Practice of airway clearance in critically ill patients: a cross-sectional survey of respiratory therapists and physiotherapists in China

Introduction

The physiological components of the airway clearance system include effective mucociliary clearance system, adequate fluid intake, an effective cough reflex and patent airways (1,2). Due to differences in underlying diseases and disease progression, critically ill patients generally have artificial airways, complicated infections, immobilization (prolonged bed rest) and other factors, which usually impair one or more of the above mechanisms, leading to decreased airway clearance ability (3,4). The purpose of airway clearance therapy is to enhance one or more of the above physiological functions (5), thereby improving the overall airway clearance effect, reducing the occurrence of adverse pulmonary events, and improving the prognosis of critically ill patients (6-10).

Based on implementation approaches, airway clearance therapy is broadly divided into pharmacological (n-acetylcysteine, ambroxol hydrochloride, bromhexine, etc.) (11) and non-pharmacological modalities, the latter generally termed manual or mechanical airway clearance techniques (ACTs) (12). In response to the functional decline of airway clearance caused by different impaired mechanisms, corresponding intervention measures need to be selected (13-15). These measures can be divided into three categories (16-18): (I) increasing inspiratory volume, such as postural drainage which may indirectly increase inspiratory volume, incentive spirometry (IS), non-invasive mechanical ventilation (NIV), intermittent positive pressure breathing (IPPB), manual/mechanical hyperinflation, continuous positive airway pressure (CPAP), forced expiratory technique (FET) and active cycle of breathing technique (ACBT), they also increase expiratory volume in the meantime; (II) increasing expiratory flow rate, such as postural drainage, cough/huff training, assisted cough, expiratory muscle training, mechanical insufflation-exsufflation (MI-E); (III) oscillation, such as percussion, manual/mechanical vibration, high-frequency chest wall oscillation (HFCWO) vests, intrapulmonary percussive ventilation (IPV), continuous high-frequency oscillation therapy (CHFO) (19), oscillating positive expiratory pressure (O-PEP) devices (20). If the patient is in a critical condition, airway suction can be selected, including sputum suction through artificial airways and natural lumens.

At present, domestic and foreign studies related to ACT mainly focus on diseases characterized by a significant decline in airway clearance function such as chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF), etc. It has been confirmed that ACT can effectively improve the clearance ability of these patients, improve their quality of life, and enhance prognosis (21-24). However, due to the variety of types and implementation methods of ACT, not all treatment methods have been verified by research and there are some cases of non-compliant use (13,25-27). Even in patients with specific diseases that have been extensively studied, no standardized operation procedures for ACT have been formed. Most critically ill patients have comorbidities, once the patient enters the acute phase of the disease, the implementation of the plan may have to be interrupted. That’s the reason why there are relatively few studies on ACT in such patients, and the level of evidence is not high (28,29). The lack of standardized operating procedures has led clinical staff to rely more on their own clinical experience in practical work, resulting in highly subjective treatment methods (3).

Airway management, prevention of pulmonary complications and early rehabilitation in critically ill patients are core responsibilities of respiratory therapists (RTs) and physiotherapists (PTs), with regional variations in specific duties (16,30). This study aims to understand the current status of airway clearance practice in the Chinese mainland by distributing questionnaires to RTs and PTs in different regions, including their preferences for different techniques, parameter selection, and main challenges. It is hoped to provide data support for the standardization and normalization of ACT-related operations. Furthermore, this study investigated the reasons why individuals fail to implement or rarely implement ACT, with the aim of identifying potential solutions. We hypothesized that while ACT is widely utilized in Chinese intensive care units (ICUs), there is a significant gap between clinical practice and evidence-based recommendations, primarily driven by hospital grading, regional resource disparities, and the lack of standardized training among RTs and PTs. We present this article in accordance with the STROBE reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2026-1-0089/rc).

