Title: Perioperative Oxygen Therapy: An overview of systematic reviews and meta-analyses
Funder: Department of Health and Social Care

Abstract: AIM: To provide a summary of why, how and when we should give oxygen to which patients around the time of their surgery. This summary will guide healthcare professionals with the use of oxygen in patient care, as well as find out what future research is needed._x000D_ _x000D_ BACKGROUND: Oxygen is regularly given to patients before, during and after surgery in order to prevent harmful effects of low oxygen levels (hypoxaemia) and complications. However, some studies suggest too much oxygen (hyperoxia) may do more harm than good. We do not currently know when and how oxygen should be given, which patients should receive oxygen and whether there are specific types of surgery or reasons when we should give more or less oxygen._x000D_ _x000D_ DESIGN AND METHODS: We will summarise the key research looking at the use of oxygen around the time of surgery by searching the electronic databases and finding all published systematic reviews. One researcher will select relevant reviews, describe their methods, report their findings and rate the review quality against a recognised checklist. Another researcher will work separately through the same process and check that all information is correct. We will overcome the limitations of previous reviews by undertaking broad analyses using data from reviews across different clinical areas to provide a full picture of the evidence. _x000D_ _x000D_ We will produce a visual map to identify the circumstances where there is evidence to show whether or not we should give oxygen. From the included reviews, we will summarise the information which tells us whether higher concentration of oxygen is beneficial or harmful, if so when and how we should give oxygen. We will include data on different types of surgery and patient groups to find which type of surgery and patients will benefit from oxygen. By looking at available data for gaps, we will also highlight areas where future research is needed. _x000D_ _x000D_ We have an expert team of senior researchers with the expertise and skill to complete this type of specialist review. To guide our project, we will form an advisory panel which includes patients and healthcare professionals involved with patient care during surgery. They will help set up our reviews so we include all research that is relevant to patients and clinicians. When we have completed our research, the group will help us interpret and summarise what we have found. _x000D_ _x000D_ PATIENT AND PUBLIC INVOLVEMENT: Our research team includes a patient research partner who has experience of undergoing and recovering from major surgery. They have agreed to work closely on the project at every stage to provide their views and share their experience. Two further patients will join advisory panel to guide the review, looking at results and writing the report of what we find. They will also help us produce user-friendly summaries of our results so we can share our results with the public._x000D_ _x000D_ DISSEMINATION: We will share information about the project from the start, as it progresses and also at the end. We will actively inform patients, members of the public and healthcare professionals who are involved in the care of patients during surgery. We will use our close links with key stakeholders, such as Royal College of Anaesthetists, Perioperative Clinical Trials Network and Royal College of Nursing, to share our findings. We will share simple, plain English as well as medical summaries of the project through spoken, pictorial and written information, including social media.

Lay abstract: BACKGROUND_x000D_ It is estimated that 1 in 20 people undergo anaesthesia for surgery each year. Oxygen is routinely given to patients during and after surgery to prevent and treat hypoxaemia. Hypoxaemia may be particularly harmful due to stress and inflammatory response from surgery, potentially causing organ damage post-surgery. High concentration of oxygen has been recommended as a strategy to reduce surgical site infections, however, there are also evidence of potential harm associated with liberal use of oxygen. A panoramic overview of these reviews examining the effectiveness of different approaches is needed to aid clinical decision making and the direction of future research. _x000D_ _x000D_ AIM_x000D_ To conduct an overview of systematic reviews and meta-analyses to answer the research question, ‘For which type of surgery, at which stage of care, in which sub-groups of patients, delivered under what conditions are different types of perioperative oxygen therapy clinically effective?’_x000D_ _x000D_ METHODS_x000D_ Relevant reviews will be identified using index terms and text words related to oxygen therapies and surgeries through searches of key electronic databases including MEDLINE and EMBASE, Cochrane Database, Epistemonikos, PROSPERO, the International HTA Database, and the DARE archives. Searches will not be limited by time period or publishing language. Titles and abstracts of records retrieved will be screened by two reviewers independently. Each review will be mapped according to types of surgery, timepoints in surgical pathway and comparisons made (e.g. different oxygenation strategies or delivery device). Reviews with the most comprehensive and up-to-date coverage of relevant literature will be chosen as anchoring reviews. Standardised data will be extracted, including definition of oxygen therapy, summaries of interventions and comparators, patient population and surgery, and assessment of overall certainty of evidence. For clinical outcomes and adverse events, the overall pooled findings and results of subgroup and sensitivity analyses (where available) will be extracted. Trial-level data will be extracted for surgical site infections, death and potential trial-level effect modifiers such as risk of bias and outcome definition to facilitate quantitative data, which will adopt a multiple indication review approach with panoramic meta-analysis and meta-regression. Findings will be summarised with evidence map._x000D_ _x000D_ PPI_x000D_ Our proposal received positive support by local PPI group. A PPI co-applicant has joined to provide input throughout research delivery, including design, analysis, and dissemination. Two further PPI members will be invited to join a wider advisory panel. This panel is made up of key stakeholders including patients and clinicians involved in the care of patients undergoing surgery. The AP will review our final protocol, mapping of studies, synthesis strategy and interpretation. The AP will also guide our overview to produce clinically relevant recommendations and conclusions. _x000D_ _x000D_ DISSEMINATION_x000D_ We will share our research through PROSPERO registration and publication of the review protocol. The final project report will be published in NIHR Journals Library. We will prepare secondary publications examining oxygenation strategy and delivery device separately. We will present our findings to key stakeholders and professional bodies and NICE. We will present the findings at conferences and produce infographics as well as a lay summary to be shared with the public.

Research activity codes: 6.1 PHARMACEUTICALS
Health categories: GENERIC HEALTH RELEVANCE