Serum bupivacaine concentrations and transplacental transfer following repeated epidural administrations in term parturients during labour.

Bupivacaine is the most widely used local anaesthetic in obstetrics for epidural analgesia. Nineteen women (mean age 26.9 +/- 5.3 years) who underwent epidural analgesia during labour were included in this study. All parturients received a first injection of 21.8 +/- 2.5 mg 0.25% plain bupivacaine. The following administrations were given on request: 0.25% concentration was used when cervix uteri was supple, and a 0.375% concentration when it was tonic. Blood samples were collected 5 min after the first injection and then every 30 min until delivery. At delivery blood samples were collected from the infant umbilical cord vein and from the arm vein of the mother. Bupivacaine was assayed by high pressure liquid chromatography. Serum data were analyzed for each patient using a non-compartmental model. Bupivacaine was rapidly detected in serum, and maximal concentration was reached between 5 and 35 min. Pharmacokinetic parameters were estimated in 17 women after the first injection: 87 +/- 35 min for elimination half-life, 60 +/- 19 L for apparent volume of distribution and 0.5 +/- 0.3 L/min for plasmatic clearance. For a mean total duration of labour and total dose administered of respectively 222 +/- 115 min and 57.1 +/- 28.7 mg the mean value of the foeto-maternal ratio was 0.29 +/- 0.10. The infant maximal serum concentration was 0.26 microgram/mL. No side effects were spontaneously reported by the parturients and all infants had an Apgar score of 10 at 5 min after the delivery. We confirm the fast systemic absorption and rapid elimination of bupivacaine which may be used without risk of acute toxicity both in mother and child, even when it is used in a 0.375% concentration.

[Intravenous anesthesia for cesarean section. Comparison of propanidid and methohexital]. / Anesthésie intraveineuse pour césarienne. Comparaison du propanidide et du métohexital.

Propanidid and methohexital were compared retrospectively to assess the possible neonatal depression following general anesthesia for caesarean section: both have rapid onset and short duration of action and their transplacental passages are similar. Anesthesia was induced with equivalent doses of the two agents in 90 women (45 in each group). For each anesthetic agent, three subgroups were defined according to the indications, depending on emergency criteria and fetal state. There was no significant statistical difference (Student test) regarding clinical and biochemical criteria except for the fetal arterial pH which was more acidic in the propanidid group. In both groups, Apgar scores, arterial and venous pH were significantly more altered when caesarean section was performed for acute fetal depression.

[Labor under peridural anesthesia. Experience at the Maternity Center of the Amiens CHRU]. / L'accouchement sous péridurale. Expérience de la Maternité du CHRU d'Amiens.

The study has been carried out on 476 epidural deliveries. 69 per cent of the patients were satisfied. Amongst the 31 per cent of unsatisfied, most claimed that the analgesia was not sufficient, mainly due to delayed re-injections. Instead of a continuous administration, the authors prefer the use of a bolus which is better adapted to the different times of labour. 80 per cent of the patients who had a caesarian delivery under epidural anaesthetic were very satisfied. The efficacy of the re-injection for post-operative analgesia is also to be noted (92 per cent success). Finally, whatever the stage of perfection of the epidural technique, it is always better to associate the latter with a good psychoprophylaxis.