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O Langeron

Publications and source records attributed to O Langeron.

14 recordsLinked to original sources
PubMed1996

Oxygen consumption and delivery relationship in brain-dead organ donors.

The oxygen delivery (DO2) and consumption (VO2) relationship in brain-dead organ donors is unknown. Therefore, in a prospective study, we determined the DO2/VO2 relationship in 21 consecutive brain-dead patients. Patients were allocated to one of two groups, according to plasma lactate concentration: normal (group NL, n = 11) or high (> 2.5 mmol litre-1) (group HL, n = 10). VO2 was measured independently, using indirect calorimetry, under control conditions, during low DO2 challenge with PEEP administration, and high DO2 challenge with inflation of medical antishock trousers and volume expansion or blood transfusion, as required. Under control conditions, there were no significant differences between groups NL and HL in haemodynamic or oxygenation variables, both groups having a low VO2 (mean 114 (SD 21) ml min-1 m-2). In group HL there was a different DO2/VO2 relationship pattern, with a dependent VO2 only. The mean slope of the DO2/VO2 relationship was significantly higher in group HL than in group NL (0.12 (0.09) vs 0.04 (0.07), P < 0.05). We conclude that brain death was associated with a low VO2, and patients in group HL exhibited DO2/VO2 dependency which was not observed in patients in group NL.

Adolescent↗
PubMed1995

[Combination of propofol-sufentanil on somatosensory evoked potentials in surgery of the spine].

OBJECTIVES: Most anaesthetics depress cortical somatosensory evoked potentials (CSEPs). However, the modification of CSEPs during total intravenous anaesthesia using propofol remaining still unknown, justified this trial. TYPE OF STUDY: Open, prospective, clinical study. METHODS: Nine consecutive patients requiring CSEPs monitoring for spine surgery, were studied. Anaesthesia was induced with propofol (2.5 mg.kg-1 then 10 mg.kg-1.h-1) and sufentanil (0.50 micrograms.kg-1 then 0.25 micrograms.kg-1.h-1). Maximum positive (P40) and negative (N50) waweform latencies, and the peak to peak amplitude of CSEPs (posterior tibial nerve stimulation, cortical recording), were recorded before induction, 30 min, 1 and 2 h after induction, and at the end of surgery. Data are means +/- SD. RESULTS: Duration of anaesthesia was 260 +/- 73 min. Propofol induced significant lengthening of CSEPS (P40: from 37 +/- 10 up to 41 +/- 11 ms; N50: from 45 +/- 11 up to 51 +/- 14 ms), and a significant decrease in amplitude (from 1.9 +/- 0.9 down to 0.8 +/- 0.4 microV), but these changes were stable from 30 min after the induction to the end of spine surgery. A motor response was obtained 29 +/- 14 min after the end of anaesthetic administration. CONCLUSIONS: Total intravenous anaesthesia with propofol and sufentanil induces a small but stable lengthening of CSEPs latency and a stable decrease of its amplitude, which enable an appropriate monitoring of CSEPs during spine surgery.

Adult↗
PubMed1995

In vitro effects of eltanolone on rat myocardium.

BACKGROUND: Eltanolone is a new short-acting intravenous induction agent. However, its effects on intrinsic myocardial contractility remain unknown. METHODS: The effects of eltanolone and its solvent (soya bean emulsion) on the intrinsic contractility of rat left ventricular papillary muscles were investigated in vitro (Krebs-Henseleit solution, 29 degrees C, pH 7.40, Ca2+ 0.5 mM, stimulation frequency 12 pulses/min). We studied contraction; relaxation; contraction-relaxation coupling under high and low loads; and postrest potentiation. RESULTS: Eltanolone (0.1, 0.3, 1, 3, and 10 micrograms.ml-1) induced no significant inotropic effect, as shown by the lack of changes in maximum unloaded shortening velocity and active isometric force. Eltanolone did not significantly modify the contraction-relaxation coupling under low load, suggesting that it did not modify calcium uptake by the sarcoplasmic reticulum. Eltanolone did not significantly modify the contraction-relaxation coupling under high load, suggesting that it did not modify calcium myofilament sensitivity. Eltanolone decreased the postrest potentiation in a concentration-dependent manner (from 150 +/- 14% to 118 +/- 9% at 10 micrograms.ml-1, P < 0.001), suggesting a decrease in the maximum capacity of calcium release by the sarcoplasmic reticulum, whereas its solvent did not. However, eltanolone did not slow postrest potentiation recovery, as shown by the absence of significant changes in the recovery slope, tau (4.5 +/- 1.4 vs. 3.8 +/- 1.0 beats; difference not statistically significant). CONCLUSIONS: Eltanolone induced no significant inotropic effect on rat myocardium. It induced a decrease in the calcium release function of the sarcoplasmic reticulum, but this effect was not sufficiently important to modify the inotropic properties.

