Preoperative hyperbaric oxygen therapy for abdominal and gastrointestinal surgeries: a systematic review protocol

Preoperative hyperbaric oxygen therapy for abdominal and gastrointestinal surgeries: a systematic review protocol | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Systematic Review Preoperative hyperbaric oxygen therapy for abdominal and gastrointestinal surgeries: a systematic review protocol Lucas Venturini Rezende, Roberto Carlos Araujo, Raphael Costa Araujo, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9141481/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background : Major abdominal and gastrointestinal surgeries are frequently associated with significant postoperative complications, notably anastomotic leakage and mortality. Preoperative hyperbaric oxygen therapy (HBOT) has been proposed as an adjunctive intervention to optimize tissue oxygenation and improve surgical outcomes. Objective : To evaluate the clinical effects of preoperative HBOT on postoperative outcomes in adult patients undergoing abdominal or gastrointestinal surgery. Methods : This systematic review will include randomized controlled trials (RCTs) and observational studies (such as cohort and case-control studies). We will search MEDLINE (via PubMed), Embase, and LILACS for studies comparing preoperative HBOT to standard surgical care without HBOT. The primary outcomes will be postoperative mortality and the incidence of anastomotic leakage. Secondary outcomes include postoperative pain and length of hospital stay. Two independent reviewers will screen studies, extract data, and assess the risk of bias. If applicable, a meta-analysis will be performed. PROSPERO Registration: CRD420261339389 Hyperbaric oxigenation therapy gastrointestinal 1. Introduction 1.1 Rationale Major abdominal and gastrointestinal surgeries are frequently associated with significant postoperative complications, notably anastomotic leakage and mortality [ 1 , 2 ]. Despite advancements in surgical techniques and standard perioperative care, inadequate tissue oxygenation and local ischemia at the surgical site remain critical factors that impair wound healing and increase morbidity. These complications not only prolong the length of hospital stays and inflate healthcare costs but also severely impact patient recovery and overall survival. Preoperative hyperbaric oxygen therapy (HBOT) has emerged as a promising adjunctive intervention to optimize patients prior to surgery. By delivering 100% oxygen under increased atmospheric pressure, HBOT significantly enhances systemic and local tissue oxygen tension, promotes angiogenesis, reduces edema, and exhibits antimicrobial properties. Consequently, administering HBOT in the preoperative period may precondition vulnerable tissues, mitigate the risk of ischemic complications such as anastomotic leaks, and ultimately improve postoperative outcomes, including reduced pain, shorter hospitalizations, and lower mortality rates. 1.2 Objectives The primary objective of this systematic review is to evaluate the clinical impact of preoperative hyperbaric oxygen therapy (HBOT) on patients undergoing abdominal or gastrointestinal surgeries. Specifically, this study aims to assess the correlation between preoperative HBOT and postoperative mortality rates, determine its efficacy in reducing the incidence of anastomotic leakage. Secondary outcomes include postoperative pain (assessed by validated scales), postoperative nausea and vomiting (PONV), incidence of postoperative ileus (POI), and length of hospital stay. 2. Methods This protocol is reported in accordance with the Preferred Reporting Items for Systematic review and Meta-Analysis Protocols (PRISMA-P) guidelines [ 3 ]. 2.1 Eligibility Criteria Population: Adult patients (aged 18 years or older) scheduled for abdominal or gastrointestinal surgeries. Intervention: Administration of Hyperbaric Oxygen Therapy (HBOT) in the preoperative period. Comparator: Adult patients undergoing abdominal or gastrointestinal surgery who did not receive preoperative HBOT, receiving standard perioperative care only (or sham HBOT). Outcomes: Primary outcomes include postoperative mortality and anastomotic leakage. Secondary outcomes include postoperative pain (assessed by validated scales) and length of hospital stay. Study Design: Randomized controlled trials (RCTs) and observational studies (including cohort and case-control studies). Exclusion Criteria: Pediatric population (children and adolescents < 18 years of age); studies focusing exclusively on postoperative HBOT administration; surgical procedures involving areas other than the gastrointestinal tract or the abdominal wall; case reports, editorials, and animal studies. 