659374.fig.009a
(a)
659374.fig.009b
(b)
659374.fig.009c
(c)
659374.fig.009d
(d)
Figure 9: The chronic preparation model using goat fetuses at 0.9 gestation. Under general anesthesia, (a) fetal head and neck was exteriorized, (b) catheters and electrodes were placed, (c) fetus was returned to the uterine cavity and recovered from surgical stresses for 4 days, and (d) hypoxic experiments were performed by adding nitrogen gas through the maternal endotracheal catheter.