Non-invasive measurement of pulse pressure variation using a finger-cuff method in obese patients having laparoscopic bariatric surgery

Pulse pressure variation (PPV) is a dynamic cardiac preload variable used to predict fluid responsiveness. PPV can be measured non-invasively using innovative finger-cuff systems allowing for continuous arterial pressure waveform recording, e.g., the Nexfin system [BMEYE B.V., Amsterdam, The Netherlands; now Clearsight (Edwards Lifesciences, Irvine, CA, USA)] (PPV(Finger)). However, the agreement between PPV(Finger) and PPV derived from an arterial catheter (PPV(ART)) in obese patients having laparoscopic bariatric surgery is unknown. We compared PPV(Finger) and PPV(ART) at 6 time points in 60 obese patients having laparoscopic bariatric surgery in a secondary analysis of a prospective method comparison study. We used Bland–Altman analysis to assess absolute agreement between PPV(Finger) and PPV(ART). The predictive agreement for fluid responsiveness between PPV(Finger) and PPV(ART) was evaluated across three PPV categories (PPV < 9%, PPV 9–13%, PPV > 13%) as concordance rate of paired measurements and Cohen’s kappa. The overall mean of the differences between PPV(Finger) and PPV(ART) was 0.5 ± 4.6% (95%-LoA − 8.6 to 9.6%) and the overall predictive agreement was 72.4% with a Cohen’s kappa of 0.53. The mean of the differences was − 0.7 ± 3.8% (95%-LoA − 8.1 to 6.7%) without pneumoperitoneum in horizontal position and 1.1 ± 4.8% (95%-LoA − 8.4 to 10.5%) during pneumoperitoneum in reverse-Trendelenburg position. The absolute agreement and predictive agreement between PPV(Finger) and PPV(ART) are moderate in obese patients having laparoscopic bariatric surgery. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s10877-020-00614-8) contains supplementary material, which is available to authorized users.