2.2 Information Sources and Search Strategy A comprehensive literature search will be conducted in the following electronic databases: MEDLINE (via PubMed), Embase, and LILACS. The search will be performed without restrictions regarding publication date or language. The search strategy was developed using a combination of controlled vocabulary (e.g., Medical Subject Headings - MeSH, and Emtree) and free-text words related to hyperbaric oxygenation and gastrointestinal/abdominal surgeries. The base search strategy optimized for MEDLINE (via PubMed) is as follows: ("Hyperbaric Oxygenation"[Mesh] OR "Hyperbaric Oxygen Therapy" OR "HBOT" OR "Hyperbaric Oxygen") AND ("Digestive System Surgical Procedures"[Mesh] OR "Bariatric Surgery"[Mesh] OR "Anastomosis, Surgical"[Mesh] OR "Gastrointestinal Surgery" OR "Abdominal Surgery") This strategy will be adapted to meet the specific syntax requirements of the other electronic databases. For Embase, equivalent Emtree terms will be utilized, and for LILACS, the equivalent Health Sciences Descriptors (DeCS) will be applied. In addition to the database searches, the reference lists of all included studies and relevant review articles will be manually screened to identify any additional eligible studies. 2.3 Study Selection and Data Extraction Retrieved records will be exported to a reference manager, and duplicates will be removed. Two independent reviewers will screen titles and abstracts. Full-text articles of potentially relevant studies will be assessed for eligibility. Any disagreements will be resolved through discussion or consultation with a third reviewer. Data extraction will be performed using a standardized form, capturing study characteristics, patient demographics, intervention details, and outcome data. 2.4 Risk of Bias Assessment The methodological quality and risk of bias of the included studies will be assessed independently by two reviewers. For randomized controlled trials, the Cochrane Risk of Bias 2 (RoB 2) tool will be used [ 4 ]. For observational studies, the Risk Of Bias In Non-randomized Studies - of Exposure (ROBINS-E) tool will be applied [ 5 ]. 2.5 Data Synthesis If sufficient homogenous data are available, a quantitative synthesis (meta-analysis) will be conducted using appropriate statistical software (e.g., Review Manager or R). Treatment effects will be expressed as Risk Ratios (RR) or Odds Ratios (OR) for dichotomous data, and Mean Differences (MD) for continuous data, with 95% Confidence Intervals (CI). Heterogeneity will be assessed using the I2 statistic. If a meta-analysis is not feasible due to clinical or methodological heterogeneity, a narrative synthesis of the findings will be provided in accordance with the Synthesis Without Meta-analysis (SWiM) reporting guideline [ 6 ]. Finally, the overall certainty of the evidence will be assessed using the GRADE approach [ 7 ]. 3. Discussion This systematic review will comprehensively synthesize the available evidence regarding the efficacy and safety of preoperative hyperbaric oxygen therapy (HBOT) in abdominal and gastrointestinal surgeries. By strictly adhering to the PRISMA guidelines, this study aims to provide robust data that could potentially influence future perioperative care protocols, minimizing the risk of severe complications such as anastomotic leakage, postoperative ileus, and mortality. A potential limitation of this planned review is the anticipated clinical and methodological heterogeneity among the included studies, particularly concerning variations in surgical techniques and specific HBOT regimens (e.g., pressure levels and number of sessions). Nevertheless, mapping the current state of the evidence and identifying these gaps will be crucial for guiding future high-quality randomized controlled trials in this field. Declarations Ethics approval and consent to participate Not applicable. This study is a systematic review protocol, which involves the synthesis of data from previously published literature. It does not involve human participants, data, or tissue; therefore, ethical approval and consent to participate are not required. Consent for publication Not applicable. Availability of data and materials Not applicable. This is a systematic review protocol, and no primary data have been collected or analyzed yet. Data sharing is not applicable to this article. Competing interests The authors declare that they have no competing interests. