Figure 3. The physiological effects of cerebral ischaemia for 30 min (from time zero), with or without cerebral cooling (indicated with blue symbols) induced from 3 h until either 48 or 72 h after reperfusion in term‐equivalent fetal sheep.

The panels show, in descending order, temporal changes in extradural temperature (°C), electroencephalographic (EEG) power (decibels) and spectral edge frequency (hertz) in ischaemia–normothermia (black circles), ischaemia–hypothermia 48 h (light blue circles) and ischaemia–hypothermia 72 h groups (dark blue circles). EEG activity was suppressed in all groups during and immediately after ischaemia followed by a transient increase during seizures from 8 to 48 h. EEG activity in the ischaemia–normothermia group remained low for the remainder of the experiment, whereas both hypothermia groups showed a significant recovery in power and spectral frequency from 24 to 72 h (P = 0.05). Rewarming at 48 h was associated with loss of EEG power in the ischaemia–48 h hypothermia group, which did not occur with rewarming at 72 h (P = 0.05). Data are means ± SEM.