| Course | N415 Research / Evidence-Based Practices |
|---|---|
| Module | Module 5 |
| Paper type | Evidence appraisal paper |
| Length | About 1,078 words, 6 pages |
| Format | APA 7 student paper |
| School | Aspen University |
| Program | Pre-licensure BSN |
| Updated | September 2026 |
Free sample paper for N415 Module 5
Twenty-Seven Trials, Mostly Weak: Placing and Appraising a Meta-Analysis on Humidified Low-Flow Oxygen
Student Name
Pre-licensure BSN Program, Aspen University
N415: Research / Evidence-Based Practices
Instructor Name
Month Day, Year
Twenty-Seven Trials, Mostly Weak: Placing and Appraising a Meta-Analysis on Humidified Low-Flow Oxygen
A search produces a pile of sources; levels of evidence put them in order. This paper ranks the sources gathered for a question raised on my medical unit, whether low-flow nasal oxygen, up to 4 liters, needs a bubble humidifier, and then appraises the source at the top of the pile, a systematic review and meta-analysis of humidified and non-humidified low-flow oxygen (Wen et al., 2017). The appraisal uses AMSTAR 2, a tool built to judge the confidence a reader can place in a review (Shea et al., 2017).
A Hierarchy for an Intervention Question
For questions about whether an intervention works, systematic reviews of randomized trials sit at Level I, single well-designed randomized trials at Level II, controlled trials without randomization at Level III, cohort and case-control studies at Level IV, reviews of descriptive or qualitative studies at Level V, single descriptive or qualitative studies at Level VI, and the opinion of authorities and expert committees at Level VII (Melnyk & Fineout-Overholt, 2023). The hierarchy reflects how well each design protects against bias when answering a question of cause and effect.
| Source | Design | Level | What it adds |
|---|---|---|---|
| Wen et al. (2017) | Meta-analysis of 27 randomized trials | I | Pooled effects on dryness, nosebleeds, contamination and infection |
| Poiroux et al. (2018) | Randomized non-inferiority trial | II | Patient discomfort by flow rate |
| Tang et al. (2024) | Cross-sectional survey of 243 nurses | VI | Why nurses keep humidifying |
| Mooren et al. (2023) | Qualitative interview study | VI | What patients fear about oxygen |
| O'Driscoll et al. (2017) | National guideline | VII in this hierarchy | Expert recommendation built on the evidence |
Level Is Not Quality
A Level I source can be weak, and a Level VI source can be excellent for the question it asks. Level describes design; quality describes how well that design was carried out. A meta-analysis that pools poorly conducted trials produces a precise-looking answer built on uncertain parts. That is why the review at the top of this table needs its own appraisal before a unit acts on it. It is also why the guideline appears at the bottom of the hierarchy even though, for practice, it may carry the most weight: the British Thoracic Society guideline states that low-flow oxygen does not need humidification (O'Driscoll et al., 2017), but its authority depends on the evidence beneath it.
The Review in Brief
Wen et al. (2017) set out to determine the effects of humidified compared with non-humidified low-flow oxygen in adults. They searched six databases, PubMed, EMBASE, ScienceDirect, the Cochrane Library and two Chinese databases, for randomized trials from 1980 to 2016, and they report following Cochrane recommendations. They included 27 trials with 8,876 patients and pooled results as risk ratios or weighted mean differences using fixed or random effects models. Non-humidified oxygen was associated with less bacterial contamination of humidifier bottles and fewer respiratory infections. There were no significant differences in dry nose, dry nose and throat, nosebleeds, chest discomfort, the smell of oxygen or oxygen saturation. The authors concluded that routine humidification is not justified but noted that most included trials were of poor quality.
Appraisal With AMSTAR 2
The review's question includes the elements a reader needs: adults, low-flow oxygen, humidified compared with non-humidified delivery and several outcomes. Its search was broad, and including two Chinese databases was a strength, since humidifying all oxygen has been routine in China and Japan and many trials were published there. Restricting inclusion to randomized trials fits an intervention question. The review assessed and reported the quality of its trials, and its conclusion reflects that assessment rather than ignoring it, which AMSTAR 2 treats as a critical domain (Shea et al., 2017). Other critical domains must be checked in the full text rather than assumed: whether a protocol was registered before the review began, whether the list of excluded studies was given with reasons, how heterogeneity was handled when choosing between fixed and random effects, and whether publication bias was examined. On the information reported, overall confidence is best rated low to moderate, mainly because the pooled estimates rest on weak trials.
