[Autotransfusion using Cell Saver III. Experience with 90 cases of surgery of the spine in childhood and adolescence]. / Autotransfusion par Cell Saver III. Expérience de 90 cas de chirurgie du rachis chez l'enfant et l'adolescent.

Intra-operative transfusion was used with Cell Saver Haemonetics III in 90 children undergoing spinal surgery for scoliosis. This technic keeps pace with controlled bleeding by collecting and processing shed blood and reinfusing washed packed red cells. During high blood loss procedures this device allowed to save up 51% of shed red cells. Our study of the intra-operative bleeding and its replacement was assessed with calculation using an individual regression line for each patient. Statistical analysis was performed by using multivariate correlation and "step wise analysis".

A comparison of alfentanil pharmacokinetics in children and adults.

The pharmacokinetics of alfentanil have been studied in eight children aged between 4 and 8 yr and five adults during general anesthesia. All patients were given 20 micrograms/kg alfentanil as an intravenous bolus injection. Plasma concentrations were measured at intervals up to 6 h by radioimmunoassay. Plasma protein binding was measured by equilibrium dialysis using tritiated alfentanil. The optimal pharmacokinetic model for alfentanil was an open two-compartment model. Total apparent volume of distribution (Vdss) was 457 +/- 160 ml/kg in adults and 163 +/- 110 ml/kg in children (P less than 0.01). When recalculated by surface area Vdss was still decreased in children (P less than 0.01). Plasma clearance (Cl) was similar in the two groups. Terminal elimination half-life was significantly shorter in children (40 +/- 9 min) than in adults (97 +/- 22 min; P less than 0.01). The shorter elimination half-life could be due to the smaller total apparent volume of distribution in children. Plasma protein binding was comparable between children and adults and could not explain the smaller volume of distribution in children. It is suggested that the smaller volume of distribution of alfentanil in children is a result of the decreased percentage of fat tissue in children.

Pharmacokinetics and pharmacodynamics of vecuronium and pancuronium in anesthetized children.

The pharmacokinetics and pharmacodynamics of vecuronium and pancuronium were determined in 12 children (3-6 yr) undergoing minor surgery under 60% nitrous oxide, 1 MAC halothane anesthesia. When the level of anesthesia and the electromyograph (EMG) recording of the adductor pollicis were stable, an intravenous bolus of vecuronium (100 micrograms/kg) or pancuronium (100 micrograms/kg) was administered. Plasma concentrations of the two muscle relaxants were determined for 6 hr after the administration by means of a fluorimetric assay followed by a thin layer chromatography. Plasma concentrations of vecuronium and pancuronium declined biexponentially in children and no metabolites could be detected in plasma. The elimination half-lives of vecuronium and pancuronium did not differ significantly. The volume of distribution at steady state (Vdss) was greater (P less than 0.05) after vecuronium (320 +/- 181 ml/kg; mean +/- SD) than after pancuronium (203 +/- 36 ml/kg). Plasma clearance of vecuronium (2.8 +/- 0.9 ml X min-1 X kg-1) was greater than that of pancuronium (1.7 +/- 0.2 ml X min-1 X kg-1; P less than 0.05). Plasma concentrations measured at 10%, 50%, or 90% recovery of the EMG response did not differ significantly for vecuronium and pancuronium. Thus the shorter duration of action of vecuronium is probably due to its greater apparent volume of distribution, as well as to its higher plasma clearance. Thus although the elimination half-lives are comparable, the plasma disappearance of vecuronium is more rapid than that of pancuronium.

Clinical pharmacology of vecuronium in children. Studies during nitrous oxide and halothane in oxygen anaesthesia.

