Figure 1

Validation of vODM. A. ODM measurements of the venous occlusion pressure (VOP, mmHg) conform linearly with actual ICP measurements made in critically ill patients with invasive canulation and continuous monitoring or taken in the OR at time of shunting or obtained through lumbar puncture. 12 patients with acute or decompensated hydrocephalus from various etiologies (intracranial hemorrhage n = 4, obstructive n = 2, 'NPH' = 2, communicating n = 2) and 1 each with acute trauma and midline tumor removal, underwent either ventriculostomy or lumbar puncture. They were measured in a total of 16 encounters by either of 3 operators who were blinded to the actual instantaneous ICP. The recorded ICPs ranged from 1.0 to 40.6 mm Hg. The individual points are the mean of 3-5 rapidly successive ODM readings of the VOP (mmHg) plotted against a single actual ICP reading (the fitted line is ICP = 1.07 VOP- 4.6; r = 0.85; (- - - -) denote 95% confidence limits). B. ROC curve for vODM data in A. Area under curve (AUC) is 0.89 (95% CI 0.73-1.05, p < .01).