Cerebral autoregulation testing after aneurysmal subarachnoid hemorrhage: The phase relationship between arterial blood pressure and cerebral blood flow velocity

Lang, E; Diehl, Rolf R.; Mehdorn, H. Maximilian

doi:10.1097/00003246-200101000-00031

Cited by 169 publications

(111 citation statements)

References 33 publications

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“…[17,18] The concept of impaired autoregulation mechanisms on admission in patients who later develop DCI has also been described in other articles. [4,7,9,13,15,19] This study also showed that CTP is a practical and useful tool to compare perfusion on admission and during follow-up in patients with SAH since in 87% of patients a good quality admission and follow-up scan was obtained and no side effects of the CT scanning with contrast occurred. Often, transcranial Doppler (TCD) monitoring is used for follow-up monitoring in patients with SAH for the presence of vasospasm.…”

Section: Discussionmentioning

confidence: 57%

“…In the hyperacute stage after SAH, intracranial pressure raises and cerebral perfusion pressure drops with consequently a decrease in CBF. [14,15] In the compensation for decreases further and the ability of vessels to dilate is exhausted, the CBF starts to decrease. The brain can compensate for this by increasing the extraction of oxygen from the blood.…”

Section: Discussionmentioning

confidence: 99%

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Global and focal cerebral perfusion after aneurysmal subarachnoid hemorrhage in relation with delayed cerebral ischemia

et al. 2008

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Introduction The pathogenesis of delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH) is unclear. We assessed whether DCI relates to focal or global cerebral perfusion on admission and on follow-up imaging. Materials and methods Twenty-seven SAH patients underwent computed tomography (CT) perfusion (CTP) on admission and at clinical deterioration or 1 week after admission in clinically stable patients. We compared global and focal (least perfused territory) perfusion in patients with DCI (n=12), clinically stable patients (n=7), and patients with non-DCI-related deterioration (n=8). Results Global cerebral blood flow (CBF) increased on follow-up: 29% (95% confidence interval (CI) 15% to 43%) in patients with DCI, 12% (95%CI −1% to 25%) in stable patients, and 20% (95%CI 4% to 36%) in patients with non-DCI-related deterioration. Focal CBF decreased in patients with DCI, (−23%; 95%CI −58% to 12%) but increased in patients with non-DCI-related deterioration (23%; 95%CI −26% to 55%) and stable patients (7%; 95%CI −30% to 45%). On follow-up, global CBF was lower in patients with DCI (70.0 ml per 100 g/min) than in clinically stable patients (81.6; difference 11.6; 95%CI 0.8 to 22.5 ml per 100 g/min) but comparable to patients with non-DCI-related deterioration (67.6; difference −2.4; 95%CI −11.9 to 7.2 ml per 100 g/min). Focal CBF was lower in patients with DCI (30.7) than in clinically stable patients (53.6; difference 22.9; 95%CI 5.1 to 40.6 ml per 100 g/min) and patients with non-DCI-related deterioration (46.6; difference 15.9; 95%CI −2.6 to 28.4 ml per 100 g/min) Conclusion Our results suggest that DCI is more likely a focal than a global process.

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Section: Discussionmentioning

confidence: 57%

Section: Discussionmentioning

confidence: 99%

Global and focal cerebral perfusion after aneurysmal subarachnoid hemorrhage in relation with delayed cerebral ischemia

et al. 2008

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“…In the comparison of a CPP-or a ICP-oriented therapy, Robertson et al [39] showed a decrease in ischemic insult in CPP-oriented therapy, but an increase in respiratory complications with no convincing differences in outcome. There is agreement that body positioning may influence CPP and that it should be individualized for each patient based upon various data [13,25,41,47].…”

Section: Discussionmentioning

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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“…The mean flow index, Mx, which is derived from mean FV and CPP and its noninvasive version, Mxa, where ABP is used instead of CPP, have been previously investigated in patients with SAH. 3,35 In the present study, we have used an alternative index derived from systolic values of FV as previously described. 13,31,32 In one study of 32 patients with SAH changes in autoregulation during vasospasm were identified more accurately with Mx than with Sx.…”

Section: Methodological Considerationsmentioning

confidence: 99%

“…It has been described that cerebral autoregulation may become disturbed after subarachnoid hemorrhage (SAH), [1][2][3][4][5][6][7] which has been associated with development of delayed cerebral ischemia (DCI). 1,2,[5][6][7][8][9] The transient hyperemic response test (THRT) is a transcranial Doppler (TCD) based method, which characterizes the changes in cerebral blood flow velocity (FV) after a brief compression of the common carotid artery.…”

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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Cerebral autoregulation testing after aneurysmal subarachnoid hemorrhage: The phase relationship between arterial blood pressure and cerebral blood flow velocity

Cited by 169 publications

References 33 publications

Global and focal cerebral perfusion after aneurysmal subarachnoid hemorrhage in relation with delayed cerebral ischemia

Global and focal cerebral perfusion after aneurysmal subarachnoid hemorrhage in relation with delayed cerebral ischemia

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

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