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J Clin Monit Comput (2012) 26:191196 DOI 10.1007/s10877-012-9359-8
Visual estimation of pulse pressure variation is not reliable: a randomized simulation study
Joseph Rinehart Tanzeem Islam Rob Boud
Allison Nguyen Brenton Alexander
Cecilia Canales Maxime Cannesson
Received: 13 December 2011 / Accepted: 28 March 2012 / Published online: 11 April 2012 Springer Science+Business Media, LLC 2012
Abstract Pulse pressure variation (PPV) can be monitored several ways, but according to recent survey data it is most often visually estimated (eyeballed) by practitioners. It is not known how accurate visual estimation of PPV is, or whether eyeballing of PPV in goal-directed uid therapy studies may limit the ability to blind the control group to PPV value. The goal of this study was to test the accuracy of visual estimation of PPV. Using a simulator program designed by the authors that runs on a PC, 20 residents and 19 attendings were shown ve arterial pressure waveforms each with different PPV values (range 130 %) moving at one of three sweep speeds (6.25, 12.5, or 25 mm/s) and asked to determine the PPV. There was a weak but signicant relationship between true PPV and eyeball PPV (r2 = 0.22; p \ 0.01). The agreement between true PPV and eyeball PPV was 3.3 8.7 %. The mean percent error was 122 %. The rate of correct response group classication was 65 %. Mean percent error was higher the faster the waveform sweep speed (130 % at 25 mm/s vs. 117 % at 6.25 mm/s), and correct responsiveness classication lower (58 % at 25 mm/s vs. 69 % at6.25 mm/s). The results from this study show that eyeballing the arterial pressure waveform in order to evaluate pulse pressure variation is not accurate.
Keywords Pulse-pressure variation Visual estimation
Computer simulation Fluid-responsiveness
1 Introduction
Pulse pressure variation (PPV) has been shown to be the best predictor of uid responsiveness in mechanically ventilated patients under general anesthesia, in the intensive care unit, and in the operating room [1, 2]. Today, PPV can be evaluated using three different techniques: (1) it can be manually calculated as it was rst described [3], (2) it can be visually estimated or eyeballed [4], or (3) it can be monitored automatically using dedicated devices [5]. A recent survey conducted among...