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Background: Diagnostic ultrasound has revolutionized obstetric practice. Doppler techniques provided in vivo studies of the fetus-placental and uterus-placental circulations, in an increasingly precise manner. The assessment of fetal well-being is essential in obstetric practice, however, in veterinary medicine, there is a deficit of ultrasound parameters related to fetal distress. The main of this research was to determine the hemodynamic characteristics and behavior, through Doppler ultrasonography, of maternal-fetal vessels during the final third of gestation in bitches with fetuses under stress, as well as correlating them with each other and with fetal distress. Materials, Methods & Results: An observational, prospective study was carried out, in which 30 healthy bitches were examined, during the last third of pregnancy, with fetuses under fetal distress. Fetuses were evaluated in 2 stages: (1st): 50-54 days and (2nd): 55-60 days of gestation. All fetuses were calmly assessed, one by one, and fetal heart rate (FHR) was measured 5 times, for at least 3 min, to identify and confirm fetal distress. At least 3 fetuses were evaluated in each bitch and each measurement was performed in triplicate, setting a hemodynamic mean for each value evaluated. The flow pattern in the middle cerebral artery (MCA), internal carotid artery (ICA) and umbilical artery (UA) was evaluated. The analyzed vessel was initially visualized in B mode, followed by evaluation by color and spectral Doppler. The variables observed were: peak systolic velocity (PSV), end diastolic velocity (EDV) and the resistivity (RI) and pulsatility (PI) index, as well as the systole/diastole ratio (S/D). The analysis of RI and PI of the umbilical artery showed a statistically significant difference between the mean values found for the times studied, increasing from time 1 to time 2. For middle cerebral and internal carotid arteries, PI, RI and the relationship systole/diastole (S/D), showed a statistically significant difference between the mean values found for the times studied, decreasing from time 1 to time 2. Discussion: Fetal heart rate (HR) findings are considered normal above 200 beats per minute (bpm), only if preceded by acceleration and deceleration. This fact confirms the presence of fetal stress, by this parameter, for the fetuses in the present study. Corroborating the picture of fetal distress, another study concluded that HR tends to increase up to 20 days before delivery, a fact that did not occur in the study in question, where animals in the same gestational period were evaluated. Recent research has concluded that an elevated umbilical artery PI at 28 weeks of gestation, in the absence of fetal growth restriction or prematurity, is associated with some adverse cognitive findings in 12-year-olds children. In the present study, a progressive increase in this index was observed throughout the final third of pregnancy. Although the pups were not monitored after birth, this data serves as a warning for veterinarians, and can be useful in the assessment and diagnosis of possible postnatal nervous alterations. Like what was found in the present study, a study reported that from the 4th week to birth, the PSV of the umbilical artery (UA) increased almost linearly, with high significance. For the middle cerebral arteries, the PI showed a statistically significant difference between the mean values found for the times studied, however, decreasing throughout the final third of pregnancy. [ABSTRACT FROM AUTHOR]

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 hemodynamically normal values in the final third of gestation in bitches, of the umbilical, uteroplacental, middle cerebral and internal carotid arteries, correlating the obtained Doppler velocimetric indexes, for the assessment of the feto-placental circulation, and prediction 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). These were 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 fetuses were evaluated. Also, the systole/diastole (S/D) ratio of these vessels was evaluated. The data obtained were subjected to analysis of variance and Tukey test, using a P value equal to 5%. A significant difference was observed between velocities and Doppler velocimetric indexes between the 2 phases of the gestational final third in all studied vessels. There was an increase in the values of PSV and EDV and a decrease in the indexes, as the probable date of delivery approached. The analysis 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 artery, similarly to the umbilical artery, the PSV and EDV values showed an increase between P1 and P2, while the S/D ratio decreased up to 60 days of gestation (P2). The IR and IP of these vessels decreased during the study interval in pregnant bitches. The