Hemodynamic gestational adaptation in bitches

Abstract

Throughout pregnancy, maternal hemodynamic adaptation is needed to ensure proper uterine perfusion and fetal development. When the uteroplacental vascular system is formed, starting with reduced resistance to uterine arterial flow, this results in decreased total vascular resistance, an activation of neuroendocrine vasoactive peptides, an increase in circulating blood and changes in the cardiovascular system morphophysiology to respond to the increasing demands of uterine perfusion. There has been considerable study of hemodynamic adaptation in pregnant women and this assessment has become a diagnostic tool for fatal obstetric disorders. However, in bitches the available information in this regard is limited; therefore a parallel was drawn between other species of animals and women, in order to subsidize the paucity of information about this process and facilitate the understanding of maternal-fetal hemodynamic adaptation in pregnant bitches. This review and literature analysis aimed\ to discuss morphophysiological cardiovascular adaptations during pregnancy and the possible disorders that can affect this process in pregnant female dogs.

Cardiovascular Evaluation in Bitches in Oestrus, Pregnancy and Puerperium

“…As showed in our results, there was a tendency to SBP reduction, that is directly influenced by peripheral vascular resistance and cardiac output [5]. During the gestation, there is a 40% increase in cardiac output in women, while in pregnant bitches, an increase of 23% is suggested as a way of responding to increased circulating blood volume [2]. To balance this out, the pregnant uterus acts to lower the pressure of the vascular system, causing a significant decrease in vascular resistance and consequent physiological reduction in SBP [3].…”

“…To perform the echocardiographic examination, an ultrasound device (Mylab TM 30VET Gold) 2 , with two sectoral transducers at a frequency of 1 to 4 MHz was used. Longitudinal and transverse cuts of the heart were performed according to recommendations by Boon [7].…”

Perinatal Cardiovascular Evaluation in Dorper Sheep Echocardiographic Description and Behavior of the Heart Rate Variability on the Field

“…These increases in PR may also be explained by the increased venous return during pregnancy (Almeida et al, 2017). Despite the clinical PR increase, the mean for maternal PR remained within the reference values for the species (90-115 bpm).…”

>b<Avaliação de parâmetros respiratórios e hemodinâmicos durante a gestação em cadelas de conformação braquiocefálica>/b<

“…São Paulo, 2018.........................................................48 Tabela 13 -Média e erro padrão das variáveis dopplervelocimétricas da artéria umbilical nos distintos grupos experimentais. São Paulo, (DUVEKOT et al, 1993;BLANCO et al, 2011;ALMEIDA et al, 2017) e adequada perfusão para a unidade útero-placentaria e fetal (LEE, 1991), por aumento do débito cardíaco (SKERMAN et al,1991) e expansão do volume sanguíneo materno. A circulação útero-placentária não possui auto-regulação e, portanto, sua perfusão depende da pressão arterial materna (HILL, PICKINPAUGH, 2008).…”

“…Frente às mudanças morfofisiológicas e bioquímicas inerentes ao período gestacional, o sistema cardiovascular responde com adaptações hemodinâmicas (ALMEIDA et al, 2017), permitindo atender à maior demanda metabólica exigida pela unidade materno-fetal. O desenvolvimento fetal e o aumento da taxa metabólica requerem maior fluxo sanguíneo (SKERMAN et al,1991;LEE, 1991;HAMEED, SKLANSKY, 2007).…”