[The influence of the bupivacaine epidural anesthesia on the rabbit myometrium contractile activity and the functional state of the fetuses in induced labor].

BACKGROUND: The influence of bupivacaine (0.5% - 1 ml) epidural anesthesia (EA) on 15 pregnant rabbit females induced in labor by oxytocin on the 30th day of pregnancy in chronic experiment was conducted. MATERIALS AND METHODS: 26 pregnant rabbit females took part in the investigation. 11 females were included in the control group and 15--to the main group. Both groups retrospectively were divided in two on the fact of the delivery during the experiment. For each 5-minute interval the contractile activity of the myometrium (number of uterine contractions, duration and amplitude of the one uterine contraction), functional state of fetuses and female (ECG) were evaluated. Registration of the parameters was carried out simultaneously with the help of electrodes which were administrated in the myometrium, to the fetuses and females on the 28th day of pregnancy. RESULTS: It was shown that EA influence on the myometrium contractile activity and functional state of fetuses and female depends on the female delivery readiness. CONCLUSION: In the case of the optimal one short-term increase of the contractile activity (on the 15th minute after EA) with no significant fetal heart rate changes were observed. In the case of its absence no significant influence was revealed. Moderate female tachycardia in both groups under EA was registered more pronounced in delivery one group.

[The influence of the bupivacaine regional anesthesia on the contractile activity of the uterus and the functional state of the fetus].

The study in chronic experiment on 26 pregnant rabbit females induced in labor by oxytocin on the 30th day ofpregnancy was conducted. The effects of bupivacaine (0,5% - I ml) epidural anesthesia (EA) on the contractile activity of the uterus, the functional state of the females and their fetuses were studied. On the 28th day of pregnancy under thiopental anesthesia electrodes were administered: to thefetus - ECG, in the female myometrium for recording electrical activity. In order to check the uterus mechanical activity the original sensor was used filled by graphite, which was placed around one horn of the uterus. The contractile activity of the myometrium was evaluatedfor each 5-minute interval by the number ofuterine contractions, duration and amplitude of one uterine contraction. The functional state offemale fetuses and rabbit female were evaluated by the frequency change of the heart rate. In 12 females occured to delivery. Registration of uterine contractions, heart rate of the female and fetuses were carried out simultaneously and continuously throughout the whole experiment. It was shown that under standard conditions EA didn't induce changes in uterine activity parameters of the female located in its natural position, and didn't affect on the fetal heart rate (3-factor analysis of variance - ANOVA). 10minutes after EA, the momentary acceleration of female heart rate (9%) was recorded in relation to the reference level, which may be associated with transient hypotension. Thus, in conditions of our experience the bupivacaine (0,5% - 1,0 ml) EA in induced labor of female rabbit has no significant effect on the uterus contractile activity and the functional state of the fetus. Short-term adaptive tachycardia is registered in females.