Abstract TP369: Blood Pressure Dynamics During Long Sitting Position In Acute Ischemic Stroke Patients: Prevalence Of Orthostatic Hypotension.

Abstract

Background and Purpose: Long sitting positioning (LSP) using head of bed elevation is an important part of early rehabilitation and mobilization for patients with acute ischemic stroke. However, little is known about orthostatic hypotension (OH) during LSP, which is potential risk factor for ischemic stroke recurrence. This study aimed to investigate the prevalence of OH during LSP and its related factors. Methods: Patients with acute ischemic stroke were enrolled in this study (n=246, male: 68.1%, mean age 74.7y). Ten-minutes LSP by 70-degree head of bead elevation with successive blood pressure (BP) measurement was conducted a week after their stroke. BP was measured for three times on un-affected arm: pre-measurement in supine position, 1 and 10 minutes after beginning of LSP. OH was defined as ≥20 mmHg fall in systolic BP (SBP) and/ or ≥10 mmHg fall in diastolic BP (DBP) from pre-measurement in supine position. Potential related factors such as demographics, comorbidities, stroke severity, baseline BP were investigated by multivariate logistic analysis. Results: The overall prevalence of OH were 15.0% (n=37) at 1 minute and 20.3% (n=50) at 10 minutes after beginning of LSP. Patients with OH at 1 minute were more likely to have higher supine DBP (p=0.034), and patients with OH at 10 minutes were more likely to have higher supine SBP (p=0.004) and DBP (p<0.001). In multivariate logistic analysis showed that older age (OR [95%CI], 1.05[1.01-1.09]), male gender (3.15[1.19-8.33]) and higher supine DBP (1.03[1.00-1.06]) were independently associated with the OH at 1 minute after LSP. Similarly, older age (1.05[1.01-1.08]) and higher supine DBP (1.05[1.03-1.08]) were independently associated with OH at 10minutes after LSP. Conclusions: The OH prevalence at 1 minute after beginning of LSP was similar to previous studies which defined OH as hypotension in upright position. However, the prevalence rose remarkably at 10 minutes after LSP, while temporary hemodynamic instability would recover within one minute in healthy adults. These results implicated that impaired activity of the autonomic nervous system in acute ischemic stroke patients was associated with defect in hemodynamics regulation, especially in the patients with older age and/or higher supine BP.