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Authors' contributions LR and RCAJ conceptualized the study, formulated the research question, and designed the protocol. LR and RCAJ developed the literature search strategy, defined the eligibility criteria, and drafted the initial manuscript. All the authors critically reviewed the methodology, refined the risk of bias assessment strategy, and provided significant intellectual input. All authors actively participated in reviewing and editing the manuscript. All authors read and approved the final manuscript. Acknowledgements Not applicable. References Oines L, Krarup AL, Krarup PM, Jorgensen LN. Therapeutic improvement of colonic anastomotic healing under complicated conditions: A systematic review. World J Gastrointest Surg. 2016;8(5):423-34. Brouwer WJ, Oines L, Krarup AL, Krarup PM, Jorgensen LN. Pharmacological interventions for improved colonic anastomotic healing: a meta-analysis. World J Gastroenterol. 2014;20(35):12647-58. Moher D, Shamseer L, Clarke M, Ghersi D, Liberati A, Petticrew M, et al. Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015 statement. Syst Rev. 2015;4(1):1. Sterne JAC, Savović J, Page MJ, Elbers RG, Blencowe NS, Boutron I, et al. RoB 2: a revised tool for assessing risk of bias in randomised trials. BMJ. 2019;366:l4898. Sterne JA, Hernán MA, Reeves BC, Savović J, Berkman ND, Viswanathan M, et al. ROBINS-I: a tool for assessing risk of bias in non-randomised studies of interventions. BMJ. 2016;355:i4919. Campbell M, McKenzie JE, Sowden A, Katikireddi SV, Brennan SE, Ellis S, et al. Synthesis without meta-analysis (SWiM) in systematic reviews: reporting guideline. BMJ. 2020;368:l6890. Guyatt GH, Oxman AD, Vist GE, Kunz R, Falck-Ytter Y, Alonso-Coello P, et al. GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ. 2008;336(7650):924-6. Additional Declarations No competing interests reported. Supplementary Files PrismaP.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9141481","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Systematic Review","associatedPublications":[],"authors":[{"id":611326019,"identity":"f0129103-fde2-4f34-98e4-bcaae54e594f","order_by":0,"name":"Lucas Venturini Rezende","email":"data:image/png;base64,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","orcid":"","institution":"Hospital Evangélico, Cachoeiro de Itapemirim","correspondingAuthor":true,"prefix":"","firstName":"Lucas","middleName":"Venturini","lastName":"Rezende","suffix":""},{"id":611326020,"identity":"981a217f-1755-42b0-a22f-b8e61e9c9886","order_by":1,"name":"Roberto Carlos Araujo","email":"","orcid":"","institution":"Hospital Evangélico, Cachoeiro de Itapemirim","correspondingAuthor":false,"prefix":"","firstName":"Roberto","middleName":"Carlos","lastName":"Araujo","suffix":""},{"id":611326021,"identity":"4388b5d8-1ebd-462b-b3ee-ac51f8a0381b","order_by":2,"name":"Raphael Costa Araujo","email":"","orcid":"","institution":"Hospital Evangélico, Cachoeiro de Itapemirim","correspondingAuthor":false,"prefix":"","firstName":"Raphael","middleName":"Costa","lastName":"Araujo","suffix":""},{"id":611326022,"identity":"4641772d-109b-4411-bf0f-0f287b92d5b9","order_by":3,"name":"Ricardo Dardengo Gloria","email":"","orcid":"","institution":"Hospital Evangélico, Cachoeiro de Itapemirim","correspondingAuthor":false,"prefix":"","firstName":"Ricardo","middleName":"Dardengo","lastName":"Gloria","suffix":""},{"id":611326023,"identity":"b722d16a-baf2-40c6-a66e-da6b0f5fa873","order_by":4,"name":"Rogerio Dardengo Gloria","email":"","orcid":"","institution":"Hospital Evangélico, Cachoeiro de Itapemirim","correspondingAuthor":false,"prefix":"","firstName":"Rogerio","middleName":"Dardengo","lastName":"Gloria","suffix":""}],"badges":[],"createdAt":"2026-03-16 19:53:30","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9141481/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9141481/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":105565920,"identity":"b4cfa237-a934-413e-a6c1-4edac18c21fc","added_by":"auto","created_at":"2026-03-27 12:54:46","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":382975,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9141481/v1/89957a5a-2abe-436d-863f-319b06d69943.pdf"},{"id":105354414,"identity":"3f2b2515-032b-4872-8020-ad8fd3c8bede","added_by":"auto","created_at":"2026-03-25 06:30:17","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":24213,"visible":true,"origin":"","legend":"","description":"","filename":"PrismaP.docx","url":"https://assets-eu.researchsquare.com/files/rs-9141481/v1/599136a6379d466facd7b59f.