Cahiers d'anesthésiologie
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Despite of a chronic volume overload the left ventricle function of pregnant women is preserved by both afterload reduction (arterial vasodilatation) and a facilitation of heart filling through an increase in peripheral venous tone. Fetal oxygenation results from an equilibrium between placental and umbilical blood flows. During regional anaesthesia the sympathetic blockade leads to a peripheral vasodilatation (mainly in the capacitive territories) which is the cause of arterial hypotension through a decrease in cardiac output. ⋯ Finally regional anaesthesia is beneficial for the mother and the fetus through a reduction in plasma catecholamines, provided that arterial pressure remains unchanged. Thus during pregnancy-induced hypertension (PIH) epidural analgesia leads to an improvement of the reduced placental blood flow. However PIH renders the women susceptible to sympathetic blockade and the fetus easily vulnerable to an additional stress factor like acute decrease in placental flow due to hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)
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Cahiers d'anesthésiologie · Jan 1994
[How can we improve the efficacy of morphine analgesia without increasing adverse effects?].
The use of opioids for postoperative pain relief is associated with the occurrence of side effects whatever the technique of administration. One may consider different solutions to reduce these side effects, while maintaining an adequate analgesia level. Combination of different pharmacological types of analgesic agents is defined as "balanced analgesia". ⋯ Alpha 2 adrenergic agonists, acting at the level of the dorsal horn of the spinal cord, also strengthen and prolong analgesia induced by epidural or spinal opioids. Finally, local anaesthetic solutions in low concentration may potentiate the analgesic effect of opioids, also improving the quality of analgesia. These different combinations have to be considered in view of the surgical procedure performed, the patient condition and the possibilities of monitoring in any given care unit.
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Pain is a major factor of respiratory decompensation after chest trauma. General and/or regional analgesia improve alveolar ventilation, make physiotherapy easier and often avoid mechanical ventilation. Concerning regional techniques, epidural, intercostal and interpleural routes have their respective indications and contraindications, benefits and risks. When suitable, epidural analgesia appears to be the preferable technique.