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Intrapartum Fetal Stimulation Testing
Author(s) -
Umstad Mark,
Bailey Catherine,
Permezel Michael
Publication year - 1992
Publication title -
australian and new zealand journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.734
H-Index - 65
eISSN - 1479-828X
pISSN - 0004-8666
DOI - 10.1111/j.1479-828x.1992.tb01951.x
Subject(s) - medicine , caesarean section , fetus , fetal distress , scalp , blood sampling , obstetrics , fetal heart rate , cardiotocography , obstetrics and gynaecology , pregnancy , heart rate , surgery , blood pressure , genetics , biology
EDITORIAL COMMENT: We accepted this paper for publication since it reports findings with a test which could rationalize selection of the fetus with cardiotocographic abnormalities in labour in whom capillary blood sampling is indicated. We agree with the authors that the findings need confirmation in a larger series. Our reviewer commented that the vibroacoustic stimulation test (VAST) should only be used when the fetal heart abnormality is sufficient to cause clinical concern of fetal well‐being. We need more information in order to judge the importance of the findings. Table 2 shows that only 3 of the 60 tracings showed reduced variability prior to VAST; how then can provocation of accelerations of 15 beats per minute or more reassure the obstetrician that fetal blood sampling is not indicated, when the trace was already reactive in for example, a case with late decelerations? Moreover further study should examine the response to VAST when cardiotocographic abnormalities are associated with fetal immaturity or maternal narcotic drug therapy. The fact of the matter is that many major centres no longer perform fetal scalp blood sampling in labour; when there is fetal distress the patient is delivered, vaginally if conditions are favourable, or by Caesarean section if they are not. Most obstetricians and patients are happy with this philosophy of obstetric practice and the increased Caesarean section rate it causes. Is it really necessary to repeatedly, invasively, sample fetal condition when things are not progressing favourably in labour? VAST would be marvellous if it could safely, from the fetal point of view, allow labour to continue when the obstetrician considers that vaginal delivery is imminent. Summary: Intrapartum vibroacoustic stimulation testing (VAST) had a sensitivity of 100%, a specificity of 59.6% and a positive predictive value of 27.6% for the detection of fetal acidosis in this study of 60 cases. The use of VAST could significantly reduce the requirement for fetal capillary blood sampling. However, fetal scalp stimulation (FSS) was found to be an unreliable test to exclude fetal acidosis.