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Biomedical subjects

P Adnet

Publications and source records attributed to P Adnet.

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

[Malignant hyperthermia and appendicular sepsis. Can they be differentiated during surgical procedure?].

OBJECTIVE: To assess the possibility to differentiate clinically intraoperative malignant hyperthermia (MH) and sepsis. STUDY DESIGN: Comparative retrospective study of clinical cases. PATIENTS: Sixteen patients operated on for acute appendicitis and developing clinical signs of MH confirmed or not by in vitro caffeine halothane contracture tests (IVCT). METHOD: To isolate the patients' characteristics with regard to the diagnosis of sepsis and MH crisis. To compare both groups of clinical features with results of IVCT. RESULTS: The diagnosis of MH sensitivity has been excluded in ten hyperthermic patients and confirmed in four others with IVCT. No correlation was existing between the importance of perioperative sepsis, MH features and IVTC results. CONCLUSIONS: This study confirmed the difficulty to differentiate clinically MH and sepsis during surgery. Considering the severe outcome of MH crisis, it is recommended to start the specific therapy even in case of appendicular sepsis.

Adolescent↗
PubMed1997

Identification of heterozygous and homozygous individuals with the novel RYR1 mutation Cys35Arg in a large kindred.

BACKGROUND: Malignant hyperthermia (MH) is a potentially fatal, often autosomal dominant, disorder of skeletal muscle and is triggered in susceptible people by all commonly used inhalational anesthetics. In this article, the authors describe a malignant hyperthermia susceptible (MHS) kindred in which both parents of the proband are MHS and are first-degree cousins. Haplotype analysis in this kindred with chromosome 19 linked markers revealed that the proband and another sibling were homozygous for the affected RYR1 allele. METHODS: Eighteen members of this large pedigree were investigated, with a clinical examination for signs of a myopathy, a caffeine halothane contracture test, a histo-enzymologic study on the muscle biopsies, and linkage analysis on genomic DNA isolated from family blood samples. RYR1 cDNA was amplified by polymerase chain reaction and was cloned and sequenced, facilitating mutation detection. RESULTS: Linkage analysis demonstrated linkage between RYR1-linked markers and MH susceptibility in this family. DNA sequencing identified a T to C transition at nucleotide position 103, resulting in the substitution of an arginine for cysteine 35, representing the most N-terminal mutation reported to date in the RYR1 gene. This mutation segregates fully with the MHS trait, generating a lod score of 4.65 in favor of linkage to MHS at a recombination frequency of 0.0. CONCLUSIONS: The proband in this kindred is the first reported homozygote to have presented with an MH episode. The homozygotes in this pedigree do not have an overt myopathy. The sensitivity of muscle samples to caffeine clearly distinguished the two homozygotes from other heterozygous-susceptible individuals. No clear differentiation was observed with the halothane contracture results.

Adolescent↗
PubMed1995

[Detection of gas embolism in neurosurgery by capnography. Apropos of 32 patients surgically treated in seated position].

Hitherto dreaded and dreadful, air embolism has since the past few years a better prognosis owing to new techniques of early detection. The present study concerns a series of 32 neurosurgical patients who were operated in the sitting position under continuous capnography. This method not only provides global monitoring (metabolic, haemodynamic and respiratory) but also allows early detection of any significant migration of air or gas into the blood vessels. The incidence of air embolism in this series was 31% (10 patients out of 32). The onset of air embolism was diagnosed on a rapidly progressive fall in the expired fraction of CO2 (FECO2), in spite of a normal blood pressure. Early treatment prevented further complications. Therefore capnography is a sensitive and reliable method of air embolism detection intraoperatively. Its use in the operating room and intensive care unit should be systematic whenever air embolism may occur.

Adolescent↗
PubMed1994

[Use of Diprivan in muscular diseases and malignant hyperthermia].

An unknown myopathy can be revealed by the administration of an anaesthetic agent. The symptoms are those of malignant hyperpyrexia (MH). The MH phenotype can be detected by means of contracture tests in vitro. All anaesthetics, excepting the triggering agents, can be given. The safety of propofol as an induction and maintenance agent in this category of patients has been demonstrated. When the presence of a myopathy is known before an anaesthetic, the administration of succinylcholine associated or not with a halogenated inhalational agent carries a risk of severe complication. Among the anaesthetic agents having little effect on the skeletal muscle, propofol seems interesting, also because of its pharmacokinetic properties. Myopathy is difficult to diagnose, either because the patient undergoes surgery before being symptomatic or because he is only a carrier of MH. In case of an abnormal reaction following the administration of recognized triggering agents or the occurrence of MH, the procedure should be discontinued. In case of absolute necessity, the procedure may be continued but with non-triggering agents only.

