Although whole-body hypothermia recently has been reported effective in improving the neurologic outcome after cardiac arrest, it is contraindicated in the management of trauma patients with hemorrhagic shock. To provide selective brain cooling in this situation, the authors speculated about the feasibility of hypothermic retrograde jugular vein flush (HRJVF). This preliminary study was conducted to test the effectiveness of brain cooling after HRJVF in rats without hemorrhagic shock.
After jugular vein cannulation with cranial direction, Sprague–Dawley rats were randomized into a normal control group, a group that underwent flush with cold saline at 4°C, or a group that underwent flush with saline at a room temperature of 24°C. A Servo-controlled heat lamp was applied for all the rats to keep their rectal temperature at 37 ± 0.5°C. Their brain temperature and cerebral blood flow were checked.
Within the 10-minute period of cold saline flush (1.7 mL/100 g), brain temperature was immediately decreased, and this cooling effect could be maintained for at least 20 minutes. Cerebral blood flow was significantly increased after HRJVF, then returned gradually to the baseline as brain temperature elevated.
This study successfully demonstrated a significant cooling effect in rat brain by HRJVF. For preservation of brain function, HRJVF may be useful in resuscitation for trauma patients with hemorrhagic shock after further studies on animals with shock.