Continuous Assessment of Cerebral Autoregulation in Subarachnoid Hemorrhage

Soehle, Martin; Czosnyka, Marek; Pickard, John D.; Kirkpatrick, Peter J.

doi:10.1213/01.ane.0000111101.41190.99

Cited by 127 publications

(109 citation statements)

References 41 publications

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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%

“…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. 35 However, a cohort study of 300 patients with head injury showed that Sxa had a stronger association with outcome than Mxa. 31 Relationship of Continuous Indices, Sxa and TOxa, with Transient Hyperemic Response Ratio Both Sxa and TOxa showed good accuracy for predicting impaired autoregulation as seen by a THRR of p1.09, without significant differences between the two methods.…”

Section: Methodological Considerationsmentioning

confidence: 99%

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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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Section: Methodological Considerationsmentioning

confidence: 99%

Section: Methodological Considerationsmentioning

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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“…Disturbed autoregulation has been shown to be associated with unfavorable outcome after head injury [9], vasospasm after subarachnoid hemorrhage [10], and the possibility to use autoregulation to define an individual target for cerebral perfusion pressure is suggested (recommendation, level III) in the latest edition of the Brain Trauma Foundation Guidelines for the management of severe traumatic brain injury [11].…”

Section: Abpmentioning

confidence: 99%

Near-Infrared Spectroscopy can Monitor Dynamic Cerebral Autoregulation in Adults

et al. 2008

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Objective To study the correlation between a dynamic index of cerebral autoregulation assessed with blood flow velocity (FV) using transcranial Doppler, and a tissue oxygenation index (TOI) recorded with near-infrared spectroscopy (NIRS). Methods Twenty-three patients with sepsis, severe sepsis, or septic shock were monitored daily on up to four consecutive days. FV, TOI, and mean arterial blood pressure (ABP) were recorded for 60 min every day. An index of autoregulation (Mx) was calculated as the moving correlation coefficient between 10-s averaged values of FV and ABP over moving 5 min time-windows. The index Tox was evaluated as the correlation coefficient between TOI and ABP in the same way. The indices Mx and Tox, ABP and arterial partial pressure of CO 2 were averaged for each patient. Results Synchronized slow waves, presenting with periods from 20 s to 2 min, were seen in the TOI and FV of most patients, with a reasonable coherence between the signals in this bandwidth (coherence >0.5). The indices, Mx and Tox, demonstrated good correlation with each other (R = 0.81; P < 0.0001) in the whole group of patients. Both indices showed a significant (P < 0.05) tendency to indicate weaker autoregulation in the state of vasodilatation associated with greater values of arterial partial pressure of CO 2 or lower values of ABP. Conclusion NIRS shows promise for the continuous assessment of cerebral autoregulation in adults.

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“…Thus, inappropriate volume loading or periods of spontaneous or induced hypertension may aggravate brain edema. However, awareness of autoregulation as an important protective mechanism for patients with SAH and traumatic brain injury increases [10,11,25,46,47].…”

Section: Head Elevation and Cerebral Hemodynamicsmentioning

confidence: 99%

“…The indices of autoregulation are calculated as moving correlation coefficients between spontaneous slow changes in MAP and slow changes in systolic (systolic index; Sx) or mean (mean index; Mx) flow velocities (FV), which can be used as indicators of autoregulation [11,37,46]. The higher the FV, the more impaired the cerebral autoregulation [46]. The pressure reactivity index (PRx), described by Czosnyka et al [10], measures the correlation between ABP and ICP waves and may reflect cerebral autoregulation in response to blood pressure changes.…”

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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Continuous Assessment of Cerebral Autoregulation in Subarachnoid Hemorrhage

Cited by 127 publications

References 41 publications

Cerebral Autoregulation after Subarachnoid Hemorrhage: Comparison of Three Methods

Cerebral Autoregulation after Subarachnoid Hemorrhage: Comparison of Three Methods

Near-Infrared Spectroscopy can Monitor Dynamic Cerebral Autoregulation in Adults

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

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