{
    "abstract": "Anesthesia is associated with alterations in end-tidal (ET) respiratory gases from the awake state. These alterations result in marked vasoactive changes in regional cerebral blood flow (rCBF). Altered regional cerebrovascular reactivity (rCVR) is linked to neurologic dysfunction. We examined these differences in reactivity from prior work by focusing on the ratio of vasoconstriction with hyperoxia/hypocapnia (HO/hc):vasodilation with hypercapnia (HC) using magnetic resonance imaging pseudo-continuous arterial spin labelling (pCASL) to measure rCBF and compare rCVR The distribution and magnitude of these ratios could provide insights into rCBF during clinical anesthesia and inform future research into the origins of postoperative delirium (POD).\nTen healthy subjects underwent cerebral blood flow (CBF) studies using pCASL with computer-controlled delivery of ET gases to assess flow effects of hyperoxia, hypercapnia, and hyperoxia/hypocapnia as part of a larger study into cerebrovascular reactivity. The vasoconstrictor stimulus was compared with the vasodilator stimulus by the ratio HO/hc:HC.\nHyperoxia minimally decreased whole brain CBF by -\u00a00.6%/100 mm Hg increase in ETO\nIn awake humans, marked rCBF changes occurred with alterations in ET respiratory gases common under anesthesia. Such heterogeneous reactivity may be relevant to future studies to identify those at risk of POD.\nR\u00e9SUM\u00e9: OBJECTIF: L\u2019anesth\u00e9sie est associ\u00e9e \u00e0 des alt\u00e9rations des gaz respiratoires t\u00e9l\u00e9-expiratoires par rapport \u00e0 l\u2019\u00e9tat d\u2019\u00e9veil. Ces alt\u00e9rations entra\u00eenent des changements vasoactifs marqu\u00e9s dans le d\u00e9bit sanguin c\u00e9r\u00e9bral r\u00e9gional (DSCR). Une alt\u00e9ration de la r\u00e9activit\u00e9 c\u00e9r\u00e9brovasculaire r\u00e9gionale (rCVR) est li\u00e9e au dysfonctionnement neurologique. Nous avons examin\u00e9 ces diff\u00e9rences de r\u00e9activit\u00e9 dans des \u00e9tudes ant\u00e9rieures en nous concentrant sur le rapport entre la vasoconstriction et l\u2019hyperoxie/hypocapnie (HO/hc):vasodilatation et l\u2019hypercapnie (HC), en utilisant une technique d\u2019imagerie par r\u00e9sonance magn\u00e9tique dite pCASL (pour pseudo-continuous arterial spin labelling) pour mesurer le DSCR et comparer la rCVR. La distribution et l\u2019ampleur de ces rapports pourraient fournir des renseignements concernant le DSCR pendant l\u2019anesth\u00e9sie clinique et \u00e9clairer la recherche future sur les origines du delirium postop\u00e9ratoire (DPO). M\u00e9THODE: Dix volontaires sains ont subi des \u00e9tudes de d\u00e9bit sanguin c\u00e9r\u00e9bral (DSC) \u00e0 l\u2019aide d\u2019une pCASL avec un contr\u00f4le g\u00e9r\u00e9 par ordinateur des gaz t\u00e9l\u00e9-expiratoires pour \u00e9valuer les effets sur le d\u00e9bit de l\u2019hyperoxie, de l\u2019hypercapnie, et de l\u2019hyperoxie/hypocapnie dans le cadre d\u2019une plus grande \u00e9tude sur la r\u00e9activit\u00e9 c\u00e9r\u00e9brovasculaire. Le stimulus vasoconstricteur a \u00e9t\u00e9 compar\u00e9 au stimulus vasodilatateur par le rapport de HO/hc:HC. R\u00e9SULTATS: L\u2019hyperoxie a diminu\u00e9 de fa\u00e7on minimale le DSC du cerveau entier de \u2212\u00a00,6 %/100 mmHg en ETO",
    "authors": [
        {
            "affiliation": "Department of Anesthesiology, Perioperative and Pain Medicine, University of Manitoba, 2nd Floor, Harry Medovy House, 671 William Ave., Winnipeg, MB, R3E 0Z2, Canada. wacmutch@shaw.ca.\nCanada North Concussion Network, Winnipeg, MB, Canada. wacmutch@shaw.ca.",
            "firstname": "W Alan C",
            "initials": "WAC",
            "lastname": "Mutch"
        },
        {
            "affiliation": "Department of Anesthesiology and Pain Medicine, University of Toronto, Toronto, ON, Canada.\nThornhill Medical, Toronto, ON, Canada.\nDepartment of Physiology, University of Toronto, Toronto, ON, Canada.",
            "firstname": "James",
            "initials": "J",
            "lastname": "Duffin"
        }
    ],
    "conclusions": null,
    "copyrights": "\u00a9 2021. Canadian Anesthesiologists' Society.\n\u00a9 2021. Canadian Anesthesiologists' Society.",
    "doi": "10.1007/s12630-021-02042-x\n10.3174/ajnr.A4679\n10.1113/jphysiol.2013.259150\n10.3389/fnins.2018.00409\n10.1113/jphysiol.2007.129395\n10.1136/bmjopen-2014-006014\n10.1089/neu.2020.7272\n10.1016/j.neuroimage.2018.07.007\n10.1016/j.resp.2016.01.004\n10.1212/WNL.0000000000003373\n10.1016/j.nicl.2016.09.009\n10.1016/j.sleep.2020.04.029\n10.1016/j.msard.2020.102309\n10.1016/j.neuroimage.2014.01.051\n10.1136/jnnp.2009.188078\n10.1016/j.neuroimage.2015.01.050\n10.1371/journal.pmed.0040173\n10.1016/j.neuroimage.2003.12.042\n10.1186/s13054-020-2800-3\n10.1016/j.jclinane.2016.10.028\n10.1007/s12630-018-1249-1\n10.3389/fneur.2018.00678\n10.3389/fnagi.2017.00274\n10.1016/j.mri.2007.07.003\n10.1113/JP279237\n10.1113/JP280301\n10.1016/j.bja.2019.08.024\n10.1097/ANA.0000000000000231\n10.1016/j.jstrokecerebrovasdis.2017.08.035\n10.1148/radiol.2021203568\n10.1016/j.neurobiolaging.2021.01.033\n10.1172/JCI101995\n10.1378/chest.128.1.430\n10.1097/ALN.0000000000003014\n10.1007/s12028-013-9921-3\n10.1176/appi.ajp.2012.11060976\n10.3171/2015.6.JNS15972",
    "journal": "Canadian journal of anaesthesia = Journal canadien d'anesthesie",
    "keywords": [
        "anesthesia",
        "carbon dioxide",
        "cerebral blood flow",
        "delirium",
        "oxygen",
        "postoperative complications"
    ],
    "methods": null,
    "publication_date": "2021-06-10",
    "pubmed_id": "34105067",
    "results": "Hyperoxia minimally decreased whole brain CBF by -\u00a00.6%/100 mm Hg increase in ETO",
    "title": "Differential regional cerebral blood flow reactivity to alterations in end-tidal gases in healthy volunteers.",
    "xml": "<Element 'PubmedArticle' at 0x788504701170>"
}