Abstract

Rehabilitation interventions, including structured pulmonary rehabilitation (PR) programs, can improve symptoms, exercise tolerance, and quality of life for people with chronic respiratory diseases. However, in Japan, physical therapists provide rehabilitation care across care pathways both within and outside formal PR programs, and consensus-based minimum standards for physical therapists’ essential knowledge and skills have not yet been clearly articulated. This study aimed to establish expert consensus on the minimum standards (essential knowledge and skills) required for physical therapists providing rehabilitation care for people with chronic respiratory diseases in Japan, irrespective of whether care is delivered within a formal pulmonary rehabilitation program. A two-round e-Delphi study was conducted. An expert panel of 39 experienced physical therapists from Japanese clinical and academic settings evaluated 114 potential items for inclusion as minimum standards based on a predefined 70% consensus threshold. Consensus was achieved for 105 items. The final standards span knowledge relevant to chronic respiratory disease (CRD) rehabilitation care (including common management approaches and relevant devices), patient assessment and outcome measurement (including respiratory and physical function, activity/activities of daily living (ADL), and patient-reported outcomes), and rehabilitation interventions (including exercise and activity/ADL training). Items specific to invasive line management/monitoring (e.g., arterial line–related competencies) did not reach consensus, consistent with the intent to define baseline standards across CRD rehabilitation contexts rather than intensive care unit (ICU)-specific practice standards. These standards could inform training curricula and continuing professional development, help guide policy-making and service planning by clarifying baseline expectations across care settings, and provide a reference point for future cross-national comparisons following contextual adaptation. Future research should evaluate implementation feasibility in diverse healthcare settings and support periodic review and updating of the standards as clinical evidence and service contexts evolve.

Introduction

The prevalence of chronic respiratory diseases (CRDs) was estimated at 454.6 million cases in 2019 [1], a figure expected to rise with global population growth and aging [2]. CRDs were the third leading cause of death worldwide in 2019 [1]. These diseases impose a high burden [1], with approximately 50% of people experiencing difficulties in activities of daily living (ADLs) [3,4] and diminished quality of life (QOL) [5–7].

Pulmonary rehabilitation (PR) is a structured, multidisciplinary program that combines patient education, exercise training, nutritional support, and psychosocial support, and has been shown to improve dyspnea, exercise tolerance, and QOL in people with CRDs [8–12]. International clinical practice guidelines and policy statements consistently recommend PR and emphasize exercise-based rehabilitation, with physical therapists playing a key role in assessment, individualized exercise prescription, and symptom and functional monitoring [13–16]. However, physical therapy is not synonymous with PR, and physical therapists may provide rehabilitation care for people with CRDs both within and outside formal PR programs across care pathways (e.g., in primary-care physical therapy practice for chronic obstructive pulmonary disease) [17,18].

Despite the established effectiveness of PR, access to and uptake of PR remain inconsistent across countries and healthcare systems, including substantial variation in service availability, referral, and participation [15,19–23]. Barriers to delivering and accessing PR (and rehabilitation care for people with CRDs more broadly), including referral to PR where available, are multifactorial and operate at multiple levels including system/service factors, clinician factors, and patient-level access/participation constraints, —beyond clinicians’ knowledge alone—encompassing service capacity and resources, variability in referral pathways and interprofessional coordination, and clinicians’ knowledge, beliefs, and environmental constraints [15,16,18,24–26]. Such implementation gaps, together with limited standardization of assessment and outcome measurement in CRD rehabilitation, may contribute to heterogeneity in rehabilitation content and evaluation across care settings [27–30].

In response to these implementation and standardization challenges, international initiatives have sought to harmonize respiratory physical therapy education and competency expectations, exemplified by the European Respiratory Society Respiratory Physiotherapy HERMES syllabus and harmonised curriculum [31–33]. International clinical practice guidelines and policy statements for pulmonary rehabilitation also define core program components and describe the role of physical therapists within structured PR [13–16]; however, they generally do not provide consensus-based minimum standards that apply to physical therapists delivering rehabilitation care for people with CRDs across the broader care continuum (including settings outside formal PR programs). In parallel, consensus-based minimum standards for physiotherapists have been developed internationally in other specialized settings (e.g., critical care), including Australia/New Zealand, the United Kingdom, South Africa, Nigeria, and Japan, demonstrating the feasibility of Delphi-derived frameworks to articulate baseline expectations in physical therapy practice [34–38]. Nevertheless, published consensus-based minimum standards specifically targeting physical therapists providing rehabilitation care for people with CRDs across care settings remain limited, despite growing international work on outcome domains, core outcome sets, and related educational content in pulmonary rehabilitation and CRD care [17,28,39–41].

