Dataset Information

Cerebral blood flow velocity changes during upright positioning in bed after acute stroke: an observational study.

ABSTRACT:

Objectives

National guidelines recommend mobilisation in bed as early as possible after acute stroke. Little is known about the influence of upright positioning on real-time cerebral flow variables in patients with stroke. We aimed to assess whether cerebral blood flow velocity (CBFV) changes significantly after upright positioning in bed in the acute stroke phase.

Design

Observational study.

Participants

47 patients with acute ischaemic stroke measured in the subacute phase after symptom onset and 20 healthy controls.

Primary and secondary outcome measures

We recorded postural changes in bilateral transcranial Doppler (primary outcome) and simultaneously recorded near-infrared spectroscopy, end-tidal CO2, non-invasive blood pressure data and changes in neurological status (secondary outcomes).

Methods

Postures included the supine, half sitting (45°), sitting (70°) and Trendelenburg (-15°) positions. Using multilevel analyses, we compared postural changes between hemispheres, outcome groups (using modified Rankin Scale) as well as between patients and healthy controls.

Results

The mean patient age was 62±15 years and median National Institute of Health Stroke Scale score on admission was 7 (IQR 5-14). Mean proportional CBFV changes on sitting were not significantly different between healthy controls and affected hemispheres in patients with stroke. No significant differences were found between affected and unaffected stroke hemispheres and between patients with unfavourable and favourable outcomes. During upright positioning, no neurological worsening or improvement was observed in any of the patients.

Conclusions

No indications were found that upright positioning in bed in mild to moderately affected patients with stroke compromises flow and (frontal)oxygenation significantly during the subacute phase of stroke. Supine or Trendelenburg positioning does not seem to augment real-time flow variables.

SUBMITTER: Aries MJ

PROVIDER: S-EPMC3752059 | biostudies-literature | 2013 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Cerebral blood flow velocity changes during upright positioning in bed after acute stroke: an observational study.

Aries Marcel J MJ Elting Jan Willem JW Stewart Roy R De Keyser Jacques J Kremer Berry B Vroomen Patrick P

BMJ open 20130814 8

<h4>Objectives</h4>National guidelines recommend mobilisation in bed as early as possible after acute stroke. Little is known about the influence of upright positioning on real-time cerebral flow variables in patients with stroke. We aimed to assess whether cerebral blood flow velocity (CBFV) changes significantly after upright positioning in bed in the acute stroke phase.<h4>Design</h4>Observational study.<h4>Participants</h4>47 patients with acute ischaemic stroke measured in the subacute phas ...[more]

PMID: 23945730

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Project description:Background: Neurovascular coupling enables a rapid adaptation of cerebral blood flow (CBF) to support neuronal activities. Whether this mechanism is compromised during the acute phase after ischemic stroke remains unknown. In this study, we applied a phase-amplitude cross-frequency coupling (PAC) algorithm to investigate multimodal neuro signals including CBF velocity (CBFV), and electroencephalography (EEG). Methods: Acute ischemic stroke patients admitted to the Neurointensive Care Unit, Tiantan Hospital, Capital Medical University (Beijing, China) with continuous monitoring of 8-lead EEG (F3-C3, T3-P3, P3-O1, F4-C4, T4-P4, P4-O2), non-invasive arterial blood pressure (ABP), and bilateral CBFV of the middle cerebral arteries or posterior cerebral arteries were retrospectively analyzed. PAC was calculated between the phase of CBFV in frequency bands (0-0.05 and 0.05-0.15 Hz) and the EEG amplitude in five bands (δ, θ, α, β, γ). The global PAC was calculated as the sum of all PACs across the six EEG channels and five EEG bands for each patient. The hemispherical asymmetry of cross-frequency coupling (CFC) was calculated as the difference between left and right PAC. Results: Sixteen patients (3 males) met our inclusion criteria. Their age was 60.9 ± 7.9 years old. The mean ABP, mean left CBFV, and mean right CBFV were 90.2 ± 31.2 mmHg, 57.3 ± 20.6 cm/s, and 68.4 ± 20.9 cm/s, respectively. The PAC between CBFV and EEG was significantly higher in β and γ bands than in the other three bands. Occipital region (P3-O1 and P4-O2 channels) showed stronger PAC than the other regions. The deceased group tended to have smaller global PAC than the survival group (the area under the receiver operating characteristic curve [AUROC] was 0.81, p = 0.57). The unfavorable outcome group showed smaller global PAC than the favorable group (AUROC = 0.65, p = 0.23). The PAC asymmetry between the two brain hemispheres correlates with the degree of stenosis in stroke patients (p = 0.01). Conclusion: We showed that CBFV interacts with EEG in β and γ bands through a phase-amplitude CFC relationship, with the strongest PAC found in the occipital region and that the degree of hemispherical asymmetry of CFC correlates with the degree of stenosis.

Dataset Information

Cerebral blood flow velocity changes during upright positioning in bed after acute stroke: an observational study.

Objectives

Design

Participants

Primary and secondary outcome measures

Methods

Results

Conclusions

Publications

Cerebral blood flow velocity changes during upright positioning in bed after acute stroke: an observational study.

Similar Datasets

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