Anesthesia, Intravenous↗
PubMed1994

[Lack of sensitivity to per-anesthetic malignant hyperthermia in 32 patients who developed neuroleptic malignant syndrome].

The aim of this study was to verify whether a relationship exists between neuroleptic malignant syndrome (NMS) and anaesthetic-induced malignant hyperthermia (MH) or not. The in vitro halothane-caffeine tests were performed on muscle tissue obtained from 32 patients with documented NMS episodes. The diagnosis of NMS relied on Levenson's criteria. The results, expressed in accordance with the criteria of the European MH Group, defined 29 subjects as MH non-susceptible. Three patients were classified as MH equivocal. These findings demonstrate the lack of any link between NMS and MH. Therefore, patients with a history of NMS are not likely to be at risk of developing MH and special measures against MH are not required for anaesthesia in these patients.

Adolescent↗
PubMed1994

Intermittent left bundle branch block revealed during anaesthesia.

Intermittent left bundle branch block is uncommon. During anaesthesia,, left bundle branch block may be related to hypertension or tachycardia and its occurrence makes the diagnosis of acute myocardial ischaemia or infarction difficult. Patients with intermittent left bundle branch block often develop established left bundle branch block, which may represent an earlier state of ischaemic heart disease. Cardiological investigation of our patient after operation did not point towards an organic cause of intermittent left bundle branch block.

Aged↗
PubMed1994

Detection of a novel common mutation in the ryanodine receptor gene in malignant hyperthermia: implications for diagnosis and heterogeneity studies.

Malignant hyperthermia (MH) is a potentially fatal autosomal dominant disorder of skeletal muscle and is triggered in susceptible people by all commonly used inhalational anaesthetics. To date, the ryanodine receptor gene (RYR1) has been shown to be mutated in a small number of malignant hyperthermia susceptible (MHS) cases. To determine if a common RYR1 mutation exists that might account for a significant number of MHS cases, we have investigated the RYR1 gene in unrelated patients for the presence of new mutations by the single-stranded conformation polymorphism method and have identified a novel Gly341Arg mutation which accounts for approximately 10% of Caucasian MHS cases. The implications of this common mutation in MHS diagnosis and heterogeneity studies are discussed.

Base Sequence↗
PubMed1994

[Hemodynamic effects of genu-pectoral position during the surgery of lumbar disk herniation: spinal anesthesia versus general anesthesia].

Spinal anesthesia (SA) for lumbar disk surgery in the genu-pectoral position (GP) has been proposed as an alternative to general anesthesia (GA). This study compares the haemodynamic effects of GP in two groups of patients undergoing either SA (n = 43) or GA (n = 40). Mean arterial pressure (MAP) and heart rate (HR) were recorded before and after GP. MAP and HR were significantly lower in the GA group after GP. We conclude that SA during GP for lumbar disk surgery is haemodynamically well tolerated.

Adult↗
PubMed1993

[The detection of gas embolisms in neurosurgery caused by joint monitoring with capnography and the Swan-Ganz probe. (Apropos of 7 patients operated on in the sitting position].

The aim of this study was to detect per-operative venous gas embolism in neurosurgery using capnography coupled to the Swan-Ganz catheter method. Using both methods, our study, carried out on seven patients operated in the sitting position, showed an occurrence of air embolism in four cases. The diagnosis of air embolism was made on a rapid and progressive drop of FECO2 with, at the same time, a rise of the pulmonary arterial pressure.

Adult↗
PubMed1992

Sodium lactate reversal of electrophysiological effects of imipramine in guinea-pig ventricular myocardium.

