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Biomedical subjects

J Marty

Publications and source records attributed to J Marty.

At least 127 records · Page 7Linked to original sources

Acebutolol and diacetolol plasma levels in patients undergoing myocardial revascularization with hypothermic cardiopulmonary bypass.

Cardiopulmonary bypass (CPB) has been reported to alter the disposition of numerous drugs and consequently to modify their plasma levels. The present study was designed to delineate the time course of acebutolol (a cardioselective beta-blocker) and diacetolol (its main metabolite) plasma levels in seven patients undergoing myocardial revascularization with hypothermic CPB. All patients were given oral acebutolol twice daily until 3 hours before surgery. Initiation of CPB produced an immediate and significant, but transient, decrease in acebutolol and diacetolol plasma concentrations. Cessation of CPB was not associated with an increase in plasma beta-blocker levels. It is concluded that CPB does not induce major alterations in the time course of acebutolol and diacetolol plasma concentrations.

Acebutolol↗

[Evaluation of the quality of preoperative electrocardiogram interpretation by anesthesiologists].

This prospective study aimed to assess the quality of interpretation by Teaching Hospital anaesthesiologists of preoperative electrocardiograms (ECG). It was carried out over a period of 7 months, and included 500 patients scheduled for elective surgery. The ECG was first interpreted by the anaesthesiologist during the preoperative visit, and later during the postoperative period, by a cardiologist. The two interpretations were compared using the following criteria: minor anomalies, which would not influence the anaesthetic technique already selected; major anomalies, which, on the other hand, are known to increase anaesthetic morbidity and mortality rates, thereby influencing the choice of anaesthetic technique; and interpretative errors concerning only the major anomalies, i.e. anomalies not seen by the anaesthesiologist (false negatives), anomalies found which did not exist (false positives), and erroneous or incomplete interpretation. Interpretation of the ECG by the anaesthesiologist was written on the anaesthetic record for only 156 patients (31.2%). Among the 500 ECG's, 141 were found to be abnormal by the cardiologist (28.2%). Seventy-three of them had 1 or more major abnormalities. Of the 156 ECG's interpreted by an anaesthesiologist, 64 (41%) were abnormal. The overall error rate was 21.1%, the major error rate being 7.1%. The overall false negative rate was 12.8%, with 7 major ischaemic abnormalities (4.5%) having not been found, including 4 (2.6%) diagnostic errors. About 3.8% of ECG's were wrongly interpreted as abnormal by the anaesthesiologist; all errors were of minor importance, but nevertheless responsible for delayed surgery, loss of time, and extra expenditure in laboratory tests.(ABSTRACT TRUNCATED AT 250 WORDS)

Academic Medical Centers↗

The use of midazolam and flumazenil in cardiovascular diagnostic and therapeutic procedures.

Sedation is sometimes required for cardiovascular diagnostic or therapeutic procedures. Midazolam may be proposed in these situations because of its duration of action and because of its moderate haemodynamic effects. However, the use of midazolam implies that the standards of safety required for all anaesthetic techniques have been applied. The changes in haemodynamic data induced by the administration of midazolam must be taken into account in interpretation of the catheterisation report. At the end of investigation, flumazenil can be administered safely to reverse residual sedative effects of midazolam but its use does not exempt from normal monitoring during the recovery period.

Cardiovascular Diseases↗

Beta-adrenergic receptor function is acutely altered in surgical patients.

