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Marek Czosnyka - One of the best experts on this subject based on the ideXlab platform.

  • Midline Shift in patients with closed traumatic brain injury may be driven by cerebral perfusion pressure not intracranial pressure
    Journal of Neurosurgical Sciences, 2019
    Co-Authors: Danilo Cardim, Peter Smielewski, Chiara Robba, Joseph Donnelly, Bernhard Schmidt, Eric A Schmidt, Michal Bohdanowicz, Marek Czosnyka
    Abstract:

    BACKGROUND In traumatic brain injury (TBI), swelling may disturb the potentially uniform pressure distribution in the brain, producing sustained intercompartmental pressure gradients which may associate with Midline Shift. The presence of pressure gradients is often neglected since bilateral invasive intracranial pressure (ICP) monitoring is not usually considered because of risks and high costs. We evaluated the presence of interhemispheric pressure gradients using bilateral transcranial Doppler (TCD) as means for non-invasive ICP (nICP) monitoring in TBI patients presenting Midline Shift. METHODS From a retrospective cohort of 97 TBI patients with arterial blood pressure (ABP), ICP and bilateral TCD monitoring, 24 presented unilateral lesion and Midline Shift confirmed by computer tomography. nICP and non-invasive cerebral perfusion pressure (nCPP) on the left and right brain hemispheres were retrospectively calculated using a mathematical model associating TCD-derived cerebral blood flow velocity and ABP. RESULTS The nCPP difference was correlated with Midline Shift (R=-0.34, p<.01) showing a tendency to record higher CPP at the side of expansion. Accordingly, nICP at the side of expansion was significantly lower in comparison to the compressed side (18.86 [±5.71] mmHg (mean ± standard deviation) versus 20.30 [±6.78] mmHg for expansion and compressed sides, respectively). Subsequently, nCPP was greater on the side of brain expansion (79.48±7.84, 78.03±8.93 mmHg [p<.01], for expansion and compressed sides, respectively). CONCLUSIONS TCD-based interhemispheric nCPP difference showed significant correlation with Midline Shift. Cerebral perfusion pressure was greater on the side of brain expansion, acting as the driving force to Shift brain structures.

  • nonlinear pressure flow relationship is able to detect asymmetry of brain blood circulation associated with Midline Shift
    Journal of Neurotrauma, 2009
    Co-Authors: Kun Hu, Chungkang Peng, Eric A Schmidt, Mentzung Lo, Vera Novak, Ajay Kumar, Marek Czosnyka
    Abstract:

    Abstract Reliable and noninvasive assessment of cerebral blood flow regulation is a major challenge in acute care monitoring. This study assessed dynamics of flow regulation and its relationship to asymmetry of initial computed tomography (CT) scan using multimodal pressure flow (MMPF) analysis. Data of 27 patients (38 ± 15 years old) with traumatic brain injury (TBI) were analyzed. Patients were selected from bigger cohort according to criteria of having Midline Shift on initial CT scan and intact skull (no craniotomy or bone flap). The MMPF analysis was used to extract the oscillations in cerebral perfusion pressure (CPP) and blood flow velocity (BFV) signals at frequency of artificial ventilation, and to calculate the instantaneous phase difference between CPP and BFV oscillations. Mean CPP-BFV phase difference was used to quantify pressure and flow relationship. The TBI subjects had smaller mean BP-BFV phase Shifts (left, 8.7 ± 9.6; right 10.2 ± 8.3 MCAs, mean ± SD) than values previously obtained in ...

  • nonlinear pressure flow relationship is able to detect asymmetry of brain blood circulation associated with Midline Shift
    Journal of Neurotrauma, 2009
    Co-Authors: Vera Novak, Eric A Schmidt, Ajay Kumar, Marek Czosnyka
    Abstract:

    Reliable and noninvasive assessment of cerebral blood flow regulation is a major challenge in acute care monitoring. This study assessed dynamics of flow regulation and its relationship to asymmetry of initial computed tomography (CT) scan using multimodal pressure flow (MMPF) analysis. Data of 27 patients (38 +/- 15 years old) with traumatic brain injury (TBI) were analyzed. Patients were selected from bigger cohort according to criteria of having Midline Shift on initial CT scan and intact skull (no craniotomy or bone flap). The MMPF analysis was used to extract the oscillations in cerebral perfusion pressure (CPP) and blood flow velocity (BFV) signals at frequency of artificial ventilation, and to calculate the instantaneous phase difference between CPP and BFV oscillations. Mean CPP-BFV phase difference was used to quantify pressure and flow relationship. The TBI subjects had smaller mean BP-BFV phase Shifts (left, 8.7 +/- 9.6; right 10.2 +/- 8.3 MCAs, mean +/- SD) than values previously obtained in healthy subjects (left, 37.3 +/- 7.6 degrees; right, 38.0 +/- 8.9 degrees; p < 0.0001), suggesting impaired blood flow regulation after TBI. The difference in phase Shift between CPP and BFV in the left and right side was strongly correlated to the Midline Shift (R = 0.78; p < 0.0001). These findings indicate that the MMPF method allows reliable assessment of alterations in pressure and flow relationship after TBI. Moreover, mean pressure-flow phase Shift is sensitive to the displacement of Midline of the brain, and may potentially serve as a marker of asymmetry of cerebral autoregulation.

Robert F Spetzler - One of the best experts on this subject based on the ideXlab platform.

  • safety and accuracy of bedside external ventricular drain placement
    Neurosurgery, 2008
    Co-Authors: Udaya K Kakarla, Louis J Kim, Steven W Chang, Nicholas Theodore, Robert F Spetzler
    Abstract:

    OBJECTIVE To study the safety and accuracy of ventriculostomy by neurosurgical trainees. METHODS Initial computed tomographic studies of 346 consecutive patients who underwent bedside ventriculostomy were reviewed retrospectively. Diagnosis, catheter tip location, Midline Shift, and procedural complications were tabulated. To analyze catheter placement, we used a new grading system: Grade 1, optimal placement in the ipsilateral frontal horn or third ventricle; Grade 2, functional placement in the contralateral lateral ventricle or noneloquent cortex; and Grade 3, suboptimal placement in the eloquent cortex or nontarget cerebrospinal fluid space, with or without functional drainage. Statistical analysis was performed using Fisher's exact test and a weighted kappa coefficient. RESULTS Diagnoses included the following: subarachnoid hemorrhage, n = 153 (44%); trauma, n = 64 (18%); intracerebral hemorrhage/intraventricular hemorrhage, n = 63 (18%); and other, n = 66 (20%). There were 266 (77%) Grade 1, 34 (10%) Grade 2, and 46 (13%) Grade 3 catheter placements. Hemorrhagic complications occurred in 17 (5%). Four patients (1.2%) were symptomatic, with two (0.6%) requiring surgery. Inter- and intraobserver agreement was almost perfect (kappa = 0.846 and 0.922, respectively) as applied to our grading system. Rates of suboptimal placement were highest in patients with Midline Shift (P = 0.059) and trauma (P = 0.0001). Rates of optimal placement were highest in patients with subarachnoid hemorrhage (P = 0.003) and when the catheter was placed ipsilateral to the side of Midline Shift (P = 0.063). Neither the resident's training experience nor the side of placement seemed to affect accuracy. CONCLUSION Bedside ventriculostomy is a safe and accurate procedure for intracranial pressure monitoring and cerebrospinal fluid drainage.

  • safety and accuracy of bedside external ventricular drain placement commentaries
    Neurosurgery, 2008
    Co-Authors: Udaya K Kakarla, Louis J Kim, Steven W Chang, Nicholas Theodore, Robert F Spetzler, Alex B Valadka, James M Drake, Gordon J Mccomb, Allan H Friedman, Christopher S Ogilvy
    Abstract:

    OBJECTIVE: To study the safety and accuracy of ventriculostomy by neurosurgical trainees. METHODS: Initial computed tomographic studies of 346 consecutive patients who underwent bedside ventriculostomy were reviewed retrospectively. Diagnosis, catheter tip location, Midline Shift, and procedural complications were tabulated. To analyze catheter placement, we used a new grading system: Grade 1, optimal placement in the ipsilateral frontal horn or third ventricle; Grade 2, functional placement in the contralateral lateral ventricle or noneloquent cortex; and Grade 3, suboptimal placement in the eloquent cortex or nontarget cerebrospinal fluid space, with or without functional drainage. Statistical analysis was performed using Fisher's exact test and a weighted K coefficient. RESULTS: Diagnoses included the following: subarachnoid hemorrhage, n = 153 (44%); trauma, n = 64 (18%); intracerebral hemorrhage/intraventricular hemorrhage, n = 63 (18%); and other, n = 66 (20%). There were 266 (77%) Grade 1, 34 (10%) Grade 2, and 46 (13%) Grade 3 catheter placements. Hemorrhagic complications occurred in 17 (5%). Four patients (1.2%) were symptomatic, with two (0.6%) requiring surgery. Inter-and intraobserver agreement was almost perfect (K = 0.846 and 0.922, respectively) as applied to our grading system. Rates of suboptimal placement were highest in patients with Midline Shift (P = 0.059) and trauma (P = 0.0001). Rates of optimal placement were highest in patients with subarachnoid hemorrhage (P = 0.003) and when the catheter was placed ipsilateral to the side of Midline Shift (P = 0.063). Neither the resident's training experience nor the side of placement seemed to affect accuracy. CONCLUSION: Bedside ventriculostomy is a safe and accurate procedure for intracranial pressure monitoring and cerebrospinal fluid drainage.

