HOBOE (Head-of-Bed Optimization of Elevation) Study: association of higher angle with reduced cerebral blood flow velocity in acute ischemic stroke. May, 2012
The new one here: which is totally useless since mild has no objective definition.
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In the HeadPoST trial -- a cluster crossover trial involving 114 hospitals around the world -- there was no significant difference in changes in modified Rankin Scale (mRS) scores at 90 days between the two post-stroke strategies (OR 1.01, 95% CI 0.92-1.10, P=0.84), Craig Anderson, MD, PhD, of The George Institute in Australia, and colleagues reported at the International Stroke Conference here.
"There was no difference at all in any of the measures of disability, but conversely, we didn't show any extra harms, we didn't find any extra risk of pneumonia," Anderson said during a press briefing. "We couldn't find any clear signal of benefits or harms in any of the subgroups that we have examined. So we can't make any clear recommendations for policy about whether there could be benefits or harms of a specific head position in acute stroke."
"Whether we can improve upon what nature is [doing] by positioning or pumps or other things is debatable," he added. "I guess our study shows maybe it's not possible to do that naturally."
Researchers who were not involved in the study cautioned that most of the included patients had mild strokes, so the question as to which strategy should be preferred for those with more severe strokes remains unanswered.
"It's quite conceivable people with larger vessel strokes presumably might benefit more from the head position being flat," said Bruce Ovbiagele, MD, of Medical University of South Carolina in Charleston, who moderated the session at which the findings were presented. "There could be a difference there. The type of population they had in this study is reflective of the kind of patients we see for most part, but when you think about the potential underlying pathophysiology, those large-vessel [patients] might benefit from lying flat."
Anderson noted that a recent Doppler study suggested that lying flat increases blood flow, which would be important following ischemic stroke. Thus, having recovering patients take on the supine position could be beneficial by increasing blood flow to the brain.
On the other hand, laying flat could be tied to complications such as aspirating stomach contents or saliva, contributing to pneumonia risk.
AHA/ASA guidelines for the early management of patients with acute ischemic stroke suggest that non-hypoxic patients who are able to tolerate it should lay in the supine position, while patients at risk for airway obstruction or aspiration and those with suspected elevated intracranial pressure should have the bed tilted 15 to 30 degrees.
There's little evidence, however, regarding which position is optimal, and physicians must balance competing interests and patient tolerance, Anderson said.
To assess which strategy might prove superior, the researchers recruited hospitals to a cluster crossover trial, in which they first assigned 70 patients to one strategy, and then the participating centers crossed over and assigned a subsequent 70 patients to the other strategy.
Overall, they assessed just over 11,000 patients from 114 hospitals in 19 countries, with large populations from the U.K. and China. Mean patient age was 68, 40% were female, and the median NIHSS score was 4.
In addition to finding no difference in the unadjusted shift in mRS scores at 90 days, there were no differences in further controlled analyses; nor were there any differences among subgroups assessed by age, gender, region, or severity.
Additionally, there were no differences whether patients had an ischemic or hemorrhagic stroke, Anderson reported.
He cautioned that laying flat was uncomfortable to many patients, potentially raising the issue of compliance.
Ralph Sacco, MD, of the University of Miami, a past president of the American Heart Association and president-elect of American Academy of Neurology, who was not involved in the study, noted that more data to show how well hospitals and patients followed the protocols could be helpful.
"These patients had more mild stroke, which means they are more likely to be getting up and walking around," he noted.
Sacco echoed other researchers' concerns about the study's majority of mild stroke patients being a limitation, as patients with worse disease may potentially have different outcomes.
"We need more subgroup analysis to know if large strokes with signs of edema show any benefit," Sacco said. "The important [question] here is whether those with large strokes -- hemorrhages or infarcts -- that may even have signs of early edema" would do better.
The authors reported reimbursement from Takeda China and Boehringer Ingelheim for speaker fees and travel expenses.
- Reviewed by F. Perry Wilson, MD, MSCE Assistant Professor, Section of Nephrology, Yale School of Medicine and Dorothy Caputo, MA, BSN, RN, Nurse Planner
International Stroke ConferenceSource Reference: Anderson CS, et al "Head position in stroke trial: An international cluster crossover randomized trial" ISC 2017; Abstract LB1.