Foetal Oxygenation During Caesarean Section

Rorke, M. J.; Davey, D. A.; Dutoit, H. J.

doi:10.1097/00006254-196905000-00006

Cited by 3 publications

(5 citation statements)

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“…In the human, Rorke, Davey & Du Toit (1968) showed that at Caesarean section, the foetal umbilical arterial oxygen tension was lower when the mother was ventilated with 100 % oxygen, than when ventilated with 66-6 % oxygen. Baraka (1970) found that the foetal oxygen tension correlated well with the maternal when the Pco2 was in the range 78-200mmHg, but not when it was in the range 200-500 mmHg.…”

Section: Introductionmentioning

confidence: 99%

The effects of maternal hypercapnia on foetal oxygenation and uterine blood flow in the pig.

Hanka¹,

Lawn²,

Mills³

et al. 1975

The Journal of Physiology

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SUMMARY1. The purpose of this investigation was to determine the effects of maternal hyperoxaemia and hypercapnia on the uterine vascular bed and foetal oxygenation in the large white sow at 80-90 days gestation.2. When maternal hyperoxaemia was induced with 100 % oxygen, there was a highly significant rise in the maternal arterial oxygen tension, but no other significant blood gas or vascular changes were observed.3. When mild maternal hypercapnia was superimposed on maternal hyperoxaemia (oxygen plus 6 % carbon dioxide), the oxygen tension and saturation of both the maternal uterine venous and foetal umbilical venous bloods were significantly increased. Similar but more pronounced increases were found when severe hypercapnia was induced (oxygen plus 50 % carbon dioxide) but in this case all blood samples showed dramatic changes in Pco, and pH. These changes were accompanied by an increase in the systemic blood pressure and uterine blood flow, and a decrease in uterine vascular resistance. 4. When mild hypercapnia was induced without hyperoxaemia (air plus 5 % carbon dioxide) significant increases were recorded in the oxygen tension and saturation of uterine venous and foetal umbilical venous bloods. Systemic and uterine arterial blood pressure rose, the uterine blood flow increased, and uterine vascular resistance fell. 5. It was concluded that the increased foetal oxygen tension during maternal hypercapnia was the result of the increased uterine blood flow and greater mass delivery of oxygen to the placenta, so that once the oxygen requirements of the placental tissues themselves were exceeded there would be an increased oxygen gradient at the site of gas exchange.

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Section: Introductionmentioning

confidence: 99%

The effects of maternal hypercapnia on foetal oxygenation and uterine blood flow in the pig.

Hanka¹,

Lawn²,

Mills³

et al. 1975

The Journal of Physiology

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“…There is, however, a curvilinear relationship, so that the increment of fetal P Oa values for any given change of maternal P Oa will be less the higher the maternal P Oa . This type of relationship has been demonstrated in humans by RORKE et al [10], and in sheep by COMLINE et al [4]. Thus, the fetus appears to be protected from high levels of P O(l [2].…”

Section: Discussionmentioning

confidence: 82%

“…The small amount of physically dissolved oxygen at high P 0o levels will in no way compensate for the reduced blood flow, provided the mother is fully oxygenated in the control Situation. If this reduction of placental blood flow during hyperoxia also occurs in man it might at least partly explain the results of RORKE et al [10], in which the change from 66 to 100 per cent of inspired oxygen to the mother actually caused a decrease of the P o> in the umbilical vein and artery.…”

Section: Discussionmentioning

confidence: 88%

“…RORKE et al [10] in humans and several investigators using animals [5,4,1] have demonstrated that an increase of maternal oxygen tension causes only a disproportionately small increase of fetal oxygen tension. Such an effect might be explained by the fact that the placental venous P Oz increases only moderately and thus that the pressure head for oxygen diffusion is not elevated in proportion to maternal arterial P O2 .…”

Section: Introductionmentioning

confidence: 99%

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The uterine and maternal placental blood flow during hyperoxia

Karlson¹,

Kjellmer²

1974

Journal of Perinatal Medicine

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“…These findings have been confirmed in healthy volunteers [10,11] and patients with congestive heart failure, in whom the effect is more pronounced [12]. Maternal hyperoxia has been shown to correlate poorly with fetal oxygenation [13] and may have no effect on fetal oxygenation [14] or may even reduce it [15]. Maternal hyperoxia has been shown to cause placental vasoconstriction [16,17], decreased fetal heart rate [18] and increase markers of free radical activity from the placenta, and hence oxygen may be associated with a detrimental effect on the fetus [19].…”

mentioning

confidence: 66%

Effects of normobaric hyperoxia on haemodynamic parameters of healthy full‐term parturients

et al. 2007

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SummaryFifteen healthy, full-term women with singleton pregnancies were exposed to an increased F I O 2 of 0.4 and their haemodynamic responses measured with a non-invasive transthoracic bio-impedance monitor. There was a mean reduction in cardiac index from 3.18 to 3.03 l.min There were no significant changes in stroke index, heart rate or mean arterial pressure. This study demonstrates that even a moderate increase in inspired oxygen fraction has significant effects on the cardiovascular system of the term parturient.

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Foetal Oxygenation During Caesarean Section

Cited by 3 publications

References 0 publications

The effects of maternal hypercapnia on foetal oxygenation and uterine blood flow in the pig.

The effects of maternal hypercapnia on foetal oxygenation and uterine blood flow in the pig.

The uterine and maternal placental blood flow during hyperoxia

Effects of normobaric hyperoxia on haemodynamic parameters of healthy full‐term parturients

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