P Peray

Université de Nîmes, Nismes, Languedoc-Roussillon, France

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Publications (30)101.55 Total impact

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    ABSTRACT: The sensory blockade induced by a lidocaine-bupivacaine mixture combines the faster onset of lidocaine and the longer duration of bupivacaine. The current study compared the effects of large doses lidocaine (16 mg/kg), bupivacaine (4 mg/kg), and a mixture of 16 mg/kg lidocaine-4 mg/kg bupivacaine on hemodynamic and cardiac electrophysiologic parameters in anesthetized and ventilated piglets. After carotid artery cannulation, a double micromanometer measured mean aortic pressure, left ventricular end diastolic pressure, and the first derivative of left ventricular pressure. Electrocardiogram recording and a bipolar electrode catheter measured RR, PQ, QRS, QT C, JT C, AH, and HV intervals. Lidocaine, bupivacaine, or the mixture was administered intravenously over 30 s, and studied parameters were measured throughout 30 min. Mean aortic pressure decreased in all groups ( P < 0.05). The first derivative of left ventricular pressure was decreased in all groups ( P < 0.001) but to a greater extent with the mixture compared with lidocaine ( P < 0.04). RR, QT C, and JT C intervals were similarly increased in all groups ( P < 0.05). In all groups, PQ, AH, HV, and QRS intervals were widened ( P < 0.001). The lengthening of PQ was greater with bupivacaine ( P < 0.02). The lengthening of AH was greater and delayed with bupivacaine compared with lidocaine ( P < 0.03). The lengthening of HV and the widening of QRS were greater and delayed with bupivacaine ( P < 0.01). The widening of QRS was greater with the mixture than with lidocaine ( P < 0.01). The alterations of ventricular conduction parameters are greater with 4 mg/kg bupivacaine than with a mixture of 16 mg/kg lidocaine-4 mg/kg bupivacaine, whereas the hemodynamic parameters are similarly altered.
    Anesthesiology 01/2003; 98(1):96-103. · 5.16 Impact Factor
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    ABSTRACT: Background: The sensory blockade induced by a lidocaine–bupivacaine mixture combines the faster onset of lidocaine and the longer duration of bupivacaine. The current study compared the effects of large doses lidocaine (16 mg/kg), bupivacaine (4 mg/kg), and a mixture of 16 mg/kg lidocaine–4 mg/kg bupivacaine on hemodynamic and cardiac electrophysiologic parameters in anesthetized and ventilated piglets.
    Anesthesiology 12/2002; 98(1):96-103. · 5.16 Impact Factor
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    ABSTRACT: To identify the risk factors of failure and immediate complication of subclavian vein catheterization (SVC). Prospective observational study. Surgical critical care unit of a tertiary university hospital. Critically ill patients requiring a first SVC. Subclavian vein catheterization was attempted in 707 patients without histories of surgery or radiotherapy in the subclavian area. Failed catheterizations, arterial punctures, pneumothoraces and misplacements of the catheter tip were recorded. Risk factors of failure and immediate complication were isolated among patients' characteristics, procedure parameters (side and number of venipunctures) and the operator's experience using a univariate +/- multivariate analysis. Five hundred sixty-two SVCs (79.5%) were achieved without adverse events. Among the remaining 145 catheterizations, 67 (9.5%) failures, 55 (7.8%) arterial punctures, 22 (3.1%) pneumothoraces and 30 (4.2%) misplacements of the catheter tip occurred. More than one venipuncture was the only risk factor of failed catheterization [2 venipunctures, odds ratio =7.4 (2.1-26); >2 venipunctures, odds ratio =49.1 (16.8-144.1)]. More than one venipuncture and age 77 years or more were predictive of the occurrence of immediate complications [2 venipunctures, odds ratio =3.6 (1.8-7.0); >2 venipunctures, odds ratio =14 (7.7-25.3); age >or=77, odds ratio =1.8 (1.0-3.1)]. The operator's training was not predictive of failed catheterization or immediate complication. For SVC, more than one venipuncture is predictive of failed catheterization and immediate complication. Age 77 years or more was predictive of immediate complications.
