Fig. 2

Bland-Altman plot showing differences for each pair of SBP measurements together with bias (dashed red line) and limits of agreement (solid red line). The horizontal black line would reflect perfect agreement between IBP and NIBP at all blood pressures. In this case, the dashed red line slopes upwards, which suggests that the overall bias is towards NIBP overestimating SBP during hypotension and underestimating SBP during hypertension