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003ePreoperative hyperbaric oxygen therapy for abdominal and gastrointestinal surgeries: a systematic review protocol\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cdiv id=\"Sec2\" class=\"Section2\"\u003e \u003ch2\u003e1.1 Rationale\u003c/h2\u003e \u003cp\u003eMajor abdominal and gastrointestinal surgeries are frequently associated with significant postoperative complications, notably anastomotic leakage and mortality [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDespite advancements in surgical techniques and standard perioperative care, inadequate tissue oxygenation and local ischemia at the surgical site remain critical factors that impair wound healing and increase morbidity. These complications not only prolong the length of hospital stays and inflate healthcare costs but also severely impact patient recovery and overall survival.\u003c/p\u003e \u003cp\u003ePreoperative hyperbaric oxygen therapy (HBOT) has emerged as a promising adjunctive intervention to optimize patients prior to surgery. By delivering 100% oxygen under increased atmospheric pressure, HBOT significantly enhances systemic and local tissue oxygen tension, promotes angiogenesis, reduces edema, and exhibits antimicrobial properties. Consequently, administering HBOT in the preoperative period may precondition vulnerable tissues, mitigate the risk of ischemic complications such as anastomotic leaks, and ultimately improve postoperative outcomes, including reduced pain, shorter hospitalizations, and lower mortality rates.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e1.2 Objectives\u003c/h2\u003e \u003cp\u003eThe primary objective of this systematic review is to evaluate the clinical impact of preoperative hyperbaric oxygen therapy (HBOT) on patients undergoing abdominal or gastrointestinal surgeries. Specifically, this study aims to assess the correlation between preoperative HBOT and postoperative mortality rates, determine its efficacy in reducing the incidence of anastomotic leakage. Secondary outcomes include postoperative pain (assessed by validated scales), postoperative nausea and vomiting (PONV), incidence of postoperative ileus (POI), and length of hospital stay.\u003c/p\u003e \u003c/div\u003e"},{"header":"2. Methods","content":"\u003cp\u003eThis protocol is reported in accordance with the Preferred Reporting Items for Systematic review and Meta-Analysis Protocols (PRISMA-P) guidelines [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e2.1 Eligibility Criteria\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003ePopulation: Adult patients (aged 18 years or older) scheduled for abdominal or gastrointestinal surgeries.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eIntervention: Administration of Hyperbaric Oxygen Therapy (HBOT) in the preoperative period.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eComparator: Adult patients undergoing abdominal or gastrointestinal surgery who did not receive preoperative HBOT, receiving standard perioperative care only (or sham HBOT).\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eOutcomes: Primary outcomes include postoperative mortality and anastomotic leakage. Secondary outcomes include postoperative pain (assessed by validated scales) and length of hospital stay.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eStudy Design: Randomized controlled trials (RCTs) and observational studies (including cohort and case-control studies).\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eExclusion Criteria: Pediatric population (children and adolescents\u0026thinsp;\u0026lt;\u0026thinsp;18 years of age); studies focusing exclusively on postoperative HBOT administration; surgical procedures involving areas other than the gastrointestinal tract or the abdominal wall; case reports, editorials, and animal studies.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Information Sources and Search Strategy\u003c/h2\u003e \u003cp\u003eA comprehensive literature search will be conducted in the following electronic databases: MEDLINE (via PubMed), Embase, and LILACS. The search will be performed without restrictions regarding publication date or language.