This systematic review of intervention studies (nursing interventions) will be planned and reported according to the Preferred Reporting Items for Systematic Reviews and Meta Analyses 2020 (PRISMA 2020) [14, 15]. The systematic review protocol was registered in the Prospective International Register of Systematic Reviews (PROSPERO), registration number “XX”.
The research question was developed according to the acronym Population, Intervention, Comparison or Control and Outcome (PICO): Which nursing interventions are more effective for the prevention of corneal injury in critically ill sedated and mechanically ventilated patients?
Hypothesis: the use of a polyethylene moist chamber and ocular gel lubricant appear to be the most effective nursing interventions for the prevention of corneal injury in critically ill patients.
Will be conducted in the following electronic databases: Cinahl, Cochrane CENTRAL, Embase, Lilacs, Livivo, PubMed, Scopus, and Web of Science. Grey literature search will be carried out on Google Scholar [14, 15]. The reference lists of eligible studies will be screened for additional relevant research. No language or year of publication restrictions will be applied for the selection of primary studies.
Study selection and data extraction: will be performed in two steps. First, two reviewers will evaluate independently the studies according to titles and abstracts for inclusion according to the eligibility criteria. If the title and abstract are not enough to elucidate the initial selection of the papers, the full evaluation of these ones will be carried out.
Inclusion criteria: adult and/or elderly sedated and mechanically ventilated patients admitted to ICUs. Exclusion criteria: neonates or children’s patients and those without sedation and/or mechanical ventilation will be excluded.
Intervention: any form of nursing intervention for the prevention of corneal injury in ICU will be included.
Comparator: critically ill adult and/or elderly patients who did not receive preventive interventions for corneal injury.
Outcomes: the outcome measures will include healthy cornea or reduction of corneal injury.
Study design: will be include randomized controlled trials, non-randomized controlled trials, and cohort studies .
At the end of the search, the results will be transferred to the Rayyan platform for double-blind selection of articles by the reviewers (which can be accessed for free at: https://rayyan.qcri.org). Any disagreement of the selection process will be resolved by discussion with a third reviewer [14, 15]. The selected articles will be stored in the EndNote® platform to remove duplicates and for analytical purposes [14, 15].
Risk Of Bias And Quality Of Evidence
The methodological quality of the Randomized Clinical Trials (RCTs) will be assessed using the Cochrane risk-of-bias assessment tool for randomized trials (RoB 2.0). RoB 2.0 is composed of 22 items grouped into five domains to assess the different types of bias, including: Bias arising from the randomization process, Bias due to deviations from intended interventions, Bias due to missing outcome data, in measurement of the outcome, and in selection of the reported result. The following response options will be used: ‘yes’, ‘probably yes’, ‘probably no’, ‘no’, ‘not applicable’, and ‘no information’. The overall risk of bias assessment will be carried out and will be classified as:
Low risk of bias: when the study is judged at low risk of bias for all domains for thw result.
Some concerns: when the study points out some issues in at least one domain for the result but does not present a high risk of bias for any domain.
High risk of bias: the study presents a high risk of bias in at least one domain for the result, or the study is judged to have some issues in multiple domains in a way that substantially lowers confidence in the result.
The quality of non-randomized studies will be assessed using the Risk of Bias of Interventions (ROBINS-I) tool .
Cohort studies will be evaluated by the modified version of the Newcastle-Ottawa Scale . This tool evaluates studies based on 8 domains using a star system, which are divided into 3 criteria: patient selection, comparability of study groups, and outcome assessment. High-quality studies at low risk of bias could receive a maximum of 9 stars. Studies that have obtained 8, 7, or 6 stars will be considered to have moderate quality, and a rating of 5 stars or less are low quality studies.
The certainty of the evidence will be assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system.
Data Synthesis And Analysis
Quantitative synthesis will be performed through meta-analysis depending on data availability [14, 28]. In this study, the outcome of the interventions will be used if the intervention aimed to prevent or to reduce the likelihood of corneal injury . Estimates from studies reporting binary outcomes (dichotomous variables) will be pooled using the reported Relative Risk (RR) or Odds Ratio (OR) with a 95% confidence interval (CI). Studies reporting outcomes assessed through continuous variables will be grouped using mean differences and the inverse variance method. The standard mean differences will be used to combine studies that measured the same outcome but used different methods . If necessary, data transformation will be conducted to convert continuous effect size measurements, and OR into RR. Further information about data transformation is available elsewhere . Analysis of the cost-effectiveness of interventions will not be performed.
A network meta-analysis will be carried out to compare the different types of interventions for the prevention of corneal injury in critically ill patients, even if they were not directly compared in the primary studies. Forest plot will be used to identify the different types of interventions compared with no treatment. The differences between the interventions will be measured by head-to-head analysis. The Surface under the cumulative ranking value (SUCRA value) will be used to identify which intervention has the highest effectiveness [14, 28].
Statistical heterogeneity will be assessed by visual inspection of a forest plot, χ2 test or the I2 statistic test. The interpretation of I2 will be: 0–40%: might not be important; 30–60%: moderate heterogeneity; 50–90%: substantial heterogeneity; 75–100%: considerable heterogeneity. The importance of the observed value of I2 depends on (i) magnitude and direction of effects and (ii) strength of evidence for heterogeneity [14, 28].
Subgroup analysis will be performed, if possible, to identify potential modifiers effect such as participant characteristics including sex, age and type and duration of the intervention. Sensitivity analysis will also be performed to assess the impact of studies with high risk of bias. It will be discussed whether studies with lower quality will be excluded based on sample size, evidence, and the influence of the effect on group size . Statistical analyses will be performed by Cochrane's Review Manager Software (v.5.4).