    Intensive Care Medicine 08/2002; 28(8):1036-41. · 5.54 Impact Factor
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    ABSTRACT: The study of induced circulatory changes requires simultaneous assessment of multiple regional circulations because of interactions and compensatory mechanisms. Positive end expiratory pressure mechanical ventilation (PEEP) is known to cause marked, and potentially deleterious, cardiovascular changes. Our aim was to use a comprehensive approach to assess PEEP-induced circulatory changes in open vs closed abdomen animals. In the anesthetized rabbit, we used implantable Doppler micro-probes to measure blood flow simultaneously in the ascending aorta, inferior vena cava, portal vein, hepatic artery, common carotid artery, and renal artery. We studied spontaneously breathing animals (Group A), and open (Group B) and closed abdomen (Group C) animals mechanically ventilated at 0 (ZEEP) and 12 cm H(2)O PEEP. In Group A, all biological and hemodynamic variables remained unchanged for three hours at the end of the surgical procedure. In Groups B and C, ZEEP produced no significant hemodynamic change. PEEP induced a decrease in carotid, hepatic, and renal artery blood flow in Groups B and C, a decrease in heart rate and mean arterial blood pressure in Group B, and a decrease in aorta blood flow in Group C. These experimental results demonstrate the usefulness of the comprehensive approach of circulatory changes, and confirm that PEEP may have deleterious effects on regional blood flow, even without significant change in cardiac output, especially when the abdomen is open.
    Canadian Journal of Anaesthesia 04/2002; 49(3):302-8. · 2.13 Impact Factor
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    ABSTRACT: Ropivacaine is less potent and less toxic than bupivacaine. We administered these two local anesthetics in a cardiac electrophysiologic model of sodium thiopental-anesthetized and ventilated piglets. After assessing the stability of the model, bupivacaine (4 mg/kg) and ropivacaine (6 mg/kg) were given IV in two groups (n = 7) of piglets. No alteration in biological variables was reported throughout the study. Bupivacaine and ropivacaine similarly decreased mean aortic pressure from 99 +/- 22 to 49 +/- 31 mm Hg and from 87 +/- 17 to 58 +/- 28 mm Hg, respectively, and decreased the peak of the first derivative of left ventricular pressure from 1979 +/- 95 to 689 +/- 482 mm Hg/s and from 1963 +/- 92 to 744 +/- 403 mm Hg/s, respectively. Left ventricular end-diastolic pressure was similarly increased from 6 +/- 5 to 9 +/- 5 mm Hg and from 6 +/- 4 to 12 +/- 4 mm Hg, respectively. Bupivacaine and ropivacaine similarly lengthened the cardiac cycle length (R-R; from 479 +/- 139 to 706 +/- 228 ms and from 451 +/- 87 to 666 +/- 194 ms, respectively), atria His (from 71 +/- 15 to 113 +/- 53 ms and from 64 +/- 6 to 86 +/- 10 ms, respectively), and QTc (QTc = QT x R-R(-0.5), Bazett formula; from 380 +/- 71 to 502 +/- 86 ms and from 361 +/- 33 to 440 +/- 56 ms, respectively) intervals. Bupivacaine altered to a greater extent the PQ (the onset of the P wave to the Q wave of the QRS complex) (from 97 +/- 20 to 211 +/- 60 ms versus from 91 +/- 8 to 145 +/- 38 ms, P < 0.05), QRS (from 58 +/- 3 to 149 +/- 34 ms versus from 60 +/- 5 to 101 +/- 17 ms, P < 0.05), and His ventricle interval (from 25 +/- 4 to 105 +/- 30 ms vs from 25 +/- 4 to 60 +/- 30 ms, P < 0.05) than ropivacaine. A 6 mg/kg ropivacaine dose induced similar hemodynamic alterations as 4 mg/kg bupivacaine. However, bupivacaine altered the variables of ventricular conduction (QRS and His ventricle) to a greater extent. IMPLICATIONS: A 6 mg/kg ropivacaine dose induced similar hemodynamic alterations as 4 mg/kg bupivacaine. However, bupivacaine altered the variables of ventricular conduction (QRS and His ventricle) to a greater extent.
