Effect of the gestational phase on haemodynamics and haemogasometric variables in mares submitted to general anaesthesia protocol and influences on the fetus

• Grant number: 20/01387-0
• Support type: Scholarships in Brazil - Doctorate
• Effective date (Start): September 01, 2020
• Effective date (End): August 31, 2024
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal researcher: Renata Gebara Sampaio Dória
• Grantee: Pedro Henrique Salles Brito
• Home Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil

Abstract

In Veterinary Medicine, it is often necessary to perform emergency surgical procedures on pregnant animals. In these cases, fetal monitoring during the anesthetic procedure is rarely performed and, currently, there are several opinions about which method would be the most suitable for this monitoring. During general inhalation anesthesia in pregnant mares, there are risks that maternal hemodynamic and hemogasometric changes may compromise uteroplacental perfusion and/or fetal oxygenation, increasing the risk of abortion or premature births. In Human Medicine, in most cases, adequate fetal monitoring is not carried out, but monitoring through ultrasound is recommended and the presence of an obstetric team ready to intervene when they identify fetal distress. Generally, only emergencies and elective surgeries that do not pose a risk to the fetus are performed, avoiding, as much as possible, general anesthesia in pregnant women. When possible, the preference for performing the procedure is in the middle third of pregnancy. In the case of horses, cases such as acute abdomen, they are often surgical emergencies, requiring general inhalation anesthesia in pregnant mares, in different gestational phases, with systemic changes resulting from the disease involved. In these cases, the main parameter available to assess fetal distress is heart rate, which is directly correlated to fetal cardiac output. This project idealizes submitting healthy mares, in the initial, middle and final gestation thirds, to general inhalation anesthesia with isofluorane, in the dorsal recumbency, and to carry out hemodynamic and blood gas measurements of the mother, correlating these data with those of fetal monitoring, obtained by abdominal ultrasound, to in order to predict the effects of the gestational phase on anesthetic risk, both for the mare and the fetus. In addition, the reverse Trendelemburg group will be instituted, in an attempt to improve ventilatory parameters during the final third of gestation. (AU)