When to measure BP for orthostatic hypotension diagnosis?

Careful monitoring is needed in measuring orthostatic blood pressure (BP) for orthostatic hypotension diagnosis at the emergency department among older patients (aged ≥60 years) with high blood urea nitrogen (BUN) as BP can drop quickly within 1 min, suggests a recent study.

In contrast, clinicians can measure BP for a longer time in younger people (aged <40 years) as BP drop occurs slowly after 3 min.

The authors sought to identify the time of BP drop in the orthostatic hypotension test and to propose a realistic and appropriate duration in the said test. To do this, they retrospectively reviewed 879 consecutive patients (mean age, 61 years; 44 percent women) with positive results on the orthostatic hypotension test in the emergency department.

Orthostatic hypotension was defined as drop in standing systolic BP of at least 20 mm Hg or standing diastolic BP of at least 10 mm Hg from their supine values after standing for 5 min. BP measurements were done at 1, 3, and 5 min after standing.

Of the patients, 684 (77.8 percent) had BP drop meeting orthostatic hypotension criteria at 1 min, while 152 (17.3 percent) and 43 (4.9 percent) did so at 3 and 5 min, respectively.

Multivariable analysis revealed the independent association of older age (≥60 years) and higher BUN (≥15.5 mg/dl) with early BP drop at 1 min and of younger age (<40 years) with later BP drop at 5 min even after controlling for potential confounders.