    Anesthesia & Analgesia 01/2002; 93(6):1598-605, table of contents. · 3.30 Impact Factor
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    ABSTRACT: Measurement of the time elapsed from the decision to use a pulmonary artery catheter to the onset of the adapted treatment. Prospective study. Critical care unit of a university hospital. A total of 104 critically ill patients. The time elapsed from the decision to use a pulmonary artery catheter to the onset of the adapted treatment. Five time intervals (availability, preparation, catheterization, data collection, and therapeutic intervals) were individualized according to the times of decision of pulmonary artery catheter insertion, operator's hand washing, venipuncture, postoperative dressing, data collection, and the effective onset of subsequent therapy. Among 120 used pulmonary artery catheters, seven could not be inserted. The time to use the pulmonary artery catheter was never shorter than 45 mins (median value = 120 mins). For availability, preparation, catheterization, data collection, and therapeutic intervals, the median values were 30, 20, 20, 20, and 10 mins, respectively. The availability and data collection intervals were shortened during the night period and the fourth quarter of the study, respectively. The pulmonary artery catheter use is time consuming. However, the availability and data collection intervals could be shortened.
    Critical Care Medicine 03/2000; 28(2):355-9. · 6.12 Impact Factor
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    ABSTRACT: The aim of the study was to determine whether facilitation of reentry by potassium-channel openers is related to dispersion of refractoriness and/or modification of anisotropic properties of ventricular myocardium. The dispersion of ventricular effective refractory period (VERP), longitudinal and transverse ventricular conduction velocities (thetaL and thetaT, respectively), and wavelength [lambda = VERP x theta(L or T)] were studied in Langendorff-perfused left ventricular epicardium in 20 rabbits during infusion of incremental doses of levcromakalim or nicorandil. Dispersion of refractoriness was assessed using standard deviation of VERP mean (SD-VERP), dispersion index (DI; SD-VERP/mean VERP), and maximum dispersion (Dmax = VERPmax - VERPmin). Ventricular conduction velocities and anisotropic ratio were not modified, whatever the dose used. VERP and lambda were significantly shortened at high concentrations of levcromakalim and nicorandil. At these doses, SD-VERP, DI, and Dmax were increased significantly. Analysis of ventricular tachycardia induction, performed using a high-resolution ventricular mapping system, confirmed that heterogeneity and shortening of VERP were factors inducing functional conduction block. Our data suggest that, in rabbit left ventricular epicardium, functional conduction block facilitating the occurrence of reentry could be initiated by shortening and, especially, by dispersion of refractoriness during infusion of potassium-channel openers.
    The American journal of physiology 03/1999; 276(2 Pt 2):H413-23. · 3.28 Impact Factor
  • Regional Anesthesia and Pain Medicine 01/1999; 24. · 3.46 Impact Factor
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    ABSTRACT: Catheterization of the subclavian vein may lead to severe complications. The current randomized study compared a technique of pulsed Doppler ultrasonography guidance and the standard method for subclavian vein catheterization. Standard and Doppler ultrasonography guidance methods were performed by the same physician in 286 patients, 143 in each group. Primary end points were immediate complications (arterial puncture, pneumothorax, wrong position of catheter tip), failures, the number of subclavian vein catheterizations with immediate complication or failure, the number of skin punctures per catheterization, and the time to placement of the guide wire. The secondary end points were the determination of predicting factors of successful cannulation in each group. Both groups were similar according to morphologic parameters of the patients. A greater number of subclavian vein catheterizations were performed on the right side using Doppler guidance (105 vs. 73, P < 0.01). Doppler guidance decreased complications (5.6% vs. 16.8%, P < 0.01), largely because of a smaller number of catheters for which the tip was defined to be in incorrect position (0.7% vs. 7.7%, P < 0.01). The time to catheterization was longer with Doppler guidance (300 vs. 27 s, P < 0.001). Failures, catheterizations of the subclavian vein with immediate complications or failure, and the total number of skin punctures per catheterization were similar in both groups. Using Doppler guidance, the presence of a good Doppler signal (124 of 143) was predictive of successful catheterization (123 successful cannulations, P < 0.001). Doppler guidance reduces the incidence of inappropriately positioned subclavian catheters.
