High Flow Nasal Oxygen for Acute Type 2 Respiratory Failure: A Systematic Review and Meta-Analysis Protocol
Bibliographic record
Abstract
Abstract Background Acute Type 2 respiratory failure (AT2RF) is defined by hypercapnia (>6kPa) and these patients require ventilatory support in a significant proportion of cases. Non-invasive ventilation (NIV) is effective in preventing escalation to invasive mechanical ventilation (IMV) but has a high failure rate. High flow nasal oxygen (HFNO) is a novel device that integrates humidified air with oxygen at flow rates of up to 60 L/min. Various additional benefits including carbon-di-oxide (CO2) clearance have been attributed to HFNO. This systematic review aims to determine whether the use of HFNO for patients with AT2RF 1) improves arterial CO2 (PaCO2), 2) improves other clinical and patient-centred outcomes and 3) assess any potential harms. Method Searches for relevant studies will be conducted in MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials, with no language restrictions. In addition, we will search Google Scholar and the references of all articles for any pertinent studies not found in our initial search. With the assistance of a professional librarian, we will develop a systematic search strategy using appropriate keywords and MeSH terms. We will identify trials that examined the efficacy of HFNO in adult AT2RF patients. We will include randomised trials and observational studies that compared two or more modalities of oxygen delivery that includes high flow nasal oxygen as one of the modes with the comparator being low flow oxygen and/or non-invasive ventilation. The primary outcome is change in PaCO2 level while other clinical and patient centred outcomes will be collected. Two reviewers will independently assess studies for eligibility, data extraction and quality appraisal. We will conduct a meta-analysis and/or a narrative summary as appropriate. Discussion HFNO is utilised extensively in clinical practice with widening indications of use. The effects of HFNO includes CO2 clearance and PEEP benefits that may be beneficial to patients with AT2RF. While current publications indicate a beneficial role, no systematic review has attempted to summarise the evidence for this indication. The results of the proposed systematic review will summarise the current evidence to guide practice, guideline development and the design of future trials. Systematic review registration PROSPERO CRD42019148748. (https://www.crd.york.ac.uk/prospero/)
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.028 | 0.009 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.020 | 0.007 |
| Bibliometrics | 0.005 | 0.012 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.005 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; both teacher heads agree on what is shown here.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".