title: Venous blood redistribution alters the accuracy of Omron HEM-705CP.
abstract: BACKGROUND
  Validation procedures of automated blood pressure measuring devices are carried out at rest only.
  
  
  METHODS
  We aimed to determine whether venous blood redistribution affects the accuracy of the OMRON HEM-705CP (Osc). Lower body negative pressure stimulus (-40 mmHg) (LBNP) was used to simulate changes of body position.
  
  
  METHODS
  Fifty-four young healthy volunteers had their blood pressure (BP) measured simultaneously by Osc and mercury sphygmomanometer (HgS) at rest (at 3 and 5 min) and during LBNP (at 7 and 9 min).
  
  
  RESULTS
  Differences (delta) between HgS and Osc for systolic and diastolic BP (SBP and DBP) were calculated. The deltaSBP obtained in minute 9 (deltaSBP-9) was bigger than the one taken in minute 5(deltaSBP-5) (-2.89+/- 4.3 versus -1.35+/-5.2 mmHg, P<0.02). The rest of the deltaSBP values and all the deltaDBP values were constant at rest and during venous blood redistribution caused by LBNP. We calculated the fall in SBP separately for HgS and Osc by subtracting SBP-9 from SBP-5 for each patient. The fall measured by Osc was bigger than by HgS (-5.87+/-4.0 versus -4.3+/-4.5 mmHg; P<0.02). When graded according to British Hypertension Society protocol, Osc remained in the class of recommendation (A or B) for every minute of the procedure.
  
  
  CONCLUSIONS
  Even if an oscillometric device passes various validation tests, they do not give sufficient information about its accuracy during venous blood redistribution. This knowledge is of particular importance when BP regulation abnormalities occurring during changes in body position are diagnosed with the oscillometric method.
authors.affiliation: Department of Internal Medicine and Endocrinology, Medical University of Warsaw, Warsaw, Poland. mczark@amwaw.edu.pl
authors.forename: Marek
authors.initials: M
authors.lastname: Czarkowski
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Mikulska
authors.forename: Mariusz
authors.initials: M
authors.lastname: ZEbrowski
authors.forename: Anna
authors.initials: A
authors.lastname: Baran
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Rózanowski
mesh_terms: D000328:Adult; D001775:Blood Circulation; D001794:Blood Pressure / Q000502:physiology; D001795:Blood Pressure Determination / Q000295:instrumentation* / Q000379:methods / Q000592:standards; D015924:Blood Pressure Monitors / Q000592:standards*; D005260:Female; D006801:Humans; D007024:Hypotension, Orthostatic; D008297:Male; D009991:Oscillometry; D011187:Posture; D014680:Veins