Related Experiment Videos
Transcranial Doppler blood flow velocity versus 133Xe clearance cerebral blood flow during mild hypothermic
H P Grocott1, D W Amory, E Lowry
1Department of Anesthesiology, Duke Heart Center, Duke University Medical Center, Durham, NC 27710, USA.
Insights
Transcranial Doppler (TCD) middle cerebral artery blood flow velocity (Vmca) poorly correlates with cerebral blood flow (CBF) during mild hypothermic cardiopulmonary bypass (CPB). This suggests TCD may not be a reliable tool for assessing brain perfusion in this setting.
Area of Science:
- Neuroscience
- Cardiovascular Science
- Medical Technology
Background:
- Transcranial Doppler (TCD) is utilized during cardiopulmonary bypass (CPB) for monitoring cerebral emboli and estimating cerebral perfusion.
- Assessing cerebral perfusion during CPB is critical for preventing neurological complications.
Purpose of the Study:
- To compare Transcranial Doppler (TCD) middle cerebral artery blood flow velocity (Vmca) with 133Xe clearance cerebral blood flow (CBF) measurements.
- To determine the utility of TCD Vmca in assessing cerebral perfusion during mild hypothermic CPB.
Main Methods:
- Thirty-four patients undergoing mild hypothermic CPB (35°C) were studied.
- Vmca and 133Xe CBF were compared at 10, 30, and 60 minutes after CPB initiation.
- Linear regression analysis was performed on interval and pooled data.
Main Results:
- Correlation coefficients between Vmca and CBF varied across time points (r = 0.32 to 0.48).
- The pooled data showed a significant but weak correlation (r = 0.34, p = 0.003).
Conclusions:
- Transcranial Doppler (TCD) Vmca demonstrates a relatively poor correlation with cerebral blood flow (CBF) during mild hypothermic CPB.
- These findings question the reliability of TCD Vmca as a sole indicator of cerebral perfusion in this specific clinical context.
Objective:
Transcranial doppler (TCD) is used during cardiopulmonary bypass (CPB) to assess cerebral emboli and to estimate cerebral perfusion. We sought to compare TCD middle cerebral artery blood flow velocity (Vmca) to 133Xe clearance cerebral blood flow (CBF) measurements during mild hypothermic CPB thus determining its utility in cerebral perfusion assessment.
Methods:
Thirty-four patients undergoing mild hypothermic CPB (35 degrees C) were studied and had comparisons of Vmca and 133Xe CBF at three time intervals, 10, 30 and 60 min after the institution of CPB. Linear regression analysis was performed on data from each of the 3 intervals as well as for pooled data from all 3 periods.
Results:
The correlation coefficients for the 3 time periods were, r = 0.32 (p = 0.12), r = 0.32 (p = 0.11), r = 0.48 (p = (0.02), respectively. The pooled data correlation had a coefficient of 0.34 (p = 0.003).
Conclusion:
These findings suggest that TCD Vmca is a relatively poor correlate of CBF during mild hypothermic CPB.