Purpose: To determine the effect of epidural analgesia on biochemical markers of stress, plasma oxytocin concentrations and frequency of uterine contractions during the first stage of labour. Methods: Nine nulliparous women, in spontaneous labour, with a singleton fetus and cervical dilatation < 5 cm were enrolled. Epidural bupivacaine 0.25% (range I 0 -14 ml) was administered and bilateral sensory blockade to ice 0-8 -L4) achieved. Blood samples were collected before the epidermal block and every I0 min for one hour after the block was achieved for the measurement of plasma beta-endorphin, cortical, glucose, lactate and oxytocin concentrations. No exogenous oxytocin was given. Intensity of pain was assessed at the time of the blood sampling using a I0 cm visual analogue scale (VAS). The frequency of uterine contractions was recorded for 60 rain before and after the epidural block.Results: There was a decrease in plasma beta-endorphin and cortisol concentrations after epidural block (P < 0.01).There were no changes in plasma glucose and lactate concentrations. The mean VAS for pain decreased I0 rain after epidural block was achieved and remained < 2 throughout the study period (P < 0.001 ). Mean plasma oxytocin concentrations did not change. The frequency of uterine contractions before and after the epidural block was similar. Condusions: The metabolic stress response to the pain of labour was attenuated by epidural analgesia. In contrast, plasma oxytocin concentration and frequency of uterine contractions were unaffected by the attenuation of metabolic stress response.Object~ : D&erminer reffet de l'analg&ie p&idurale sur les marqueurs biochimiques de stress, les concentrations plasmatiques d'oxytocine et la frdquence des contractions ut&ines pendant le premier stade du travail. M&hode : Neuf femmes nullipares, en travail spontan6, porteuse d'un seul foetus et pr&entant une dilatation du col de l'ut&us < 5 cm, ont dtd recrut&s. On a administrd de la bupivaca'ine p&idurale ~ 0,25 % (de I0 ~ 14 ml) et on a procddd ~ un blocage sensoriel bilat&al ~ la glace (-I-8 -I_4). On a prdlevd des &hantillons de sang avant le point dermique et ~ toutes les I0 minutes pendant une heure apt& le bloc afin de mesurer les concentrations plasmatiques de 13-endorphine, de cortisol, de glucose, de lactate et d'oxytocine. On n'a pas administrd d'oxytocine exog~ne. l'intensitd de la douleur a 6td dvalu6e au moment des prdl~vements sanguins en utilisant une &helle visuelle analogique (EVA) de 10 cm. La frdquence des contractions ut&ines a &d enregistr6e pendant 60 minutes avant et apr& I'analg6sie p&idurale. R&ultats : On a observd une baisse de la 13-endorphine plasmatique et des concentrations de cortisol apr& ranalg&ie p&idurale (P < 0,01). II n'y a pas eu de changements dans les concentrations de glucose et de lactate. La moyenne de rEVA pour la dou~eur a diminu~, I0 minutes apr~s le bloc p6ridural et est demeur& < 2 pendant toute la dur& de l'&ude (m < 0,00 I). Les concentrations moyennes d'oxytocine front pas changd. La frdquence...

Cardiac arrest occurred on arrival in the recovery room after emergency Caesarean section under subarachnoid block. The patient was resuscitated successfully and recovered with no adverse effects. The current literature is reviewed and the pathophysiological mechanisms involved in the aetiology of cardiac arrest under subarachnoid block are discussed. Early use of adrenaline to treat severe bradycardia or hypotension is recommended.