Abe Guz Fellowship

Why is breathlessness important?

• It is estimated that up to a quarter of the general population and half of severely ill patients are affected by breathlessness.[1]
• In patients with chronic obstructive pulmonary disease (COPD), it has been shown to be a better predictor of mortality than forced expiratory volume in 1 s (FEV1). In patients with heart disease it is a better predictor of mortality than angina. Breathlessness [4] is also associated with decreased functional status and worse psychological health in older individuals living at home.[4]
• Despite its tremendous burden, breathlessness is often underestimated by clinicians. For example, while clinicians reported that less than 30% of patients with lung cancer experienced moderate to severe breathlessness, over 50% of their patients reported the occurrence of this symptom. [5]
• The prevalence of chronic breathlessness is difficult to ascertain, due to studies reporting both acute and chronic breathlessness, but it has been reported to affect between 9% and 59% of the general population. A higher prevalence of chronic breathlessness has been reported in individuals over 70 years of age, with breathlessness in these patients being associated with worsening functional decline and increased five year mortality. Additionally, the aetiology of chronic breathlessness is multifactorial in approximately one third of cases, with common co-existing conditions contributing to symptomatology. [6]
• Five main aetiological categories account for most cases of chronic breathlessness (duration >1 month):
  • Pulmonary disease
  • Cardiovascular disease
  • Respiratory muscle dysfunction
  • Psychogenic breathlessness
  • Deconditioning/obesity.[7]
• Weighted grand mean prevalence of breathlessness in patients with advanced cancer was 58%; in advanced cancer the prevalence of episodic breathlessness has been recorded at 70.9%. [8]

Measuring breathlessness

• Breathlessness is a subjective experience and thus the gold standard for breathlessness assessment is based on patient self-report.[1]
• Commonly used objective physiological measures such as respiratory rate or oxygen saturations only have a weak association with subjective sensations of breathlessness. In general, lung function tests correlate poorly with the sensation of breathlessness and relatively normal values should not preclude enquiring about breathlessness.
• The European Society of Medical Oncology (ESMO) recommends that:
  • Breathlessness assessment should include a unidimensional measure of severity, a measure of multi-dimensional functional impact, and patient interview.[9]
• Measures of severity include the Visual Analogue Scale (VAS) and the Borg Rating of Perceived Exertion (RPE) scale.
• There are many multi-dimensional measures of breathlessness validated for use in clinical practice – some examples can be found at https://www.thoracic.org/members/assemblies/assemblies/pr/outcome-measures/dyspnea-breathlessness.php

Managing breathlessness

• General approach to breathlessness management:
  • Optimise the underlying condition as much as possible
    • Could inhaler technique be improved or intensity increased in COPD?
    • Could diuresis improve breathlessness in your patient with heart failure?
    • Have you considered reversible causes of breathlessness in your patient with cancer – pleural effusions, pulmonary emboli, anaemia?
  • Smoking cessation advice in all patients who smoke
  • Consider psychological and social impact of the underlying condition – could addressing causes of anxiety improve their symptoms?
  • Give brief advice to increase physical activity levels, reassure and encourage: “It’s not harmful to make yourself breathless”, refer patients with lung or heart disease who feel limited by their symptoms for exercise rehabilitation
  • Prioritise evidence based non-pharmacological interventions prior to pharmacological interventions
• Use the Breathing, Thinking, Functioning model to address patient concerns about their breathlessness:
  • Breathing domain
    • Dysfunctional breathing patterns are well recognised in breathless individuals without underlying respiratory pathology. Features include apical breathing, higher ratio of inspiratory to expiratory length, absence of end-expiratory pause and frequent sighs or yawns. Breathing pattern disorders occur in about a third of asthma patients, and although there has been no research in other respiratory conditions, such as COPD, there is extensive anecdotal evidence that dysfunctional breathing patterns do occur. Breathless patients experience a sense of ‘needing more air’ and, therefore, may consciously or subconsciously increase their tidal volume or respiratory rate, breathing predominantly using the upper chest and accessory muscles. Apical breathing causes reliance on fatiguable accessory muscles of respiration, underutilising the efficient and relatively fatigue-resistant diaphragmatic muscle, further increasing the work of breathing and intensifying breathlessness.
    • Interventions specific to problems with the breathing domain include:
      • Breathing Techniques
      • Handheld fan use
      • Airway Clearance Techniques
      • Inspiratory muscle training
      • Chest wall vibration
      • Non-invasive ventilation
      • Thinking domain
        • It is well-recognised that the anxiety or fear caused by breathlessness can, in turn, augment the perception of breathlessness. This vicious cycle can lead to a rapidly escalating sense of panic, which most breathless patients experience at some point. The neural processing for this feedback loop is likely to occur in the cortico-limbic areas of the brain, involved in both breathlessness perception and processing of emotion. In addition, anxiety increases the respiratory rate and can cause muscle tension in both the ventilatory pump and other skeletal muscles, so further increasing the work of breathing and respiratory demand.

• Interventions specific to problems with the thinking domain include:
• • • • Cognitive behavioural therapy
      • Relaxation techniques
      • Mindfulness
      • Acupuncture
  • Functioning domain
    • As breathlessness is so unpleasant, it is natural to avoid it by reducing activity. However, inactivity leads to muscle deconditioning, with reduced oxidative capacity, muscle fibre atrophy and fibre type shift from type 1 (oxidative) to type IIb (glycolytic) fibres. This increases the demand on the respiratory system and worsens breathlessness further. Patients intuitively understand this ‘deconditioning vicious cycle’, being aware that less ‘fit’ people are more breathless on exertion. Family members and other carers can unwittingly compound the situation, by trying to help through doing activities that the patient might otherwise have done.
  • Interventions specific to problems with the functioning domain include:
    • Pulmonary rehabilitation
    • Activity promotion
    • Walking aids
    • Pacing
    • Neuromuscular electrical stimulation
  • Pharmacological interventions
    • Pharmacological treatments for the sensation of breathlessness should only be considered once all of the factors above have been considered as the evidence of benefit is limited or disputed and there is evidence of harms. Where evidence supports the use of some medications, this tends to be in patients with severe or terminal breathlessness
      • Opioids
        • In general are not recommended for patients with non-malignant disease – where used, short acting opioids appeared to be more safe, have potential to lessen dyspnoea and improve exercise endurance, supported benefit in managing episodes of breathlessness and providing prophylactic treatment for exertional dyspnoea.
        • In patients already taking opioids for cancer-related pain, the available evidence signals that opioids have a positive effect on breathlessness among opioid-tolerant individuals but overall there is very low quality evidence
      • Benzodiazepines
        • There is no evidence for or against benzodiazepines for the relief of breathlessness in people with advanced cancer and COPD. Benzodiazepines caused more drowsiness as an adverse effect compared to placebo, but less compared to morphine. Benzodiazepines may be considered as a second- or third-line treatment, when opioids and non-pharmacological measures have failed to control breathlessness.
      • Corticosteroids
        • Corticosteroids should not be routinely given to unselected patients with cancer for palliation of dyspnoea.
      • Antidepressants
        • Antidepressants impact on neurotransmitters involved in various brain circuits potentially affecting breathlessness – however despite positive case series, randomised controlled trials have been negative.