\u003c/p\u003e \u003cp\u003eThe search strategy was developed using a combination of controlled vocabulary (e.g., Medical Subject Headings - MeSH, and Emtree) and free-text words related to hyperbaric oxygenation and gastrointestinal/abdominal surgeries. The base search strategy optimized for MEDLINE (via PubMed) is as follows:\u003c/p\u003e \u003cp\u003e(\"Hyperbaric Oxygenation\"[Mesh] OR \"Hyperbaric Oxygen Therapy\" OR \"HBOT\" OR \"Hyperbaric Oxygen\") AND (\"Digestive System Surgical Procedures\"[Mesh] OR \"Bariatric Surgery\"[Mesh] OR \"Anastomosis, Surgical\"[Mesh] OR \"Gastrointestinal Surgery\" OR \"Abdominal Surgery\")\u003c/p\u003e \u003cp\u003eThis strategy will be adapted to meet the specific syntax requirements of the other electronic databases. For Embase, equivalent Emtree terms will be utilized, and for LILACS, the equivalent Health Sciences Descriptors (DeCS) will be applied. In addition to the database searches, the reference lists of all included studies and relevant review articles will be manually screened to identify any additional eligible studies.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Study Selection and Data Extraction\u003c/h2\u003e \u003cp\u003eRetrieved records will be exported to a reference manager, and duplicates will be removed. Two independent reviewers will screen titles and abstracts. Full-text articles of potentially relevant studies will be assessed for eligibility. Any disagreements will be resolved through discussion or consultation with a third reviewer. Data extraction will be performed using a standardized form, capturing study characteristics, patient demographics, intervention details, and outcome data.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Risk of Bias Assessment\u003c/h2\u003e \u003cp\u003e The methodological quality and risk of bias of the included studies will be assessed independently by two reviewers. For randomized controlled trials, the Cochrane Risk of Bias 2 (RoB 2) tool will be used [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. For observational studies, the Risk Of Bias In Non-randomized Studies - of Exposure (ROBINS-E) tool will be applied [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e2.5 Data Synthesis\u003c/h2\u003e \u003cp\u003eIf sufficient homogenous data are available, a quantitative synthesis (meta-analysis) will be conducted using appropriate statistical software (e.g., Review Manager or R). Treatment effects will be expressed as Risk Ratios (RR) or Odds Ratios (OR) for dichotomous data, and Mean Differences (MD) for continuous data, with 95% Confidence Intervals (CI). Heterogeneity will be assessed using the I2 statistic. If a meta-analysis is not feasible due to clinical or methodological heterogeneity, a narrative synthesis of the findings will be provided in accordance with the Synthesis Without Meta-analysis (SWiM) reporting guideline [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Finally, the overall certainty of the evidence will be assessed using the GRADE approach [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Discussion","content":"\u003cp\u003eThis systematic review will comprehensively synthesize the available evidence regarding the efficacy and safety of preoperative hyperbaric oxygen therapy (HBOT) in abdominal and gastrointestinal surgeries. By strictly adhering to the PRISMA guidelines, this study aims to provide robust data that could potentially influence future perioperative care protocols, minimizing the risk of severe complications such as anastomotic leakage, postoperative ileus, and mortality. A potential limitation of this planned review is the anticipated clinical and methodological heterogeneity among the included studies, particularly concerning variations in surgical techniques and specific HBOT regimens (e.g., pressure levels and number of sessions). Nevertheless, mapping the current state of the evidence and identifying these gaps will be crucial for guiding future high-quality randomized controlled trials in this field.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eEthics approval and consent to participate\u003c/p\u003e\n\u003cp\u003eNot applicable. This study is a systematic review protocol, which involves the synthesis of data from previously published literature. It does not involve human participants, data, or tissue; therefore, ethical approval and consent to participate are not required.\u003c/p\u003e\n\u003cp\u003eConsent for publication\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003eAvailability of data and materials\u003c/p\u003e\n\u003cp\u003eNot applicable. This is a systematic review protocol, and no primary data have been collected or analyzed yet. Data sharing is not applicable to this article.