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Uptake of halothane by the foetal lamb in utero

Abstract

The uptake of halothane by the normal foetus in utero was determined, using the pregnant ewe as an experimental animal model. Six pregnant ewes of 125–135 days gestation were surgically prepared under general anaesthesia. Potyvinyl catheters were placed in the maternal femoral artery and vein and in the foetal femoral artery and vein and the axillary artery. Each animal was allowed to recover for 24–36 hours prior to study. On the day of the experiment a tracheostomy was performed and after a control period, the ewe was anesthetized with 1.5 per cent halothane in oxygen. During each study, maternal and foetal blood pressure were continuously recorded. Simultaneous maternal and foetal arterial halothane concentrations were measured to construct an uptake curve for the foetus. During the study, foetal mean arterial blood pressure fell significantly (27per cent). There were no significant changes in foetal or maternal pulse rate or acidbase status. Halothane appeared in the foetal blood by two minutes but foetal halothane levels remained significantly lower than maternal for 24 minutes. We conclude that halothane crosses the placenta rapidly and produces a decrease in foetal blood pressure but no change in foetal oxygenation or acid-base status.

Résumé

La résorption d’halotane chez le foetus normal in utero a été mise en évidence avec notre expérience chez la brebis gravide. Six brebis gravides de 125–135 jours en gestation ont étv préparées pour l’opération chirurgicale avec I’anesthésie générate. On a placé des cathéters dans I’artére et la veine fémorales maternelles ainsi que dans l’artere fimorale du foetus et l’artére axillaire. Chaque brebis pouvait récupérer de 24 à 36 heures avant notre expérience. Le jour de I’expérience, on effectua une trachétomie et apres la période de contrôle, la brebis fut anesthésiée avec 1.5 pour cent d’halotane contenu dans I’oxygène. Pendant la durée de notre étude, la tension artérielle maternelle et celle du foetus furent mesurées continuellement. Les concentrations simultanées d’halotane du débit artériel maternel nel et fatal ont été mesurés afin d’obtenir une courbe de résorption du foetus. Durant le cours de notre expérience, la tension artérielle moyenne du foetus baissa de facon significative (27 pour cent), II n’y a pas eu de changements significatifs de la fréquence du pouls chez la brebis et le fcztus ni de l’équilibre acido-basique. L’halotane passe dans le sang festal en deux minutes mats le niveau d’halotane reste significativement plus bas que celui de la brebis. Nous concluons done que I’halotane passe rapidement dans le placenta et engendre une baisse de la tension artérielle du fcetus. Cependant, on n’observe pas de changements dans l’oxygénation du foetus ni de l’équilibre acido-basique.

References

  1. 1

    Latta IP, Waldron BA. Anesthesia for caesarean section. Br J Anaesth 1977; 49:371–8.

  2. 2

    Moir DD. Anesthesia for caesarean section: An evaluation of a method using low concentrations of halothane and 50 per cent of oxygen. Br J Anaesth 1970; 42:136–142.

  3. 3

    Marx GF. Placental transfer of anesthetic agents. Anesthesia Rounds, Vol. IV, No. 3, Ayerst Laboratories, pp 8–23,1973.

  4. 4

    Rolbin SH, Levinson G, Shnider SM. Current status of anesthesia for cesarean section. Weekly Anes- thesiology Update, Vol. 1, Lesson 7, Weekly Anes- thesiology Update, Inc., Princeton, N.J., 1977.

  5. 5

    Davies DD. A method of gas chromatography using electron-capture detection for the determination of blood concentrations of halothane, chloroform, trichloroethylene. Br J Anaesth 1978; 50:147–155.

  6. 6

    Zar JH. One-sample hypothesis. Chapter 8 inBiostatistical Analysis, Prentice-Hall, Inc. N.J., 1974.

  7. 7

    Geddes IC, Brand L, Finster M, et al. Distribution of Halothane82 Br in maternal and fetal guinea pig tissues. Br J Anaesth. 1972; 44:542–547.

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Correspondence to D. R. Biehl or J. Côté or J. G. Wade or G. A. Gregory or D. Sitar.

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Biehl, D.R., Côté, J., Wade, J.G. et al. Uptake of halothane by the foetal lamb in utero. Can Anaesth Soc J 30, 24–27 (1983). https://doi.org/10.1007/BF03007712

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Key Words

  • Anaesthetics
  • volatile: halothane
  • pharmako-kinetics
  • foetus