Level of agreement between Nexfin non-invasive arterial pressure with invasive arterial pressure measurements in children

We compared Nexfin non-invasive arterial pressure measurements using a novel small finger cuff with intra-arterial pressure in the paediatric setting in order to establish the level of agreement between both methods. The study included 41 children aged 216 yr admitted for surgery or paediatric intensive care with an intra-arterial catheter as part of standard monitoring. Values of systolic (SAP), diastolic (DAP), and mean arterial pressure (MAP) were obtained simultaneously from the intra-arterial catheter and the non-invasive Nexfin monitor. Data were analysed using intra-class correlation (ICC) coefficients and the BlandAltman analysis. A non-invasive arterial pressure signal was obtained in the majority of patients. The reproducibility of arterial pressure measurements over time by both non-invasive and invasive techniques was high, with ICC coefficients ranging from 0.94 to 0.98. The BlandAltman analysis for SAP, DAP, and MAP revealed a bias with 95 limits of agreement of 13.5 (39.7; 12.8), 0.2 (12.8; 13.2), and 2.6 (17.7; 12.5) mm Hg, respectively. Linear regression suggested a weak correlation of SAP and the bias between intra-arterial and Nexfin SAP measurements (intercept 4.9 mm Hg, 0.29; P0.01). Nexfin non-invasive arterial pressure measurements are feasible in paediatric patients. Nexfin accurately reflects the intra-arterial MAP and DAP curves, but seems to underestimate SAP compared with intra-arterial pressure. These results suggest that Nexfin may be used in low-to-moderate risk children without severe systemic hypotension, who require beat-to-beat haemodynamic monitoring but do not have an indication for invasive measurements.