This gap is particularly relevant in Japan, where the rapid growth in the physical therapist workforce has heightened the need for a structured educational system to ensure consistent, high-quality rehabilitation care for people with CRDs, especially among newly qualified therapists [42,43]. Drawing on literature on applicability, transferability, and adaptation in health guidance development and implementation [44,45], the applicability and transferability of minimum standards may be influenced by contextual differences (e.g., healthcare system organization and resources, educational pathways and scope of practice, and cultural expectations regarding professional roles and patient engagement). Accordingly, we present the current minimum standards as a Japan-specific baseline; when considering use in other settings, local stakeholders should assess relevance and feasibility and adapt as needed. Establishing consensus-based minimum standards could support clinical practice and education by providing a shared baseline for essential knowledge and skills. Therefore, this study aimed to establish expert consensus on the minimum standards (knowledge and skills) required of physical therapists providing rehabilitation care for people with CRDs in Japan, irrespective of whether care is delivered within a formal PR program.

Materials and methods

Results

Of the 51 expert panel candidates, 44 agreed to participate in the study. Among these participants, 39 (89%) participated in both the first and second rounds of the Delphi survey.

The 39 participants who completed both rounds represented a highly experienced group of physical therapists. The majority reported over 10 years of clinical experience, held respiratory-related professional credentials (e.g., certifications/specialist credentials in respiratory physical therapy and/or respiratory care), and reported peer-reviewed publications on respiratory physical therapy. The panel was evenly balanced between experts from medical facilities (51%) and those from academic or educational institutions (49%) (Table 1).

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Table 1. Characteristics of the participants (n = 39).

https://doi.org/10.1371/journal.pone.0344464.t001

In the first round, ≥ 70% of the respondents rated 104 of the 114 items as “highly recommended” or “recommended” for inclusion as minimum standards, whereas a consensus was not reached for ten items. In the second round, one of the ten items for which a consensus was not achieved in the first round was rated as “highly recommended” or “recommended” by ≥ 70% of the respondents (Table 2). Ultimately, consensus was achieved on 105 items for inclusion as minimum standards through the Delphi rounds. Of these items, 64 were classified as “highly recommended,” and 41 items were classified as “recommended.” A consensus was not reached for nine items (Fig 1). To facilitate rapid identification of areas with stronger consensus, items are organized into seven clearly labeled domains/categories (Domains 1–7) in Table 2 and S4 Table (knowledge of CRDs, medical devices/equipment, mechanical ventilation, pathophysiology, medical tests, assessment items, and programs), and within each domain/category items classified as “highly recommended” (stronger consensus) versus “recommended” are explicitly indicated in the tables. Of the 105 items included as minimum standards, the largest number related to assessment items (n = 39), whereas no-consensus items were concentrated in the medical devices/equipment domain (n = 4) and the assessment domain (n = 3) (S4 Table). Detailed round-by-round results for all 114 items are available in S3 Table, and the final consensus designation for each candidate item (n = 114)—“highly recommended,” “recommended,” or “no consensus”—is presented in S4 Table. A domain-level summary of the final consensus designations is provided in S5 Table. Balance- and falls-related constructs were not included as prespecified candidate items and therefore were not evaluated during the Delphi rounds; accordingly, they are not represented as standalone items in Table 2 and S3–S4 Tables.

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Table 2. Round-by-round agreement and final consensus designation for each candidate item (n = 114), organized by domain/category (Domains 1–7).

https://doi.org/10.1371/journal.pone.0344464.t002

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Fig 1. The flow of rounds throughout the e-Delphi study and summary of consensus outcomes.

