HOBOE (Head-of-Bed Optimization of Elevation) Study: Association of Higher Angle With Reduced Cerebral Blood Flow Velocity in Acute Ischemic Stroke

Hunter, Abigail Jade; Snodgrass, Suzanne J.; Quain, Debbie; Levi, Christopher

doi:10.2522/ptj.20100271

Cited by 41 publications

(53 citation statements)

References 36 publications

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“…Only 5 studies evaluated MFV in different positions after AIS and were included; one of them was excluded because it used single-photon emission computed tomography to measure CBF. Finally, inclusion criteria were met by 4 nonrandomized studies, of which 3 investigated MFV both on the side affected and unaffected by stroke [17,19,20] and 1 reported MFV only on the affected side [18]. The study year, number of patients, time from symptom onset to TCD, bed angle and outcome in these 4 studies are summarized in table 2.…”

Section: Resultsmentioning

confidence: 99%

“…Although variance of the mean difference in MFV was not reported in 2 of the studies [19,20], we estimated it using variance in MFV at each head position and the rho value of 0.8, which was conservatively defined based on the rho values in the other 2 studies (range 0.88-0.99) [17,18]. Overall estimates of effect and 95% confidence intervals (CI) were calculated using a random-effects model and inverse variance weighting (weighting by the precision of the estimate in each study).…”

Section: Methodsmentioning

confidence: 99%

“…A systematic review concluded that there was an equivocal effect of body position on CBF and other measures of physiological homeostasis in patients with AIS [16]. An underlying hypothesis generated by several small observational studies that have used transcranial Doppler ultrasonography (TCD) after AIS (affecting the anterior circulation) is that passive vasodilatation occurs in the ischemic tissue, so an increase in cerebral mean flow velocity (MFV) in the lying flat position due to gravitational force and/or recruitment of collateral vessels could increase residual CBF [17,18]. We undertook a systematic review with meta-analysis to quantify the effect of different head positions on MFV measured by TCD in patients with AIS and determined the potential mechanisms for benefit (or harm) of randomizing to bed position in a clinical trial.…”

Section: Introductionmentioning

confidence: 99%

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Head Position and Cerebral Blood Flow Velocity in Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

Olavarría

Arima²,

Anderson³

et al. 2014

Cerebrovasc Dis

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Background: Patients with acute ischemic stroke (AIS) have impaired vasomotor reactivity, especially in the affected cerebral hemisphere, such that they may depend directly on systemic blood pressure to maintain perfusion to vulnerable ‘at risk' penumbral tissue. As the sitting up position may affect cerebral perfusion by decreasing cerebral blood flow (CBF) in salvageable tissue, positioning AIS patients with their head in a lying flat position could increase CBF through collateral circulation or gravitational force. We wished to quantify the effect of different head positions on mean flow velocity (MFV) by transcranial Doppler ultrasonography (TCD) in AIS patients to assess the potential for benefit (or harm) of head positioning in a clinical trial. Methods: We performed a systematic review and meta-analysis of observational studies with TCD to evaluate differences in cerebral MFV between the lying flat and sitting up head positions in AIS. For each study and each comparison, we obtained the mean value of changes in MFV and its variance. Results: A total of 303 studies were identified, but 298 were excluded for varying reasons; 4 papers met the inclusion criteria and 57 patients were included in the meta-analysis for calculation of the overall mean difference in MFV. We found a significant increase in MFV from a bed angle of 30 to 15° (4.6 cm/s, 95% confidence interval, CI, 2.9-6.2, p < 0.001) and from 30 to 0° (8.3 cm/s, 95% CI 5.3-11.3, p < 0.001) in the affected hemisphere but not on the normal side in AIS patients. Conclusions: In AIS patients, MFV increased significantly in the side affected by the stroke but not in the unaffected side when they were positioned in a lying flat head position at 0 or 15° compared to an upright head position at 30°. The clinical significance of these findings is now undergoing further randomized evaluation in the international multicenter Head Position in Acute Stroke Trial (HeadPoST).

