Doppler ultrasonography of the umbilical artery and middle cerebral artery during pregnancy of dogs French Bulldog breed underwent caesarean delivery

Gestational ultrasonographic evaluation is a critical tool for predictions of delivery time, as well as changes in maternal-fetal physiology, which can occur in late pregnancy. The French bulldog breed is well known by showing difficulties during natural parturition, so the determination of fetal maturity is essential in these animals for cesarean delivery decision. Twenty-six dogs French bulldog breed with average weight of 20 ± 2,80kg and average age between 3 and 5 years were evaluated by doppler ultrasonography for vascular flow patterns measurement of umbilical artery (UA) and middle cerebral artery (MCA). Vascular flow values were correlated with the respective average heart rate. The equipment used was a SonoSite ultrasound M-Turbo (USA, Washington), coupled to sectoral (5-8 mHz) and linear probes (12-15mHz). The calculations of gestational ages were performed automatically by measuring the biparietal diameter and abdominal diameter (tables inserted in the data platform by the authors). The vascular flow measurements were made by adjusting the pulse repetition frequencies (PRF) to the vessels studied as well as maintaining an insonation angle smaller than 20. The systolic flow velocities (SFV) and resistivity index (RI) were presented as follows: (a) after 28 days of pregnancy – HR= 245±3.45 bpm, UA, SFV= 37±1.24cm / s, RI= 0.87±0.06. (b) 40 days of pregnancy – HR= 235±2.73 bpm, UA, SFV = 42±1.13cm / s, RI= 0.82±0.04; MCA, SFV = 31±1.15cm / s, RI= 0.72±0.05. (c) after 56 days of pregnancy – HR= 215±1.60 bpm, AU, SFV= 53±1.21cm/s, RI= 0.89±0.04; MCA, SFV= 27±1.2 cm/s, RI= 0.64±0.08. The monitoring of the UA and MCA flows promoted valuable information on cesarean delivery decision. The hemodynamic effects promoted by increasing the RI of the UA (which tends to decrease in situations of normal and natural delivery) and the the reduction of SFV and the RI of the MCA associated with the relaxation of this artery assisted in the decision of cesarean delivery. The relaxation of the MCA was positively correlated HR reduction (r =0.86). All study animals were underwent caesarean delivery and there were no complications or death puppies, during the procedure and post-partum. The study identified vascular changes that may contribute to safe intervention by caesarean surgery in dogs french bulldog breed.