Methods

Questionnaire design and participant recruitment

This questionnaire was co-developed by an interdisciplinary panel of 5 experienced critical care, respiratory therapy and rehabilitation specialists from Zhongshan Hospital, Fudan University, Sir Run Run Shaw Hospital and PLA General Hospital. Guided by the systematic engineering theory of questionnaire design (31), it ensured content validity and fillability, with the core logic of “accurately measuring practice status, identifying implementation barriers and collecting improvement suggestions”. Aligned with professional standards for critical care respiratory and rehabilitation therapy (29,32,33), the questionnaire was structured into four sections: (I) demographic characteristics: age, gender, occupation, experiences, professional title, education level, workplace, hospital grade, setting, and bed capacity; (II) overview of ACT clinical application: duration, frequency, timing, indications, methods, adverse effects, and efficacy assessment. A 5-point Likert scale (always/often/sometimes/rarely/never) quantified ACT use frequency, adverse events, and other indicators; (III) experience with specific ACT devices: experience with four devices—percussion therapy device, HFCWO, MI-E, and CHFO—was assessed based on usage patterns, parameter selection, comfort, and efficacy and (IV) challenges and suggestions for improvement: addressing barriers to implementation and recommendations for enhancing ACT practices. The English version of the questionnaire is provided in Appendix 1.

Exclusion criteria: individuals with no clinical frontline experience (<6 months); those with frequent department transfers who were unable to clarify whether they were exposed to ACT in their daily work. A pilot test was conducted prior to the formal distribution of the questionnaire to evaluate its feasibility, readability, and logicality; 15 PTs and RTs were invited to complete the pilot survey. Feedback from the participants was collected to revise ambiguous items and optimize the questionnaire structure, and the pilot data were not included in the final analysis.

The survey was distributed via social media, online platforms, and the survey tool Wenjuanxing from July 14 to August 13, 2023. A total of 66 liaisons from 28 provinces and cities across China helped in recruiting participants. Responses were reviewed independently by two investigators, and only questionnaires that are fully completed and without conflicts are considered valid.

Ethical considerations

The study was approved by the Medical Ethics Committee of Zhongshan Hospital, Fudan University (No. B2023-232R), conducted in accordance with the Declaration of Helsinki and its subsequent amendments, and informed consent was obtained from all participants. This article has been registered under the registration number: ChiCTR2300075280.

Statistical analysis

Descriptive statistics were used to present continuous variables as mean ± standard deviation and categorical variables as frequencies (percentages). Chi-squared test was adopted for the difference analysis of constituent ratios between groups, and Kruskal-Wallis H test was used for the difference analysis of ordinal categorical variables with graded data. Data analysis was conducted using Python 3.13.

Results

Adopting snowball sampling with clearly defined participants, this study distributed 1,278 targeted questionnaires to eligible subjects (online sample), yielding 1,246 completed responses (response rate: 97.5%). After excluding 18 duplicates and 24 invalid questionnaires with obvious errors, 1,204 remained. Among these, 220 participants who did not perform airway clearance therapy during the study period only completed the “Challenges and suggestions for improvement” section, while the remaining 984 full respondents formed the primary cohort for statistical analysis. Detailed information is provided in Figure S1.

Demographic characteristics

Demographic characteristics of participants who perform airway clearance therapy (Group Yes, n=984) and non-performers (Group No, n=220) are shown in Table 1, Group No refers to the population that did not implement frontline ACT during the study period. Statistically significant differences were observed between the two groups in gender (P=0.03), hospital level (P<0.001), age (P=0.004), and department bed capacity (P<0.001), with no significant differences in other characteristics (all P>0.05). In Group Yes, males accounted for 51.5% and Grade A tertiary hospitals for 79.3%, both higher than Group No (43.2% and 56.4%, respectively). Group Yes had a younger mean age (33.2±6.4 vs. 34.3±6.7 years in Group No) and more department beds (23.1±15.5 vs. 16.1±10.9 in Group No). Both groups were predominantly RTs (91.1% vs. 93.6%), had bachelor’s degrees as the main education level (80.7% vs. 86.4%), and were dominated by intermediate titles (including attending physicians, chief nurses, and chief technologists, all of which are intermediate-level clinical titles) and 6~10 years of work experience. General ICU (GICU) was the primary department (≈46.7% each) followed by respiratory ICU (RICU), with balanced regional distribution across eastern, central, western, and northeast China.

