Evidence-Based Practice in Respiratory Care

Overview

Evidence-based practice (EBP) integrates the best available research evidence with clinical expertise and the patient's values and preferences to guide care. For respiratory therapists, this means going beyond protocol habit or what was done “last decade” and grounding each clinical decision in current, appraised evidence. EBP is not about ignoring experience — it is about combining experience with what the literature actually supports, filtered through what matters to the individual patient.

The AARC, credentialing organizations, and accrediting bodies all emphasize EBP competency because it drives better patient outcomes, reduces unwarranted variation, and keeps practice current as research evolves. Understanding the EBP process is foundational to professional practice and is tested on board examinations.

Key Concepts

The EBP process is commonly organized around five steps, known as the five A's:

1. Ask a focused clinical question. Use the PICO framework — Population, Intervention, Comparison, Outcome — to frame a searchable, answerable question. A well-formed PICO question narrows the literature search and makes it easier to judge whether a study applies to your patient.
2. Acquire the best available evidence. Search peer-reviewed databases (PubMed, CINAHL, Cochrane Library) using terms derived from your PICO question. Filter for study designs that are most likely to answer your question and for recency where guidelines evolve quickly.
3. Appraise the evidence for validity and applicability. Not all studies are equal. Evaluate the study design, sample size, risk of bias, statistical significance, and clinical relevance. A finding that is statistically significant may still be too small to matter clinically.
4. Apply it, integrating clinical judgment and patient values. Translate the evidence into a care decision. Factor in the patient's preferences, comorbidities, and individual circumstances, and apply your clinical expertise to determine whether the evidence fits this particular situation.
5. Assess the outcome and adjust. Evaluate whether the change produced the expected result. If it did not, revisit the question and the evidence. This closing step turns EBP into a continuous improvement cycle rather than a one-time event.

The hierarchy of evidence

Study designs are not interchangeable. They differ in their susceptibility to bias and their ability to establish causation. The hierarchy below ranks designs from strongest to weakest — a key concept for appraising the literature and for understanding why systematic reviews carry more weight than a single case report.

When appraising a source, identify where it sits in the hierarchy before accepting its conclusions. A single expert opinion may be valuable when evidence is absent, but it should not outweigh a well-conducted RCT when one exists.

From evidence to the bedside

Research findings reach clinical practice through several translational mechanisms that respiratory therapists encounter daily:

• AARC Clinical Practice Guidelines (CPGs). The American Association for Respiratory Care publishes CPGs that synthesize the evidence on specific clinical topics — from oxygen therapy to bronchial hygiene — and assign graded recommendations based on evidence quality. CPGs are updated as new evidence emerges and provide a rigorously developed starting point for institutional protocols.
• RT-driven protocols. Institutions operationalize CPG recommendations into site-specific protocols that empower respiratory therapists to assess patients and adjust care (such as oxygen titration or weaning ventilator support) without requiring a separate physician order at each step. Protocol-driven care has been shown to reduce length of mechanical ventilation and improve consistency.
• Quality-improvement cycles. Methods such as Plan-Do-Study-Act (PDSA) allow teams to test evidence-based changes on a small scale, measure the result, and iterate. This closes the fifth step of the EBP process — assessing the outcome — and embeds continuous improvement into departmental culture.
• Journal clubs and continuing education. Regular review of current literature keeps clinicians aware of evolving evidence between guideline updates. The AARC and CoARC both emphasize lifelong learning as a professional obligation.

Common Pitfalls

• Relying on tradition or anecdote.“We have always done it this way” is not evidence. Practices that predate rigorous study may be ineffective or harmful — EBP exists precisely to surface and replace them.
• Treating all studies as equal.A case report describing one patient's response is not equivalent to a multi-center RCT. Always locate a source in the evidence hierarchy before weighting its conclusions.
• Ignoring patient values and preferences. EBP is not algorithmic. The best evidence still must be filtered through what the individual patient wants and what is feasible given their circumstances and goals of care.
• Skipping the outcome assessment step. Applying a change without evaluating the result breaks the cycle. Without step five, there is no way to know whether the intervention worked — or caused unintended harm.
• Confusing statistical significance with clinical significance. A p-value below 0.05 does not automatically mean the effect is large enough to matter at the bedside. Always look at effect size and confidence intervals alongside p-values.

Key Takeaways

FAQ

Related Resources

Sources

1. Kacmarek RM, Stoller JK, Heuer AJ. Egan's Fundamentals of Respiratory Care. 12th ed. Elsevier; 2021. Quality and evidence-based respiratory care.
2. Guyatt G, Rennie D, Meade MO, Cook DJ. Users' Guides to the Medical Literature: A Manual for Evidence-Based Clinical Practice. 3rd ed. McGraw-Hill; 2015.