Description #
This unit is designed to help students and clinically registered physiotherapists develop a better understanding of the skills involved in performing the technique of assisted cough. It will also provide an understanding of the clinical reasoning process behind the application of assisted cough. The prerequisites to this unit are CCBSP-004. At the end of this unit the subject will have an understanding of the clinical reasoning, contraindications/restrictions, and proper application of assisted cough. The evaluation process includes a Pre/Post Knowledge and Clinical Scenario tests.
Learning Objectives
- At the completion of this unit the student will be able to:
- Know the components of a cough.
- Know the innervations of the muscles of Inspiration and expiration.
- Know the indications for an assisted cough.
- Know the contraindications and precautions for performing an assisted cough.
- Understand the concept of augmenting inspiration.
- Know how to safely apply assisted cough as a treatment technique.
Introduction to Assisted Cough #
What is a cough?
A deep inspiratory breath is followed by forced expiration with a closed glottis which then opens to allow for rapid expiratory airflow (Morice, 2008).
For a physically intact adult peak expiratory flows normally reach 7 to 12 L/Sec (Bach 1993)
What is an assisted cough?
A manual assisted cough involves the manual application of abdominal pressure and or costal lateral compression using various hand placements on expiration to augment the patient’s voluntary cough effort.
An assisted cough can increase peak expiratory flow rates by up to seven fold. (Harvey 2008)
Theory of assisted cough “Inspiratory Phase” #
This section discusses the importance of the inpiratory phase of an assisted cough.
It is important to take a deep breath before the forced expiration to be effective in getting enough air behind the sectretions in order to effectively clear them.
What are the innervations of the muscles of Inspiration?
What is a deep breath?
We measure Forced vital capacity to determine a person’s capacity for a deep breath.
A forced vital capacity is the measure of the air forced out by the client after a maximal inspiration.
A figure of 15mls/kg is used as an indicator of when to consider ventilator support.
Consider the relationship of the level of injury to the spinal cord with respect to respiratory dysfunction as reflected in the vital capacity.
Clinical reasoning point
This indicates how important it is to consider supplementing the inspiration during an assisted cough.
How can we supplement inspiration?
GPS: Glossopharageal breathing is a technique of breathing, which consists of a stroke like action of the tongue along with constricting action of the pharynx pumping air through the larynx into the lungs.
IPPB: Intermittent positive pressure breathing
Volume ventilator:
Breath stacking: the client takes a deep breath then holds it and then stacking another breath on top using a Resuscitation bag
Theory of assisted cough “Expiratory phase” #
This section discussed the importance of the expiratory phase of an assisted cough.
It is important to create sufficient expiratory force to effectively clear secretions.
What are the innervations of the muscles of expiration?
Consider the relationship of the level of injury to the spinal cord with respect to respiratory dysfunction as it is reflected in the cough function.
Clinical reasoning point
Therefore Do NOT vibrate when prforming an assisted cough. There is no clinical benefit to vibrating the abdomen. The purpose of an assisted cough is to mimic a normal cough. If you vibrate you loose the force required to achieve this goal. Vibration is a treatment technique that may be performed prior to an assisted cough but not during the cough.
Indication for an assisted cough #
When is assisted cough indicated?
An assisted cough is indicated when the client is unable to effectively clear secretions through a normal cough mechanism due to neurological impairment. Leading to the impairment of the expiratory muscles resulting in the inability to generate sufficient expiratory flow rate. E.g. Spinal cord injury, ALS, Neuromuscular dystrophy, Postpolio-myelitis etc For example a T4 paraplegic has their diapghram and some intercoastals for maximal inspiaration but minimal abdominalsfunction for forced expiration.
When is an assisted cough not indicated?
Consider when the client has an ineffective cough that is not due to neurological impairment it is in appropriate to push through functioning abdominal muscles.
Contraindications and precautions for an assisted cough #
What are the Contraindications and precautions for an assisted cough technique?
How to perform an assisted cough #
How do you perform an assisted cough?
Position the client:
The client may be supine, side lying or sitting. This depends upon your clinical reasoning and the circumstances. Is this a cough needed immediately when the client is in their chair or is it a part of a Respiratory treatment session.
Landmark:
Abdomen place hand above the umbilicus and at least 2 inches below the ziphoid.
Chest wall place palm in contact with the upper and/or lower ribs.
Body mechanics:
Standard position the wrists are in neutral, elbows straight not locked, shoulders relaxed and not internally rotated, shoulders square to hips, legs in a lunge position to ensure a weight shift. Adjust the height of the bed to mid thigh height with two clinicians consider using a stool or placing a knee on the bed. Ensure the brakes are on. Don’t twist.
Some hand position options include:-
Timing and coordination is critical to be effective.
Coordinate timing of cough with the client’s respiratory pattern
Communicate with the client and any other clinician involved on which breath you assist the cough,
Instruct re inspiration. Deep breath or supplemented deep breath
Amount of force
The constant manual pressure is applied as the patient starts to exhale.
Apply enough pressure to mimic the action of the muscles suc that the cough is effective
without causing pain.
The duration of the pressure should be until the client starts to inhale again
Do not vibrate
You lose valuable force needed to create the expiratory flow needed for the cough
There is no therapeutic benefit to vibrating the abdomen
(Please see video page)
Dosage
The number of assisted coughs required will be determined by several factors including:-
The amount required to effectively clear the client’s secretions.
The clients fatigue level
Evaluation
Ensure you evaluate the effectiveness of the procedure along with the client’s ability to tolerate it.
Using SaO2, facial expression, verbal communication, work of breathing, auscultation,
amount cleared, Pre versus post assessment findings.
