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I have completed bits of my EM training from India. Currently I am boarded with credentials from Christian Medical College, Vellore and also from the prestigious Royal College of Emergency Medicine, UK.  I am currently working in London as an A&E doctor, trying to appreciate the differences in the practise and culture of Emergency Medicine across different healthcare systems. I have always been an avid FOAMed supporter because FOAMed played an indispensable role during the days of my initial training. Through this blog, I aspire to disseminate knowledge and stay up to date with the EM literature. 

Monday, March 20, 2017

Utility of Lying/Standing Blood Pressure (Orthostatic Vitals)

What is Orthostatic Hypotension?
A patient is considered to have orthostatic hypotension when the systolic blood pressure falls by more than 20 mm Hg,m or diastolic blood pressure drop by more than 10 mm Hg, or pulse rise of more than 20-30 beats per minute within 3-5 minutes of standing. 

Don't be surprised if you hear different numbers from med students/nurses. There is a great deal of variation in how Orthostatics are checked and what numbers are used to call them significant. 


Image taken from http://www.antonygormley.com/sculpture/item-view/id/249
Ideally, Orthostatic Vitals should be done after the patient has been supine for about 5 minutes with the head flat. A drop in BP and increase in HR is a normal compensatory mechanism but it is thought that in mild dehydration, this normal response is exaggerated. Vitals are checked first in supine position and then after 3-5 minutes of standing. 

Symptoms of orthostatic hypotension are lightheadedness, dizziness, blurred vision, weakness, fatigue, nausea, palpitations, headache, and syncope.


When do we get Orthostatic Vitals?

Lying/Standing blood pressure or Orthostatic Vitals are generally done for patients with h/o volume loss (vomiting, dehydration, syncope, those who are on diuretics, alpha blockers) to make an assumption about their volume status. Majority of physicians treat orthostatic hypotension with Oral/IV fluids regardless of a patient's Orthostatic Symptoms. 




I often get asked about this whenever I try and admit a high risk syncope under Internal Medicine. Emergency Physicians are aware of these pitfalls of Orthostatic Vitals, but we continue to play this game of numbers to sell admits to our colleagues who strongly believe in Orthostatics. Watch Anand Swaminathan diving into the literature behind these numbers.


How reliable are Orthostatic Vitals to predict mild dehydration?
Current literature states that orthostatic vital signs are highly unreliable to predict mild volume loss. Almost 50% can test positive for orthostatic vitals even when asymptomatic. In addition, elderly may have multiple other reasons such as autonomic neuropathy, medications that interfere with orthostatic vitals making them even more unreliable. Looking for orthostatic symptoms is more reliable than treating the numbers. 


Orthostatic Hypotension Debunked - Anand Swaminathan from Statenislandem on Vimeo.


Problems with Orthostatic Vitals

  • Poor Sensitivity and Specificity
  • Poor reliability in elderly due to altered physiology, mediations, neuropathies
  • Time Consuming (Nurses hate doing it!)
  • Wide variation in how these numbers are interpreted 
  • Often not done in an ideal manner


Take Home:

  • Treat the patient, not these numbers (Treat Orthostatic Symptoms)
  • Orthostatic Vitals are not reliable to predict mild volume loss


References:


1.         Naccarato M, Leviner S, Proehl J, et al. Emergency Nursing Resource: orthostatic vital signs. Journal of emergency nursing: JEN : official publication of the Emergency Department Nurses Association. Sep 2012;38(5):447-453.
2.         Koziol-McLain J, Lowenstein SR, Fuller B. Orthostatic vital signs in emergency department patients. Annals of emergency medicine. Jun 1991;20(6):606-610.
3.         Ooi WL, Barrett S, Hossain M, Kelley-Gagnon M, Lipsitz LA. Patterns of orthostatic blood pressure change and their clinical correlates in a frail, elderly population. Jama. Apr 23-30 1997;277(16):1299-1304.
4.         Skinner JE, Driscoll SW, Porter CB, et al. Orthostatic heart rate and blood pressure in adolescents: reference ranges. Journal of child neurology. Oct 2010;25(10):1210-1215.
5.         Stewart JM. Transient orthostatic hypotension is common in adolescents. The Journal of pediatrics. Apr 2002;140(4):418-424.
6.         Baraff LJ, Schriger DL. Orthostatic vital signs: variation with age, specificity, and sensitivity in detecting a 450-mL blood loss. The American journal of emergency medicine. Mar 1992;10(2):99-103.
7.         Witting MD, Wears RL, Li S. Defining the positive tilt test: a study of healthy adults with moderate acute blood loss. Annals of emergency medicine. Jun 1994;23(6):1320-1323.
8.         Johnson DR, Douglas D, Hauswald M, Tandberg D. Dehydration and orthostatic vital signs in women with hyperemesis gravidarum. Academic emergency medicine : official journal of the Society for Academic Emergency Medicine. Aug 1995;2(8):692-697.

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