Udaya K Kakarla - One of the best experts on this subject based on the ideXlab platform.

  • safety and accuracy of bedside external ventricular drain placement
    Neurosurgery, 2008
    Co-Authors: Udaya K Kakarla, Louis J Kim, Steven W Chang, Nicholas Theodore, Robert F Spetzler
    Abstract:

    OBJECTIVE To study the safety and accuracy of ventriculostomy by neurosurgical trainees. METHODS Initial computed tomographic studies of 346 consecutive patients who underwent bedside ventriculostomy were reviewed retrospectively. Diagnosis, catheter tip location, Midline Shift, and procedural complications were tabulated. To analyze catheter placement, we used a new grading system: Grade 1, optimal placement in the ipsilateral frontal horn or third ventricle; Grade 2, functional placement in the contralateral lateral ventricle or noneloquent cortex; and Grade 3, suboptimal placement in the eloquent cortex or nontarget cerebrospinal fluid space, with or without functional drainage. Statistical analysis was performed using Fisher's exact test and a weighted kappa coefficient. RESULTS Diagnoses included the following: subarachnoid hemorrhage, n = 153 (44%); trauma, n = 64 (18%); intracerebral hemorrhage/intraventricular hemorrhage, n = 63 (18%); and other, n = 66 (20%). There were 266 (77%) Grade 1, 34 (10%) Grade 2, and 46 (13%) Grade 3 catheter placements. Hemorrhagic complications occurred in 17 (5%). Four patients (1.2%) were symptomatic, with two (0.6%) requiring surgery. Inter- and intraobserver agreement was almost perfect (kappa = 0.846 and 0.922, respectively) as applied to our grading system. Rates of suboptimal placement were highest in patients with Midline Shift (P = 0.059) and trauma (P = 0.0001). Rates of optimal placement were highest in patients with subarachnoid hemorrhage (P = 0.003) and when the catheter was placed ipsilateral to the side of Midline Shift (P = 0.063). Neither the resident's training experience nor the side of placement seemed to affect accuracy. CONCLUSION Bedside ventriculostomy is a safe and accurate procedure for intracranial pressure monitoring and cerebrospinal fluid drainage.

  • safety and accuracy of bedside external ventricular drain placement commentaries
    Neurosurgery, 2008
    Co-Authors: Udaya K Kakarla, Louis J Kim, Steven W Chang, Nicholas Theodore, Robert F Spetzler, Alex B Valadka, James M Drake, Gordon J Mccomb, Allan H Friedman, Christopher S Ogilvy
    Abstract:

    OBJECTIVE: To study the safety and accuracy of ventriculostomy by neurosurgical trainees. METHODS: Initial computed tomographic studies of 346 consecutive patients who underwent bedside ventriculostomy were reviewed retrospectively. Diagnosis, catheter tip location, Midline Shift, and procedural complications were tabulated. To analyze catheter placement, we used a new grading system: Grade 1, optimal placement in the ipsilateral frontal horn or third ventricle; Grade 2, functional placement in the contralateral lateral ventricle or noneloquent cortex; and Grade 3, suboptimal placement in the eloquent cortex or nontarget cerebrospinal fluid space, with or without functional drainage. Statistical analysis was performed using Fisher's exact test and a weighted K coefficient. RESULTS: Diagnoses included the following: subarachnoid hemorrhage, n = 153 (44%); trauma, n = 64 (18%); intracerebral hemorrhage/intraventricular hemorrhage, n = 63 (18%); and other, n = 66 (20%). There were 266 (77%) Grade 1, 34 (10%) Grade 2, and 46 (13%) Grade 3 catheter placements. Hemorrhagic complications occurred in 17 (5%). Four patients (1.2%) were symptomatic, with two (0.6%) requiring surgery. Inter-and intraobserver agreement was almost perfect (K = 0.846 and 0.922, respectively) as applied to our grading system. Rates of suboptimal placement were highest in patients with Midline Shift (P = 0.059) and trauma (P = 0.0001). Rates of optimal placement were highest in patients with subarachnoid hemorrhage (P = 0.003) and when the catheter was placed ipsilateral to the side of Midline Shift (P = 0.063). Neither the resident's training experience nor the side of placement seemed to affect accuracy. CONCLUSION: Bedside ventriculostomy is a safe and accurate procedure for intracranial pressure monitoring and cerebrospinal fluid drainage.

