Automatic and manual Doppler velocimetry measurements of the uterine artery in pregnant ewes.

We aimed to compare measurements of speed and blood flow parameters obtained manually and automatically in the uterine arteries of pregnant ewes. Eighteen Santa Inês ewes, confirmed to be pregnant, were followed every 2 weeks until parturition. The systolic peak (PS), end diastolic velocity (ED), maximum and average speed in the cardiac cycle (TAMAX and TAMEAN, respectively), pulsatility index (PI), resistance index (RI) and the systole/diastole (S/D) ratio and body flow volume (BFV) was measured. We began the wave evaluation automatically, then the observer manually marked the beginning and end of the wave. To determine the differences between manual and automatic methods, a t-test was used for each of the study variables (PS, ED, TAMAX, TAMEAN, PI, RI, S/D, and BFV), with p<0.05 considered significant. Both methods were found to be effective for producing estimates for the variables analyzed. With the exception of the IP, IR and S/D (p<0.05), no significant differences were found between the methods. The manual method underestimated the PI (1.00±0.21×1.04±0.20), S/D (2.51±0.43×2.40±0.44) and RI (0.57±0.07×0.59±0.07) compared with the automatic method (p<0.05). The weakest correlations between methods were identified for the PI, RI and S/D variables (p<0.001). Manual evaluation allowed more accurate identification of the beginning and end of the systole and diastole, which may influence the outcome of some variables.