Application status of ACT implementation

Overview of ACT implementation

ACT services are provided by RTs/PTs even during nights (60.0%) and weekends (78.5%). Most respondents (79.6%) used ACT for both therapeutic and prophylactic purposes. The typical total daily ACT duration was 30–60 minutes (54.8%). Billing limitations were observed: most hospitals could only partially charge for ACT (74.7%), and 21.3% could not charge for ACT at all (Table S1).

Different ACT exhibited varying utilization frequencies (Table S2). According to survey results, the techniques most frequently rated as “always” included: mucolytics (41.5%), nebulized expectorants (55.8%), enhanced warming and humidification (66.4%), early mobilization (35.8%), postural drainage (50.7%), manual percussion (49.9%), percussion therapy device (42.7%), mechanical hyperinflation (29.2%), and suctioning via artificial airway (51.4%).

Those most frequently rated as “often” included: HFCWO (25.6%), abdominal breathing exercises (30.8%), directed cough (39.9%), FET (25.4%), autogenic drainage (32.9%), blind suctioning via the nasal or oral route (40.1%), bronchoscopy (43.2%), and bronchoalveolar lavage (37.0%).

Techniques most frequently rated as “sometimes” included: manual compression (33.1%), ACBT (22.9%), and pharyngeal stimulation (36.3%).

Those most frequently rated as “rarely” included: nebulized hypertonic saline (33.7%), instillation of saline into the airway for stimulation (33.6%), and manual hyperinflation (29.1%).

Techniques most frequently rated as “never” included: IPV (50.8%), CHFO (54.1%), MI-E (50.1%), IS (51.0%), non-gravity O-PEPs (52.1%), gravity O-PEPs (57.2%) and RC cornet (a non-gravity O-PEPs) (64.6%). Figure 1 illustrates the frequency of these interventions.

Figure 1 Overview of ACT implementation. ACBT, active cycle of breathing technique; CHFO, continuous high-frequency oscillation therapy; FET, forced expiratory technique; HFCWO, high frequency chest wall oscillation; IPV, intrapulmonary percussion ventilation; IS, incentive spirometer; MI-E, mechanical insufflation-exsufflation; O-PEPs, oscillatory positive expiratory pressure devices.

Details of ACT implementation

Prophylactic ACT was deemed necessary for patients with “poor lung function” (80.1%) and “comorbid chronic lung diseases” (80.0%). Therapeutic ACT was commonly initiated for “audible rhonchi” (96.3%), “difficulty coughing” (95.8%), “marked hypoxemia” (91.7%), and “significant imaging findings” (88.1%). Efficacy was primarily assessed via “sputum volume and properties” (99.0%), “SpO₂” (95.2%), “auscultation” (94.4%), and “arterial blood gas analysis” (93.8%). ACT planning mainly considered “patients’ airway and discharge status” (99.2%), “patient tolerance and comfort” (97.8%), and “personal clinical experience” (89.2%) (see Table 2). During ACT implementation, changes in vital signs were occasionally observed: heart rate (41.9%, “sometimes”), blood pressure (47.0%), SpO₂ (41.2%), and respiratory rate (42.6%, “often”). Some reported occasional increases in pain (48.4%) and cardiac arrhythmia (53.2%, “rarely”) (see Table 3).

Usage preferences for specific devices

Percussion therapy device

Most users (84.5%) preferred frequency “1–2 times/day” (69.2%), “medium oscillation (9–15 Hz)” (68.6%), and duration “15–30 minutes” (56.7%). Comfort was rated “good” (60.5%), while efficacy was “average” (54.5%) (see Figure 2A).

