Presumed normal hemodynamic values of the arteries in the final third period of gestation in bitches

ABSTRACT

Background: Doppler ultrasonography enables the investigation of vascular blood flow indexes in gestational assessment,being able to detect vascular resistances that can affect fetal and maternal circulation, such as cases of placental insufficiency, associated with fetal cerebral oxygenation deficit and fetal distress. The study aims to assume hemodynamicallynormal values in the final third of gestation in bitches, of the umbilical, uteroplacental, middle cerebral and internal carotidarteries, correlating the obtained Doppler velocimetric indexes, for the assessment of the feto-placental circulation, andprediction of fetal viability indexes, fetal centralization and probable date of delivery.Materials, Methods & Results: Thirty healthy bitches were examined in the final third of gestation (40-60 days). Thesewere evaluated by Doppler ultrasonography at 2 times (T) T1 between 40-50 days; T2 between 51-60 of gestation.At each time point, the peak systolic velocities (PSV) and end-diastolic velocities (EDV) used to obtain the pulsatility(IP) and resistivity (IR) indexes of the umbilical, uteroplacental, middle cerebral and internal carotid arteries of fetuseswere evaluated. Also, the systole/diastole (S/D) ratio of these vessels was evaluated. The data obtained were subjected toanalysis of variance and Tukey test, using a P value equal to 5%. A significant difference was observed between velocitiesand Doppler velocimetric indexes between the 2 phases of the gestational final third in all studied vessels. There was anincrease in the values of PSV and EDV and a decrease in the indexes, as the probable date of delivery approached. Theanalysis of the umbilical cord IR showed an increase from P1 to P2 (P < 0.05), while the IP decreased at the same time.For all studied variables there was a statistically significant difference (P < 0.05). In the uteroplacental...