    Anesthesiology 06/1998; 88(5):1195-201. · 5.16 Impact Factor
  • Regional Anesthesia and Pain Medicine 01/1998; 23. · 3.46 Impact Factor
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    ABSTRACT: The aims of the study were to verify the effects of ketamine on ventricular conduction velocity and on the ventricular effective refractory period, to determine its effects on anisotropy and on homogeneity of refractoriness, and to use wavelength to determine whether ketamine has antiarrhythmic or arrhythmogenic properties. A high-resolution epicardial mapping system was used to study the effects of 50, 100, 150, and 200 microM racemic ketamine in 15 isolated, Langendorff-perfused rabbit hearts. Five hearts were kept intact to study the effects of ketamine on spontaneous sinus cycle length (RR) interval and its putative arrhythmogenic effects. In 10 other hearts, a thin epicardial layer was obtained by an endocardial cryoprocedure (frozen hearts) to study ventricular conduction velocity, ventricular effective refractory periods (five sites), and ventricular wavelength. Ketamine induced a concentration-dependent lengthening of the RR interval. Ketamine slowed longitudinal and transverse ventricular conduction velocity with no anisotropic change, and it prolonged the ventricular effective refractory period with no significant increase in dispersion. Ventricular longitudinal and transverse wavelengths tend to increase, but this was not statistically significant. Finally, no arrhythmia could be induced regardless of the ketamine concentration. Ketamine slowed ventricular conduction and prolonged refractoriness without changing anisotropy or increasing dispersion of refractoriness. Although these effects should result in significant antiarrhythmic effects of ketamine, this should not be construed to suggest a protective effect in ischemic or other abnormal myocardium.
    Anesthesiology 01/1998; 87(6):1417-27. · 5.16 Impact Factor
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    ABSTRACT: Background:: The aims of the study were to verify the effects of ketamine on ventricular conduction velocity and on the ventricular effective refractory period, to determine its effects on anisotropy and on homogeneity of refractoriness, and to use wavelength to determine whether ketamine has antiarrhythmic or arrhythmogenic properties.
    Anesthesiology 11/1997; 87(6):1417–1427. · 5.16 Impact Factor
  • Annales Françaises d Anesthésie et de Réanimation 08/1997; 16(6):677-677. · 0.84 Impact Factor
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    ABSTRACT: This study was designed (a) to test and (b) to compare proarrhythmic effects of levcromakalim and nicorandil; and (c) determine the mechanism of arrhythmia initiation by using high-resolution ventricular epicardial mapping on 44 Langendorff-perfused rabbit hearts. Eighteen hearts were kept intact and received incremental doses (1-500 microM) of levcromakalim, nicorandil, and isosorbide dinitrate. In 26 hearts, a thin layer of epicardium was obtained after endocardial cryotechnique (frozen hearts). In intact hearts, isosorbide dinitrate did not produce any arrhythmia. In contrast, levcromakalim induced spontaneous ventricular fibrillation (VF) in all hearts at 50 microM, whereas only one VF occurred at 500 microM nicorandil. These three drugs produced a dose-dependent bradycardia in intact hearts. In frozen hearts, arrhythmias were induced by 5 microM levcromakalim and 50 microM nicorandil. Isosorbide dinitrate had no proarrhythmogenic effect. Epicardial mapping showed that most of induced ventricular tachycardias were based on reentry around an arc of functional conduction block. Ventricular conduction velocities did not change, but levcromakalim and nicorandil shortened ventricular effective refractory period. We conclude that (a) levcromakalim and nicorandil, used in toxic concentrations, have direct proarrhythmic effects; (b) nicorandil proarrhythmogenic effects are 10 times less marked than those of levcromakalim (arrhythmia is solely the result of the potassium channel opener property of nicorandil); and (c) most of ventricular tachycardias induced are based on reentry.
    Journal of Cardiovascular Pharmacology 02/1997; 29(1):109-18. · 2.38 Impact Factor
  • Annales Françaises d Anesthésie et de Réanimation 01/1997; 16(6):676-676. · 0.84 Impact Factor
  • Anesthesiology 01/1997; 87(6):1417-1427. · 5.16 Impact Factor
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    ABSTRACT: Electrophysiologic and proarrhythmogenic effects of imipramine were studied by use of 21 Langendorff-perfused rabbit hearts and high-resolution mapping to analyze epicardial activation of the left ventricle. In 16 hearts, a thin layer of epicardium was obtained by an endocardial cryotechnique (frozen hearts). Five hearts were kept intact (nonfrozen imipramine-treated group). Preparation stability was verified in six frozen hearts. In 10 frozen and in 5 nonfrozen hearts, 0.01, 0.1, 1.0, 2.0 and 5.0 micrograms/ml imipramine were administered. In nonfrozen imipramine-treated hearts, imipramine induced bradycardia at 5.0 micrograms/ml (291.8 +/- 40.5 vs. 495.2 +/- 54.4 msec, P = .02), one A-V block at 5.0 micrograms/ml and two monomorphic ventricular tachycardias (MVT) at 2.0 and 5.0 micrograms/ml. In 4/10 frozen hearts, three MVT were induced at 1.0 microgram/ml imipramine and one MVT at 2.0 micrograms/ml imipramine. All MVT were based on reentry around a line of functional conduction blocks. Imipramine (2.0 micrograms/ml) slowed longitudinal and transversal ventricular conduction velocities at a pacing cycle length of 1000 msec from 71.7 +/- 6.1 to 63.0 +/- 7.7 cm/sec (P = .008) and from 32.9 +/- 2.6 to 27.7 +/- 2.8 cm/sec (P = .009), respectively, and prolonged ventricular effective refractory period from 141.9 +/- 9.3 to 279.1 +/- 112.6 msec (P = .03). Imipramine induced dose- and use-dependent slowing of ventricular conduction velocity facilitating functional conduction blocks and reentrant MVT.
