Anesthesia for non-obstetric surgery during late term pregnancy in mares.
Authors: Brito Pedro Henrique Salles, Ferreira Marília Alves, Rusch Elidiane, Arantes Julia de Assis, Carregaro Adriano Bonfim, Valadão Carlos Augusto Araújo, Ghantous Giovana Fumes, Dória Renata Gebara Sampaio
Journal: PloS one
Summary
# Anesthesia for Non-Obstetric Surgery During Late Pregnancy in Mares When late-term pregnant mares require surgical intervention unrelated to parturition, clinicians face a delicate balancing act between maternal and fetal welfare, yet evidence on safe anaesthetic protocols remains limited. Brito and colleagues monitored nine mares in their final month of gestation throughout 90-minute general inhalation anaesthetic episodes in dorsal recumbency, tracking maternal haemodynamics (cardiac output, arterial pressures, central venous pressure), blood gas status, and fetal heart rate at regular intervals. The anaesthetic period produced predictable but significant changes: maternal tachycardia, elevated mean and diastolic arterial pressures, hypothermia, and respiratory acidosis developed, whilst cardiac output remained stable but stroke volume decreased along with pulmonary arterial and central venous pressures—notably, fetal heart rate dropped markedly during anaesthesia. Despite these considerable physiological perturbations, outcomes for both dam and foetus were favourable, suggesting that procedures lasting up to 90 minutes do not necessarily compromise maternal-fetal prognosis, though the respiratory acidosis and reduced fetal heart rate warrant careful intraoperative monitoring. For practitioners managing pregnant mares requiring urgent non-obstetric surgery, this work provides reassurance that general inhalation anaesthesia is feasible within this timeframe, but highlights the importance of aggressive ventilatory support to mitigate respiratory acidosis and close fetal surveillance throughout the procedure.
Read the full abstract on PubMed
Practical Takeaways
- •Non-obstetric surgery under general anesthesia can be performed safely in late-term pregnant mares when necessary, with hemodynamic monitoring to 90 minutes
- •Expect respiratory acidosis and fetal bradycardia during anesthesia; these transient changes do not necessarily indicate fetal compromise in this timeframe
- •Monitor maternal vital signs closely (heart rate, blood pressure, temperature) and use appropriate supportive care during and after anesthesia in pregnant mares
Key Findings
- •General inhalation anesthesia in late-term pregnant mares caused increased heart rate, mean arterial pressure, and diastolic pressure with decreased temperature
- •Respiratory acidosis developed during anesthesia
- •Fetal heart rate significantly decreased during maternal anesthesia
- •Hemodynamic changes observed over 90 minutes did not appear to negatively affect maternal or fetal outcomes