Estimation of pulse pressure variation and cardiac output in patients having major abdominal surgery: a comparison between a mobile application for snapshot pulse wave analysis and invasive pulse wave analysis

Pulse pressure variation (PPV) and cardiac output (CO) can guide perioperative fluid management. Capstesia (Galenic App, Vitoria-Gasteiz, Spain) is a mobile application for snapshot pulse wave analysis (PWAsnap) and estimates PPV and CO using pulse wave analysis of a snapshot of the arterial blood pressure waveform displayed on any patient monitor. We evaluated the PPV and CO measurement performance of PWAsnap in adults having major abdominal surgery. In a prospective study, we simultaneously measured PPV and CO using PWAsnap installed on a tablet computer (PPV(PWAsnap), CO(PWAsnap)) and using invasive internally calibrated pulse wave analysis (ProAQT; Pulsion Medical Systems, Feldkirchen, Germany; PPV(ProAQT), CO(ProAQT)). We determined the diagnostic accuracy of PPV(PWAsnap) in comparison to PPV(ProAQT) according to three predefined PPV categories and by computing Cohen’s kappa coefficient. We compared CO(ProAQT) and CO(PWAsnap) using Bland-Altman analysis, the percentage error, and four quadrant plot/concordance rate analysis to determine trending ability. We analyzed 190 paired PPV and CO measurements from 38 patients. The overall diagnostic agreement between PPV(PWAsnap) and PPV(ProAQT) across the three predefined PPV categories was 64.7% with a Cohen’s kappa coefficient of 0.45. The mean (± standard deviation) of the differences between CO(PWAsnap) and CO(ProAQT) was 0.6 ± 1.3 L min(− 1) (95% limits of agreement 3.1 to − 1.9 L min(− 1)) with a percentage error of 48.7% and a concordance rate of 45.1%. In adults having major abdominal surgery, PPV(PWAsnap) moderately agrees with PPV(ProAQT). The absolute and trending agreement between CO(PWAsnap) with CO(ProAQT) is poor. Technical improvements are needed before PWAsnap can be recommended for hemodynamic monitoring.