Figure 2 Usage preferences for specific devices. (A) Percussion therapy device: application status and preferred therapy parameters. (B) HFCWO: application status and parameter settings. (C) MI-E: usage patterns and pressure settings. (D) CHFO: application status and parameter preferences. Proportion is expressed as percentage (%). ACT, airway clearance technique; CHFO, continuous high-frequency oscillation therapy; HFCWO, high frequency chest wall oscillation; MI-E, mechanical insufflation-exsufflation.

High-frequency chest wall oscillation (HFCWO)

A total of 54.9% used HFCWO, with preferences for “1–2 times/day” (72.6%), “medium intensity” (80.9%), “medium frequency” (78.3%), and “30–60 minutes” (72.0%). Comfort and efficacy were both rated “good” (53.5% and 51.3%) (see Figure 2B).

MI-E

A total of 30.2% used MI-E, typically “1–2 times/day” (65.7%), “cough trak mode” (76.4%), “medium positive pressure (25–50 cmH₂O)” (83.8%), and “medium negative pressure” (81.5%). Comfort was “moderate” (56.2%), but efficacy “good” (68.0%) (see Figure 2C).

CHFO

A total of 17.3% used CHFO, with preferences for “1–2 times/day” (65.3%), “medium flow (180°)” (57.7%), “high frequency (max 240±40)” (72.4%), and “5–15 minutes” (78.8%). Most rated comfort and efficacy as “good” (60.0% and 63.5%) (see Figure 2D).

Challenges and recommendations for improvement

Overall, the challenges to ACT implementation and corresponding improvement recommendations align between Group Yes and Group No. Key challenges include “lack of equipment/supplies, etc.” (86.9% vs. 89.1%), “shortage of specialized personnel” (86.1% vs. 86.8%), “lack of awareness” (85.8% vs. 79.5%, P=0.03), “absence of protocols” (78.3% vs. 75.9%), “insufficient theoretical knowledge” (74.3% vs. 72.3%), “no in-hospital ACT billing” (72.7% both), “patient non-cooperation” (58.7% vs. 61.4%), and “patient economic hardship” (57.0% vs. 54.1%).

Both groups recommended “enhancing training and awareness” (91.5% vs. 91.8%), “improving equipment access” (89.1% vs. 89.5%), “establishing protocols” (88.3% vs. 89.5%), “introducing billing items” (84.7% vs. 86.4%), “promoting ACT engagement” (81.0% vs. 82.3%), “enhancing patient education” (78.8% vs. 77.3%), “improving relevant reimbursement system” (72.4% vs. 76.8%), and “standardizing documentation” (68.5% vs. 73.2%).

For training, both prioritized “hands-on practice” (94.1% vs. 93.6%), but Group Yes preferred shorter sessions while Group No favored longer ones (P=0.02) (see Table S3).

Discussion

In China, RTs/PTs often work closely with physicians to implement integrated airway management protocols, which include both pharmacological and mechanical interventions. This survey provides a practitioner-level snapshot of ACT implementation in China that can inform future consensus statements and guidelines. With participants exceeding previous similar studies (29,34) and coverage across 28 provinces, this sample is representative and well-structured. Key findings are as follows: (I) significant variations in ACT utilization frequency; (II) multi-faceted rationales for selecting ACT interventions and evaluating their effectiveness; (III) for specific ACT (percussion therapy devices, HFCWO, MI-E, CHFO), despite variations in usage preferences, a general consensus was observed; (IV) consistency in the main barriers to ACT implementation and corresponding improvement suggestions.

