Masterclass 13 - Dyspnoea: A Treatable Trait

The physiological causes of exercise limitation can be broadly classified into the following categories: i) cardiovascular limitation (incapacity of the heart and the circulation to deliver an adequate blood flow), ii) ventilatory limitation (decreased capacity of the diaphragm, respiratory muscles, thoracic cage and airway to function as a mechanical pump for air), ii) pulmonary gas exchange limitation (inefficient oxygen and carbon monoxide transport between lung alveoli and the pulmonary circulation), and iv) peripheral limitation (abnormal oxidative metabolism in skeletal muscles).


In clinical practice, we often encounter patients who complain of dyspnoea, but either the aetiology of the dyspnoea is obscure, or the severity of dyspnoea is disproportionate to the clinical assessment, lung function test and pulmonary or cardiac imaging findings. or patients have multiple co-morbidities that could have contributed to their symptom. 


The cardiopulmonary exercise test (CPET) stresses a patient with maximal exercise so that functional inadequacies in the physiological system that are not detectable at rest can be uncovered. A standard CPET simultaneously measures: the work exerted by the patient against an incremental load, gas exchange at the mouth level (oxygen consumption (V̇O₂), minute ventilation (V̇E), and carbon dioxide production (V̇CO₂)), pulse oximetry, electrocardiogram, blood pressure, as well as the patient's perceived severity of breathlessness and lower limb fatigue. The cause of exercise limitation can be determined by an integrative interpretation of these measurements. In particular, dynamic respiratory mechanics can be assessed with inspiratory capacity manoeuvres, complementing the measurement of breathing reserve to determine the presence of ventilatory limitation. Limitation due to abnormal pulmonary gas exchange can be confidently determined by arterial blood gas sampling during the CPET. Illustrative cases on the use of CPET in evaluation of dyspnoea will be discussed in the lecture.


CPET is an integrative physiological evaluation and it rarely pinpoints a specific clinical diagnosis. While there are published guidelines such as the 2003 American Thoracic Society/American College of Chest Physicians statement and the 2019 European Respiratory Society statement, there remains a large heterogeneity in the interpretative strategies of CPET results. Additionally, high-quality reference equations are lacking. It is important that clinicians are aware of these limitations of CPET.

Chronic breathlessness, breathlessness persisting despite optimal treatment, is a central symptom in many conditions, notably respiratory and cardiac diseases, and advanced cancer. Breathlessness is strongly associated with decreased activity and poorer clinical outcomes, including worse quality of life and increased rates of anxiety and depression. In patients with COPD breathlessness has been shown to be a stronger predictor of mortality than lung function tests and in heart disease it is a better predictor of mortality than angina. However, for some patients, the experience of breathlessness is poorly explained by the findings of medical tests. That is, quantitative markers for disease severity do not always align with a patient's report of subjective symptoms, such as breathlessness. These discrepancies, alongside the multifaceted and subjective nature of breathlessness, make its assessment and treatment challenging. 
Recent literature describes breathlessness as a multidimensional subjective symptom. Many breathlessness researchers use the model of pain multidimensionality as a helpful analogy to study breathlessness; both incorporate sensory-qualities, and are unpleasant and evoke emotions that motivate behaviour. This approach has provided a foundation to develop multidimensional scales to assess breathlessness. While a variety of instruments are available for assessing breathlessness, the majority assess the impact of breathlessness, rather than its sensory and affective dimensions. The Dyspnoea-12 was published in 2010 and was developed for assessment of the multiple dimensions of breathlessness; physical (sensory) and affective. It has been translated into more than 20 languages. 
This presentation will describe chronic breathlessness and its multi-dimensional experience. It will summarise the application of the Dyspnoea-12 to assess breathlessness.

The Dyspnoea-12 (D-12) scale is a validated tool designed to assess the perception of dyspnoea and its physical and affective impacts in individuals with chronic obstructive pulmonary disease (COPD). Its Chinese version (D-12-C) has been developed and validated for Chinese-speaking populations, offering culturally relevant insights. This study explores the use of D-12-C in Hong Kong, focusing on its application in local acute hospitals, including COPD clinics and pulmonary rehabilitation programmes (PRP).


