Cerebrovascular physiology – article alert #89

Brain autoregulation

452- Baroreflex and Cerebral Autoregulation Are Inversely Correlated – Nasr et al.

453- A comparison of dynamic cerebral autoregulation across changes in cerebral blood flow velocity for 200 s – Müller and Osterreich

454- Static autoregulation in humans: a review and reanalysis –  Numan et al.

455- Monitoring of Cerebral Autoregulation – Czosnyka and Miller

Pre-syncope and the brain

456- Case report: (Pre)syncopal symptoms associated with a negative internal jugular venous pressure – Olesen et al.

Traumatic brain injury

457- Current concepts of optimal cerebral perfusion pressure in traumatic brain injury – Prabhakar et al.

Nitric oxide and the brain

458- Nitric oxide and cerebrovascular regulation – Tabatabaei and Girouard

High altitude and the brain

459- Ventilatory Chemosensitivity, Cerebral and Muscle Oxygenation, and Total Hemoglobin Mass Before and After a 72-Day Mt. Everest Expedition – Cheung et al.

Head/neck/body positioning and the brain

460- Effect of head and neck positioning on cerebral perfusion during shoulder arthroscopy in beach chair position – Salazar et al.

461- Prone Position Is Associated with Mild Cerebral Oxygen Desaturation in Elderly Surgical Patients – Deiner et al.

Upcoming meetings – Cerebrovascular physiology

There are two upcoming meetings that will definitely be of interest for those into cerebrovascular physiology research…

The Brain and BrainPET 2015 meeting will take place in Vancouver, Canada, from June 27th-30th, 2015.

For more information: Brain 2015

The Fifth International Meeting on Cerebral Haemodynamic Regulation (CARNet meeting) will be held in Southampton, UK, from July 13th-15th, 2015.

For more information: CARnet meeting 2015

Cerebrovascular physiology – article alert #88

Cardiac surgery and the brain

443- A systematic review of cerebral oxygenation-monitoring devices in cardiac surgery – Douds et al.

Hypoxia and the brain

444- Cerebral blood flow response to acute hypoxic hypoxia – Harris et al.

Brain reactivity to carbon dioxide

445- Cerebrovascular Reactivity to Carbon Dioxide Under Anesthesia: A Qualitative Systematic Review – Mariappan et al.

446- Measuring cerebrovascular reactivity: what stimulus to use? Fierstra et al.

447- Assessment of Cerebrovascular Reactivity during Resting State Breathing and Its Correlation with Cognitive Function in Hypertension – Hajjar et al.

Cardiopulmonary bypass and the brain

448- The impact of haemodilution and bypass pump flow on cerebral oxygen desaturation during cardiopulmonary bypass – A comparison of two systems of cardiopulmonary bypass – Bennett et al.

Diabetes and the brain

449- Cerebral hemodynamics and systemic endothelial function are already impaired in well-controlled type 2 diabetic patients, with short-term disease – Palazzo et al.

Exercise and the brain

450- Cerebral volumetric changes induced by prolonged hypoxic exposure and whole-body exercise – Rupp et al.

Blood pressure and the brain

451- Fundamental relationships between blood pressure and cerebral blood flow in humans-  Tzeng et al.

Article alert – Special edition

Below are two important papers recently published challenging the assumption that the diameter of the middle cerebral artery remains constant in response to hypocapnia and hypercapnia (using MRI technology) as previously reported.

Cerebral blood flow velocity underestimates cerebral blood flow during modest hypercapnia and hypocapniaCoverdale et al.

Assessment of middle cerebral artery diameter during hypocapnia and hypercapnia in humans using ultra high-field MRIVerbree et al.

Overall, these results suggest that the middle cerebral artery vasodilates in response to hypercapnia and vasoconstricts in response to hypocapnia, and that changes in blood flow velocity monitored with transcranial Doppler methodology (which assumes a constant diameter of the middle cerebral artery) underestimate changes in cerebral blood flow with some important implications for the evaluation of cerebrovascular reactivity to carbon dioxide. These results also question the validity of transcranial Doppler ultrasound, at least during changes in carbon dioxide…

Because science is not that simple and the fact that these two studies do not agree on everything, I suggest you to read the invited editorial related to the two above-mentioned papers:

Transcranial Doppler ultrasound: Valid, Invalid, or Both ? Ainslie and Hoiland

Fascinating readings !

Maybe we could further discuss the results/methodology related to these papers over here ?

What do you think ?

Cerebrovascular physiology – article alert #87

Sepsis and the brain

436- Transcranial Doppler to assess sepsis-associated encephalopathy in critically ill patients – Pierrakos et al.

Cardiovascular disease and the brain

437- The Synergistic Effects of Anxiety and Cerebral Hypoperfusion on Cognitive Dysfunction in Older Adults With Cardiovascular Disease – Alosco et al.

Brain monitoring

438- Cerebral blood flow velocity underestimates cerebral blood flow during modest hypercapnia and hypocapnia – Coverdale et al.

Subarachnoid hemorrhage and the brain

439- Bilateral Failure of Cerebral Autoregulation is Related to Unfavorable Outcome After Subarachnoid Hemorrhage – Budohoski et al.

Preeclampsia and the brain

440- Cerebral Oximetry Assessed by Near-Infrared Spectrometry During Preeclampsia: An Observational Study: A Preliminary Study of the Impact of Magnesium Sulfate Administration – Guerci et al.

Vasopressors and the brain

441- Differing effects when using phenylephrine and norepinephrine to augment cerebral blood flow after traumatic brain injury in the immature brain – Friess et al.

Exercise and the brain

442- Evidence Cerebral Blood-Flow Regulation Mediates Exercise-Cognition Links in Healthy Young Adults – Guiney et al.