    Journal of Pharmacology and Experimental Therapeutics 08/1996; 278(1):170-8. · 3.89 Impact Factor
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    ABSTRACT: Large and equipotent doses of several local anesthetics were administered in a cardiac electrophysiologic model on closed-chest dogs. Five groups of pentobarbital-anesthetized dogs were each given intravenously 16 mg/kg lidocaine, 12 mg/kg mepivacaine, 4 mg/kg or 8 mg/kg etidocaine, and 4 mg/kg bupivacaine. Lidocaine induced bradycardia, slowing of atrioventricular node conduction (AH), and marked hemodynamic depression, represented by a decrease in mean aortic pressure (MAoP), in the peak of first derivative of left ventricular pressure (LVdP/dt(max)) and by an increase in left ventricular end-diastolic pressure (LVEDP). Atrial pacing at pacing cycle length (PCL) of 298 ms did not enhance the alteration of variables of ventricular conduction (His ventricle [HV] interval and QRS duration). Mepivacaine induced slight alteration of electrophysiologic variables. Atrial pacing at PCL of 312 ms did not enhance the alteration of HV and QRS duration. Mepivacaine induced transient hemodynamic depression. Etidocaine (4 mg/kg) induced electrophysiologic and hemodynamic alterations similar to mepivacaine but artrial pacing at PCL of 330 ms enhanced HV lengthening and QRS widening (P < 0.05). Etidocaine (8 mg/kg) induced marked impairment of PR, HV, QRS, and QT, and dramatic hemodynamic depression represented by a decrease in MAoP from 123.5 +/- 16.2 at baseline to 36.5 +/- 8.3 mm Hg at 1 min (P < 0.001) and of LVdP/dtmax) from 1446 +/- 379 to 333 +/- 93 mm Hg/s (P < 0.001). Bupivacaine induced dramatic impairment of electrophysiologic variables. Bupivacaine also decreased LVDP/dtmax (from 1333 +/- 347 to 617 +/- 299,P < 0.001) and increased LVEDP. We conclude that mepivacaine induced moderate cardiotoxicity. In contrast, lidocaine induced dramatic hemodynamic depression while etidocaine and bupivacaine markedly impaired both electrophysiologic and hemodynamic variables. This double impairment could explain the great difficulty in resuscitating patients who have had cardiotoxic accidents induced by etidocaine or bupivacaine.
    Anesthesia & Analgesia 04/1996; 82(3):648-56. · 3.30 Impact Factor
  • Survey of Anesthesiology 01/1996; 40(4).
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    ABSTRACT: The purpose of the study was to compare cardiac output (CO) measurement by continuous (CTD) with that by conventional thermodilution (TD) in critically ill patients. In 19 of 20 critically ill patients requiring a pulmonary artery catheterism, 105 paired CO measurements were performed by both CTD and TD. Regression analysis showed that: CTD CO = 1.18 TD CO - 0.47. Correlation coefficient was 0.96. Bias and limit of agreement were -0.8 and 2.4 L.min-1, respectively. When a Bland and Altman diagram was constructed according to cardiac index ranges, biases were -0.2 and -0.3 and -0.8 L.min-1.m-2 and limits of agreement were 0.3, 0.7 and 1.6 L.min-1.m-2 for low (< 2.5 L.min-1.m-2), normal (between 2.5 and 4.5 L.min-1.m-2) and high (> 4.5 L.min-1.m-2) cardiac indexes, respectively. It is concluded that CTD, compared with TD, is a reliable method of measuring CO, especially when cardiac index is < or = 4.5 L.min-1.m-2.
    Canadian Journal of Anaesthesia 11/1995; 42(11):972-6. · 2.13 Impact Factor