TABLE 1

Lexicon of airway clearance and breathing techniques

Airway clearance techniques
Active cycle of breathing [10, 11]	A cycle of deep breathing exercises interspersed with breathing control, followed by the FET (a combination of 1 or 2 huffs^# interspersed with periods of breathing control)
Autogenic drainage [10, 11]	Composed of three phases:
	1. unsticking the peripheral mucus by breathing at low lung volumes (below FRC)
	2. collecting the mucus in the middle airways by breathing at mid lung volumes close to FRC
	3. evacuating the secretions from the central airways by breathing at higher lung volumes
Positive expiratory pressure therapy [10, 11]	Provides a constant pressure to the airways throughout expiration using an expiratory resistance device with a one-way valve
ELTGOL (total slow expiration with open glottis) [12]	The patient lies in a lateral decubitus position and breathes out slowly through an open glottis from FRC to residual volume
Manually assisted cough [13, 14]	Thoracic or abdominal compression added to augment the expiratory effort of a cough
Mechanical insufflation-exsufflation [13, 14]	A device gradually inflates the lungs using positive pressure, immediately follows an abrupt change to negative pressure that produces a rapid exhalation
Breathing strategies
Incentive spirometry [10]	Use of a handheld device that provides patients with visual feedback regarding their performance during deep breathing exercises; it can be provided by flow- or volume-based spirometers
Deep breathing exercises [10]	Full inspiration to TLC, with or without a 2–3 s hold at the end of inspiration, followed by relaxed expiration
	Adequate expiratory time is required to allow complete expiration
	Compared to a rapid inspiration, a slow inspiration allows a more homogeneous distribution of ventilation
Positive pressure [10]	Applying positive pressure throughout inspiration to the airways and lungs by asking the patients to breathe using a device that attaches to them via a face mask or a mouthpiece

FET: forced expiratory technique; FRC: functional residual capacity; TLC: total lung capacity. ^#: a huff is described as a deep inspiration followed by a forced expiration with the glottis open.