Change in estimated cerebral perfusion pressure after treatment with nimodipine or magnesium sulfate in patients with preeclampsia

Belfort, Michael A.; Saade, George R.; Yared, Marwan; Grünewald, Charlotta; Herd, J. Alan; Varner, Michael W.; Nisell, Henry

doi:10.1016/s0002-9378(99)70569-7

Cited by 76 publications

(47 citation statements)

References 20 publications

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“…Since the introduction of transcranial Doppler, the concept of non-invasive estimation of CPP and ZFP has evolved, and several formulae are in use [11,16,17]. Aaslid et al first described a method of estimating CPP [18].…”

Section: Discussionmentioning

confidence: 99%

“…Cerebral perfusion pressure was then calculated as (V 0 ⁄ V 1 ) · ABP, where ABP = arterial blood pressure and ABP ⁄ V 1 represents vascular resistance. Belfort et al [11] modified this, taking (BP mean -BP diastolic ) ⁄ (FV mean -FV diastolic ) to represent resistance and creating the following formula for CPP:…”

Section: Discussionmentioning

confidence: 99%

“…All these methods remain essentially unvalidated. In this study, we used the method described by Belfort et al [11] because of its simplicity and applicability to patients without the need for invasive blood pressure monitoring. As in the bench model study, a number of ZFP values were negative, especially during inhalation of nitrous oxide.…”

Section: Discussionmentioning

confidence: 99%

“…Analogue outputs of maximum FV determined using the outer envelope of the velocity-power spectra were taken for analysis. Time averaged mean and diastolic flow velocity (FV mean and FV diastolic ), and simultaneously recorded mean and diastolic blood pressure (BP mean and BP diastolic ) were used to calculate CPP and ZFP using the following formulae [11]:…”

Section: Methodsmentioning

confidence: 99%

“…It is not clear which of these effects predominates, nor is the net change in ZFP that occurs during the inhalation of nitrous oxide known. We used the method described by Belfort et al [11] to assess the effect of the inhalation of nitrous oxide 50% on estimated CPP and ZFP in healthy volunteers.…”

mentioning

confidence: 99%

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Effects of inhaled nitrous oxide 50% on estimated cerebral perfusion pressure and zero flow pressure in healthy volunteers*

2005

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SummaryThe role of vascular tone in determining cerebral perfusion pressure is increasingly being appreciated. It has been suggested that zero flow pressure, the arterial pressure at which blood flow ceases, represents the effective downstream pressure of the cerebral circulation. Nitrous oxide is a cerebral vasodilator and may therefore decrease zero flow pressure and increase cerebral perfusion pressure. However, these effects may be opposed by the increase in intracranial blood volume produced by cerebral vasodilation. We studied eight healthy volunteers at normocapnia and studied the effects of the inhalation of nitrous oxide 50% on estimated cerebral perfusion pressure and zero flow pressure using transcranial Doppler ultrasonography. We found that nitrous oxide 50% significantly increased estimated cerebral perfusion pressure (p = 0.03), whilst decreasing zero flow pressure (p = 0.01). These results suggest that the vasomotor effects of nitrous oxide predominate in determining the effective downstream pressure of the cerebral circulation in healthy individuals.

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