In Round 1, consensus for inclusion (≥70% of panelists rating an item as 4 [recommended] or 5 [highly recommended]) was achieved for 104 of 114 items, and 10 items were carried forward to Round 2. In Round 2, one additional item met the inclusion criterion, resulting in 105 items included as minimum standards (64 classified as “highly recommended” and 41 as “recommended”) and nine items with no consensus. Items are organized by domain/category in Table 2 and S4 Table, and a domain-level summary of final designations is provided in S5 Table to enable rapid identification of areas with stronger consensus (items classified as “highly recommended”).

https://doi.org/10.1371/journal.pone.0344464.g001

In summary, the items recommended as minimum standards spanned seven domains/categories of physical therapy practice (Table 2 and S3–S5 Tables). These included patient assessment (e.g., level of consciousness, physical assessment of the respiratory system), functional evaluation (e.g., muscle strength, ADL performance, exercise capacity), and patient-reported outcomes (e.g., dyspnea status, health-related QOL, and psychological status) (Table 2), which summarizes consensus ratings for the 114 prespecified candidate items. For terminology clarity within the mechanical ventilation domain, ‘Noninvasive Ventilation’ is used here as an umbrella term that includes bilevel positive airway pressure (BPAP; often referred to clinically as BiPAP), whereas Continuous Positive Airway Pressure is listed separately as a distinct candidate item.

Discussion

This e-Delphi study established expert consensus among physical therapists on 105 minimum standards (knowledge and skills) considered necessary by the panel for physical therapists providing rehabilitation-oriented care for people with CRDs in Japan, including but not limited to PR programs. These standards may provide a foundation for harmonizing physical therapy practice and informing education and training in Japan.

The methodological rigor of this study is supported by its panel size and high participant retention. The panel size and completion rate were comparable to those reported in previous Delphi studies that developed minimum standards for physical therapists in specialized practice settings [34,36–38]. Retention across the two rounds was high (89%), which supports the stability of the consensus process and aligns with recommendations to report and consider attrition in Delphi studies [58]. The provision of anonymised group feedback between rounds, a common feature of (e-)Delphi designs, may also help sustain engagement in iterative consensus processes [48].

A key finding is that the standards identified in this study map closely onto domains emphasized in international initiatives to standardize outcome measurement in CRD rehabilitation care, including pulmonary rehabilitation [17,28,40]. Important domains such as exercise capacity, health-related QOL, and muscle function are consistent with the core domains prioritized in a recent core outcome set for pulmonary rehabilitation in COPD [40] and with work to define outcome domains and measures for COPD in physical therapy practice [17]. At the same time, international perspectives highlight ongoing heterogeneity in outcome measurement and assessment practices in pulmonary rehabilitation and related CRD rehabilitation care, underscoring the need for context-sensitive standardization [28,30].

Although the present study focused on physical therapists providing rehabilitation care for people with CRDs, our findings also show conceptual commonalities with minimum standards developed for physical therapists working in critical care settings, particularly with respect to core assessment competencies (e.g., respiratory assessment, muscle strength, functional mobility, activities of daily living, and cough effectiveness) [34,36–38]. These overlaps suggest that certain foundational knowledge and skills may be shared across clinical settings, while the required depth and context of application differ by setting. Importantly, we reference ICU minimum standards solely to contextualize areas of overlap and boundary conditions; this study does not aim to establish minimum standards for physical therapy in the ICU.

The lack of consensus on invasive line/monitoring–related items (e.g., arterial line and central venous catheter; all remaining below the prespecified 70% threshold across both rounds, Table 2) should be interpreted as delineating boundary conditions for minimum standards intended to apply across CRD rehabilitation settings. Because the Delphi survey did not elicit structured qualitative rationales for ratings, the following interpretation is necessarily contextual and inferential.

Notably, the panel endorsed several device-related competencies that may be encountered across CRD care pathways (e.g., oxygen delivery systems, noninvasive ventilation, tracheostomy-related devices, and suctioning), whereas vascular/invasive line items did not reach consensus. One plausible explanation is that invasive vascular monitoring is highly embedded in ICU workflows for critically ill patients and is closely coupled with safety management during mobilization, but expectations regarding the physical therapist’s role in interpreting or troubleshooting such devices may vary across institutions and multidisciplinary teams. Guidance on ICU mobilization safety describes device-related adverse events (including intravascular catheter removal or dysfunction) as key considerations during mobilization, underscoring that invasive devices sit within a high-acuity safety framework [60,61]. In contrast, in many routine CRD rehabilitation contexts (e.g., outpatient and community-based services), invasive vascular monitoring is not routinely available and is less commonly a prerequisite for physical therapy assessment. Therefore, non-endorsement of invasive line/monitoring–related items should not be interpreted as suggesting these practices are unimportant; rather, it indicates that they may be better positioned as setting-specific competencies contingent on patient acuity, resources, and local role delineation.

