Summary and Conclusions
The influence of different oxygen concentrations of foetal oxygenation and neonatal clinical status during general anaesthesia for elective caesarean section was evaluated in 75 term-pregnant women. One-third of the patients received what we designated as a low oxygen concentration (28 per cent or 33 per cent), one-third a medium concentration (65 per cent), and one-third a high concentration (93 per cent or 97 per cent).
Oxygen tensions in both maternal and foetal bloods as well as oxygen saturation and content of foetal bloods increased significantly with increases in the inspired oxygen concentration. Foetal oxygenation was lowest and time to sustained respiration longest when maternal PaO2 was below 100 torr. Foetal oxygenation was highest and time to sustained respiration shortest when maternal PaO2 was 300 torr or more; no further foetal or neonatal change occurred as the maternal oxygen tension rose above 300 torr.
An inspired oxygen concentration of at least 65 per cent is recommended for caesarean section anaesthesia.
Résumé
L'influence de différentes concentrations d'oxygène sur le fœtus et le nouveau né pendant l'anesthésie générale pour césariennes sélectives a été evaluée chez 75 grossesses à terme. Un tiers des patients a reçu ce que nous avons designé comme concentration basse d'oxygène (28 pour cent ou 33 pour cent); un tiers a reçu une concentration moyenne (65 pour cent) et le dernier tiers une concentration forte (93 pour cent ou 97 pour cent).
Les tensions et saturations sanguines d'oxygène chez la mère et chez le fœtus ont augmenté proportionellement avec la fraction inspirée d'oxygène. L'oxygénation fœtale fut la plus basse et le temps de respiration soutenue le plus élevé quand la tension maternelle d'oxygène fut au dessous de 100 torr. L'oxygénation fœtale fut maximale et le temps de respiration soutenue le plus court quand la tension maternelle d'oxygène fut à ou dessus de 300 torr. Aucun changement fœtal ou néonatal n'a été observé quand la tension d'oxygène maternelle fut au dessus de 300 torr.
Une concentration d'oxygène inspiré d'au moins 65 pour cent est recommendée pour l'anesthésie de la césarienne.
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Marx, G.F., Mateo, C.V. Effects of different oxygen concentrations during general anaesthesia for elective caesarean section. Canad. Anaesth. Soc. J. 18, 587–593 (1971). https://doi.org/10.1007/BF03026178
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DOI: https://doi.org/10.1007/BF03026178