Jugular vein temperature reflects brain temperature during hypothermia

Purpose: The neuroprotective properties of mild to moderate hypothermia are well recognized but may not be employed correctly because brain temperatur e cannot usually be measured directly. This study investigated the jugular vein as a more accessible site that accurately reflects the actual brain te mperature during mild, induced hypothermia. Methods: We selected ten mongre l dogs (mean weight 12 +/- 2 kg) and measured temperatures of the brain, ju gular vein, cisterna magna, pulmonary artery and rectum during hypothermia, including cooling and rewarming. The brain temperature needle probe was in serted 2.0 cm into the parenchyma. A temperature probe was placed in the ci sterna magna with an epidural needle. Swan-Ganz thermistor probes measured the jugular venous and pulmonary artery blood temperatures. Result: The bra in temperature decreased from 37.5 +/- 0.3 to 33.0 +/- 0.3 degrees C over a verage 150 +/- 45 min cooling period. Stable cool was maintained for 245 +/ - 32 min, followed by 165 +/- 50 min for rewarming from 33.5 +/- 0.3 to 37. 5 +/- 0.3 degrees C. Jugular, cisterna magna and pulmonary arterial blood ( PAB), but not rectal temperature, were close to brain temperature during st able cool. The mean jugular and cisterna magna temperatures were near the b rain temperature at 0.1 degrees C higher and 0.1 degrees C lower, respectiv ely. No significant effects of hypothermia were noted on hemodynamics in an y phase. Conclusion: Jugular vein temperature, along with cisterna magna an d pulmonary artery blood and rectal temperature, reflected brain temperatur e during hypothermia. The jugular vein and cisterna magna sites more sensit ively reflected brain temperature than other sites. (C) 2000 Elsevier Scien ce Ireland Ltd. All rights reserved.