In Hong Kong, D-12-C serves as a dual-purpose tool for baseline assessment and outcome measurement in PRPs. Its integration into pre- and post-PRP evaluations enables healthcare professionals to capture both physical and emotional dimensions of dyspnoea. Findings derived from D-12-C are compared with similar studies, enriching understanding of its utility and providing a basis for future improvements in patient care. The analysis includes physical and affective components, with follow-ups tailored to individual patient needs.


Healthcare professionals appreciate the straightforward administration of D-12-C, promoting its broader adoption across various settings. Its implementation fosters enhanced understanding of dyspnoea, improving care for patients in Hong Kong and other Chinese-speaking regions. This study encourages further use of D-12-C to support comprehensive, patient-centered respiratory care.

Dyspnea is the common and typical symptoms reported by patients diagnosed with COPD. Dyspnea measurement is integrated in the global clinical guideline and dyspnea in daily life can be measured by a number of detailed questionnaires conducted by occupational therapist that are more discriminant and sensitive to change. 


Non-pharmacological treatment is complementary to pharmacological treatment and should form part of the comprehensive management of COPD as recommended by the Global initiative for COPD, Inc. (2024). Pulmonary rehabilitation is thus one of the most significant non-pharmacological treatment to managing dyspnea. It is based on thorough patient assessment followed by patient-tailored therapies that include, but are not limited to, exercise training, education, self-management intervention aiming at behavior change, designed to improve the physical and psychological condition of people with chronic respiratory disease and to promote the long-term adherence to health-enhancing behaviors. 


The occupational therapy educational components of dyspnea management in pulmonary rehabilitation are fundamentally integral to the format and success of the programme. Education comes into every aspect of rehabilitation and in discrete educational sessions. The intention of the educational element is to support the lifestyle and behavioral change and assist self-management to promote decision making and self-efficacy. 


The occupational therapy strategies in managing dyspnea include coordinated breathing generalization in activities of daily living, energy conservation application in everyday self-care & household demands, environment adaptation, stress management & relaxation, baduanjin class & community integration.


Facilitative use of motivational interviewing and cognitive-behavioral therapy may have a preventative as well as a treatment role, and could be incorporated into routine rehabilitation programme. Patients' thought distortions, maladaptive behaviors, symptoms and associated distress can be reduced through learning the specific information-processing skills and coping mechanisms.

Chronic respiratory diseases (CRD) pose a significant burden to patients and healthcare system globally. Optimal treatment requires provision of both pharmacological and non-pharmacological therapies. While pharmacological treatments undoubtedly receive significant attention, non-pharmacological therapies are often being neglected. In fact, pulmonary rehabilitation (PR) is a crucial non-pharmacological intervention for not only chronic obstructive pulmonary disease (COPD), but also various CRD including asthma, bronchiectasis, interstitial lung diseases (ILD), and even pulmonary hypertension. To maximize its benefits, it should be "a comprehensive intervention based on a thorough patient assessment followed by patient tailored therapies that include, but not limited to, exercise training, education, and behavior change, designed to improve the physical and psychological condition of people with chronic respiratory disease and to promote the long-term adherence to health-enhancing behaviors" – the definition of PR provided by the American Thoracic Society/European Respiratory Society statement in 2013 that remains in use today. 
The benefits of PR are well established. It improves patients' symptom, restore their functional capacities, and enhance their overall quality of life, thereby reducing morbidity, mortality, and healthcare utilization. Despite all the proven benefits, globally its utilization remains suboptimal due to low uptake and poor completion rates, which adversely affected PR outcomes. Common barriers include transportation issues, frequent hospital visits for PR, and high travel costs. With advancement in medical technology, incorporating telemedicine into conventional PR could be a potential solution as it enhances PR accessibility through overcoming these geographical barriers. This lecture would compare various tele-PR models and their clinical outcomes, emphasizing that supervised home-based tele-PR programs are preferable to unsupervised web-based approaches. The multi-disciplinary supervised home-based tele-PR program implemented at my center would be used as an example to illustrate how tele-PR could broaden the scope of conventional PR, making it more accessible and beneficial for a wider range of CRD patients.