The results show that ACT is widely used clinically, including during night shifts and holidays. However, the type of ACT employed vary significantly across institutions. Commonly used methods—such as intravenous or nebulized expectorants, enhanced warming and humidification, manual techniques, and routine suctioning—are more accessible and familiar (35-37). In contrast, device-based techniques are less frequently utilized, likely due to limited device availability and insufficient practitioner awareness and training. We speculate this phenomenon may stem from the following factors: firstly, ACT that do not require equipment are easier to implement and can be performed at any time. These methods (such as suctioning, warming and humidification, nebulization, etc.) are also repeatedly mentioned in guidelines and consensuses (28,38), as they can effectively alter the viscosity of secretions and are one of the key factors determining treatment success (39,40). Secondly, advanced equipment is predominantly available in developed regions and higher-tier hospitals which is reflected in the volume of related research publications (39,41,42). In contrast, developing countries, regions, and primary care hospitals have limited access to such equipment, resulting in naturally lower utilization rates (43). Additionally, the lack of specialized training for healthcare professionals in China further contributes to underutilization of these devices. Even in developed countries, the lack of knowledge among practitioners remains a major barrier to ACT utilization (27).

Most participants agreed on the timing and criteria for initiating ACT. Early ACT is recommended for high-risk patients, such as those with poor pulmonary function or chronic lung diseases, to prevent pulmonary complications. Decisions to initiate ACT were primarily based on auscultation, symptom changes, and imaging findings, with effectiveness assessed using similar parameters (13). Notably, nearly all participants emphasized the importance of considering the patient’s individual condition and tolerance when designing ACT regimens, aiming to avoid severe adverse effects. This reflects a patient-centered approach (44,45).

Usage patterns for the four ACT devices varied, likely reflecting differences in equipment availability across hospitals and ICUs. Parameter settings were generally conservative and focused on safety, with “medium” settings being the most common. Among the devices, only HFCWO and CHFO were rated as “good” for both comfort and efficacy. For the percussion therapy device and MI-E, achieving high efficacy often compromised patient tolerance, suggesting the need to balance these factors when selecting ACT devices.

Individuals who are in Group Yes and those in Group No showed a high overall consistency in recognizing barriers to therapy implementation. The only statistically significant difference was found in insufficient awareness, with a surprisingly higher proportion in Group Yes (85.8% vs. 79.5%, P=0.03). This could be explained by their direct involvement in clinical practice, which makes them more sensitive to cognitive gaps in treatment protocols and patient management—especially with the rapid evolution of emerging technologies. As they are accountable for treatment efficacy and patient safety, and cognitive deficits may directly cause clinical errors, they attach greater importance to improving their professional cognition. Conversely, non-practitioners have limited hands-on experience, leading to a weaker perception of such cognitive inadequacies. Compared with other major and pressing barriers that urgently need to be addressed, the establishment and improvement of ACT-related charging items seem less imminent. However, we cannot overlook the fact that the implementation of such charging items is actually indispensable in the long run. Improving the charging system can help promote ACT on a broader scale, stimulate the enthusiasm of relevant personnel for its application, and thereby drive the overall standardized development of ACT.

Key limitations include: (I) potential over-representation of tertiary hospitals (90.7%), which may under-represent lower-tier facilities. The sample renders conclusions most applicable to such settings, with secondary/primary hospital results for reference only. This 8:1:1 stratification is justified by tertiary hospitals’ superior resources, larger case volumes and wider technical applications, as well as the scarcity of RTs/PTs in lower-level hospitals, which ensures adequate statistical power. Future studies should include more lower-level hospitals to improve conclusion generalizability. (II) Significant differences in the regional distribution of participants, with underrepresentation in remote areas. (III) Among the participants included in this study, despite the presence of different educational backgrounds, the sample size was insufficient to support differential analysis. Future studies should further expand the survey scope and recruit more participants with diverse educational backgrounds. (IV) Imbalance in the number of PTs and RTs which may under-represent PTs. PTs’ limited role in ICUs in China (due to critically ill patients’ poor rehabilitation engagement) led to low response rates and poor representativeness of this subgroup. (V) Absence of a direct audit of device availability, which complicates interpretation of between-site differences in device use. (VI) Due to differences in patient characteristics and staff work habits across departments, preferences for ACTs vary. This study mainly included GICU staff. Analysis of the available data indicated statistically significant differences in the utilization frequency of certain ACTs between the GICU and other departments (Table S2), while the practical clinical significance of such disparities remains unclear. Future research should focus on these differences, analyze their causes, and propose better recommendations to improve overall ACT utilization. (VII) Limited by variations in hospital equipment, we surveyed only four widely studied ACT devices. The usage of other devices still requires further investigation in the future.

