Evaluation of Vibro Acoustic Stimulation Test as a Predictor of Fetal Outcome in High Risk Pregnancies in Early Labour

Neela, M (2006) Evaluation of Vibro Acoustic Stimulation Test as a Predictor of Fetal Outcome in High Risk Pregnancies in Early Labour. Masters thesis, Madras Medical College, Chennai.

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Abstract

1. 400 cases of High risk pregnant women after 37 completed weeks in early labour were recruited for the study. 2. All the cases were clinically examined routine ultrasonogram was performed for gestational age and liquor status. 3. Vibro – acoustic stimulation was performed using an electronic artificial larynx in all these cases and the tracings were classified as reactive and non reactive based on the fetal heart acceleration to the acoustic stimuli. 4. In the non – reactive VAST traces cases, early artificial rupture of the membrane was performed to see the colour of liquor. 5. The mode of delivery and test delivery interval was noted. 6. The adverse perinatal outcome was analysed with relevance to the thick meconium stained liquor, and Apgar score of < 7. In the present study majority were primigravida in the age group of 20 – 25 years. Of the 400 patients 78% had reactive and 22% had non – reactive VAST. Among clear liquor, VAST was reactive in 84% and non reactive in 16%. Among thick MSL, VAST was reactive in 35% and NR in 65%. VAST non reactive in 60% of clear liquor and 40% meconium stained liquor. In selected cases (33 patients) where fetal distress was indicated by non reactive VAST or meconium staining of liquor, earlier intervention was undertaken. They were delivered within 2 hours by Emergency LSCS. • Among those two were moderately asphyxiated and 1 was severely asphyxiated and admitted in NICU. The rest had good apgar because of earlier intervention. • Of the patients subjected to VAST 61% were delivered by LN while 3% and 36% were delivered by LSCS and forceps respectively following reactive VAST. • Of the non reactive VAST group more than half delivered by LSCS. Among those 79% babies had good Apgar. • Among patients who undergone CS for fetal distress 57% had non reactive VAST and 43% had reactive VAST. • The study was conducted in High risk pregnancy patients. Among 400 patients, 44% had crossed EDD. 28% were preeclamptic patients and 15% were complicated by Oligo hydramnios. Few had GDM. The rest had high risk factor like anemia, placenta previa, heart disease, epilepsy, BOH. • Most patients (40%) delivered babies with birth weight between 2.6 – 3 kg. 24% were low birth weight babies and 1% macrosomic babies whose mother had GDM. • Among patients with reactive VAST 96% babies had good apgar and 4% only had apgar < 7. • It indicates reactive VAST was associated with high specificity and negative predictive value. Among patients with non reactive VAST 81% babies had good apgar and 19% babies had apgar < 7. It indicates VAST was associated with low sensitivity and positive predictive value. Incidence of fetal distress was highest with non reactive than with reactive VAST (11%). The factors that were considered as abnormal outcome are : a 5 min apgar score less than 7, thick meconium stained liquor or admission to the NICU. In reactive VAST group 93.4% of babies had good fetal outcome. It gives assurance that reactive response indicates fetal well being. In non reactive VAST group, 38% of babies had poor fetal outcome and 62% had good fetal outcome. CONCLUSION: Vibroacoustic stimulation in the early intrapartum period may be used as a non invasive screening method for rapid intrapartum assessment of fetal well being. • It gives an early prediction of fetal compromise in high risk pregnancies • A reactive response to VAST was associated with high specificity and negative predictive value. VAST was associated with low sensitivity and positive predictive value. • In the abnormal VAST, high correlation with adverse perinatal outcome was seen. • In crowded labour rooms with limited monitors as in teaching hospitals, the VAST is very useful to detect high risk cases and to monitor them effectively and helps the obstetricians in the appropriate and timely intervention. • It is therefore suggested to add VAST to NST monitors in the busy labour rooms which allow immediate intervention to be taken in non reactive traces. • VAST thus proves to be a safe and rapid test of fetoplacental sufficiency.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Vibro Acoustic Stimulation Test ; Predictor ; Fetal Outcome ; High Risk Pregnancies ; Early Labour.
Subjects: MEDICAL > Obstetrics and Gynaecology
Depositing User: Subramani R
Date Deposited: 03 Dec 2017 06:23
Last Modified: 05 Dec 2017 00:43
URI: http://repository-tnmgrmu.ac.in/id/eprint/4152

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