studied variables showed a statistically significant difference when analyzed comparatively between P1 and P2 (P < 0.05). As for the middle cerebral artery and internal carotid artery, the PSV and EDV values increased until the end of pregnancy. Likewise, the Doppler velocimetric values and the S/D ratio decreased until the end of pregnancy (P2). Discussion: The hemodynamic values obtained for the umbilical artery and uterine artery were significantly different between 40 and 50 days of gestation (P1) and 50 and 60 days of gestation (P2), with a decrease in vascular resistance and an increase in velocities. It can be related to a greater association of maternal-fetal blood perfusion, due to the increased demand for the development of the fetus. The Middle Cerebral Artery (MCA) also showed changes between P1 and P2, with an increase in PSV and EDV in the final third of pregnancy, and the S/D ratio was reduced, differing significantly between P1 and P2. The systolic (PSV) and diastolic (EDV) flow velocities of the internal carotid artery increased progressively, while the IR, IP and the S/D ratio decreased, between the evaluated periods (P1 and P2), providing greater flow in canine fetuses, maintaining normal heart rate, indicating positive fetal viability. [ABSTRACT FROM AUTHOR]

Background: Peccaries (Tayassu tajacu, Linnaeus, 1758) are wild suiformes that belong to the Tayassuidae family. Electrocardiography is an important technique for cardiovascular evaluation. Analysis of various intervals, segments, complexes and waveforms of electrocardiographic (ECG) traces aids in the diagnosis of cardiac alterations and in the differentiation of congenital and acquired heart diseases from physiological cases. However, in wild animal medicine, the various patterns of normality and the evaluation of electrical traces associated with heart disease have not yet been sufficiently elucidated. The purpose of this study was to characterize the electrocardiographic (ECG) traces of peccaries sedated using ketamine and xylazine. Materials, Methods & Results: Fourteen healthy adult animals that were subjected to digital ECG examination were used. Animals with evidence of systemic diseases, cardiovascular abnormalities (murmurs or arrhythmias), or any degree of valve insufficiency observed on echocardiogram and animals that exhibited excessive stress during the examination were excluded from the study. All animals presented with a normal sinus rhythm. A combination of 15 mg/kg of ketamine hydrochloride and 3 mg/kg of midazolam maleate was applied intramuscularly for chemical immobilization. The animals were manipulated after 15 min, when the onset of the anaesthetic effect was verified, for a duration of 45 min, and no reinforcement dose was necessary to complete the electrocardiographic examination. No significant differences were observed in the P-wave duration, PR interval and QT interval between genders (P > 0.05). No significant differences were found between the amplitudes of the P and R waves between males and females (P > 0.05). The observed P waves were small, monophasic and positive. The QRS complex was positive in the DI, DII, DIII, aVF, V4 and V10 derivations and negative in the aVR, aVL, V1 and V2 derivations. In 71% of the animals, the T wave showed negative polarity in the DI, DII, DIII, aVL, aVF, and V10 derivations and positive polarity in the aVR, V1, V2 and V4 derivations. The ST segment was isoelectric in 100% of the animals. GraphPad Prism 7 (La Jolla, CA, USA) software was used to analyze the data, with non-parametric tests used to test for differences in the variables between the sexes. In these tests, a P-value of 0.05 was considered to indicate statistical significance. Discussion: Although studies on the cardiac electrophysiology of wild animals have previously shown good results for several species, this is the first study concerning the standardization ECG traces for peccaries. However, due to the wild nature of these animals, their manipulation for handling and data collection purposes is only feasible under chemical containment, although other studies have used non-anaesthetized agoutis. It is not known to what extent these results may have been influenced by the effects of stress. Drugs used for this function may have direct effects on cardiac function. Therefore, the presumed normal ECG values, as well as the recognition of changes due to drug or iatrogenic interactions, are of fundamental importance. This protocol provided high-quality anaesthetized peccary ECG traces, allowing reliable measurements of waves and intervals and assessment of the cardiac rhythm and heart rate. The surface registry digital ECG recording technique used with chemical containment allowed good monitoring and rapid acquisition and was well tolerated by the animals. [ABSTRACT FROM AUTHOR]