Author Response: Let It Breathe: Mastering Spontaneous Breathing Trials

Dear Editor,

We appreciate the interest of Passos and Lourenço in our clinical practice guideline (CPG). We hope our CPG positively contributes to the care of critically ill patients. CPGs add to the body of scientific evidence that supports clinical decision making, policy making, and education.¹ Most important, CPGs are intended to improve patient outcomes.

From a methodological perspective, the American Association for Respiratory Care has evolved in how CPGs are developed. Goodfellow² notes this change in the July 2024 issue of Respiratory Care. This systematic approach to guideline development is necessary for meeting international standards to avoid bias, summarize the evidence, and provide readers with a resource to develop protocols, further test hypotheses, and ultimately guide patient care.¹ Importantly, we have adopted the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to developing CPGs.³ The GRADE process has 2 components—a systematic review of the certainty of evidence and development of recommendations.^4,5

Our reliance on systematic reviews to synthesize the evidence meets international standards set by the GRADE Working Group.^4,5 With these standards, either the CPG working group writes their own systematic review or they rely on published systematic reviews if they exist. The certainty of the evidence is rated as high, moderate, low, or very low. Once the evidence has been assessed, recommendations are written, and the strength of the recommendations rely on a balance between desirable and undesirable outcomes.^1,4,5

As noted by Passos and Lourenço, study design, population, and outcome measures must be considered. We acknowledge our use of low or very low certainty of evidence, (ie, our reliance on observational and quasi-experimental studies), and we encourage curious researchers to further explore these topics with higher-quality study designs so that our collective knowledge may be increased. Low or very low certainty of evidence does not preclude recommendations. Recommendations are not limited to those that can be supported by randomized controlled trials (RCTs). Careful reading of our recommendations clearly indicates that all are conditional and that some are associated with low or very low certainty of the evidence.³

Our CPG was written with a primary focus on acutely ill mechanically ventilated patients, which we should have made clearer in the manuscript. We regret any confusion that this might have introduced. As noted, by Passos and Lourenço, further research is needed to understand the implications of these guidelines in different patient populations, such as those receiving prolonged mechanical ventilation. We did identify one RCT that included subjects liberating from prolonged mechanical ventilation.⁶ We used that study not to address ventilator liberation in patients receiving prolonged mechanical ventilation but rather as indirect evidence related to pressure support ventilation versus T-piece during a spontaneous breathing trial. Again, our research question was not specific to this population. We look forward to future guidelines that address questions regarding liberation from prolonged mechanical ventilation and the implications of discontinuation of mechanical ventilation in a variety of patient populations.

The GRADE approach provides a list of considerations for use when writing recommendations and grading the strength or weakness of recommendations. Our recommendations are all conditional.³ We acknowledge the limitations that may be present due to the values and preferences of clinicians, patients and their families, and policy makers. These recommendations, as well as the certainty of the evidence, were determined by the GRADE process.¹

The barriers to implementation of CPGs are important. Resources, clinician time, preconceived biases, and institutional culture hamper the implementation process. As experienced researchers, clinicians, and educators, we understand the implications of standardized patient care. Despite evidence dating to the late 1990s, challenges remain with implementation of ventilator liberation protocols. As we note in our recommendations, local culture may often dictate how and when the guidelines are implemented. Notably, CPGs are written not only for clinicians but for other stakeholders.¹ The perspectives of different stakeholders do not always align. For this reason, and so that patients may benefit from improvements in quality of care, we encourage clinicians to implement guidelines in a methodical fashion. Basing quality improvement projects on these guidelines will not only help refine the application of these guidelines but will also add to the body of evidence.

We encourage readers to consider for themselves the rigor of our methods and weigh the pros and cons of implementation. We are encouraged by the interest that has already been taken in our guideline and look forward to more research advancing strategies that assist in patient liberation from mechanical ventilation.