Eric A Schmidt - One of the best experts on this subject based on the ideXlab platform.

  • Midline Shift in patients with closed traumatic brain injury may be driven by cerebral perfusion pressure not intracranial pressure
    Journal of Neurosurgical Sciences, 2019
    Co-Authors: Danilo Cardim, Peter Smielewski, Chiara Robba, Joseph Donnelly, Bernhard Schmidt, Eric A Schmidt, Michal Bohdanowicz, Marek Czosnyka
    Abstract:

    BACKGROUND In traumatic brain injury (TBI), swelling may disturb the potentially uniform pressure distribution in the brain, producing sustained intercompartmental pressure gradients which may associate with Midline Shift. The presence of pressure gradients is often neglected since bilateral invasive intracranial pressure (ICP) monitoring is not usually considered because of risks and high costs. We evaluated the presence of interhemispheric pressure gradients using bilateral transcranial Doppler (TCD) as means for non-invasive ICP (nICP) monitoring in TBI patients presenting Midline Shift. METHODS From a retrospective cohort of 97 TBI patients with arterial blood pressure (ABP), ICP and bilateral TCD monitoring, 24 presented unilateral lesion and Midline Shift confirmed by computer tomography. nICP and non-invasive cerebral perfusion pressure (nCPP) on the left and right brain hemispheres were retrospectively calculated using a mathematical model associating TCD-derived cerebral blood flow velocity and ABP. RESULTS The nCPP difference was correlated with Midline Shift (R=-0.34, p<.01) showing a tendency to record higher CPP at the side of expansion. Accordingly, nICP at the side of expansion was significantly lower in comparison to the compressed side (18.86 [±5.71] mmHg (mean ± standard deviation) versus 20.30 [±6.78] mmHg for expansion and compressed sides, respectively). Subsequently, nCPP was greater on the side of brain expansion (79.48±7.84, 78.03±8.93 mmHg [p<.01], for expansion and compressed sides, respectively). CONCLUSIONS TCD-based interhemispheric nCPP difference showed significant correlation with Midline Shift. Cerebral perfusion pressure was greater on the side of brain expansion, acting as the driving force to Shift brain structures.

  • nonlinear pressure flow relationship is able to detect asymmetry of brain blood circulation associated with Midline Shift
    Journal of Neurotrauma, 2009
    Co-Authors: Kun Hu, Chungkang Peng, Eric A Schmidt, Mentzung Lo, Vera Novak, Ajay Kumar, Marek Czosnyka
    Abstract:

    Abstract Reliable and noninvasive assessment of cerebral blood flow regulation is a major challenge in acute care monitoring. This study assessed dynamics of flow regulation and its relationship to asymmetry of initial computed tomography (CT) scan using multimodal pressure flow (MMPF) analysis. Data of 27 patients (38 ± 15 years old) with traumatic brain injury (TBI) were analyzed. Patients were selected from bigger cohort according to criteria of having Midline Shift on initial CT scan and intact skull (no craniotomy or bone flap). The MMPF analysis was used to extract the oscillations in cerebral perfusion pressure (CPP) and blood flow velocity (BFV) signals at frequency of artificial ventilation, and to calculate the instantaneous phase difference between CPP and BFV oscillations. Mean CPP-BFV phase difference was used to quantify pressure and flow relationship. The TBI subjects had smaller mean BP-BFV phase Shifts (left, 8.7 ± 9.6; right 10.2 ± 8.3 MCAs, mean ± SD) than values previously obtained in ...

