Unique cutpoints for sitting-to-standing orthostatic vital signs.
The study objective was to describe the distribution of normal changes in vital signs related to moving from a sitting to a standing position. Subjects were free of cardiovascular disease and determined to be euvolemic by structured interview. Vital signs were measured after a minimum of 5 minutes of sitting and after 1 minute of standing. Among 176 subjects, mean differences in parameters (+/- standard deviation) were as follows: pulse increase, 5.3 +/- 6.6 beats per minute (bpm); systolic blood pressure (SBP) decrease, 1.2 +/- 9.8 mmHg; and shock index (SI) increase, 0.05 +/- 0.07 bpm/mmHg. These changes are less extreme than those previously published for changes from lying to standing. Unique tilt test positivity criteria and their expected specificities are as follows: pulse increase >/=20 bpm (0.98), SBP decrease >/=20 mmHg (0.97), SI increase >/=0.2 (0.99), ROSI >/=1.3 (0.95). Sitting-to-standing tilt tests require positivity criteria distinct from those published for lying-to-standing tilt tests.
Witting
Michael D
MD
Division of Emergency Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA. mwitt001@umaryland.edu
Gallagher
Katherine
K
D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D004244:Dizziness / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D017063:Outcome Assessment, Health Care; D011187:Posture / Q000502:physiology*; D011674:Pulse; D012016:Reference Values; D012680:Sensitivity and Specificity; D018667:Tilt-Table Test; D013997:Time Factors