Overdose cardiac effects of imipramine are due to fast Na channel blockade and are clinically reversed by administration of sodium lactate which induces alkalosis (about pH 7.50) and hypernatremia (about 8 mM). The mechanisms of this beneficial effect of Na lactate were explored in vitro on guinea-pig ventricular myocardium using the microelectrode technique. The time-course effects of the clinically relevant concentration of 10 microM imipramine on action potential characteristics were examined at pH 7.20 and pH 7.50. To test whether alkalinisation per se is important or whether an increase in Na concentration plays a major role in the reversal effect, preparations were exposed to increasing concentrations (1, 3, 10, 30, 100 mM) of either Na lactate, bicarbonate or chloride in the absence or in the presence of 10 microM imipramine at pH 7.50. The influence of elevating osmolality was evaluated with equivalent concentrations of sucrose. Imipramine alone significantly depressed Vmax and shortened action potential duration at all phases of repolarisation. All three high sodium solutions reversed imipramine effects. However the reversal effect was already obvious with 10 mM Na lactate and 10 mM NaHCO3 but not 10 mM NaCl. Osmolality did not reverse the imipramine-induced Vmax depression. The results suggest that at the clinically relevant 10 mM concentration, sodium lactate and bicarbonate may displace imipramine from its receptor site on the Na channel by causing alkalosis at the membrane level without profoundly affecting the driving force of the Na current, whereas at the upper concentrations, the increase in Na ion concentrations is predominantly involved in the reversal of imipramine effects.

Action Potentials↗
PubMed1990

[Intravascular volume expansion and intravenous nimodipine in the treatment of cerebral vasospasm after surgical treatment of intracranial aneurysm].

The advantage of calcium antagonist on cerebral arterial spasm during the peri-operative period has been recently demonstrated. However, the role of volemia and cardiac output in the pathogenesis of arterial spasm seems predominant. The basal hemodynamic profile of 17 patients operated for an intracranial aneurysm was investigated. The hemodynamic and neurological modifications induced by treatment with nimodipine, modification of blood volume and the use of inotropic drug was subsequently analysed. In 8 patients there was a clearcut hypovolemia with diminished cardiac index whereas in 9 other patients there were low filling pressures with an unmodified cardiac index. As early as the 48th hour of treatment, there was an improvement of Hunt and Hess score in 12 patients whereas in 5 others the score remained unchanged. Two death occurred due to the extension of secondary ischemic lesions. This study seems to confirm the aggravating role of hypovolemia in the occurrence of vasospasm and the neurological improvement due to the association of a calcium antagonist, restoration of blood volume with or without a vasoconstrictor.

Adult↗
PubMed1989

[Screening tests for malignant hyperthermia susceptibility].

The ideal screening test for malignant hyperthermia susceptibility (MHS) has yet to be discovered. It should be simple noninvasive, yet totally specific and sensitive. Until such an ideal test becomes available, allowing simple routine preoperative screening, tests should only be used in certain specific situations. These include: patients in whom a clinical crisis was suspected; the members of the family of a subject labeled MHS because of a fatal, or otherwise, crisis, or in whom tests were positive; patients with other pathological conditions which could be linked to malignant hyperthermia (MH) (some myopathies, effort or stress MH, neuroleptic malignant syndrome). The various tests proposed in the literature aim at revealing MHN subjects, using or not a triggering agent, halothane most often. However, detecting these abnormalities sometimes gives greater insight into the physiopathology of MH than in the detection of an individual patient's susceptibility. The tests have been classified as in vivo, electrophysiological, blood, and in vitro muscle biochemical, morphological, and pharmacological tests. The discovery of new tests gives renewed hope: CPK levels, platelet tests, calcium sarcoplasmic reticular reuptake, lymphocyte Quin 2 test, nuclear magnetic resonance spectroscopy. However, experts worldwide agree that the only reference test to this day remains the in vitro halothane caffeine contracture tests. These tests have shown their reliability; they must be performed on muscle strips obtained from surgically removed muscle biopsies, by laboratories used to this technique and who have at their disposal a sufficiently large group of MHS subjects with a clear-cut clinical crisis, as well as controls. The patients must therefore travel to these laboratories. The design of common protocols for European laboratories on one hand, and the North American laboratories on the other, is a good guarantee of the reliability of these tests.

Animals↗
PubMed1989

Effect of propofol on the malignant hyperthermia susceptible pig model.

Anaesthetic techniques for malignant hyperthermia susceptible (MHS) patients should include drugs which do not trigger MH and provide stress free conditions. Thus all new drugs should be screened for their susceptibility to trigger MH. We have screened propofol, using the MHS pig model. In none of the animals exposed to propofol, were there signs of MH, even after challenge with suxamethonium. However, the same animals developed MH when exposed to halothane alone or with suxamethonium. Despite the problems of extrapolating from this study to man, it is unlikely that propofol may trigger an episode of MH.

Anesthetics↗