SummaryWe studied the potentiation of analgesia for labour by the addition of clonidine to epidural low-concentration levobupivacaine with sufentanil in a randomised, double-blinded study. We enrolled primiparous women who were in spontaneous labour. The study solutions, made of 100 ml levobupivacaine 0.0625% plus sufentanil 0.45 lg.ml )1 and either 150 lg clonidine or no clonidine, were used for induction of analgesia, and for its maintenance with self-administered boluses and a continuous background infusion. The need for additional epidural boluses during labour was lower and analgesia and maternal satisfaction were better in the clonidine (n = 57) than in the control group (n = 58). Blood pressure was lower and the rate of instrumental delivery higher in the clonidine group. Clonidine (1.36 lg.ml) added to the epidural solution of lowconcentration levobupivacaine improves the quality of analgesia. The relevance of the haemodynamic effects should be explored in larger validation studies. To relieve pain during labour with the fewest side effects possible, different solutions have been proposed. These include lowering the concentration of local anaesthetics and ⁄ or adding opioids to the anaesthetic solution, and developing less toxic drugs than bupivacaine [1]. We recently studied the effects of two formulations of levobupivacaine (0.0625% and 0.125%) for analgesia during labour in primiparous women, both with sufentanil 0.45 lg.ml )1 [2]. The solution was patient-administered after a first injection of 15-20 ml for induction. With low-concentration levobupivacaine, analgesia was sometimes insufficient, while high-concentration levobupivacaine provided better analgesia, but doses sometimes exceeded recommended limits. We hypothesised that addition of low-dose clonidine to low-concentration levobupivacaine would improve the quality of analgesia without exceeding recommended dose limits. Clonidine is known to potentiate epidural analgesia through inhibition of nociceptive transmission in the spinal cord via a2 receptors and through local anaesthetic effects [3,4]. Although epidural clonidine for labour is usually administered as a single injection [5,6], the addition of clonidine in epidural infusions has also been shown to improve analgesia during labour [7][8][9][10][11]. However, as concentrations over 2 lg.ml )1 may lead to more side effects [8,[10][11][12], we chose a safer dose of 150 lg of clonidine, diluted in our prefilled bags,

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Circulatory failure occurs in about 10% of patients with pulmonary embolism, resulting from a massive obstruction of the pulmonary arterial bed. Hemodynamic and respiratory features are well established; they involve precapillary pulmonary hypertension, low cardiac output state, elevated filling pressure for the right ventricle, and venous admixture. More recently, two-dimensional echocardiography permitted the visualization of pulmonary artery and right heart enlargement, reduced right ventricular ejection fraction, and tricuspid regurgitation. Evaluated by this latter means, left ventricular systolic function appeared unchanged, but diastolic function might be reduced by septal bulging.

We assessed hemodynamics, total lung and chest wall compliance (CT) and gas exchange using two different levels of PEEP during controlled ventilation in two different groups of patients with ARF; in the first group (Group 1, 12 patients) chest X-Rays showed a symmetrical pattern of bilateral alveolar infiltrates; in the second group (Group 2, 5 patients) chest X-Ray showed a asymmetrical pattern with unilateral lobar consolidation. A first level of PEEP (best PEEP = 9 +/- 3 cm H2O) produced an improvement in CT and in gas exchange with a slight decrease in cardiac index in both groups; but improvement in PaO2 (from 64 +/-33 to 122 +/- 76 torr, p less than 0.001 in Group 1, and from 76 +/- 39 to 91 +/- 33 torr, p less than 0.05 in Group 2) and decrease in QS/QT were not as well marked in Group 2 as i Group 1. A second level of PEEP (high level PEEP: 20 +/- 4 cm H2O) produced a sharp decrease in CT and required hemodynamic support in each case (blood volume expansion with or without Dopamine infusion) to maintain cardiac index within a normal range. In Group 1 this high level PEEP produced a greater improvement in gas exchange (PaO2 increased from 122 +/- 76 to 194 +/- 76, p less than 0.01) but in Group 2 it had a deleterious effect, producing a decrease in PaO2 (from 91 +/- 33 to 76 +/- 41 torr, p less than 0.05), and an increase in QS/QT; with this higher PEEP we also noted an increase of alveolar dead space in Group 2. This study demonstrates the efficiency of high levels of PEEP to reduce QS/QT in ARF but also shows its limitations: namely reduction in cardiac performance and in efficiency if the damage to one lung is significantly more pronounced than that to the other lung.

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SynopsisComputer-aided design of plastic moldings requires knowledge of their thermal properties, e.g., thermal conductivity A, under specific conditions. For this purpose, we constructed an apparatus that measures h and functions within the 80-350°C temperature range and up to a pressure of 500 bar. It was used to carry out experiments on three types of polymers (polyamide, polystyrene, and polypropylene). This paper includes a description of the experimental setup and a presentation of the numerical modeling required for simulating the thermal behavior of test& samples whose measurements have been reported herein.

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