\u003c/p\u003e\n\u003cp\u003eCompeting interests\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eThis research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\n\u003cp\u003eAuthors\u0026apos; contributions\u003c/p\u003e\n\u003cp\u003eLR and RCAJ conceptualized the study, formulated the research question, and designed the protocol. LR and RCAJ developed the literature search strategy, defined the eligibility criteria, and drafted the initial manuscript. All the authors critically reviewed the methodology, refined the risk of bias assessment strategy, and provided significant intellectual input. All authors actively participated in reviewing and editing the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003eAcknowledgements\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eOines L, Krarup AL, Krarup PM, Jorgensen LN. Therapeutic improvement of colonic anastomotic healing under complicated conditions: A systematic review. World J Gastrointest Surg. 2016;8(5):423-34.\u003c/li\u003e\n\u003cli\u003eBrouwer WJ, Oines L, Krarup AL, Krarup PM, Jorgensen LN. Pharmacological interventions for improved colonic anastomotic healing: a meta-analysis. World J Gastroenterol. 2014;20(35):12647-58.\u003c/li\u003e\n\u003cli\u003eMoher D, Shamseer L, Clarke M, Ghersi D, Liberati A, Petticrew M, et al. Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015 statement. Syst Rev. 2015;4(1):1.\u003c/li\u003e\n\u003cli\u003eSterne JAC, Savović J, Page MJ, Elbers RG, Blencowe NS, Boutron I, et al. RoB 2: a revised tool for assessing risk of bias in randomised trials. BMJ. 2019;366:l4898.\u003c/li\u003e\n\u003cli\u003eSterne JA, Hern\u0026aacute;n MA, Reeves BC, Savović J, Berkman ND, Viswanathan M, et al. ROBINS-I: a tool for assessing risk of bias in non-randomised studies of interventions. BMJ. 2016;355:i4919.\u003c/li\u003e\n\u003cli\u003eCampbell M, McKenzie JE, Sowden A, Katikireddi SV, Brennan SE, Ellis S, et al. Synthesis without meta-analysis (SWiM) in systematic reviews: reporting guideline. BMJ. 2020;368:l6890.\u003c/li\u003e\n\u003cli\u003eGuyatt GH, Oxman AD, Vist GE, Kunz R, Falck-Ytter Y, Alonso-Coello P, et al. GRADE: an emerging consensus on rating quality of evidence and strength of recommendations. BMJ. 2008;336(7650):924-6.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Hyperbaric oxigenation therapy, gastrointestinal","lastPublishedDoi":"10.21203/rs.3.rs-9141481/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9141481/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e: Major abdominal and gastrointestinal surgeries are frequently associated with significant postoperative complications, notably anastomotic leakage and mortality. Preoperative hyperbaric oxygen therapy (HBOT) has been proposed as an adjunctive intervention to optimize tissue oxygenation and improve surgical outcomes.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eObjective\u003c/strong\u003e: To evaluate the clinical effects of preoperative HBOT on postoperative outcomes in adult patients undergoing abdominal or gastrointestinal surgery.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e: This systematic review will include randomized controlled trials (RCTs) and observational studies (such as cohort and case-control studies). We will search MEDLINE (via PubMed), Embase, and LILACS for studies comparing preoperative HBOT to standard surgical care without HBOT. The primary outcomes will be postoperative mortality and the incidence of anastomotic leakage. Secondary outcomes include postoperative pain and length of hospital stay. Two independent reviewers will screen studies, extract data, and assess the risk of bias. If applicable, a meta-analysis will be performed.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePROSPERO Registration:\u003c/strong\u003e CRD420261339389\u003c/p\u003e","manuscriptTitle":"Preoperative hyperbaric oxygen therapy for abdominal and gastrointestinal surgeries: a systematic review protocol","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-25 06:30:12","doi":"10.21203/rs.3.rs-9141481/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"4b0ecb80-062f-4bd4-a422-6cbf6a9816c4","owner":[],"postedDate":"March 25th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-03-25T06:30:12+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-25 06:30:12","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9141481","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9141481","identity":"rs-9141481","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}