This study has several limitations. The first relates to the composition of the expert panel. As it consisted exclusively of physical therapists who were JSRPT members, the findings may have limited generalizability due to geographical and cultural specificity. In addition, because participation was voluntary, self-selection (volunteer) bias is possible. Accordingly, the panel should be interpreted as reflecting the perspectives of participating experts, and volunteer self-selection may have influenced which viewpoints were represented in the consensus process. Furthermore, the panel was composed primarily of physical therapists from medical and educational institutions, potentially excluding the perspectives of those working in care facilities. Moreover, because rehabilitation care for people with CRDs is multidisciplinary, the exclusive focus on physical therapists means that the perspectives of other relevant healthcare professionals (e.g., physicians, nurses, and occupational therapists) were not incorporated, which may limit broader acceptability and transferability across team-based care pathways. Accordingly, these findings should be interpreted as PT-specific minimum standards, rather than interprofessional minimum standards. Future research should engage multidisciplinary stakeholders to assess the acceptability, contextual relevance, and implementation considerations of these PT-specific standards within team-based CRD rehabilitation, and to inform future interprofessional consensus or adaptation work.

Second, limitations are inherent to the e-Delphi method. The consensus reflects current opinions that may evolve over time due to advancements in medical knowledge and shifts in expert perspectives; therefore, the identified minimum standards should be periodically updated. Additionally, the study relied solely on quantitative ratings to reach a consensus; we did not include open-ended questions or conduct qualitative evaluations, and therefore could not systematically examine panelists’ rationales for endorsing or not endorsing specific items, nor how individual panelists operationalized specific technical items. Accordingly, interpretations of why particular items did or did not reach consensus should be considered contextual inferences rather than empirically confirmed explanations.

Third, limitations relate to content scope and real-world applicability. Because the candidate item list was developed through a targeted review of selected documents (rather than a systematic/scoping review), some potentially relevant concepts may not have been included. Although the final minimum standards include the SPPB, which contains a standing balance subtest [62], balance impairment and falls-related constructs were not included as standalone candidate items and therefore were not evaluated as independent domains in the Delphi process. This is important because systematic reviews in COPD report clinically meaningful balance impairment compared with healthy controls and support consideration of balance assessment and training within pulmonary rehabilitation, and a more recent systematic review/meta-analysis indicates that exercise-based interventions can improve several balance outcomes while effects on falls remain uncertain and targeted balance training may provide the greatest benefits [63,64]. Future updates should therefore consider whether dedicated balance assessment and falls-related outcomes should be incorporated into an expanded candidate item list and evaluated in an updated consensus process. The Delphi-derived minimum standards reflect consensus on a prespecified candidate item list and are intended to define core knowledge and skills rather than a disease-specific protocol. Because CRDs encompass heterogeneous diagnoses and severities, some subtype- or stage-specific considerations may require local adaptation. Furthermore, entities not included in the prespecified candidate list (e.g., pulmonary edema and atelectasis) were not assessed and are therefore not reflected in the final set.

Finally, external validation is pending: the feasibility, acceptability, and practical operationalization of these standards (e.g., how they inform assessment selection and exercise intensity adjustment in routine settings) should be evaluated in future implementation studies.

Conclusion

This e-Delphi study identified 105 consensus-based minimum-standard items (knowledge and skills) for physical therapists providing rehabilitation care for people with CRDs in Japan. These standards could inform training curricula and continuing professional development, could help guide policy-making and service planning by clarifying baseline expectations across care settings, and may provide a reference point for future cross-national comparisons following contextual adaptation. Future studies should evaluate implementation feasibility in routine practice and support periodic review and updating of the standards as clinical evidence and service contexts evolve.

Supporting information

Acknowledgments

We thank the members of the Japanese Society of Respiratory Physical Therapy for participating in the Delphi survey. During the preparation of this manuscript, the authors used ChatGPT (OpenAI) to assist with English language editing for clarity and conciseness. The authors reviewed and edited the text as needed and take full responsibility for the content of the publication.