Comparison of parenchymal and ventricular intracranial pressure readings utilizing a novel multi-parameter intracranial access system

Introduction: Both ventricular and parenchymal devices are available for measurement of intracranial pressure (ICP). The Hummingbird (R) Synergy Ventricular System is a novel device allowing multi-parametric neurological monitoring, including both ventricular and parenchymal ICP. The purpose of this study is to compare the congruence of the device's ventricular and parenchymal ICP readings. Methods: This single-center, quantitative, interventional study compared parenchymal and ventricular ICP readings from 35 patients with the Hummingbird (R) System. If a difference of > +/- 3 mmHg existed between an individual patient's parenchymal and ventricular values, progressive intervention strategies were applied to correct identified issues. Results: From a total of 2,259 observations, statistical analysis revealed congruence (within +/- 0-3 mmHg) of 93% of readings comparing parenchymal and ventricular ICP. Of the observations requiring intervention, 58% involved the parenchymal component, 30% involved the ventricular component, and 12% involved both components. Following prescribed interventions, 98% of readings became congruent (within +/- 0-3 mmHg). The adjusted mean difference between the two methods was -0.95 (95% CI: -0.97, -0.93) mmHg and all mean ICP readings fell between -2 and 2 mmHg. Conclusion: The Hummingbird (R) Synergy Ventricular System demonstrates congruence between ventricular and parenchymal ICP measurements within accepted parameters. Interventions required to realign parenchymal and ventricular readings serve as reminders to clinicians to be vigilant with catheter/cable connections and to maintain appropriate positioning of the ventricular drainage system. The results of this study support the recommendation to use the parenchymal ICP component for routine ICP monitoring, allowing dedication of the ventricular catheter to drainage of cerebrospinal fluid (CSF).