Anesthetics, Intravenous↗
PubMed1994

Additive effect on gas exchange of inhaled nitric oxide and intravenous almitrine bismesylate in the adult respiratory distress syndrome.

OBJECTIVE: To assess the additive effect of inhaled nitric oxide (NO) and intravenous almitrine bismesylate (ALM) on gas exchange. DESIGN: Prospective self-controlled study. SETTING: 3 medico-surgical intensive care units. PATIENTS: 17 patients with severe hypoxemia (PaO2/FIO2 ratio: 88 +/- 30 mmHg, venous admixture: 47 +/- 7%) and elevated mean pulmonary artery pressure (MPAP: 30 +/- 5 mmHg) due to adult respiratory distress syndrome (ARDS). INTERVENTIONS: 5 conditions were studied: 1) baseline, 2) 5 to 10 ppm of NO during 30 min, 3) discontinuation of NO during 30 min, 4) ALM infusion (0.5 mg/kg) during 30 min, 5) ALM infusion (0.5 mg/kg) during 30 min in combination with 5 to 10 ppm of NO. MEASUREMENT AND RESULTS: The PaO2/FIO2 ratio rose from 88 +/- 30 to 98 +/- 37 mmHg (NS) with NO alone, and from 92 +/- 25 to 130 +/- 56 mmHg (p < 0.01) with NO + ALM (p < 0.05 vs NO alone). Seven patients were considered as "NO-responders" (rise in PaO2/FIO2 ratio of 10 mmHg or more with NO); in this subgroup the PaO2/FIO2 ratio rose from 87 +/- 30 to 128 +/- 39 mmHg (p < 0.05) with NO alone, and from 93 +/- 20 to 169 +/- 51 mmHg (p < 0.01) with NO + ALM (p < 0.05 versus NO alone). MPAP decreased from 30 +/- 5 to 26 +/- 5 mmHg (p < 0.01) with NO alone, increased slightly from 28 +/- 5 to 31 +/- 5 mmHg (NS) with ALM alone and decreased to 27 +/- 5 mmHg (p < 0.05) with NO + ALM. CONCLUSIONS: NO + ALM had additive effects on gas exchange while decreasing MPAP in patients with ARDS. The effects of NO alone were small and non significant, except in a subgroup of 7 patients in whom the combination of both therapies had the more pronounced results.

Administration, Inhalation↗
PubMed1992

[Tracheal intubation in patients with cervical spine injuries using a fiber optic laryngoscope].

Eleven patients, with a cervical spine injury and scheduled for elective cervical spine fusion at least 48 h after their initial trauma, were intubated using a new fiberoptic laryngoscope (Bullard). This technique uses either a semi-rigid guide independent of the laryngoscope blade, or a rigid one attached to the blade. The cervical spine was immobilized with either a collar or a halo. General anaesthesia was carried out with thiopentone, fentanyl and vecuronium bromide. Orotracheal intubation was successful at the first attempts in 10 out of the 11 patients. No mobilization of the cervical spine occurred. In the first six patients, the semi-rigid guide was used, and the rigid one in the remaining five. The anaesthetist who carried out the intubations was always the same. Using the rigid guide was easier than the semi-rigid one. This is confirmed by the time required, 44 +/- 22 sec for the rigid guide, and 97 +/- 92 sec for the semi-rigid one. In the patient in whom this technique failed at the first attempt, endotracheal intubation was carried out by the nasal route and controlled by the fiberoptic laryngoscope. This technique enables a rapid and easy orotracheal intubation in trauma patients with an immobilized cervical spine, but careful training is necessary.

Adolescent↗
PubMed1991

[Intratracheal intubation using a fiberoptic laryngoscope].

Experience with a new type of laryngoscope (Bullard) is reported. It weighs 1,200 kg, and has fiberoptic fibers both for lighting and viewing. Angle of vision is about 55 degrees. Endotracheal intubation with this device requires a semi-rigid stylet to bend the tracheal tube at 90 degrees just above its cuff, so as to reproduce the curvature of the laryngoscope blade. Intubation is carried out in five steps: 1) introducing the laryngoscope blade, and visualising the vocal cords through its lens; 2) introducing the tube with its stylet, just above the laryngoscope blade; 3) placing the tube between the vocal cords under fiberoptic vision; 4) adjusting tube position in the trachea, the stylet still in place; 5) removing both stylet and laryngoscope. The use of this apparatus in an obese patient with reduced mobility of the cervical spine, who was ranked 4 on the Mallampati scale, is reported. The Bullard laryngoscope enabled easy tracheal intubation (duration 1 min 30 s), whereas direct laryngoscopy and the use of a Huffman prism were unsuccessful. The fiberoptic laryngoscope may be of help in case of difficult intubation.

Female↗