Evaluation of the cerebrovascular pressure reactivity index using non-invasive Finapres arterial blood pressure

M. Kasprowicz, E. Schmidt, D. J. Kim, C. Haubrich, Z. Czosnyka, P. Smielewski, M. Czosnyka

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


A pressure reactivity index (PRx) can be assessed in patients with continuous monitoring of arterial blood pressure (ABP) and intracranial pressure (ICP) as a moving correlation coefficient between slow fluctuations of these two signals within a low frequency bandwidth. The study aimed to investigate whether the invasive ABP monitoring can be replaced with non-invasive measurement of ABP using a Finapres plethysmograph (fABP) to calculate the fPRx. There is a well-defined group of patients, suffering from hydrocephalus and undergoing CSF pressure monitoring, which may benefit from such a measurement. 41 simultaneous day-by-day monitoring of ICP, ABP and fABP were performed for about 30 min in 10 head injury patients. A Bland-Altman assessment for agreement was used to compare PRx and fPRx calculations. Performance metrics and the McNemary test were used to determine whether fPRx is sensitive enough to distinguish between functioning and disturbed cerebrovascular pressure reactivity. The fPRx correlated with PRx (RSpearman = 0.92, p < 0.001; bias = -0.04; lower and upper limits of agreement: -0.26 and 0.17, respectively). The fPRx distinguished between active and passive reactivity in more than 89% cases. The fPRx can be used with care for assessment of cerebrovascular reactivity in patients for whom invasive ABP measurement is not feasible. The fPRx is sensitive enough to distinguish between functional and deranged reactivity.

Original languageEnglish
Pages (from-to)1217-1228
Number of pages12
JournalPhysiological Measurement
Issue number9
Publication statusPublished - 2010 Sept
Externally publishedYes


  • Cerebrovascular pressure reactivity index
  • Intracranial pressure
  • Noninvasive arterial blood pressure

ASJC Scopus subject areas

  • Biophysics
  • Physiology
  • Biomedical Engineering
  • Physiology (medical)


Dive into the research topics of 'Evaluation of the cerebrovascular pressure reactivity index using non-invasive Finapres arterial blood pressure'. Together they form a unique fingerprint.

Cite this