The hyperaemic response to a transient reduction in cerebral perfusion pressure

Czosnyka, Marek; Pickard, John D.; Whitehouse, Helen; Piechnik, Stefan K.

doi:10.1007/bf01406364

Cited by 63 publications

(38 citation statements)

References 14 publications

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“…Later, Smiliewski et al [45] refined it by using the transient hyperemic response ratio (THRR) [8]. For this index, the maximum increase of FV (determined by TCD) is divided by baseline values after release of the carotid compression.…”

Section: Head Elevation and Cerebral Hemodynamicsmentioning

confidence: 99%

Intracranial pressure pulse amplitude during changes in head elevation: a new parameter for determining optimum cerebral perfusion pressure?

2009

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Objective During short-term postural changes, the factors determining the amplitude of intracranial pulse pressure (ICPPA) remain constant, except for cerebrovascular resistance (CVR). Therefore, it may be possible to draw conclusions from the ICPPA onto the cerebrovascular resistance (CVR) and thus the relative change in cerebral perfusion pressure (CPP). Methods Age, sex, disease, Glasgow Coma Scale score, placement of ventricular drain, blood gas analysis, and parameters of airway management were prospectively recorded in 40 patients. The changes in intracranial pressure (ICP), CPP, mean arterial pressure (MAP), and ICPPA at head elevations of 0°, 30°, and 60°were measured and analyzed online. Status of cerebrovascular autoregulation was checked using the pressure-reactivity index (PRx). Results Altogether 36 subjects fulfilled the study conditions. Three patients had positive PRx indicating disturbed autoregulation and were excluded. Thus, 33 were left for analysis (18 females and 15 males). All of them were sedated and mechanically ventilated with Glasgow Coma scores ranging from 3-8. During change in head elevation from 0°to 60°, we found a significant (p<0.05) improvement of the ICP, an increase of the ICCPA, a reduction of the MAP, and a decrease in the CPP. Increasing ICPPA was linked to decreasing CPP (0°to 60°, r=−0.42, p<0.05).Conclusions Head elevation is an important part of the ICP and CPP therapy in neurointensive care. When searching for the patient-specific optimum upper body position, ICPPA may provide additional information. Providing that the cerebral autoregulation is intact, the lowest ICPPA of a patient corresponds to the individual upper body position with the highest CPP.

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Section: Head Elevation and Cerebral Hemodynamicsmentioning

confidence: 99%

Intracranial pressure pulse amplitude during changes in head elevation: a new parameter for determining optimum cerebral perfusion pressure?

2009

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“…It is a recognized and simple method of testing autoregulation in vivo. 2,6,8,[10][11][12][13][14][15][16][17][18] It is directly proportional to the static rate of autoregulation, which is the 'gold standard' for measuring autoregulation, 15 and it has been shown to be predictive of DCI after SAH. 2,6 However, other ways of measuring autoregulation that do not require physical or pharmacological blood pressure stimulation have been described.…”

Section: Introductionmentioning

confidence: 99%

Cerebral Autoregulation after Subarachnoid Hemorrhage: Comparison of Three Methods

Budohoski

Czosnyka

Smielewski

et al. 2012

J Cereb Blood Flow Metab

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In patients after subarachnoid hemorrhage (SAH) failure of cerebral autoregulation is associated with delayed cerebral ischemia (DCI). Various methods of assessing autoregulation are available, but their predictive values remain unknown. We characterize the relationship between different indices of autoregulation. Patients with SAH within 5 days were included in a prospective study. The relationship between three indices of autoregulation was analyzed: two indices calculated using spontaneous blood pressure fluctuations, Sxa (based on transcranial Doppler) and TOxa (based on near-infrared spectroscopy); and transient hyperemic response test (THRT) where a brief compression of the common carotid artery is used. The predictive value of indices was assessed using data from the first 5 days. Overall there was only moderate correlation between indices. However, both Sxa and TOxa showed good accuracy in predicting impaired autoregulation evidenced by a negative THRT (area under the curve (AUC): 0.788, 95% CI: 0.723 to 0.854 and AUC: 0.827, 95% CI: 0.769 to 0.885, respectively). All indices proved accurate in predicting DCI when 0-to 5-day data were used (AUC: 0.801, 95% CI: 0.660 to 0.942; AUC: 0.857, 95% CI: 0.731 to 0.984, AUC: 0.796, 95% CI: 0.658 to 0.934 for THRT, Sxa, and TOxa, respectively). Combining all three indices had 100% specificity for predicting DCI. While multiple colinearities exist between the assessed methods, multimodal monitoring of cerebral autoregulation can aid in predicting DCI.

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“…Without reducing the simulation effectiveness, Ursino and Lodi [6] offered a simplified simulation model for more practical uses. On specific areas researchers have developedbinsights on different biological parts including human intracranial biomechanical parameters, cerebrovascular autoregulation mechanism, pressure volume index [7][8][9][10][11][12][13][14] etc.…”

Section: Introductionmentioning

confidence: 99%

Post-craniectomy Intracranial Pressure Dynamics:A Novel Compartmental Model of Generalized Monro-Kellie Principle

Wang¹,

Ding²,

Zhang³

et al. 2011

IJEM

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A model of post-craniectomy intracranial pressure dynamics is proposed in this article. Defining the craniectomy distensible volume the original Monro-Kellie principle is generalized. A craniectomy compartment is added to traditional intracranial system including blood, cerebrospinal fluid, and brain parenchyma. The system equation of generalized Monro-Kellie principle is solved with 4th order runge-kutta method. Volume of the new compartment is calculated with deflection solution. The model verifies that abnormal morphology of intracranial pressure (systolic value-21mmHg and diastolic value-13mmHg) in hypertension can be reduced to a normal range (systolic value-14.5mmHg and diastolic value-13mmHg) with decompressive craniectomy. Additionally the ICP-DC Size curve provides an effective interval (about 80-200 square centimeters) of craniectomy size for practice of decompressive craniectomy.

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The hyperaemic response to a transient reduction in cerebral perfusion pressure

Cited by 63 publications

References 14 publications

Intracranial pressure pulse amplitude during changes in head elevation: a new parameter for determining optimum cerebral perfusion pressure?

Intracranial pressure pulse amplitude during changes in head elevation: a new parameter for determining optimum cerebral perfusion pressure?

Cerebral Autoregulation after Subarachnoid Hemorrhage: Comparison of Three Methods

Post-craniectomy Intracranial Pressure Dynamics:A Novel Compartmental Model of Generalized Monro-Kellie Principle

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