Proximal airway clearance techniques
| Proximal airway clearance technique name | Description | Advantages | Disadvantages | Notes and evidence base |
| Manual assisted cough (MAC) | An MAC can be delivered to the abdomen and/or the thorax. Compression of the abdomen causes a sudden increase in abdominal pressure; this causes the abdominal contents to push the diaphragm upwards, increasing expiratory airflow. Similarly, sudden thoracic compression causes air to be rapidly expelled, with acceleration of airflow toward the mouth. The technique involves the patient taking a spontaneous, or receiving an assisted, inspiration, and at the start of the cough expiratory compression is applied. | The technique is easy to perform and can be used in multiple settings and in conjunction with assisted inspiration and mechanical insufflation–exsufflation. | Requires coordination between the carer delivering the technique and the individual receiving it. May not be effective in individuals with a very weak cough. May be less effective in patients with severe scoliosis. | Simple effective technique. Been shown to increase CPF in children and adults with NMD compared with their unassisted CPF.250 |
| Assisted inspiration with either non-invasive ventilation (NIV), intermittent positive pressure breathing (IPPB), resuscitation bag or lung volume recruitment (LVR) circuit | Single breath–assisted inspiration provides a single, sustained inspiratory flow that inflates the respiratory system to the maximal desired volume. Once this volume has been attained, the patient breathes out or coughs. The use of a resuscitation bag or LVR circuit enables repeated inspirations if the patient can breath hold (air stacking (AS)). Both these techniques increase lung volumes and expiratory flows, with repeated assisted inspiration having the potential to increase this the most. | The technique is easy to perform and can be used in multiple settings. Can be used with an MAC to increase efficacy further. | Some patients have difficulty accepting extrinsic breaths. When using multiple-assisted inspirations, the patient must coordinate with the technique and be able to signal when they have received sufficient inspiratory volume. This may not be possible in those with severe learning disability. | Assisted inspiration increases CPF and lung volumes in children.251 252 Jenkins et al investigated 23 children’s ability to learn AS using an LVR circuit, 8 of whom had some degree of learning disability. Only 4 participants were unable to effectively do AS.253 |
| Mechanical insufflation–exsufflation (MI-E) | MI-E is a device that applies a positive pressure to the airway (insufflation) followed by a rapid switch to negative pressure (exsufflation), aiming to simulate the natural flow changes that occur with a cough. | Increases cough efficacy in the weakest patients (CPF <160 L/min). Has the potential to shift a large quantity of secretions. | MI-E can be difficult to perform in very young infants who are unable to accept insufflation. | MI-E has been shown to increase CPF, decrease the rates of CAP hospitalisations and reduce the length of hospital stay in NMD patients.254–256 In patients with CP, MI-E did not show any benefit over conventional physiotherapy in length of hospital stay or days on oxygen in a randomised trial of 22 patients admitted with CAP.257 |
CAP, community-acquired pneumonia; CP, Cerebral Palsy; CPF, cough peak flow; NMD, neuromuscular disorder.