Conclusions

ACT is widely implemented in Chinese ICUs, although practice patterns vary significantly. Device availability and practitioner experience are key factors influencing the selection of ACT. Major barriers related to equipment shortages, personnel constraints, and limited education hinder optimal implementation. These findings highlight the urgent need for standardized protocols, dedicated training, and greater investment in devices to promote evidence-based ACT practices.

Acknowledgments

We would like to sincerely thank all respiratory therapists and physiotherapists who participated in this study for their valuable contributions to participant recruitment and for generously sharing their time and clinical experiences. Their insights form the foundation of this study.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2026-1-0089/rc

Data Sharing Statement: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2026-1-0089/dss

Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2026-1-0089/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2026-1-0089/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was approved by the Medical Ethics Committee of Zhongshan Hospital, Fudan University (No. B2023-232R). This study was carried out in accordance with the Declaration of Helsinki and its subsequent amendments. Informed consent was obtained from all participants prior to their involvement in the study.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Clarke SW. Rationale of airway clearance. Eur Respir J Suppl 1989;7:599s-603s. [PubMed]
2. Hess DR. Airway clearance: physiology, pharmacology, techniques, and practice. Respir Care 2007;52:1392-6. [Crossref] [PubMed]
3. Esmeijer AA, Nasa P, Ntoumenopoulos G, et al. Consensus Statements on Airway Clearance Interventions in Intubated Critically Ill Patients-Protocol for a Delphi Study. Life (Basel) 2025;15:1292. [Crossref] [PubMed]
4. Roe T, Talbot T, Terrington I, et al. Physiology and pathophysiology of mucus and mucolytic use in critically ill patients. Crit Care 2025;29:68. [Crossref] [PubMed]
5. Herrero-Cortina B, Lee AL, Oliveira A, et al. European Respiratory Society statement on airway clearance techniques in adults with bronchiectasis. Eur Respir J 2023;62:2202053. [Crossref] [PubMed]
6. Chiang LL, Wang LY, Wu CP, et al. Effects of physical training on functional status in patients with prolonged mechanical ventilation. Phys Ther 2006;86:1271-81. [Crossref] [PubMed]
7. Wang X, Ma H, He X, et al. Efficacy of early pulmonary rehabilitation in severe and critically ill COVID-19 patients: a retrospective cohort study. BMC Pulm Med 2025;25:203. [Crossref] [PubMed]
8. Lippi L, de Sire A, D'Abrosca F, et al. Efficacy of Physiotherapy Interventions on Weaning in Mechanically Ventilated Critically Ill Patients: A Systematic Review and Meta-Analysis. Front Med (Lausanne) 2022;9:889218. [Crossref] [PubMed]
9. Hassan A, Lai W, Alison J, et al. Effect of intrapulmonary percussive ventilation on intensive care unit length of stay, the incidence of pneumonia and gas exchange in critically ill patients: A systematic review. PLoS One 2021;16:e0255005. [Crossref] [PubMed]
10. Jelic S, Cunningham JA, Factor P. Clinical review: airway hygiene in the intensive care unit. Crit Care 2008;12:209. [Crossref] [PubMed]
11. Lee AL, Spinou A, Basavaraj A. Addressing treatable traits in bronchiectasis through non-pharmacological therapies: a narrative review. J Thorac Dis 2025;17:4302-22. [Crossref] [PubMed]
