Figures
- FIGURE 1
Breathing pattern during autogenic drainage. TV: tidal volume; ERV: expiratory reserve volume; RV: residual volume.
- FIGURE 2
Schematic representation of breathing levels during positive expiratory pressure in an obstructed patient. TV: tidal volume; FET: forced expiration technique; TLC: total lung capacity; FRC: functional residual capacity; RV: residual volume. Courtesy L. Lannefors (Sahlgrenska University Hospital, Gothenburg, Sweden).
Tables
- TABLE 1
Optimal positioning for airway clearance techniques to enhance ventilation to obstructed regions of the lung
Optimal position Alternative, second-choice position Secretions in upper lobes Supine Side lying Secretions in middle lobe and lingula Upright Side lying or supine Secretions in right lung Adults: right-side lying
Children: left-side lyingSecretions in left lung Adults: left-side lying
Children: right-side lyingSecretions in lower lobes Upright Side lying - TABLE 2
Effects of airway clearance interventions on peak flow rates
Subjects n PEFR L·min-1 PIFR L·min-1 PEFR/PIFR ratio Frequency Hz Huff 17 302.4±121.8 124.8±85.2 2.80 Cough 17 280.2±114.6 100.8±44.4 3.07 Vibration 17 94.8±43.8 63.6±16.2 1.51 8.4±0.4 Autogenic drainage 14 85.2±28.8 50.4±13.8 1.69 Flutter 17 67.8±18.0 63.0±16.2 1.15 11.3±1.5 Percussion 18 49.8±8.4 50.4±6.0 0.99 7.3±0.3 Acapella 18 35.4±4.8 58.8±16.2 0.64 13.5±1.7 PEP 18 26.4±9.0 57.6±12.0 0.47 Data are presented as n or mean±sd. Data from [49–51]. PEFR: peak expiratory flow rate; PIFR: peak inspiratory flow rate; PEP: positive expiratory pressure.
- TABLE 3
Physiological basis for each airway clearance technique
Ventilation Expiratory airflow Oscillation Interdependence CV Breath hold Huffing# PEFR/PIFR >1.1 PEFR >30–60 L·min-1 Active cycle of breathing techniques Thoracic expansion exercises utilise interdependence Thoracic expansion exercises utilise CV Sometimes used with this technique if hypoventilating Uses forced expirations at different levels Ratio 2.8 Average 302 L·min-1 with huffing No Autogenic drainage No Yes, with breath hold Uses 3-s breath hold with each breath Only used to clear secretions from larger airways if needed Yes; emphasis is on slow inspiration and increased velocity on expiration 40–70 L·min-1 Depends on level of breathing and degree of airway obstruction No PEP No As PEP is maintained within the airways over 12–15 breaths, use of CV is maximised Not necessary as PEP is maintained within the airways over 12–15 breaths Used at end of each cycle of 12–15 breaths No
Ratio 0.47No
Average 26 L·min-1No Oscillating PEP with Flutter Oscillations at 3–5 Hz may play a role, but frequency used in Flutter is >5 Hz Yes with breath hold Uses 3-s breath hold with each breath Used at end of each cycle of 8–10 breaths Ratio 1.15 Average 68 L·min-1 2–32 Hz
Most often uses 6–26 HzOscillating PEP with Acapella Oscillations at 3–5 Hz may play a role, but frequency used in Acapella is >5 Hz As a PEP is maintained within the airways over 12–15 breaths, use of CV is maximised Not necessary Used at end of each cycle of 12–15 breaths No
Ratio 0.64Average 35.4 L·min-1 Within PEFR range needed, but would depend on viscoelastic and viscosity properties of secretions 10–18 Hz HFCWO Oscillations at 3–5 Hz may play a role, but frequency used in HFCWO is >5 Hz No No Interspersed with HFCWO Yes, expiratory flow rate is much higher than inspiratory flow rate Average 120 L·min-1 5–25 Hz CV: collateral ventilation; PEFR: peak expiratory flow rate; PIFR: peak inspiratory flow rate; PEP: positive expiratory pressure; HFCWO: high-frequency chest wall oscillation. #: each technique incorporates huffing, as used in the forced expiration technique, with the exception of autogenic drainage.
Supplementary Material
J.S. Elborn ERR-0086-2016_Elborn
Jump To
- Article
- Abstract
- Abstract
- Introduction
- Principles for optimising ventilation to obstructed regions of the lung
- Methods of utilising expiratory airflow to enhance secretion removal
- Applying physiological principles to airway clearance techniques
- Personalising airway clearance strategies
- Conclusion
- Disclosures
- Footnotes
- References
- Figures & Data
- Info & Metrics