Forty-seven children (ASA I or II) were studied during nitrous oxide-oxygen, halothane anaesthesia. The dose-response curve for vecuronium was determined after the injection of a single bolus (40, 55 or 70 micrograms kg-1) to 33 patients. The ED50 and ED95 were 31 and 64 micrograms kg-1 respectively. Fourteen children received a larger dose (100 micrograms kg-1); good intubating conditions were obtained in all of these within 2 min. After a single bolus (100 micrograms kg-1) the duration of action was 36.5 min and the recovery index was 9.3 min. In patients who received small maintenance doses (25 micrograms kg-1) after a single bolus (100 micrograms kg-1) the recovery index after the last maintenance dose was not increased. There were no significant changes in heart rate or arterial pressure. In children, vecuronium has a short duration of action and lacks cumulative or cardiovascular side affects.

[Controlled hypotension during posterior vertebral arthrodesis; value of an isoflurane-nitroglycerin combination]. / Hypotension contrôlée dans les arthrodèses vertébrales par voie postérieure, intérêt de l'association isoflurane-trinitrine.

Eighteen young patients (mean age +/- SD 15.9 +/- 3.3) scheduled for operative treatment of idiopathic scoliosis (posterior spine fusion) were studied during surgery. Deliberate hypotension (MAP less than 60 mm Hg) of long duration (greater than 2 hours) was induced using isoflurane and nitroglycerin. Hypotension was effective in less than 15 min in all patients. The mean inspiratory fraction of isoflurane employed was 2.04 +/- 0.19% for the first operative hour, and 1.36 +/- 0.20% for the second operative hour. The difference between these inspiratory fractions is highly significant (p less than 0.001), while the rate of nitroglycerin infusion was unchanged (3 micrograms X kg-1 X min-1). Heart rate increases significantly at H1 and H2 when compared to preinduction values and the product of heart rate X systolic blood pressure decreases significantly with a mean of 30% versus preinduction values. A satisfactory operative field was obtained in all cases. Blood loss was dependent of the duration of surgery, of the total blood volume of the patient, of the length of spine fusion. For each patient, a slope of blood loss was established. The mean slope was 3.74 +/- 0.39 ml X kg-1 X h-1. The determination of the slope at the end of the first operative hour allows us to predict the total blood loss during surgery. Intra operative awakening was obtained 22.8 +/- 3.7 min after isoflurane was discontinued. Isoflurane and nitroglycerin produce a stable and safe hypotension with no major hemodynamic disturbances. Isoflurane has to be discontinued 20 min before the wake-up test.

[Autotransfusion with acute hemodilution in the surgical treatment of scoliosis (author's transl)]. / Auto-transfusion per-opératoire et hémodilution aiguë en chirurgie orthopédique. Application au traitement chirurgical de la scoliose.

With the goal to reduce the number and the volume of homologous blood transfusions during surgical treatment of scoliosis and spine deformities, the authors have studied the results of 50 cases treated with immediate acute haemodilutional autotransfusion. In 40 per cent of the case neither per nor post operative homologous blood transfusion was necessary. In addition they have seen a surprising result such as a significant lowering of absolute blood loss during surgery compared to a similar series treated without haemodilutional autotransfusion. Physiopathological principles, precise technique used and limitation of the method are described.

[Anesthesia with pure enflurane in children: an electroencephalographic study (author's transl)]. / Anesthésie par l'enflurane pur chez l'enfant. Etude électroencéphalographique.

E.E.G. recordings in 10 children anesthetized with pure enflurane (Ethrane) demonstrated critical discharges in two of them and a burst suppression appearance in one case. In the first two cases, the concentrations of enflurane were 3 and 3-5% respectively, while in the third case the E.E.G. anomalies appeared after interruption of administration. These three children having benefited from assisted ventilation, the favorable role of a hypocapnea is suggested.

[Neuromuscular block control during and after anaesthesia (author's transl)]. / Contrôle de la curarisation au cours et au décours de l'anesthésie.

During many years the clinician's requirements for neuromuscular blocking drugs are satisfied by clinical investigations. Electromyographic recordings which are a satisfactory method are not useful in current practice. The use of nerve stimulators as Churchill Davidson apparatus modified for train of four impulses must reach the continental theatres, the response to neuromuscular blocking agents varying over a wide range. Five ways of stimulation can be used giving different informations, not only during anaesthesia, but so after particularly to specify the origin of some complications.