glucose infusion and blood lactate: endocrine and metabolic relationships during abdominal aortic surgery.

The hypothesis that increased intraoperative blood lactate depends both on intraoperative glucose supply and inadequate tissue oxygenation occurring during surgery was tested in anesthetized patients undergoing infrarenal abdominal aortic surgery. Twenty surgical patients received either Ringer's solution or 5% glucose solution for intraoperative volume loading. Arterial blood lactate, arterial glucose, hemodynamic variables, insulin, glucagon, cortisol, epinephrine, and norepinephrine were determined preoperatively and intraoperatively. There were no significant changes in hemodynamic values, glucagon, norepinephrine, and epinephrine compared with control values in both groups. Oxygen consumption decreased only during aortic clamping. Cortisol and lactate increased significantly 10 min after aortic clamping until the end in both groups. Glucose 5% solution infusion resulted in significantly greater blood lactate accumulation and significantly greater blood glucose and insulin levels, whereas there were no changes in the patients receiving Ringer's solution. From control until aortic clamping, lactate and glucose were significantly correlated with each other in both groups; after aortic clamping until the end of the procedure, the correlation remained constant in patients in the Ringer's group, whereas no relationship could be demonstrated in those in the glucose group. The authors conclude that intraoperative glucose administration increases intraoperative blood lactate and that blood lactate accumulation depends both on glucose supply and tissue oxygen deficit. Furthermore, none of the hemodynamic metabolic and endocrine factors were reliable for assessing tissue perfusion and metabolic demands during surgery.

Anesthesia, General↗

PubMed1987

Benzodiazepine receptor and neurotransmitter studies in the brain of suicides.

The characteristics of benzodiazepine binding sites (affinity, number heterogeneity) were studied on frozen sections of hippocampus of 7 suicides and 5 controls subjects, using biochemical and autoradiographic techniques. 3H flunitrazepam was used as ligand, clonazepam and CL 218,872 as displacing agents. Some neurotransmitters or their derivatives (GABA, catecholamines, hydroxy-indols) were evaluated quantitatively in parallel in the hippocampal tissue by liquid chromatography. We observed mainly an increase in the Ki of CL 218,872 subtype I binding sites in suicides, (7.48 +/- 1.7 to 17.24 +/- 1.7 nM, P less than 0.01), (m +/- SEM) and an increase in % of type I binding sites (30 +/- 4.2 to 42 +/- 2.5, P = 0.01). Among neurotransmitters, only norepinephrine differed significantly between controls and suicides (11.34 +/- 1.9 to 24.34 ng/g tissue, P = 0.02).

Adolescent↗

PubMed1987

[Assay of digoxin on dry-reagent strips].

An automated immunoassay for Digoxin in serum using dry-reagent strips (Stratus Dade) was evaluated, and compared with two others immunoassays (TDX Abbott and ACA Du Pont). Precision, sensitivity and specificity were satisfying, as well as correlation study, but discrepancies observed for some sera proved that these techniques still pose serious problems of specificity or of standardisation.

Digoxin↗

PubMed1986

[Creatine phosphokinases and serum and urinary myoglobin following a procedure in prolonged knee-chest position for the treatment of spondylolisthesis].

Rhabdomyolysis following the knee-chest position was studied in 15 patients scheduled for surgery for spondylolisthesis. A comparison was made between 11 patients scheduled for orthopaedic surgery: ligamentoplasty (6 patients), total hip prosthesis (5 patients) and 11 patients scheduled for long oral surgery. The measurements carried out were blood CPK before surgery, 4, 8, 12 and 24 h after the beginning of surgery, and at days 2, 3 and 4. Blood and urinary myoglobin were measured at days 1, 2, 3 and 4 after surgery. The results were tested with the Mann and Whitney test. There was no statistical change in CPK and myoglobin in the test population. Following the knee-chest position, there was a statistical increase of CPK in all patients, with great individual variations. Myoglobinaemia and myoglobinuria were observed in six patients, these not being correlated with the variations of CPK. Nevertheless, the maximal increase of CPK and myoglobin was seen in one patient, without any modification of diuresis but with an increase of creatininaemia at 220 mmol X l-1. In this series, rhabdomyolysis was real. CPK was not a good index of the release of haematic pigments, the only dangerous ones. A qualitative search for myoglobinuria is suggested, this being followed, or not, by alkalization to prevent acute renal failure.

Adolescent↗

PubMed1986

[Benzodiazepine receptors in the hippocampus of suicides].

The characteristics of benzodiazepine binding sites (distribution, number, affinity) were defined on frozen sections of suicide's hippocampus (death by hanging) labeled with 3H flunitrazepam and compared to data previously obtained on control brains. The study was carried out qualitatively by autoradiography (distribution) and quantitatively by a biochemical technique (number and affinity). As a whole, the characteristics of BZD binding sites were not modified in relation to controls, except for a very slight decrease in affinity of subtype I.

Adolescent↗