Initial and ongoing assessment #
Initial and ongoing assessment and evaluation:
Observation
- Breathing pattern
- Work of breathing
- Respiratory rate
- Colour, amount and consistency of sputum
- Pallor
- Level of alertness
Objective findings
- Palpation
- Determine flexibility of ribcage (if rigid, hand placement for cough should be on abdomen)
- Assess degree of use of diaphragm, intercostals and accessory muscles
- Location of obvious secretions
- Auscultation
- Oxygen saturation (SpO2)
- Arterial blood gas (ABG)
- Respiratory rate (RR)
- Vital capacity (VC)
- Neurological assessment – to determine innervations and activation of inspiratory and expiratory muscles.
- Oxygen requirements (FiO2)
- Any condition identified in contraindications and precautions
Monitoring requirements as necessary
· SpO2
· End tidal carbon dioxide (ETCO2)
· Electrocardiogram (ECG)
· Heart rate (HR) and blood pressure (BP)
Evaluation
- Ensure you evaluate the effectivness of the procedure along with the client’s ability to tollerate it.
- Using SpO2, facial expression, verbal communication, work of breathing, Auscultation, amount cleared, Pre versus post assesment findings.
Ventilated clients #
Ventilated Clients
Assisted cough may be performed on ventilated clients.
Consider the following as applicable:
- Preoxygenation
o Assess oxygen requirements and pre-oxygenate as necessary. Ensure oximetry is adequately monitored throughout procedure if the client has the potential to decompensate
- Inspiratory Volume Requirements
o A deep inspiration improves the efficacy of the cough maneuver. Assess the ability of the client to assist with a deep inspiration and/or provide pressure/volume assistance through the ventilator or MVU as required.
- Humidification requirements
o Ensure adequate humidification is being provided through the ventilation system in use. Meeting the client’s humidification requirements will help to thin the secretions and improve mucociliary clearance.
- Alarms
o If alarms are muted or silenced during the assisted cough procedure, ensure they are reactivated and appropriately set upon ventilator reconnection.
- Independent Breathing Time
o Assess client’s independent breathing time prior to the procedure to determine if manual ventilation is necessary if the ventilator becomes disconnected and whether the client can participate in the assisted cough maneuver.
- Ventilator Disconnection
o Determine if the ventilator is to be left connected during the procedure or if manual ventilation is more appropriate. This may be determined by suctioning and/or oxygenation requirements, adjunctive therapy, ventilator capability, alarm settings, or manual ventilation requirements. Consult Respiratory Therapist if unsure.
- Emergency Equipment
o Ensure emergency equipment is available for ventilated patients including MVU and airway equipment as needed.
- Ventilator Monitoring
o Ensure ventilator monitoring during and post-procedure. This includes checking alarms are active and appropriately set (alarm silence feature should be reset after assisted cough), pressures/volumes are compared to previous levels, artificial airway is in place and secure, tubing connections are secure, and all parameters have been reset to previous levels.
Summary of how to perform an assisted cough #
Intervention: Assisted cough
1. Wash hands and don personal protective equipment.
2. Explain the procedure to the client and obtain consent.
3. Position client according to needs based on assessment findings. This procedure is most effective when a client is supine or side lying. It can be modified to be performed in a sitting position but may not be as effective as the secretions must be moved upward against gravity and caregiver position may not be as advantageous depending on the chair. Take care to consider your body mechanics. When the client is in a wheelchair you may decide to position the chair up against a wall or bed with brakes on to reduce bouncing of the chair.
4. Landmark xiphoid, umbilicus and ribcage and place hands on client. Use hand placement positions in keeping with any limitations or precautions.
5. Palpate breathing pattern and coordinate with the client and/or secondary caregiver on timing of breaths and assisted coughs. Client will ideally participate in promoting synchronicity with inspiration, expiration and cough.
6. Encourage client to take a deep breath with or without supplemental modalities. On exhalation, apply pressure with sufficient force to create an effective cough. Start lightly and increase until effective while ensuring tolerance by the client.
o If the pressure applied is too little, the cough may be ineffective and there is a risk of patient and caregiver fatigue, as more attempts will be required to clear secretions.
o If the pressure is too forceful, it may cause pain or trauma and the client may be reluctant to continue.
7. The pressure is applied in a direction to mimic the action of the abdominals (inward and upward) and the intercostals (“bucket handle”—downward and inward).
8. Keep wrists, shoulders and back as neutral as possible and elbows almost straight, not locked. Prevent twisting through the spine. Transfer pressure for the cough using your legs, shifting weight from your back leg to your front leg vs. pushing from your upper body and arms.
9. Ensure the client’s body is not forced upward against the support surface.
10. The force should be constant without vibration or shaking.
11. Repeat assisted coughs as necessary for mucosal clearance while monitoring client tolerance.
12. Evaluate effectiveness with auscultation, SpO2, amount cleared, Oxygen requirements etc.
13. Upon completion, return client to comfortable position.
14. Doff personal protective equipment and wash hands.
Images
Videos:
The first one is 1 and 2 person Assisted Cough Techniques.
1 Person Chair #
2 Person Chair #
2 Person with mask #
What NOT to do #
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References #
References
Morice, Alyn H (2008). Rebuttal: cough is an expiratory sound, Lung, Vol. 186, issue 1 Feb 2008, Pg 7-9
Harvey, Lisa. Management of Spinal Aguide for Physiotherapists. Churchilll Livingstone 2008
Bach, John R. Smith, William, H. et all Airway secretion clearance by mechanical exsufflation for post poliomyelitis ventilator assisted individuals. Archives of Physical Medecine and Rehabilitation 1993:74: 170
Pearl, J Ramirez AR (2001). Small Bowel Perforation after a Quad Cough Maneuver. J Trauma. Jul;51(1):162-3