Fetal effects of maternal supplementary oxygen during Caesarean section
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AbstractPurpose of review: This review summarises the current issues, knowledge and research on the effects of maternal supplementary oxygen therapy on the fetus during Caesarean section. This is a controversial subject since supplementary oxygen has the potential to confer both benefits and also harm to the fetus, depending on the circumstances. Recent findings: For elective Caesarean section, breathing room air under regional anaesthesia or 30% oxygen under general anaesthesia is not associated with either maternal or fetal hypoxia. A prolonged uterine-incision-to-delivery (U-D) interval of up to 310 s is not a major factor per se for development of fetal hypoxia or acidosis, and no benefits could be derived from breathing supplementary oxygen in this situation. Although it appears rational to provide supplementary oxygen in the presence of a hypoxic or compromised fetus, to achieve meaningful increases in fetal oxygenation, a very high inspired oxygen fraction (FiO2) is required. However, it still remains unclear whether this is beneficial for the fetus. The process of damage to the hypoxic fetus is one of oxidative stress mediated by free radicals generated during reperfusion (ischaemia-reperfusion injury). Independently, hyperoxia from breathing supplementary oxygen also induces formation of free radicals by direct mitochondrial electron transfer. Although hyperoxia could lessen the severity of fetal hypoxia, there is also a theoretical risk of an enhanced reperfusion injury. This issue has not been resolved in a clinical study, but an animal study reported enhanced formation of free radicals after an episode of fetal hypoxia in the group receiving supplementary oxygen. Summary: For elective Caesarean section, current evidence suggests that supplementary oxygen is unnecessary. For emergency Caesarean section, further data are required before a conclusion can be made for its beneficial and adverse effects. Improvement of fetal oxygenation should be the primary objective, and this is achievable in the short term by using a very high FiO2. Although there is also a possibility of an enhanced reperfusion injury, particularly in the preterm and non-labouring patients, further data are necessary before a conclusion can be made. © 2004 Lippincott Williams & Wilkins.
All Author(s) ListKhaw K.S., Ngan Kee W.D.
Journal nameCurrent Opinion in Anaesthesiology
Year2004
Month8
Day1
Volume Number17
Issue Number4
PublisherLippincott Williams & Wilkins Ltd.
Place of PublicationUnited States
Pages309 - 313
ISSN0952-7907
eISSN1473-6500
LanguagesEnglish-United Kingdom
KeywordsAnaesthesia, Caesarean section, Fetal distress, Fetus, Free radical, Maternal, Oxygen

Last updated on 2021-27-02 at 00:31