Diagnostic Accuracy of Arm Conicity to Detect Inaccurate Non‐Invasive Blood Pressure Measurement in Obese Patients

. There were 531 measurements at T0 and T20 with INV and NIBP available. Of 265 for SBP, 150 (56.7%) were inaccurate and of 266 for DBP, 113 (42.5%) were inaccurate. All ROC curves for right arm slant angle, right mid-arm circumference and BMI for SBP and DBP at T0 and T20 approached a 45° line. Area under ROC curves (AUROCs) ranged from 0.47 (0.36, 0.57) to 0.64 (0.54, 0.74), suggesting poor diagnostic performance. The best performer was right arm slant angle, with AUROCs 0.63 (0.51, 0.75) for DBP and 0.69 (0.59, 0.78) for SBP for underestimation at T0. Inaccurate measurements were common. Right arm conicity, mid-arm circumference and BMI were poor classifiers of NIBP measurement error at the pre-induction and intraoperative time points. EDITORIAL COMMENT: Accuracy of NIBP measurements in obese patients is uncertain. This clinical study compared routine oscillometric clinical blood pressure methods to a reference invasive blood pressure measure in an obese cohort. Significant disagreement between these is described, demonstrating reliability problems for some of the common arm oscillometric cuff implementations.