12. Goetz RL, Vijaykumar K, Solomon GM. Mucus Clearance Strategies in Mechanically Ventilated Patients. Front Physiol 2022;13:834716. [Crossref] [PubMed]
13. Connolly B, Barclay M, Blackwood B, et al. Airway clearance techniques and use of mucoactive agents for adult critically ill patients with acute respiratory failure: a qualitative study exploring UK physiotherapy practice. Physiotherapy 2020;108:78-87. [Crossref] [PubMed]
14. Volpe MS, Guimarães FS, Morais CC. Airway Clearance Techniques for Mechanically Ventilated Patients: Insights for Optimization. Respir Care 2020;65:1174-88. [Crossref] [PubMed]
15. Volsko TA. Airway clearance therapy: finding the evidence. Respir Care 2013;58:1669-78. [Crossref] [PubMed]
16. Gosselink R, Bott J, Johnson M, et al. Physiotherapy for adult patients with critical illness: recommendations of the European Respiratory Society and European Society of Intensive Care Medicine Task Force on Physiotherapy for Critically Ill Patients. Intensive Care Med 2008;34:1188-99. [Crossref] [PubMed]
17. Belli S, Prince I, Savio G, et al. Airway Clearance Techniques: The Right Choice for the Right Patient. Front Med (Lausanne) 2021;8:544826. [Crossref] [PubMed]
18. Zhang SM, Muhetaer Y, Liu K. Assessments and exercises of cough strength in critically ill patients: a literature review. J Thorac Dis 2025;17:1080-102. [Crossref] [PubMed]
19. Hu Z, Pu X, Tang R, et al. Effect of Continuous High-Frequency Oscillation Therapy on Lung Aeration in Mechanically Ventilated Patients With Impaired Consciousness: A Multicenter Randomized Controlled Trial. Chest 2026;169:665-75. [Crossref] [PubMed]
20. Coppolo DP, Schloss J, Suggett JA, et al. Non-Pharmaceutical Techniques for Obstructive Airway Clearance Focusing on the Role of Oscillating Positive Expiratory Pressure (OPEP): A Narrative Review. Pulm Ther 2022;8:1-41. [Crossref] [PubMed]
21. Poncin W, Pautre T, Peiry A, et al. Regional ventilation distribution: effects of lateral posture and airway clearance techniques in healthy and individuals with COPD. J Appl Physiol (1985) 2025;139:1618-26. [Crossref] [PubMed]
22. Main E, Rand S. Conventional chest physiotherapy compared to other airway clearance techniques for cystic fibrosis. Cochrane Database Syst Rev 2023;5:CD002011. [PubMed]
23. Sousa AS, Rocha-Filho CR, Rocha A, et al. Non-invasive ventilation for cystic fibrosis. Cochrane Database Syst Rev 2025;11:CD002769. [PubMed]
24. Urquhart DS, Taylor E, Cunningham S, et al. Safety, feasibility and efficacy of exercise as an airway clearance technique in cystic fibrosis: a randomised pilot feasibility trial. Thorax 2026;81:140-9. [Crossref] [PubMed]
25. Ntoumenopoulos G, Hammond N, Watts NR, et al. Secretion clearance strategies in Australian and New Zealand Intensive Care Units. Aust Crit Care 2018;31:191-6. [Crossref] [PubMed]
26. Stilma W, van der Hoeven SM, Scholte Op Reimer WJM, et al. Airway Care Interventions for Invasively Ventilated Critically Ill Adults-A Dutch National Survey. J Clin Med 2021;10:3381. [Crossref] [PubMed]
27. Rose L, McKim D, Leasa D, et al. Monitoring Cough Effectiveness and Use of Airway Clearance Strategies: A Canadian and UK Survey. Respir Care 2018;63:1506-13. [Crossref] [PubMed]
28. Blakeman TC, Scott JB, Yoder MA, et al. AARC Clinical Practice Guidelines: Artificial Airway Suctioning. Respir Care 2022;67:258-71. [Crossref] [PubMed]