Interpreting the Findings With Their Limits
Two kinds of findings need different readings. The absence of differences in dryness and nosebleeds is the finding that matters most for comfort, and absence of evidence of a difference in weak trials is not proof that no difference exists. The contamination and infection findings are more plausible mechanically, since a warm bottle of water can grow bacteria, but infection outcomes in small, poorly reported trials deserve caution. The later intensive care trial, published after this review, showed that, a day into treatment, patients on flows up to 4 liters were no less comfortable without the humidifier (Poiroux et al., 2018), which strengthens the comfort conclusion for low flows without settling it for higher ones.
Applicability to a Medical Unit
Most trials came from hospitals where every oxygen patient was humidified, so their comparison is the one our unit faces. Differences in climate, equipment and patient mix limit transfer, and the review does not say how many patients received flows near the 4-liter line. Even so, the direction of all sources is the same, the harms of removing humidification appear small, and the costs and contamination risks of keeping it are real.
Where the Lower-Level Sources Fit
The survey and the interview study answer questions the meta-analysis cannot. Tang et al. (2024) found that three in four nurses in their sample used humidifiers routinely and that knowledge was weak, which suggests that any change on our unit will need education as well as evidence. Mooren et al. (2023) showed how much fear patients attach to oxygen, which is a reminder that removing a familiar piece of equipment may worry some patients and families unless nurses explain it. Neither study can say whether humidification helps. Both shape how a unit would act on the review's answer, which is why an evidence summary should keep them rather than discard everything below Level II.
Conclusion
Ranked by level, the evidence on humidifying low-flow oxygen is led by a meta-analysis and a randomized trial, with a survey and an interview study explaining why practice lags. Appraised for quality, the meta-analysis is informative but built on weak trials. Together they support stopping routine humidification at 4 liters or less, with attention to patients who report dryness, which is the recommendation the next modules turn into a unit plan.
References
Melnyk, B. M., & Fineout-Overholt, E. (2023). Evidence-based practice in nursing & healthcare: A guide to best practice (5th ed.). Wolters Kluwer.
Mooren, K., Atsma, E. M., Duinker, E., Kerstjens, H. A. M., Currow, D., & Engels, Y. (2023). "This is what lies ahead": Perspectives of oxygen-naive COPD patients on long-term oxygen use. A qualitative study. International Journal of Chronic Obstructive Pulmonary Disease, 18, 181-188. https://doi.org/10.2147/COPD.S391095
O'Driscoll, B. R., Howard, L. S., Earis, J., & Mak, V. (2017). BTS guideline for oxygen use in adults in healthcare and emergency settings. Thorax, 72(Suppl. 1), ii1-ii90. https://doi.org/10.1136/thoraxjnl-2016-209729
Poiroux, L., Piquilloud, L., Seegers, V., Le Roy, C., Colonval, K., Agasse, C., Zinzoni, V., Hodebert, V., Cambonie, A., Saletes, J., Bourgeon, I., Beloncle, F., & Mercat, A. (2018). Effect on comfort of administering bubble-humidified or dry oxygen: The Oxyrea non-inferiority randomized study. Annals of Intensive Care, 8, Article 126. https://doi.org/10.1186/s13613-018-0472-9
Shea, B. J., Reeves, B. C., Wells, G., Thuku, M., Hamel, C., Moran, J., Moher, D., Tugwell, P., Welch, V., Kristjansson, E., & Henry, D. A. (2017). AMSTAR 2: A critical appraisal tool for systematic reviews that include randomised or non-randomised studies of healthcare interventions, or both. BMJ, 358, Article j4008. https://doi.org/10.1136/bmj.j4008
Tang, N., Li, H., Zhang, J., Ling, H., Shi, L., Zhang, H., Guo, Q., & Yu, R. (2024). Nurses' knowledge, attitude, and practice of low-flow oxygen therapy and humidification. Frontiers in Medicine, 11, Article 1460079. https://doi.org/10.3389/fmed.2024.1460079
Wen, Z., Wang, W., Zhang, H., Wu, C., Ding, J., & Shen, M. (2017). Is humidified better than non-humidified low-flow oxygen therapy? A systematic review and meta-analysis. Journal of Advanced Nursing, 73(11), 2522-2533. https://doi.org/10.1111/jan.13323
What the N415 Module 5 instructions ask for
Aspen's catalog names types and levels of evidence within N415, and this sample rests on that description, the module wording itself being kept for enrolled students. A levels-of-evidence assignment usually asks you to place the sources from your search on a hierarchy, explain the placement and appraise at least one source in depth, often a systematic review. Instructors frequently name the hierarchy, such as Melnyk and Fineout-Overholt's seven levels or the Johns Hopkins model, and may require a specific appraisal tool. Check whether a table is required, whether guidelines should appear on the hierarchy, and whether the appraisal must end with a recommendation for practice. Ask whether a guideline or a qualitative study should appear on the hierarchy at all.
