Combination of vibroacoustic stimulation and acute variables of mFBP as a simple assessment method of low-risk fetuses

Can vibroacoustic stimulation improve the efficiency of a tertiary care antenatal testing unit?

OBJECTIVE

Our primary objective was to determine whether vibroacoustic stimulation (VAS) decreases time to fetal reactivity in the antenatal testing unit (ATU) of a tertiary care center.

METHODS

We performed a prospective, quality assurance initiative to determine whether VAS could increase the efficiency of our ATU. On pre-specified "VAS days," VAS was applied for 3 s, if the non-stress test was non-reactive in the first 10 min. Generalized estimating equations models were used to account for within subject correlation due to multiple appointments per patient.

RESULTS

VAS use was associated with a 3.76-min reduction in time to reactivity (21.79 vs 25.55, p = 0.011) and a 56% reduction in the need for a biophysical profile (OR: 0.44, 95% CI: 0.21-0.90). Overall, however, we found no significant decrease in time spent on the monitor or in the ATU.

CONCLUSION

Compliance with a strict VAS protocol may improve the efficiency of increasingly busy ATUs.

Computerized fetal heart rate monitoring after vibroacoustic stimulation in the anencephalic fetus

BACKGROUND

To quantify changes in fetal heart rate (FHR) parameters after vibroacoustic stimulation (VAS) and to evaluate the usefulness of VAS testing (VAST) in anencephalic fetuses. Our findings may also help to clarify the route(s) of vibration and sound transmission during VAST.

STUDY DESIGN AND SUBJECTS

We obtained the antepartum FHR tracings of 16 anencephalic fetuses, including both the nonstress test (NST) and VAST. Using a computerized monitoring system, HYFM, we determined all FHR parameters from data collected for 10 min before and 10 min after VAS, at successive gestational stages.

RESULTS

We observed three false reactive responses at term. The false reactive rate for VAST (3/16) was higher than that for NST (1/16). No FHR parameters increased significantly after VAS except for the number of fetal movements (FM), which increased significantly in all gestational groups (25th-32nd and 33rd-40th weeks).

CONCLUSIONS

These findings call attention to an increased probability of a false reactive response in VAST analysis, when the fetus is affected by a CNS disorder. Increased numbers of FM after VAS suggest that the vibratory pathway is more likely to elicit fetal response than the auditory pathway in this setting, and that the vibratory stimulation travels by subcortical rather than by cortical pathways.