C Puppo1, J Camacho2, G V Varsos3, B Yelicich4, H Gómez4, L Moraes4, A Biestro4, M Czosnyka3. 1. Emergency Department and Intensive Care Unit, Hospital de Clínicas, Universidad de la República School of Medicine, Montevideo, Uruguay. coripuppo@gmail.com. 2. Group of Ultrasound Systems and Technologies (USTG), Spanish National Research Council (CSIC), Madrid, Spain. 3. Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK. 4. Emergency Department and Intensive Care Unit, Hospital de Clínicas, Universidad de la República School of Medicine, Montevideo, Uruguay.
Abstract
BACKGROUND: Cerebral critical closing pressure (CrCP) is the level of arterial blood pressure (ABP) at which small brain vessels close and blood flow stops. This value is always greater than intracranial pressure (ICP). The difference between CrCP and ICP is explained by the tone of the small cerebral vessels (wall tension). CrCP value is used in several dynamic cerebral autoregulation models. However, the different methods for calculation of CrCP show frequent negative values. These findings are viewed as a methodological limitation. We intended to evaluate CrCP in patients with severe traumatic brain injury (TBI) with a new multiparameter impedance-based model and compare it with results found earlier using a transcranial Doppler (TCD)-ABP pulse waveform-based method. METHODS: Twelve severe TBI patients hospitalized during September 2005-May 2007. Ten men, mean age 32 years (16-61). Four had decompressive craniectomies (DC); three presented anisocoria. Patients were monitored with TCD cerebral blood flow velocity (FV), invasive ABP, and ICP. Data were acquired at 50 Hz with an in-house developed data acquisition system. We compared the earlier studied "first harmonic" method (M1) results with results from a new recently developed (M2) "multiparameter method." RESULTS: M1: In seven patients CrCP values were negative, reaching -150 mmHg. M2: All positive values; only one lower than ICP (ICP 60 mmHg/ CrCP 57 mmHg). There was a significant difference between M1 and M2 values (M1 < M2) and between ICP and M2 (M2 > ICP). CONCLUSION: M2 results in positive values of CrCP, higher than ICP, and are physiologically interpretable.
BACKGROUND: Cerebral critical closing pressure (CrCP) is the level of arterial blood pressure (ABP) at which small brain vessels close and blood flow stops. This value is always greater than intracranial pressure (ICP). The difference between CrCP and ICP is explained by the tone of the small cerebral vessels (wall tension). CrCP value is used in several dynamic cerebral autoregulation models. However, the different methods for calculation of CrCP show frequent negative values. These findings are viewed as a methodological limitation. We intended to evaluate CrCP in patients with severe traumatic brain injury (TBI) with a new multiparameter impedance-based model and compare it with results found earlier using a transcranial Doppler (TCD)-ABP pulse waveform-based method. METHODS: Twelve severe TBIpatients hospitalized during September 2005-May 2007. Ten men, mean age 32 years (16-61). Four had decompressive craniectomies (DC); three presented anisocoria. Patients were monitored with TCD cerebral blood flow velocity (FV), invasive ABP, and ICP. Data were acquired at 50 Hz with an in-house developed data acquisition system. We compared the earlier studied "first harmonic" method (M1) results with results from a new recently developed (M2) "multiparameter method." RESULTS: M1: In seven patients CrCP values were negative, reaching -150 mmHg. M2: All positive values; only one lower than ICP (ICP 60 mmHg/ CrCP 57 mmHg). There was a significant difference between M1 and M2 values (M1 < M2) and between ICP and M2 (M2 > ICP). CONCLUSION: M2 results in positive values of CrCP, higher than ICP, and are physiologically interpretable.
Authors: Christof Thees; Martin Scholz; Carlo Schaller M D; Annette Gass; Christos Pavlidis; Andreas Weyland; Andreas Hoeft Journal: Anesthesiology Date: 2002-03 Impact factor: 7.892
Authors: Georgios V Varsos; Marek Czosnyka; Peter Smielewski; Matthew R Garnett; Xiuyun Liu; Dong-Joo Kim; Joseph Donnelly; Hadie Adams; John D Pickard; Zofia Czosnyka Journal: Neurol Res Date: 2015-04-28 Impact factor: 2.448
Authors: Magdalena Kasprowicz; Jennifer Diedler; Matthias Reinhard; Emmanuel Carrera; Peter Smielewski; Karol P Budohoski; Enrico Sorrentino; Christina Haubrich; Peter J Kirkpatrick; John D Pickard; Marek Czosnyka Journal: Acta Neurochir Suppl Date: 2012
Authors: Magdalena Kasprowicz; Jennifer Diedler; Matthias Reinhard; Emmanuel Carrera; Luzius A Steiner; Peter Smielewski; Karol P Budohoski; Christina Haubrich; John D Pickard; Marek Czosnyka Journal: Ultrasound Med Biol Date: 2012-07 Impact factor: 2.998
Authors: Georgios V Varsos; Hugh Richards; Magdalena Kasprowicz; Karol P Budohoski; Ken M Brady; Matthias Reinhard; Alberto Avolio; Peter Smielewski; John D Pickard; Marek Czosnyka Journal: J Cereb Blood Flow Metab Date: 2012-11-14 Impact factor: 6.200