Inside the N415 Module 5 example
About 1,075 words fall under nine headings, with one table. The introduction links the paper to the search in Module 4. The hierarchy section defines seven levels and places five sources in a table with what each adds. Level is not quality explains why a Level I review can be weak and where the guideline fits. The review in brief reports its question, databases, trials, pooling and findings. The AMSTAR 2 section works domain by domain. Two sections interpret the findings and their applicability, one explains where the survey and the interview study fit, and the conclusion states the recommendation carried into the next module. Each source keeps the year and design shown in the table so that readers can find it quickly.
Where the marks sit in the N415 Module 5 rubric
Instructors grading this assignment usually look for correct placement of sources, a clear distinction between level and quality, and an appraisal that uses a recognized tool with judgment. Placement is accurate, and the table's last column explains what each source contributes, which a margin note highlights. The distinction between level and quality gets its own section. The appraisal uses AMSTAR 2 domains and, importantly, separates what the review reports from what must be verified, which is a mark of honest appraisal. Interpretation reads null results carefully. Points for writing and format go to a readable table and correct APA entries for seven sources. Clear headings for each AMSTAR 2 domain group make the judgment easy to follow.
Common N415 Module 5 mistakes, and how to avoid them
A frequent mistake is treating level as a grade, assuming a meta-analysis is strong because of its position. Appraise it. Students also appraise from the abstract alone and fill checklist items they cannot see; say which items need the full text. Another common problem is reading no significant difference as proof of no effect, especially when the pooled trials are weak. Some papers drop surveys and qualitative studies because of their level, although they often explain why practice lags. Keep them with their purpose stated. Finally, end with a recommendation sized to the evidence, neither overstated nor so cautious that it says nothing. State your confidence rating and the reason for it.
Write yours, or have the desk draft it
This paper is an original model document written by our desk, not a submitted student paper and not an official Aspen University document. Read it for the moves, then write your own to the instructions in your classroom. If you want one built to your exact prompt and rubric, the first custom sample is free and arrives in 24 to 48 hours.
More N415 and Pre-licensure BSN sample papers
- N415 Module 1: The Research Process Traced Through One Study
- N415 Module 2: Critique of a Randomized Oxygen Trial
- N415 Module 3: Critique of a Qualitative Oxygen Study
- N415 Module 4: PICOT Question and Documented Search
- N415 Module 6: Failure to Rescue as a Quality Indicator
- N415 Module 7: Implementation and Evaluation Plan
- N415 Module 8: Disseminating Evidence and Informatics
- N410 Module 4: Teaching Plan for Starting Hemodialysis
- N455B Module 3: Prioritizing Hypotheses in a Respiratory Case
- N437 Module 2: Sociotechnical Analysis of a System Problem
- N455A Module 5: The Clinical Judgment Model Behind NGN Items
N415 Module 5 questions, answered
What does N415 Module 5 usually ask for?
Aspen's N415 description names the types and levels of evidence, so a paper that ranks sources and appraises a systematic review is a common assignment. Check your classroom for the hierarchy your course uses.
Which appraisal tool should I use for a systematic review?
AMSTAR 2 is designed for reviews of healthcare interventions; CASP and JBI checklists are also common. Use the one your instructor names and apply each item to the review.
Is a meta-analysis always the best evidence?
It sits at the top of most hierarchies for intervention questions, but its quality depends on the trials it pools. A meta-analysis of weak trials still needs cautious reading.
Where can I find a free N415 Module 5 sample paper?
A complete levels-of-evidence paper with an AMSTAR 2 appraisal is posted on this page, table and margin notes included, free for anyone to open. It is the fifth N415 sample and appraises the review found in the Module 4 search.
Where do guidelines go on the N415 Module 5 evidence hierarchy?
In the seven-level hierarchy many courses use, expert committee opinion sits at Level VII, but evidence-based guidelines carry weight in practice because they rest on reviews. Say where your hierarchy places them and why.