Catecholamine-induced desensitization of beta-adrenergic receptors resulting in hyporesponsiveness to further stimulation has been frequently reported after an increase in endogenous catecholamines. To examine the possibility of beta-adrenoceptor desensitization due to intraoperative adrenergic activation (surgical stress), the alterations of human lymphocyte beta-adrenergic receptor density and affinity observed after anesthesia and surgery were studied using (-)125I-iodocyanopindolol binding in 19 patients undergoing noncardiac surgical procedures with general anesthesia (thiopental, fentanyl, and halothane or isoflurane). In 13 patients, repeated determinations of plasma levels of norepinephrine and epinephrine showed an increase during the surgical procedure (norepinephrine +60%; epinephrine +60%); this change was not observed in the remaining patients. A significant postoperative increase in receptor density (Bmax +25%) and a significant decrease of receptor affinity for isoproterenol (IC50 +22%) were found in the patients who experienced intraoperative adrenergic activation. By contrast, no significant change in beta-receptor density or affinity was found in the patients who had normal intraoperative adrenergic activation. In addition, heart rate responses to the postoperative changes in plasma catecholamines (an index of cardiac sensitivity to agonist) were significantly attenuated in patients who experienced both intraoperative adrenergic activation and a decrease in affinity of beta-receptor for agonist, suggesting hyporesponsiveness to beta stimulation. We conclude that beta-adrenergic receptors and, consequently, beta-adrenergic responsiveness might be altered by perioperative adrenergic activation in surgical patients.

Adult↗

A comparison study of two methods of peanut agglutinin staining with S100 immunostaining in 29 cases of histiocytosis X (Langerhans' cell histiocytosis)

Staining with peanut agglutinin (PNA) and with polyclonal antibody to S100 protein have both been recommended as aids in the diagnosis of histiocytosis X (Langerhans' cell histiocytosis). Although a large body of literature attests to the utility of S100 staining in this condition, the few published studies that involve PNA staining have employed varying methods of radically different results. We studied formaldehyde solution-fixed, paraffin-embedded tissue from 29 cases of histiocytosis X by using standard avidin-biotin immunostaining for S100 protein, as well as two published methods of PNA staining. All cases stained positively for S100 protein. By utilizing prior trypsinization and a three-step procedure, all cases also stained with PNA. With a two-step PNA-staining procedure, however, 9 cases failed to stain with PNA, and 3 cases showed a diffuse staining pattern that was not considered characteristic of Langerhans' and histiocytosis X cells. We concluded that both the S100 and the three-step PNA procedures are sensitive methods for the diagnosis of histiocytosis X.

Adolescent↗

Beta-adrenergic receptor changes during coronary artery bypass grafting.

To evaluate whether the function of beta-adrenergic receptors, essential to the biologic activity of catecholamines, is altered during coronary artery bypass grafting, we measured, in 16 patients undergoing myocardial revascularization, the density and the affinity of lymphocyte beta-adrenergic receptors before anesthesia induction (control) and at the end of cardiopulmonary bypass. Variations in the density and affinity of beta-adrenergic receptors were determined in vitro. Repeated determinations of plasma epinephrine and norepinephrine concentrations were also performed. Overall, no significant modification was observed in mean density and affinity of beta-adrenergic receptors at the end of cardiopulmonary bypass when compared with control values. However, a significant decrease (p less than 0.05) in affinity for isoproterenol was found in the six patients who had high catecholamine levels during cardiopulmonary bypass. In contrast, no significant modification of beta-adrenoreceptor affinity for isoproterenol was observed in the 10 patients who did not have this degree of adrenergic activation. In addition, beta-adrenoreceptor affinity for isoproterenol was decreased in the three patients in whom intraaortic balloon pumping was mandatory after discontinuation of cardiopulmonary bypass. We suggest that this decreased affinity of lymphocyte beta-adrenergic receptors could be related, at least in part, to a sustained adrenergic activation occurring in some patients during cardiopulmonary bypass.

Anesthesia↗

In vivo and in vitro metabolism of benzo(a)pyrene by the larva of the newt, Pleurodeles waltl.

1. The larva of the amphibian species, Pleurodeles waltl was shown to metabolize benzo(a)pyrene in vivo into a variety of oxidized products. 2. In vitro, BaP hydroxylase (AHH) activity was found in hepatic microsomes and postmitochondrial fractions from both larvae and adults of the pleurodele. 3. The clastogenic effect of BaP formation of micronuclei in the erythrocytes was shown to be related to the presence of BaP quinones in the tissues of the newt.

Animals↗

[Hemodynamic and adrenergic effects of flumazenil after general anesthesia with flunitrazepam].

