{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,26]],"date-time":"2026-10-26T09:14:51Z","timestamp":1793006091866,"version":"4.5.0"},"reference-count":20,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2020,9,6]],"date-time":"2020-09-06T00:00:00Z","timestamp":1599350400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia","award":["Meshal Alharbi"],"award-info":[{"award-number":["Meshal Alharbi"]}]},{"name":"National Institute for Health Research (NIHR Clinical Lectureship in Older People and Complex Health Needs)","award":["Jatinder Minhas"],"award-info":[{"award-number":["Jatinder Minhas"]}]},{"name":"Nihon Kohden Corporation (Japan)","award":["Emma Chung"],"award-info":[{"award-number":["Emma Chung"]}]},{"name":"The Engineering and Physical Sciences Research Council (EPSRC)","award":["Emma Chung"],"award-info":[{"award-number":["Emma Chung"]}]},{"name":"The University of Leicester LD3 programme funded through the MRC Confidence in Concept (CiC) programme","award":["Emma Chung"],"award-info":[{"award-number":["Emma Chung"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Brain Sciences"],"abstract":"<jats:p>Hypocapnia is known to affect patients with acute stroke and plays a key role in governing cerebral autoregulation. However, the impact of hypocapnia on brain tissue pulsations (BTPs) is relatively unexplored. As BTPs are hypothesised to result from cerebrovascular resistance to the inflow of pulsatile arterial blood, it has also been hypothesised that cerebral autoregulation changes mediated by hypocapnia will alter BTP amplitude. This healthy volunteer study reports measurements of BTPs obtained using transcranial tissue Doppler (TCTD). Thirty participants underwent hyperventilation to induce mild hypocapnia. BTP amplitude, EtCO2, blood pressure, and heart rate were then analysed to explore the impact of hypocapnia on BTP amplitude. Significant changes in BTP amplitude were noted during recovery from hypocapnia, but not during the hyperventilation manoeuvre itself. However, a significant increase in heart rate and pulse pressure and decrease in mean arterial pressure were also observed to accompany hypocapnia, which may have confounded our findings. Whilst further investigation is required, the results of this study provide a starting point for better understanding of the effects of carbon dioxide levels on BTPs. Further research in this area is needed to identify the major physiological drivers of BTPs and quantify their interactions with other aspects of cerebral haemodynamics.<\/jats:p>","DOI":"10.3390\/brainsci10090614","type":"journal-article","created":{"date-parts":[[2020,9,6]],"date-time":"2020-09-06T23:12:49Z","timestamp":1599433969000},"page":"614","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["The Effects of Hypocapnia on Brain Tissue Pulsations"],"prefix":"10.3390","volume":"10","author":[{"given":"Meshal","family":"Alharbi","sequence":"first","affiliation":[{"name":"Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, UK"},{"name":"College of Applied Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh 14611, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Poppy","family":"Turner","sequence":"additional","affiliation":[{"name":"Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, UK"},{"name":"School of Engineering, University of Leicester, Leicester LE1 7RH, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jonathan","family":"Ince","sequence":"additional","affiliation":[{"name":"Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mitsuhiro","family":"Oura","sequence":"additional","affiliation":[{"name":"Nihon Kohden Corporation, Tokorozawa-shi, Saitama 359-0037, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2735-8793","authenticated-orcid":false,"given":"Kelechi U.","family":"Ebirim","sequence":"additional","affiliation":[{"name":"School of Engineering, University of Leicester, Leicester LE1 7RH, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alanoud","family":"Almudayni","sequence":"additional","affiliation":[{"name":"Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, UK"},{"name":"College of Applied Medical Sciences, King Sattam bin Abdulaziz University for Health Sciences, Kharj 11564, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1654-8877","authenticated-orcid":false,"given":"Andrea","family":"Lecchini-Visintini","sequence":"additional","affiliation":[{"name":"School of Engineering, University of Leicester, Leicester LE1 7RH, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0576-9105","authenticated-orcid":false,"given":"Jatinder S.","family":"Minhas","sequence":"additional","affiliation":[{"name":"Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, UK"},{"name":"University Hospitals of Leicester NHS Trust, Leicester LE1 5WW, UK"},{"name":"NIHR Leicester Biomedical Research Centre, Leicester LE5 4PW, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3723-9085","authenticated-orcid":false,"given":"Emma M.L.","family":"Chung","sequence":"additional","affiliation":[{"name":"Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM) Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, UK"},{"name":"University Hospitals of Leicester NHS Trust, Leicester LE1 5WW, UK"},{"name":"NIHR Leicester Biomedical Research Centre, Leicester LE5 4PW, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,9,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"N101","DOI":"10.1088\/1361-6579\/aa6f9f","article-title":"PaCO2 measurement in cerebral haemodynamics: Face mask or nasal cannulae?","volume":"38","author":"Minhas","year":"2017","journal-title":"Physiol. 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