Fig. 4

Error grid analysis for mean arterial pressure comparing non-invasive and invasive measurements in patients with suspected TBI (a) and sICH (b). a Error Grid Analysis for TBI MAP (mmHg). b Error Grid Analysis for sICH MAP (mmHg). Invasive pressure (x-axis, reference standard) is plotted against non-invasive pressure (y-axis, index method). Data pairs marked by a black cross represent a concurrent data pair. Colour differentiation indicates the continuous risk level from the green (zone A, no risk) to dark red zone (zone E, dangerous risk). Zones A-E indicate: (A) no risk, no difference in clinical action, (B) low risk, benign or no treatment, (C) moderate risk, unnecessary treatment with moderate non-life-threatening consequences, (D) significant risk, unnecessary treatment with severe life-threatening consequences, (E) high risk, unnecessary treatment with severe life-threatening consequences. MAP; mean arterial pressure; TBI, traumatic brain injury; sICH, spontaneous intracranial haemorrhage