Correlates between basic science and therapeutic interventions: the theory and the practice.

Abstract

To review the science of breathlessness and demonstrate how current therapeutic interventions for breathlessness target the known underlying mechanisms. There is increasing evidence that breathlessness is experienced in multiple dimensions. The underlying mechanisms relate to the perceptual processes involved, the emotional response and the functional impact. The theory that breathlessness is perceived when there is a mismatch between the central drive to breathe and the level of ventilation remains a central concept, providing a useful theoretical framework around which many current therapies have been developed. The sites involved in the corticolimbic processing of breathlessness have been identified, though little is known about the neural pathways involved. Therapies which aim to reduce the neural respiratory drive include oxygen, exercise and opioids. Interventions which aim to improve ventilation include breathing retraining and positioning. Modulation of respiratory afferent feedback may be achieved using chest wall vibration and fan therapy. Cognitive and behavioural therapies aim to modify the emotional response to breathlessness. Opioids have been shown to modulate breathlessness at the level of the corticolimbic system, as well as the brainstem. Further work is needed to identify other relevant neurotransmitter systems in order to explore new therapies.