29. Strickland SL, Rubin BK, Haas CF, et al. AARC Clinical Practice Guideline: Effectiveness of Pharmacologic Airway Clearance Therapies in Hospitalized Patients. Respir Care 2015;60:1071-7. [Crossref] [PubMed]
30. Spapen HD, De Regt J, Honoré PM. Chest physiotherapy in mechanically ventilated patients without pneumonia-a narrative review. J Thorac Dis 2017;9:E44-9. [Crossref] [PubMed]
31. Bradburn NM, Sudman S, Wansink B. Asking Questions: The Definitive Guide to Questionnaire Design. 2nd ed. San Francisco: Jossey-Bass; 2004.
32. Chinese Thoracic Society. Respiratory Care Group of Chinese Association of Chest Physicians Respiratory Career Development Committee; Respiratory Rehabilitation Committee of Chinese Association of Rehabilitation Medicine. Expert consensus on clinical application of mechanical airway clearance techniques. Zhonghua Jie He He Hu Xi Za Zhi 2023;46:866-79.
33. Strickland SL, Rubin BK, Drescher GS, et al. AARC clinical practice guideline: effectiveness of nonpharmacologic airway clearance therapies in hospitalized patients. Respir Care 2013;58:2187-93. [Crossref] [PubMed]
34. Liu K, Yao YL, Wang YX, et al. A cross-sectional survey on the lung ultrasound training and practice of respiratory therapists in mainland China. BMC Pulm Med 2022;22:425. [Crossref] [PubMed]
35. Sontakke NG, Sontakke MG, Rai NK. Artificial Airway Suctioning: A Systematic Review. Cureus 2023;15:e42579. [PubMed]
36. American Association for Respiratory Care. Restrepo RD, Walsh BK. Humidification during invasive and noninvasive mechanical ventilation: 2012. Respir Care 2012;57:782-8. [Crossref] [PubMed]
37. Wang X, Li M, Liu Y, et al. EIT-guided chest physiotherapy for airway clearance during awake prone ventilation in ARDS: a randomized controlled trial. J Thorac Dis 2025;17:11186-99. [Crossref] [PubMed]
38. Branson RD. Secretion management in the mechanically ventilated patient. Respir Care 2007;52:1328-42; discussion 1342-7. [Crossref] [PubMed]
39. van der Lee L, Hill AM, Patman S. A survey of clinicians regarding respiratory physiotherapy intervention for intubated and mechanically ventilated patients with community-acquired pneumonia. What is current practice in Australian ICUs? J Eval Clin Pract 2017;23:812-20. [Crossref] [PubMed]
40. Gillies D, Todd DA, Foster JP, et al. Heat and moisture exchangers versus heated humidifiers for mechanically ventilated adults and children. Cochrane Database Syst Rev 2017;9:CD004711. [Crossref] [PubMed]
41. Cooper L, Johnston K, Williams M. Australian airway clearance services for adults with chronic lung conditions: A national survey. Chron Respir Dis 2023;20:14799731221150435. [Crossref] [PubMed]
42. Andersen TM, Nørstebø E, Hov B. Long-Term Mechanical Insufflation-Exsufflation Practice: A Norwegian National Survey After More Than 20 Years' Experience. Respir Care 2025;70:1093-102. [Crossref] [PubMed]
43. Bhat A, Chakravarthy K, Rao BK. Chest physiotherapy techniques in neurological intensive care units of India: A survey. Indian J Crit Care Med 2014;18:363-8. [Crossref] [PubMed]
44. Puntillo KA, Max A, Timsit JF, et al. Determinants of procedural pain intensity in the intensive care unit. The Europain® study. Am J Respir Crit Care Med 2014;189:39-47. [Crossref] [PubMed]
45. van de Leur JP, van der Schans CP, Loef BG, et al. Discomfort and factual recollection in intensive care unit patients. Crit Care 2004;8:R467-73. [Crossref] [PubMed]