W8: Active Secretion Clearance (WS) Flashcards
Main mechanism for a cough/huff?
Use changes to lung volumes and generation of rapid expiratory airflow to remove secretions from the lungs.
Goal of a cough?
Aims to clear secretions from central airways which may have been moved from the periphery via a huff.
What is the normal cough peak epiratory flow with a flow meter?
> 360L/min
How do we identify glottic closure (key component of a cough)
Listen for the expulsive component
What is the assisted cough peak flow level required to prevent retention of secretions?
160L/min
When the cough peak flow (CPF) is < 180L/min, what is the first choice of treatment? Ie in someone with a weak cough
Mechanical insufflation-exsufflation (used to augment a cough)
Provide an example of a mechanical insufflation-exsufflation device? Typical settings of this device
Phillips E70 Cough-Assist Machine
Normal settings:
Mode: Basic Auto
Insufflation: +20 cmH₂O
Exsufflation: -20 cmH₂O
Insufflation Time: 2 seconds
Exsufflation Time: 2 seconds
Pause: 1 second
Note: To generate high expiratory flows, higher pressures are required (+40 to −40 cm H2O) along with higher inspiratory to expiratory times (3 s to 2 s). MI-E settings of at least +40 to −40 cm H2O have been shown to create high enough expiratory flows to provide an effective cough.
Note: The device is connected via a 22 mm tube to either an oronasal mask or mouthpiece.
What is insufflation?
Insufflation is the act of mechanically forcing air into a person’s respiratory system.
Exsufflation: Exsufflation is a strongly forced expiration of air.
What is suctioning
Purpose?
A common procedure that removes oral and respiratory secretions from the airway and keeps it clear.
This allows for a more patent airway, improved ventilation and work of breathing (clear the obstruction and ideally not require mechanical ventilation)
Indications for insertion of artificial airways?
- Relieve respiratory distress caused by upper airway obstruction
- Facilitate suctioning of lower airway to remove excess mucus
- Allow for mechanical ventilation
- Prevent aspiration
What should be done prior to suctioning?
Suctioning can cause a decrease in oxygenation in some patients. Evidence supports before conducting any suctioning. It is suggested that preoxygenation with an FIO2 0.2 above baseline is sufficient. (de Freitas Vianna et al, 2017).
Suction catheters should occlude < ….. % of the ETT lumen or artificial airway (OPA/guedel or NPA) in paediatric and adult patients.
<50%
Recommendations for suctioning
- How far is the catheter passed down?
- Recommended duration?
- Suction pressure?
- Suction catheters are to be passed down until either the point of resistance or a cough is stimulated (hit the carina) and then the catheter should be withdrawn 1-2cm prior to continous suction
- Recommended that the duration of the suctioning procedure be limited to <15 seconds
- Suction pressures should be kept less than 200mmHg for adults and maintained at around 150mmHg or 20kPa
When is a tracheostomy required for suctioning?
Required when duration of suctioning is likely to surpass 14 days.
Open suctioning via oropharyngeal airway/guedel’s airway
Oropharangeal Airways (OPA) are rigid plastic tubes used to maintain the airway by stopping the tongue from covering the epiglottis.
They are inserted via the mouth. Therapist needs to select the appropriate size airway for each patient. A guide for measurement is from the center of the incisors to the angle of the mandible/jaw. Size is chosen based on length, rather than diameter. Different colours indicate different sizes.
Should not be used on conscious patients with an intact gag reflex (If a patient can cough, they have an intact gag reflex).