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Head Position and Cerebral Blood Flow Velocity in Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

Olavarría

Arima²,

Anderson³

et al. 2014

Cerebrovasc Dis

View full text Add to dashboard Cite

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“…Similarly, Hunter and colleagues found an increase in MFVs by a median of 26 cm/s (IQR_21.3 to 35.3), with a change in the HOB angle from 30° to 0°, in incompletely recanalized MCAs 24 h from onset of acute ischemic stroke (Hunter et al. 2011). These findings were further confirmed by Durduran et al.…”

Section: Introductionmentioning

confidence: 99%

Risk of pneumonia associated with zero‐degree head positioning in acute ischemic stroke patients treated with intravenous tissue plasminogen activator

et al. 2016

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IntroductionIn the hyperacute phase of ischemic stroke, a 0° position is recommended to increase cerebral perfusion in nonhypoxic patients able to tolerate lying flat. However, use of 0° positioning is not uniformly applied in clinical practice, most likely due to concerns of aspiration pneumonia. We aimed to determine the risk of pneumonia associated with 0° head of bed positioning in acute stroke patients treated with thrombolytic therapy.MethodsA retrospective descriptive study was conducted using prospectively collected, consecutive acute ischemic stroke patients treated with IVtPA whose head of bed was positioned at 0° for the first 24 h. Rates of hospital‐acquired pneumonia were determined using a strict adjudication process to insure accuracy of pneumonia diagnoses. Quantitative characteristics were analyzed in SPSS to compare differences between “true” pneumonia cases and nonpneumonia cases.ResultsTwenty‐four of 333 (7.2%) patients had mention the diagnosis of pneumonia in the registry and/or medical record. Of these cases, only 15 (4.5%) met evidence‐based diagnostic criteria for hospital‐acquired pneumonia. The 15 adjudicated cases had similar median admission NIHSS scores to nonpneumonia cases (10 vs. 9, respectively; P = ns), but were older (74 ± 15 vs. 64 ± 17 years; mean difference 9.889, 95 CI = 1.2–18.6; P = 0.026). A total of eight patients with pneumonia were intubated and mechanically ventilated, and one patient received bilevel positive airway pressure ventilation during the 0° positioning period. Pneumonia cases had significantly longer hospitalizations (14.5 ± 12 vs. 6.6 ± 9 days; mean difference 7.97, 95% CI = 1.1–14.8; P = 0.026) and higher median discharge mRS score (4 vs. 3: P = 0.003).ConclusionsZero‐degree head of bed positioning in the first 24 h following an acute ischemic stroke treated with IV‐tPA was associated with acceptable rates of pneumonia. Rates for pneumonia may be further reduced by eliminating use of a 0° protocol in intubated/mechanically ventilated patients.

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“…Generally, the presence of cerebral artery stenosis results in high cerebral blood flow velocity (CBFV), and the severity of this condition is a pre-disposing factor for stroke 4) . Patients with cerebral artery stenosis initially receive drug treatment; however, severe hemodynamic disorder requires surgery.…”

Section: Introductionmentioning

confidence: 99%

Effects of Resistive Exercise on Cerebral Blood Flow Velocity and Pulsatility Index of Healthy People

et al. 2012

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Abstract. [Purpose] This study compared the cerebral blood flow velocity and pulsatility index different exercise intensities before and after resistive exercises to evaluate the benefits of regular resistive exercise for the prevention of brain injuries such as stroke.[Subjects] Twelve healthy male adults were recruited for this study.[Methods] Transcranial Doppler ultrasonography was used to measure the cerebral blood flow velocity and pulsatility index. The test was conducted in 4 stages: at rest, moderate exercise, peak exercise, and recovery. After the pretest, each subject was given a 1-hour resistive exercise to be performed three times a week for 12 weeks, following which, a posttest was performed, and the resulting data were analyzed.[Results] Cerebral blood flow velocity at all stages, except systolic recovery, showed significant reductions after the intervention. The pulsatility index did not differ significantly at any stage. [Conclusion] Resistive exercise reduced cerebral blood flow velocity; therefore changes in cerebral blood flow should be monitored for the prevention of cerebrovascular diseases.

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HOBOE (Head-of-Bed Optimization of Elevation) Study: Association of Higher Angle With Reduced Cerebral Blood Flow Velocity in Acute Ischemic Stroke

Abstract: The incompletely recanalized group showed changes in MFVs at various HOB angles, suggesting that cerebral blood flow in this group may be sensitive to orthostatic variation, whereas the recanalized group maintained stable blood flow velocities.

Cited by 41 publications

References 36 publications

Head Position and Cerebral Blood Flow Velocity in Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

Head Position and Cerebral Blood Flow Velocity in Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

Risk of pneumonia associated with zero‐degree head positioning in acute ischemic stroke patients treated with intravenous tissue plasminogen activator

Effects of Resistive Exercise on Cerebral Blood Flow Velocity and Pulsatility Index of Healthy People

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