We recommend a review of the literature to understand the clinical significance, diagnosis and management of dyspnoea in critically ill, mechanically ventilated adult patients
Dyspnoea ranks among the most distressing experiences that human beings can endure. Approximately 40% of patients undergoing invasive mechanical ventilation in the intensive care unit (ICU) report dyspnoea, with an average intensity of 45 mm on a visual analogue scale from 0 to 100 mm.
Dyspnoea is described by 30-50% of mechanically ventilated patients and is associated with fear of dying.
In the past decade, great attention has been paid to pain management while very little has been paid to dyspnoea.
Therefore, the task force members decided to compile a list of six objectives that they considered relevant:
– Definition of dyspnoea
– Pathophysiology of dyspnoea
– Prevalence and severity of dyspnoea
– Detection of dyspnoea
– Identification of current strategies for dyspnoea relief
Dyspnoea, described as « the symptoms that convey an upsetting or distressing experience of breathing awareness » is equivalent to « breathlessness ».
Clinically, signs of distress are: use of accessory muscles of ventilation; nasal flaring; facial expression.
Dyspnoea occurs concomitantly with activation of brain networks involving motor, sensory and interoceptive regions. It could be termed « respiratory-related brain suffering ».
In mechanically ventilated patients, dyspnoea can be seen as an imbalance between the « demand for breathing » and the capacity of the respiratory system to « satisfy this demand » which depends partly on the level of assistance delivered by the ventilator.
Three main discomforts can be described: air hunger, excessive effort and chest constriction.
Management of ventilator settings is important but cognitive and emotional mechanisms must also be taken into consideration.
Prevalence of dyspnoea is high in mechanically ventilated patients, but is often underestimated. Patients are not asked and often are unable to self-report their feelings.
It is associated with anxiety, poor sleep, intubation risk, high risks of weaning failure, mortality, increased length of ICU stay and finally an increase of post-traumatic stress disorders.
Concerning tools to identify and quantify dyspnoea, only one multidimensional has been used in ICU – the Multidimensional Dyspnoea profile. It quantifies the effective, sensory and emotional components of dyspnoea.
For the non-communicative patients, the Respiratory Distress Observation Scale can be proposed.
Electrophysiological indicators like electromyographic activity of diaphragm or accessory respiratory muscles can help to detect or quantify the symptoms.
Few actions can relieve dyspnoea: patient reassurance; reduction of non-respiratory stimuli of respiratory drive (fever, pain…); paying attention to procedures generating dyspnoea (bronchofibroscopy…); optimisation of ventilator settings; and respiratory impedance.
Different strategies must be applied in function of the mode of ventilation (controlled, pressure support….)
Pharmacologic approaches (or not) can be used or not to help the patient.
Conclusions
Dyspnoea is frequent but often underestimated or not identified. It is associated with poor outcomes. Healthcare Professionals, and more specifically physiotherapists, must be more concerned by this problem.
Dyspnoea in acutely ill mechanically ventilated adult patients: an ERS/ESICM statement
Alexandre Demoule, Maxens Decavele, Massimo Antonelli , Luigi Camporota , Fekri Abroug , Dan Adler, Elie Azoulay, Metin Basoglu, Margaret Campbell, Giacomo Grasselli, Margaret Herridge, Miriam J. Johnson, Lionel Naccache, Paolo Navalesi, Paolo Pelosi, Richard Schwartzstein, Clare Williams, Wolfram Windisch, Leo Heunks and Thomas Similowski. Intensive Care Med (2024) 50:159–180
You can download the full article here. DOI: 10.1007/s00134-023-07246-x