Reversal of benzodiazepine-induced sedation by flumazenil has been reported to produce no or minor hemodynamic alterations although some adverse responses have been observed. To better delineate circulatory and adrenergic modifications induced by flumazenil, 20 consenting patients scheduled for short orthopedic procedures were included in a double blind controlled study. Anesthesia consisted in flunitrazepam (30 to 40 micrograms.kg-1) plus halothane (0.5 vol. % in N2O-O2, 60-40 vol. %) and alfentanil. At the end of surgery, patients received 15 minutes after discontinuation of halothane and N2O, either flumazenil (1 mg) or placebo according th randomization. Heart rate and blood pressure were obtained before reversal and repeatedly for 30 minutes following flumazenil or placebo. Level of consciousness was also assessed and blood samples were withdrawn for subsequent determination of plasma levels of norepinephrine. Flumazenil administration induced in all cases an immediate and total reversion of sedation while recovery was slow in the placebo group. No significant changes in heart rate and blood pressure values were found in both groups. By contrast, plasma levels of norepinephrine were significantly increased in all patients. It is concluded that reversal of benzodiazepine-induced sedation or anesthesia is not associated with significant variations of usual hemodynamic or adrenergic responses.

Adolescent↗

[Block of the superior laryngeal nerve for ORL endoscopy. Description of a simplified technique].

The usual anterior and lateral routes used for superior laryngeal (SL) nerve blocks are not often used because too difficult to carry out. A simpler and easier technique is described, which blocks the SL nerve at the level of the greater cornu of the hyoid bone. Because the nerve is not located accurately with this technique, a larger volume of local anaesthetic is required. This technique was tested in 31 patients scheduled for endoscopies with rigid tubes. The mean duration of endoscopy was 30 +/- 10 min. The use of 8 ml 1% lidocaine for the block 30 min surgical anaesthesia. In 2 patients, the SL nerve block alone was sufficient. In 26 others a complement with a benzodiazepine (flunitrazepam, n = 9, mean dose 0.8 mg; midazolam, n = 17, mean dose 5 mg) was required. In 4 of these patients, attempts of oesophagoscopy gave rise to hypertension and tachycardia. General anaesthesia with propofol and tracheal intubation were therefore used. In the last 3 patients, intercricothyroid jet ventilation was used, requiring general anaesthesia (propofol and succinylcholine). The SL nerve block was satisfactory in 24 patients with total vocal cord paralysis and no haemodynamic reaction to painful stimuli in the blocked area. No complication was observed. It is concluded that this technique is useful and easier to carry out than the usual ones.

Anesthesia, General↗

[Comparison of nalbuphine and pentazocine in the treatment of postoperative pain by self-administration].

The side-effects of two opioid agonist-antagonists, nalbuphine and pentazocine, were assessed when used for patient-controlled postoperative analgesia. Forty ASA I or II patients scheduled for upper abdominal surgery were randomly allocated to two equal groups. The anaesthetic technique was the same for all the patients: premedication with atropine and diazepam, induction with thiopentone and suxamethonium and maintenance with fentanyl, pancuronium, nitrous oxide and halothane. Patient-controlled computer assisted analgesia (On-Demand Analgesia Computer) was started in the recovery room at least 2 h after the last administration of fentanyl. The parameters used were: a routine hourly dose (the half of that received during the previous hour), with on demand delivery of nalbuphine (15 micrograms.kg-1) or pentazocine (45 micrograms.kg-1) aliquots respectively, with a refractory period between two demands of 4 min and a total hourly maximum dose of 16 mg and 48 mg respectively. The following parameters were measured before the start of self-administration, and every hour afterwards for 24 h: systolic (Pasys) and diastolic blood pressures, heart rate, pressure-rate product (PRP), respiratory rate, end-tidal CO2 and pain (by way of a three point scale). Analgesia was assessed on a four-point scale every 6 h. The total doses of nalbuphine and pentazocine administered were 94 +/- 43 mg and 251 +/- 150 mg respectively. The only parameters significantly different between the two groups were Pasys and PRP, being higher in the pentazocine group. There were no significant differences in the side-effects (drowsiness, nausea, vomiting, headache, amnesia, logorrhoea and urine retention). All patients in both groups were satisfied with this technique.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