Authors: Vos JJ et al., Br J Anaesth 2014 Apr 15;
The device is a reasonable substitute for traditional cuff monitoring but is not a replacement for invasive monitoring.
New devices offering continuous, noninvasive arterial pressure monitoring compare favorably with intermittent, automated cuff measurement (NEJM JW Emerg Med Mar 11 2014), but how do they compare with invasive measurement? One such device, the Nexfin®, adjusts pressure in a finger cuff 1000 times per second to maintain a constant arterial volume throughout the cardiac cycle, allowing measurement of an arterial pressure waveform.
Researchers compared readings from the Nexfin device and traditional arm cuff oscillometry with readings from continuous invasive arterial pressure monitoring in 112 patients undergoing elective surgery. In each patient, pressures were measured during a 30-minute hemodynamically stable period. The median difference in Nexfin and cuff values from the invasive values was less than 3 mm Hg. Both noninvasive devices were less accurate than invasive pressure monitoring, with comparable overall accuracy, and both failed to meet predefined precision guidelines (an indication of measurement reproducibility) of 5 mm Hg.
Both the new device and traditional monitoring were less precise than invasive monitoring. Based on these results, the Nexfin device is a reasonable substitute for traditional oscillometric cuff monitoring in hemodynamically stable patients, but neither is a replacement for invasive blood pressure monitoring.