TY - JOUR
T1 - Ultrasound tagged near infrared spectroscopy does not detect hyperventilation-induced reduction in cerebral blood flow
AU - Lund, Anton
AU - Secher, Niels H.
AU - Hirasawa, Ai
AU - Ogoh, Shigehiko
AU - Hashimoto, Takeshi
AU - Schytz, Henrik W
AU - Ashina, Messoud
AU - Sørensen, Henrik
PY - 2016
Y1 - 2016
N2 - Introduction: Continuous non-invasive monitoring of cerebral blood flow (CBF) may be important during anaesthesia and several options are available. We evaluated the CerOx monitor that employs ultrasound tagged near infrared spectroscopy to estimate changes in a CBF index (CFI).Methods: Seven healthy males (age 21-26 years) hyperventilated and were administered phenylephrine to increase mean arterial pressure by 20-30 mmHg. Frontal lobe tissue oxygenation (ScO2) and CFI were obtained using the CerOx and mean blood flow velocity in the middle cerebral artery (MCAvmean) was determined by transcranial Doppler. Blood flow in the internal and external carotid artery (ICAf and ECAf) was determined using duplex ultrasonography and forehead skin blood flow (SkBF) and oxygenation (SskinO2) by laser Doppler and white light spectroscopy.Results: During hyperventilation MCAvmean and ICAf decreased by 44% (median; interquartile range 40-49; p = 0.016) and 46% (40-53; p = 0.03), respectively. Conversely, CFI increased by 9% (2-31; p = 0.016), while no significant change was observed in ScO2. SkBF increased by 19% (9-53; p = 0.016) and SskinO2 by 6% (1-7; p = 0.047), although ECAf was unchanged. Administration of phenylephrine was not associated with any changes in MCAvmean, ICAf, ECAf, ScO2, SkBF, SskinO2, or CFI.Conclusion: The CerOx was able to detect a stable CBF during administration of phenylephrine. However, during hyperventilation MCAvmean and ICAf decreased while CFI increased, likely due to an increase in superficial tissue oxygenation. Thus, CFI does not provide an unbiased evaluation of changes in CBF.
AB - Introduction: Continuous non-invasive monitoring of cerebral blood flow (CBF) may be important during anaesthesia and several options are available. We evaluated the CerOx monitor that employs ultrasound tagged near infrared spectroscopy to estimate changes in a CBF index (CFI).Methods: Seven healthy males (age 21-26 years) hyperventilated and were administered phenylephrine to increase mean arterial pressure by 20-30 mmHg. Frontal lobe tissue oxygenation (ScO2) and CFI were obtained using the CerOx and mean blood flow velocity in the middle cerebral artery (MCAvmean) was determined by transcranial Doppler. Blood flow in the internal and external carotid artery (ICAf and ECAf) was determined using duplex ultrasonography and forehead skin blood flow (SkBF) and oxygenation (SskinO2) by laser Doppler and white light spectroscopy.Results: During hyperventilation MCAvmean and ICAf decreased by 44% (median; interquartile range 40-49; p = 0.016) and 46% (40-53; p = 0.03), respectively. Conversely, CFI increased by 9% (2-31; p = 0.016), while no significant change was observed in ScO2. SkBF increased by 19% (9-53; p = 0.016) and SskinO2 by 6% (1-7; p = 0.047), although ECAf was unchanged. Administration of phenylephrine was not associated with any changes in MCAvmean, ICAf, ECAf, ScO2, SkBF, SskinO2, or CFI.Conclusion: The CerOx was able to detect a stable CBF during administration of phenylephrine. However, during hyperventilation MCAvmean and ICAf decreased while CFI increased, likely due to an increase in superficial tissue oxygenation. Thus, CFI does not provide an unbiased evaluation of changes in CBF.
KW - Cerebral oximetry
KW - external carotid artery
KW - internal carotid artery
KW - monitoring
KW - skin blood flow
KW - skin oxygen saturation
U2 - 10.3109/00365513.2015.1101485
DO - 10.3109/00365513.2015.1101485
M3 - Journal article
C2 - 26503121
AN - SCOPUS:84947866862
SN - 0036-5513
VL - 76
SP - 82
EP - 87
JO - Scandinavian Journal of Clinical & Laboratory Investigation
JF - Scandinavian Journal of Clinical & Laboratory Investigation
IS - 1
ER -