Wednesday, December 28, 2011

orthostatic vital signs in the ED: not so useful


THEORY:
--normally, standing leads to a small fall in systolic BP (5 to 10 mmHg), an increase in diastolic BP (5 to 10 mmHg) and a compensatory increase in pulse rate (10 to 25 beats per minute)

--traditional criteria for orthostatic hypotension
  • > 20 mmHg decreased SBP
  • > 10 mmHg decreased DBP
  • Symptoms of cerebral hypoperfusion
--also seen:
  • >20 increased HR

NOT TOO USEFUL:
--study of 132 random, presumed euvolemic ED patients
--took lying & standing vitals
--HR range was from decreases 5.0 to increases 39.4 beats per minute
--SBP range was decreases 20 to increases 25.7 mm Hg
--DBP range was decreases 6.4 to increases 24.9 mm Hg
--43% had "positive" orthostatic vital signs according to currently accepted values


TO REITERATE:
--43% of likely euvolemic random ED patients had +orthostatic vitals by numbers
--43% suspected false positive, essentially
--probably not a useful test, this orthostatic vital signs thing

  

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