Rogge DE, et al. - In 35 severely obese patients (median body mass index, 47 kg/m²) undergoing laparoscopic bariatric surgery, researchers compared the performance of the vascular unloading technique (Clearsight system; Edwards Lifesciences Corp, Irvine, CA) meant for noninvasive monitoring of arterial pressure vs invasive arterial pressure measurements (radial arterial catheter) during the operation. Over a period of 45 minutes, noninvasive and invasive arterial pressure measurements were simultaneously recorded and were compared using Bland-Altman analysis (accounting for multiple measurements per subject), 4-quadrant plot/concordance analysis (2-minute interval, 5 mm Hg exclusion zone), and error grid analysis. The vascular unloading technique (Clearsight system) displayed good accuracy and precision for mean arterial pressure (MAP) and diastolic arterial pressure during laparoscopic bariatric surgery, but its accuracy and precision were only moderate for systolic arterial pressure according to Bland-Altman analysis. Good trending capabilities were demonstrated by the system. Of all vascular unloading technique–derived arterial pressure measurements, >99% were classified in no- or low-risk zones, in the error grid analysis.