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SUBCUTANEOUS OXYGEN TENSION IN THE FETAL SCALP DURING LABOUR CONTINUOUS MONITORING WITH A NEEDLE ELECTRODE
Author(s) -
Aarnoudse J. G.,
Huisjes H. J.,
Oeseburg B.,
Zijlstra W. G.
Publication year - 1981
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/j.1471-0528.1981.tb01026.x
Subject(s) - scalp , oxygen tension , electrode , clark electrode , fetus , anesthesia , oxygen , medicine , biomedical engineering , fetal monitoring , chemistry , surgery , pregnancy , biology , organic chemistry , genetics , electrolyte
Summary Continuous intrapartum PO 2 recordings were made in 25 fetuses, using a needle electrode that measures PO 2 in the subcutaneous (sc) tissue of the scalp or the breech. This small electrode is combined with a spiral ECG electrode and can be easily applied in early labour. One hour after application of the electrode in the early first stage, a mean fetal scPO 2 of 29.4±7.5 mm Hg was found. In the course of labour, scPO 2 gradually fell to a mean value of 22.2±5.6 mm Hg, recorded just before the onset of bearing down contractions, and stabilised in the second stage of labour. ScPO 2 values of less than 10 mm Hg were not recorded for a longer period except in one case of severe fetal distress. The relation between scPO 2 just before delivery and cord arterial PO 2 revealed a coefficient of correlation of 0.85. In general, scPO 2 appeared higher than tcPO 2 as described in the literature. This is ascribed to the different technique of measurement: the needle electrode measures in the deeper layers of the scalp, whereas the tc electrode is supplied with oxygen from the more superficial capillaries, where blood flow is more liable to be affected by mechanical factors.