Katarzyna Kaczmarska1,2, Magdalena Kasprowicz3, Antoni Grzanka4, Wojciech Zabołotny4, Peter Smielewski5, Despina Afroditi Lalou5, Georgios Varsos5, Marek Czosnyka4,5, Zofia Czosnyka5. 1. Department of Neurosurgery, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland. kkaczmarska@imdik.pan.pl. 2. Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland. kkaczmarska@imdik.pan.pl. 3. Department of Biomedical Engineering, Wroclaw University of Technology, Wroclaw, Poland. 4. Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland. 5. Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK.
Abstract
OBJECTIVES: The objectives were to compare three methods of estimating critical closing pressure (CrCP) in a scenario of a controlled increase in intracranial pressure (ICP) induced during an infusion test in patients with suspected normal pressure hydrocephalus (NPH). METHODS: We retrospectively analyzed data from 37 NPH patients who underwent infusion tests. Computer recordings of directly measured intracranial pressure (ICP), arterial blood pressure (ABP) and transcranial Doppler cerebral blood flow velocity (CBFV) were used. The CrCP was calculated using three methods: first harmonics ratio of the pulse waveforms of ABP and CBFV (CrCPA) and two methods based on a model of cerebrovascular impedance, as a function of cerebral perfusion pressure (CrCPinv), and as a function of ABP (CrCPninv). RESULTS: There is good agreement among the three methods of CrCP calculation, with correlation coefficients being greater than 0.8 (p < 0.0001). For the CrCPA method, negative values were found for about 20% of all results. Negative values of CrCP were not observed in estimators based on cerebrovascular impedance. During the controlled rise of ICP, all three estimators of CrCP increased significantly (p < 0.05). The strongest correlation between ICP and CrCP was found for CrCPinv (median R = 0.41). CONCLUSION: Invasive CrCP is most sensitive to variations in ICP and can be used as an indicator of the status of the cerebrovascular system during infusion tests.
OBJECTIVES: The objectives were to compare three methods of estimating critical closing pressure (CrCP) in a scenario of a controlled increase in intracranial pressure (ICP) induced during an infusion test in patients with suspected normal pressure hydrocephalus (NPH). METHODS: We retrospectively analyzed data from 37 NPH patients who underwent infusion tests. Computer recordings of directly measured intracranial pressure (ICP), arterial blood pressure (ABP) and transcranial Doppler cerebral blood flow velocity (CBFV) were used. The CrCP was calculated using three methods: first harmonics ratio of the pulse waveforms of ABP and CBFV (CrCPA) and two methods based on a model of cerebrovascular impedance, as a function of cerebral perfusion pressure (CrCPinv), and as a function of ABP (CrCPninv). RESULTS: There is good agreement among the three methods of CrCP calculation, with correlation coefficients being greater than 0.8 (p < 0.0001). For the CrCPA method, negative values were found for about 20% of all results. Negative values of CrCP were not observed in estimators based on cerebrovascular impedance. During the controlled rise of ICP, all three estimators of CrCP increased significantly (p < 0.05). The strongest correlation between ICP and CrCP was found for CrCPinv (median R = 0.41). CONCLUSION: Invasive CrCP is most sensitive to variations in ICP and can be used as an indicator of the status of the cerebrovascular system during infusion tests.
Authors: Kseniia A Trofimova; Darya I Agarkova; Alex O Trofimov; Andrew Y Abashkin; Denis E Bragin Journal: Adv Exp Med Biol Date: 2021 Impact factor: 3.650