  • nonlinear pressure flow relationship is able to detect asymmetry of brain blood circulation associated with Midline Shift
    Journal of Neurotrauma, 2009
    Co-Authors: Vera Novak, Eric A Schmidt, Ajay Kumar, Marek Czosnyka
    Abstract:

    Reliable and noninvasive assessment of cerebral blood flow regulation is a major challenge in acute care monitoring. This study assessed dynamics of flow regulation and its relationship to asymmetry of initial computed tomography (CT) scan using multimodal pressure flow (MMPF) analysis. Data of 27 patients (38 +/- 15 years old) with traumatic brain injury (TBI) were analyzed. Patients were selected from bigger cohort according to criteria of having Midline Shift on initial CT scan and intact skull (no craniotomy or bone flap). The MMPF analysis was used to extract the oscillations in cerebral perfusion pressure (CPP) and blood flow velocity (BFV) signals at frequency of artificial ventilation, and to calculate the instantaneous phase difference between CPP and BFV oscillations. Mean CPP-BFV phase difference was used to quantify pressure and flow relationship. The TBI subjects had smaller mean BP-BFV phase Shifts (left, 8.7 +/- 9.6; right 10.2 +/- 8.3 MCAs, mean +/- SD) than values previously obtained in healthy subjects (left, 37.3 +/- 7.6 degrees; right, 38.0 +/- 8.9 degrees; p < 0.0001), suggesting impaired blood flow regulation after TBI. The difference in phase Shift between CPP and BFV in the left and right side was strongly correlated to the Midline Shift (R = 0.78; p < 0.0001). These findings indicate that the MMPF method allows reliable assessment of alterations in pressure and flow relationship after TBI. Moreover, mean pressure-flow phase Shift is sensitive to the displacement of Midline of the brain, and may potentially serve as a marker of asymmetry of cerebral autoregulation.

Vera Novak - One of the best experts on this subject based on the ideXlab platform.

  • nonlinear pressure flow relationship is able to detect asymmetry of brain blood circulation associated with Midline Shift
    Journal of Neurotrauma, 2009
    Co-Authors: Kun Hu, Chungkang Peng, Eric A Schmidt, Mentzung Lo, Vera Novak, Ajay Kumar, Marek Czosnyka
    Abstract:

    Abstract Reliable and noninvasive assessment of cerebral blood flow regulation is a major challenge in acute care monitoring. This study assessed dynamics of flow regulation and its relationship to asymmetry of initial computed tomography (CT) scan using multimodal pressure flow (MMPF) analysis. Data of 27 patients (38 ± 15 years old) with traumatic brain injury (TBI) were analyzed. Patients were selected from bigger cohort according to criteria of having Midline Shift on initial CT scan and intact skull (no craniotomy or bone flap). The MMPF analysis was used to extract the oscillations in cerebral perfusion pressure (CPP) and blood flow velocity (BFV) signals at frequency of artificial ventilation, and to calculate the instantaneous phase difference between CPP and BFV oscillations. Mean CPP-BFV phase difference was used to quantify pressure and flow relationship. The TBI subjects had smaller mean BP-BFV phase Shifts (left, 8.7 ± 9.6; right 10.2 ± 8.3 MCAs, mean ± SD) than values previously obtained in ...

  • nonlinear pressure flow relationship is able to detect asymmetry of brain blood circulation associated with Midline Shift
    Journal of Neurotrauma, 2009
    Co-Authors: Vera Novak, Eric A Schmidt, Ajay Kumar, Marek Czosnyka
    Abstract:

    Reliable and noninvasive assessment of cerebral blood flow regulation is a major challenge in acute care monitoring. This study assessed dynamics of flow regulation and its relationship to asymmetry of initial computed tomography (CT) scan using multimodal pressure flow (MMPF) analysis. Data of 27 patients (38 +/- 15 years old) with traumatic brain injury (TBI) were analyzed. Patients were selected from bigger cohort according to criteria of having Midline Shift on initial CT scan and intact skull (no craniotomy or bone flap). The MMPF analysis was used to extract the oscillations in cerebral perfusion pressure (CPP) and blood flow velocity (BFV) signals at frequency of artificial ventilation, and to calculate the instantaneous phase difference between CPP and BFV oscillations. Mean CPP-BFV phase difference was used to quantify pressure and flow relationship. The TBI subjects had smaller mean BP-BFV phase Shifts (left, 8.7 +/- 9.6; right 10.2 +/- 8.3 MCAs, mean +/- SD) than values previously obtained in healthy subjects (left, 37.3 +/- 7.6 degrees; right, 38.0 +/- 8.9 degrees; p < 0.0001), suggesting impaired blood flow regulation after TBI. The difference in phase Shift between CPP and BFV in the left and right side was strongly correlated to the Midline Shift (R = 0.78; p < 0.0001). These findings indicate that the MMPF method allows reliable assessment of alterations in pressure and flow relationship after TBI. Moreover, mean pressure-flow phase Shift is sensitive to the displacement of Midline of the brain, and may potentially serve as a marker of asymmetry of cerebral autoregulation.