Changes of jugular venous blood temperature associated with measurements of cerebral blood flow using the transcerebral double-indicator dilution technique.
OBJECTIVE
The transcerebral double-indicator dilution technique is a recently developed method to measure global cerebral blood flow at bedside. It is based on bolus injection of ice-cold indocyanine green dye and simultaneous recording of resulting thermo- and dye-dilution curves in the aorta and the jugular bulb. However, with this method 40 mL of ice-cold solution is administered as a bolus. Therefore, this prospective clinical study was performed to elucidate the effects of repeated administration of indicator on absolute blood temperature and on cerebral blood flow and metabolism.


METHODS
The investigation was performed in nine male patients scheduled for elective coronary artery bypass grafting. Absolute blood temperature was measured in the jugular bulb and in the aorta before and after repeated measurements using the transcerebral double-indicator dilution technique.


RESULTS
During the investigated time course, the blood temperature in the jugular bulb, compared to the aorta, was significantly higher with a mean difference of 0.21 degrees C. The administration of an ice-cold bolus reduced the mean blood temperature by 0.06 degrees C in the jugular bulb as well as in the aorta. After the transcerebral double-indicator dilution measurements a temperature recovery to baseline conditions was not observed during the investigated time period. Cerebral blood flow and cerebral metabolism did not change during the investigated time period.


CONCLUSIONS
Repeated measurements with the transcerebral double-indicator dilution technique do not affect absolute jugular bulb blood temperatures negatively. Global cerebral blood flow and metabolism measurements remain unaltered. However, accuracy and resolution of this technique is not high enough to detect the effect of minor changes of physiological variables.
Mielck
F
F
University of Göttingen, Department of Anaesthesiology, Emergency and Intensive Care Medicine, Göttingen, Germany. fmielck@gwdg.de
Bräuer
A
A
Radke
O
O
Hanekop
G
G
Loesch
S
S
Friedrich
M
M
Hilgers
R
R
Sonntag
H
H
D000368:Aged; D000704:Analysis of Variance; D001011:Aorta; D001790:Blood Physiological Phenomena; D001831:Body Temperature / Q000502:physiology*; D001921:Brain / Q000378:metabolism; D002405:Catheterization, Central Venous; D002406:Catheterization, Peripheral; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004396:Coloring Agents; D001026:Coronary Artery Bypass; D004395:Dye Dilution Technique / Q000295:instrumentation; D006801:Humans; D007201:Indicator Dilution Techniques; D007208:Indocyanine Green; D007601:Jugular Veins; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013815:Thermodilution / Q000295:instrumentation
D004396:Coloring Agents; D007208:Indocyanine Green