RAUMED NeuroSmart Instruction Manual
Manufacturer: RAUMEDIC AG, Hermann-Staudinger-Strasse 2, 95233 Helmbrechts, Germany
zwo-541EN Rev 3 / 2022-05-03
Page 41 of 61
3.8.1 Calculation methodology for PRx, ORx and CPPopt
The following literature was used for the calculations. No conclusion whatsoever is made in this instruc-
tion manual or with the device about the clinical significance.
PRx
[1] M. Czosnyka, J. D. Pickard. “Monitoring and interpretation of intracranial pressure”. J Neurol Neuro-
surg Psychiatry. Vol 75 (6). (2004). PP 813-821
DOI: 10.1136/jnnp.2003.033126
ORx
[2] M. Jaeger, M. U. Schuhmann, Martin Soehle et al. “Continuous Monitoring of Cerebrovascular Auto-
regulation After Subarachnoid Hemorrhage by Brain Tissue Oxygen Pressure Reactivity and Its Relation
to Delayed Cerebral Infarction”. Vol 38 (3) (2007) Stroke, PP 981-986.
DOI: 10.1161/01.STR.0000257964.65743.99
[3] M. Grözinger, M. Schenk, M. H. Morgalla, et al. “The values of cerebrovascular pressure reactivity
and brain tissue oxygen pressure reactivity in experimental anhepatic liver failure.”. Neurocrit Care. Vol
17 (2) (2012). DOI: 10.1007/s12028-012-9714-0
CPPopt
[4] M. J. Aries, M. Czosnyka, K. P. Budohoski et al. “Continuous determination of optimal cerebral per-
fusion pressure in traumatic brain injury.”. Crit Care Med Vol 40 (8) (2012).
DOI: 10.1097/CCM.0b013e3182514eb6
[5] J. Donnelly, M. Czosnyka, A. Hadie et al. “Individualising thresholds of cerebral perfusion pressure
using estimated limits of autoregulation”. Crit Care Med. Vol 45 (9 (2017).
DOI: 10.1097/CCM.0000000000002575
[6] J. Donnelly, K. P. Budohoski, P. Smielewski et al. “Regulation of the cerebral circulation: bedside
assessment and clinical implications”. Crit Care Vol 20 (129) (2016).
DOI: 10.1186/s13054-016-1293-6
PRx: The Pressure Reactivity Index is the correlation between intracranial pressure (ICP) and arterial
blood pressure (ART). The correlation coefficients are calculated according to the Karl Pearson formula.
Mean values that are calculated over 10 seconds each time are used for ICP and ART. A PRx value is
calculated in a floating 5-minute period (1 min). The calculated PRx values are charted over time.
ORx: The Oxygen Reactivity Index is the correlation between oxygen partial pressure (pO2) and Cere-
bral Perfusion Pressure (CPP), whereby CPP is the difference between ART and ICP.
This document is for information only
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