Intraaortic balloon pump counterpulsation and cerebral autoregulation: An observational study

Bellapart, Judith, Geng, Shureng, Dunster, Kimble, Timms, Daniel, Barnett, Adrian G., Boots, Rob and Fraser, John F. (2010) Intraaortic balloon pump counterpulsation and cerebral autoregulation: An observational study. BMC Anesthesiology, 10 3: 1-11. doi:10.1186/1471-2253-10-3

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Author Bellapart, Judith
Geng, Shureng
Dunster, Kimble
Timms, Daniel
Barnett, Adrian G.
Boots, Rob
Fraser, John F.
Title Intraaortic balloon pump counterpulsation and cerebral autoregulation: An observational study
Journal name BMC Anesthesiology   Check publisher's open access policy
ISSN 1471-2253
Publication date 2010-03-12
Sub-type Article (original research)
DOI 10.1186/1471-2253-10-3
Open Access Status DOI
Volume 10
Issue 3
Start page 1
End page 11
Total pages 11
Place of publication London, United Kingdom
Publisher BioMed Central
Collection year 2011
Language eng
Formatted abstract
Background: The use of Intra-aortic counterpulsation is a well established supportive therapy for patients in cardiac failure or after cardiac surgery. Blood pressure variations induced by counterpulsation are transmitted to the cerebral arteries, challenging cerebral autoregulatory mechanisms in order to maintain a stable cerebral blood flow. This study aims to assess the effects on cerebral autoregulation and variability of cerebral blood flow due to intra-aortic balloon pump and inflation ratio weaning.
Methods: Cerebral blood flow was measured using transcranial Doppler, in a convenience sample of twenty patients requiring balloon counterpulsation for refractory cardiogenic shock (N=7) or a single inotrope to maintain mean arterial pressure following an elective placement of an intra-aortic balloon pump for cardiac surgery (N=13). Simultaneous blood pressure at the aortic root was recorded via the intra-aortic balloon pump. Cerebral blood flow velocities were recorded for six minute intervals at a 1:1 balloon inflation-ratio (augmentation of all cardiac beats) and during progressive reductions of the inflation-ratio to 1:3 (augmentation of one every third cardiac beat). Real time comparisons of peak cerebral blood flow velocities with systolic blood pressure were performed using cross-correlation analysis. The primary endpoint was assessment of cerebral autoregulation using the time delay between the peak signals for cerebral blood flow velocity and systolic blood pressure, according to established criteria. The variability of cerebral blood flow was also assessed using non-linear statistics.
Results: During the 1:1 inflation-ratio, the mean time delay between aortic blood pressure and cerebral blood flow was -0.016 seconds (95% CI: -0.023,-0.011); during 1:3 inflation-ratio mean time delay was significantly longer at -0.010 seconds (95% CI: -0.016, -0.004, P <0.0001). Finally, upon return to a 1:1 inflation-ratio, time delays recovered to those measured at baseline. During inflation-ratio reduction, cerebral blood flow irregularities reduced over time, whilst cerebral blood flow variability at end-diastole decreased in patients with cardiogenic shock.
Conclusions: Weaning counterpulsation from 1:1 to 1:3 inflation ratio leads to a progressive reduction in time delays between systolic blood pressure and peak cerebral blood flow velocities suggesting that although preserved, there is a significant delay in the establishment of cerebral autoregulatory mechanisms. In addition, cerebral blood flow irregularities (i.e. surrogate of flow adaptability) decrease and a loss of cerebral blood flow chaotic pattern occurs during the end-diastolic phase of each beat in patients with cardiogenic shock.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Research article

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
School of Medicine Publications
 
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Created: Mon, 14 Mar 2011, 13:19:20 EST by Sia Athanasas on behalf of Medicine - Prince Charles Hospital