A Paradox of Cerebral Hyperperfusion in the Face of Cerebral Hypotension: The Effect of Perfusion Pressure on Cerebral Blood Flow and Metabolism during Normothermic Cardiopulmonary Bypass

Philpott, Jonathan M.; Eskew, Thomas D.; Sun, You Su; Dennis, K J; Foreman, Brett H.; Fairbrother, Scott; Brown, Philip M.; Koutlas, Theodore C.; Chitwood, W. Randolph; Lust, Robert M.

doi:10.1006/jsre.1998.5370

Cited by 5 publications

(5 citation statements)

References 27 publications

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“…Intracranial pressure was found to increase during the course of CPB in paper IV and V. Similar results were reported by others in experimental studies of CPB in dogs (Philpott et al, 1998) and swine (McDaniel et al, 1994). Intriguingly, the increase in intracranial pressure was abolished in two studies when a hyperosmolar-colloidal infusion was given during normothermic and hypothermic CPB in pigs (Farstad et al, 2006, Kvalheim et al, in press) The blood brain barrier plays an important role in the maintenance of intracerebral water content.…”

Section: J 2 Intracerebral Pressuresupporting

confidence: 89%

Low perfusion pressure during CPB may induce cerebral metabolic and ultrastructural changes

Farstad

Myklebust

Kvalheim

et al. 2007

Scandinavian Cardiovascular Journal

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Section: J 2 Intracerebral Pressuresupporting

confidence: 89%

Low perfusion pressure during CPB may induce cerebral metabolic and ultrastructural changes

Farstad

Myklebust

Kvalheim

et al. 2007

Scandinavian Cardiovascular Journal

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“…9 Others have also commented on the dangers of losing flow-metabolism coupling, because the ability to increase oxygen extraction is not unlimited. 23 Contrary to an early assumption-by us and by others-that rapid and vigorous recovery of the CMRO 2 is evidence of successful cerebral protection, we have found in recent studies that a slower, more gradual recovery from hypothermic cerebral protection often correlates with a better behavioral outcome.…”

Section: Impact Of Scp Pressure On Cerebral Physiologycontrasting

confidence: 85%

Optimizing selective cerebral perfusion: Deleterious effects of high perfusion pressures

Halstead

Meier

Wurm

et al. 2008

The Journal of Thoracic and Cardiovascular Surgery

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“…the mean arterial pressure (MAP), may contribute to the occurrence of PPCI. The concept of cerebral autoregulation, has been shown to apply not only under regular physiologic conditions between MAP levels of 50–150 mmHg [ 9 , 10 ] but also during heart surgery with non-pulsatile CPB and moderate haemodilution, where the autoregulation of the cerebral blood flow (CBF) in securing a flow-metabolism coupling [ 11 – 14 ] is limited to a functional range of cerebral perfusion pressure (CPP) between 40 and 120 mmHg [ 15 ]. Based on the results from humane clinical studies, Govier et al [ 16 ] and Murkin et al [ 14 , 17 ] reported that CBF was independent of MAP down to 30 mmHg or CPP (approximately the MAP minus the jugular venous pressure) of 20 mmHg during hypothermic CPB.…”

Section: Introductionmentioning

confidence: 99%

Perfusion Pressure Cerebral Infarct (PPCI) trial - the importance of mean arterial pressure during cardiopulmonary bypass to prevent cerebral complications after cardiac surgery: study protocol for a randomised controlled trial

Vedel

Holmgaard

Rasmussen

et al. 2016

Trials

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BackgroundDebilitating brain injury occurs in 1.6–5 % of patients undergoing cardiac surgery with cardiopulmonary bypass. Diffusion-weighted magnetic resonance imaging studies have reported stroke-like lesions in up to 51 % of patients after cardiac surgery. The majority of the lesions seem to be caused by emboli, but inadequate blood flow caused by other mechanisms may increase ischaemia in the penumbra or cause watershed infarcts. During cardiopulmonary bypass, blood pressure can be below the lower limit of cerebral autoregulation. Although much debated, the constant blood flow provided by the cardiopulmonary bypass system is still considered by many as appropriate to avoid cerebral ischaemia despite the low blood pressure.Methods/designThe Perfusion Pressure Cerebral Infarct trial is a single-centre superiority trial with a blinded outcome assessment. The trial is randomising 210 patients with coronary vessel and/or valve disease and who are undergoing cardiac surgery with the use of cardiopulmonary bypass. Patients are stratified by age and surgical procedure and are randomised 1:1 to either an increased mean arterial pressure (70–80 mmHg) or ‘usual practice’ (40–50 mmHg) during cardiopulmonary bypass.The cardiopulmonary bypass pump flow is fixed and set at 2.4 L/minute/m2 body surface area plus 10–20 % in both groups.The primary outcome measure is the volume of the new ischaemic cerebral lesions (in mL), expressed as the difference between a baseline, diffusion-weighted, magnetic resonance imaging scan and an equal scan conducted 3–6 days postoperatively. Secondary endpoints are the total number of new ischaemic cerebral lesions, postoperative cognitive dysfunction at discharge and 3 months postoperatively, diffuse cerebral injury evaluated by magnetic resonance spectroscopy and selected biochemical markers of cerebral injury.The sample size will enable us to detect a 50 % reduction in the primary outcome measure in the intervention compared to the control group at a significance level of 0.05 and with a power of 0.80.DiscussionThis is the first clinical randomised study to evaluate whether the mean arterial pressure level during cardiopulmonary bypass influences the development of brain injuries that are detected by diffusion-weighted magnetic resonance imaging.Trial registrationClinicalTrials.gov, NCT02185885. Registered on 7 July 2014.Electronic supplementary materialThe online version of this article (doi:10.1186/s13063-016-1373-6) contains supplementary material, which is available to authorized users.

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A Paradox of Cerebral Hyperperfusion in the Face of Cerebral Hypotension: The Effect of Perfusion Pressure on Cerebral Blood Flow and Metabolism during Normothermic Cardiopulmonary Bypass

Cited by 5 publications

References 27 publications

Low perfusion pressure during CPB may induce cerebral metabolic and ultrastructural changes

Low perfusion pressure during CPB may induce cerebral metabolic and ultrastructural changes

Optimizing selective cerebral perfusion: Deleterious effects of high perfusion pressures

Perfusion Pressure Cerebral Infarct (PPCI) trial - the importance of mean arterial pressure during cardiopulmonary bypass to prevent cerebral complications after cardiac surgery: study protocol for a randomised controlled trial

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