{
  "abstract": "Background: Evidence suggests that intraoperative cerebral hypoxia is the main contributor of postoperative neurological complications, particularly postoperative cognitive dysfunction (POCD) and postoperative delirium (POD) in surgical patients. Permissive hypercapnia may improve cerebral oxygenation by increasing cerebral blood flow, but its perioperative benefits remain uncertain.\n\nResearch Question: In adult surgical patients, is permissive hypercapnia associated with improved cerebral oxygenation and perioperative outcomes compared with normocapnia?\n\nMethod: PubMed, Embase, Cochrane CENTRAL, and ClinicalTrials.gov were searched from inception to April 2026 for randomized controlled trials (RCTs) and cohort studies of adult surgical patients receiving permissive hypercapnia. Primary outcome included was intraoperative regional cerebral oxygen saturation (rSO2). Secondary outcomes were POCD, POD, all‐cause mortality, respiratory parameters, arterial blood gas variables, and hemodynamic outcomes.\n\nResults: Seven studies comprising 824 patients were included. Permissive hypercapnia significantly improved intraoperative rSO2 (MD = 6.65%; 95% Cl: [4.93, 8.37]; p < 0.00001), PaCO2 (MD = 10.21 mmHg (95% CI: [8.81, 11.60]; p < 0.00001), and end‐tidal CO2 (MD = 10.83 mmHg; 95% CI [7.91, 13.76]; p < 0.00001), and significantly reduced dead space fraction (MD = −6.38%; 95% CI: [–9.26, −3.50], p < 0.00001), and arterial pH (MD = −0.08; 95% CI: [‐0.09, −0.07]; p < 0.00001). Hypercapnia had no significant effect on PaO2, mean arterial pressure, and heart rate. Qualitative analysis suggested reduced incidence of POCD with no significant effect on POD.\n\nConclusion: Permissive hypercapnia improves intraoperative cerebral oxygenation while maintaining hemodynamic stability. However, the available evidence for POCD and POD is limited and heterogeneous. Larger RCTs and observational studies are needed to confirm its effects on clinical outcomes before routine implementation.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Medicine Services Institute of Medical Sciences Lahore Pakistan sims.edu.pk",
    "Department of Medicine Ameer-ud-Din Medical College Lahore Pakistan duhs.edu.pk",
    "Department of Medicine University of Health Sciences Lahore Pakistan uhs.edu.kh",
    "Department of Medicine FMH College of Medicine and Dentistry Lahore Pakistan duhs.edu.pk",
    "Faculty of Medicine Al-Azhar University Gaza State of Palestine azhar.edu.eg",
    "Department of Medicine Pakistan Institute of Medical Sciences Islamabad Pakistan pims.gov.pk",
    "Department of Medicine Sindh Government Hospital Karachi Pakistan duhs.edu.pk",
    "Department of Medicine Dow University of Health Sciences Karachi Pakistan duhs.edu.pk",
    "Department of Research Medical Research Circle (MedReC) Goma Democratic Republic of the Congo"
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 10,
  "authors": [
    {
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        0
      ],
      "name": "Areej Riaz",
      "orcid": "0009-0005-6105-1447"
    },
    {
      "affs": [
        1
      ],
      "name": "Amna Khan",
      "orcid": "0009-0003-2132-2383"
    },
    {
      "affs": [
        2
      ],
      "name": "Fatima Nawaz",
      "orcid": "0009-0004-3927-6837"
    },
    {
      "affs": [
        2
      ],
      "name": "Amna Shafaqat",
      "orcid": "0009-0008-7437-2508"
    },
    {
      "affs": [
        3
      ],
      "name": "Hadia Sheraz",
      "orcid": "0009-0009-5206-4675"
    },
    {
      "affs": [
        4
      ],
      "name": "Mohammed M. AlTelbany",
      "orcid": "0009-0006-3372-0938"
    },
    {
      "affs": [
        5
      ],
      "name": "Nauroze Khan",
      "orcid": "0009-0005-1094-3680"
    },
    {
      "affs": [
        6
      ],
      "name": "Adeel Ahmed Khan",
      "orcid": "0009-0005-6829-1582"
    },
    {
      "affs": [
        7
      ],
      "name": "Bismah Rafique Malik",
      "orcid": "0009-0009-4166-4958"
    },
    {
      "affs": [
        8
      ],
      "name": "Hermann Yokolo",
      "orcid": "0009-0002-8347-7236"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/f3ahapm5aj719.bib",
  "cited_by": 0,
  "doi": "10.1155/anrp/3569464",
  "fulltext_url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC13723312/",
  "id": "f3ahapm5aj719",
  "issns": [
    "1687-6962",
    "1687-6970"
  ],
  "landing_url": "https://doi.org/10.1155/anrp/3569464",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "Article"
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      "heading",
      "Research Article"
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      "2740|Respiratory Support and Mechanisms"
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  "pdf_url": "https://onlinelibrary.wiley.com/doi/pdfdirect/10.1155/anrp/3569464",
  "pmcid": "PMC13723312",
  "pmid": "42967190",
  "published": "2026-10-31",
  "publisher": "Wiley",
  "ris": "https://research.draconitic.com/paper/f3ahapm5aj719.ris",
  "sources": [
    {
      "first_seen": "2026-11-04T12:21:56Z",
      "native_id": "PMC13723312",
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      "url": "https://doi.org/10.1155/anrp/3569464"
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  "subjects": [
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      "field": "medicine",
      "origin": "openalex:2740|Respiratory Support and Mechanisms",
      "subfield": "general"
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  ],
  "title": "Effects of Permissive Hypercapnia Versus Normocapnia on Cerebral Oxygenation and Postoperative Outcomes in Adult Surgical Patients: A Systematic Review and Meta‐Analysis",
  "title_text": "Effects of Permissive Hypercapnia Versus Normocapnia on Cerebral Oxygenation and Postoperative Outcomes in Adult Surgical Patients: A Systematic Review and Meta‐Analysis",
  "type": "peer-reviewed",
  "updated_at": "2026-11-04T12:21:56Z",
  "url": "https://research.draconitic.com/paper/f3ahapm5aj719",
  "venue": "Anesthesiology Research and Practice",
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}