title: The impact of blood pressure cuff location on the accuracy of noninvasive blood pressure measurements in obese patients: an observational study.
abstract: OBJECTIVE
  Obesity presents many challenges to the anesthesiologist, including poorly fitting blood pressure (BP) cuffs due to the conical shape of the upper arm. The aim of this study was to determine the accuracy of noninvasive BP readings, obtained from a noninvasive BP cuff using various cuff locations and wrapping techniques, compared with invasive intra-arterial BP readings.
  
  
  METHODS
  Thirty American Society of Anesthesiologists physical status I-III obese (body mass index > 30 kg·m(-2)) individuals undergoing non-cardiac surgery were enrolled in this observational study. Serial oscillometric noninvasive BP (NIBP) measurements were taken in the patients' forearm and upper arm with two different wrapping formations (one following the contour of the upper arm, the other keeping cuff edges parallel). These NIBP measurements were compared with invasive arterial blood pressure (ABP) measurements taken from the ipsilateral radial artery. The precision and bias of the NIBP and ABP measurements were determined using Bland-Altman analysis. Analysis of variance and Welch's t test were used to determine between-group differences in bias.
  
  
  RESULTS
  There was poor agreement between the ABP measurements and all types of NIBP measurements. Each of our study participants had a least one NIBP parameter (mean arterial pressure, systolic BP, or diastolic BP) that was > 10 mmHg different than the corresponding ABP parameter. Upper arm BP measurements showed a statistically insignificant trend toward underestimating ABP. For all cuff positions and wrapping techniques, systolic BP offered the best agreement between NIBP and ABP measurements.
  
  
  CONCLUSIONS
  All the forms of NIBP cuff orientation studied had unacceptable precision and bias compared with invasive ABP measurements. When patient and/or surgical conditions necessitate accurate BP monitoring, direct arterial measurement should be considered over NIBP measurements in obese patients.
authors.affiliation: Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Anast
authors.affiliation: Anesthesiology and Perioperative Care Service, Palo Alto Veterans Affairs Health Care System, Menlo Park, CA, USA.
authors.forename: Megan
authors.initials: M
authors.lastname: Olejniczak
authors.affiliation: Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USA.
authors.forename: Jerry
authors.initials: J
authors.lastname: Ingrande
authors.affiliation: Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USA. brockutn@stanford.edu.|Stanford University Medical Center, 300 Pasteur Drive, H3580, Stanford, CA, 94305-5640, USA. brockutn@stanford.edu.
authors.forename: John
authors.initials: J
authors.lastname: Brock-Utne
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure; D001795:Blood Pressure Determination / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology*