Maternal and fetal cardiovascular and metabolic effects of intra-operative uterine handling under general anesthesia during pregnancy in sheep

Caroline J Shaw,Christoph C Lees,Dino A Giussani,Youguo Niu,Kimberley J Botting

doi:10.1038/s41598-020-67714-y

Caroline J Shaw, Christoph C Lees + Show 3 more

Open Access

https://doi.org/10.1038/s41598-020-67714-y

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Abstract

A cohort study of 6,500,000 human pregnancies showed an increased risk of adverse fetal outcomes following abdominal but not non-abdominal surgery under general anesthesia. This may be the consequence of uterine handling during abdominal surgery. However, there are no data on any effects on the cardiometabolic physiology of the fetus or mother in response to uterine manipulation in otherwise healthy pregnancy. Consequently, 9 sheep in late gestation were anesthetized with isofluorane and maternal and fetal catheters and flow probes were implanted to determine cardiovascular and metabolic changes during uterine handling. Uterine handling led to an acute increase in uterine artery vascular resistance, fetal peripheral vasoconstriction, a reduction in oxygen delivery to the femoral circulation, worsening fetal acidosis. There was no evidence of systemic fetal hypoxia, or changes in fetal heart rate, carotid blood flow or carotid oxygen delivery. Therefore, the data support that uterine handling during abdominal surgery under general anesthesia can impact adversely on fetal cardiometabolic health. This may provide a potential explanation linking adverse fetal outcomes in abdominal compared with non-abdominal surgery during pregnancy. The data have important implications for human fetal surgery where the uterus is handled, as operative procedures during late gestation under general maternal anesthesia become more prevalent.

Highlights

A cohort study of 6,500,000 human pregnancies showed an increased risk of adverse fetal outcomes following abdominal but not non-abdominal surgery under general anesthesia
While maternal arterial blood pressure and heart rate were unaltered from baseline, there was an acute fall in uterine artery blood flow, secondary to an acute increase in uterine arterial vascular resistance
The data show that direct intra-operative handling of the uterus in pregnant sheep in late gestation results in an acute fall in uterine artery blood flow, unrelated to the duration of anesthesia

Summary

Introduction

A cohort study of 6,500,000 human pregnancies showed an increased risk of adverse fetal outcomes following abdominal but not non-abdominal surgery under general anesthesia. A 2005 systematic review of 54 studies involving 12,452 pregnant women found an increased risk of surgery-induced labor, and that the risk of fetal loss was significantly raised when abdominal surgery was complicated by p eritonitis[2] These data suggest the hypothesis that there is a potential adverse effect on the fetus of abdominal surgery, which predisposes to pregnancy loss, above and beyond the effects of prolonged general anesthesia and/or maternal systemic illness or injury. In this study, we have used the well-established surgically instrumented pregnant sheep model with catheters and flow probes[4,5,6,7] to determine the effects of uterine handling on the cardiovascular and metabolic status of a healthy mother and fetus in late gestation, under general anesthesia

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