What is the proper technique for performing chest wall vibration?

Proper Technique for Performing Chest Wall Vibration

Chest wall vibration should be performed with a frequency of 5-6 Hz and applied during the expiratory phase of breathing to effectively mobilize secretions and enhance airway clearance. 1

Positioning and Preparation

• Position the patient appropriately:

  • Sitting position is generally preferred for most patients
  • Consider gravity-assisted positioning based on affected bronchopulmonary segments (review CT imaging when available) 1
  • For patients with neuromuscular disorders, positioning should optimize chest wall access

• Ensure proper hand placement:

  • Place hands flat against the chest wall over the affected area
  • Position one hand over the lower ribs in the mid-anterior axillary line (just outside the normal cardiac apex position)
  • For female patients, avoid breast tissue 1

Execution Technique

1. Application of force:

   • Apply a resultant force of approximately 70-75 N (about 7.5 kg) 2
   • Create a change in chest wall circumference of approximately 0.8 cm 2

2. Vibration frequency:

   • Maintain a consistent frequency of 5-6 Hz (5-6 cycles per second) 2
   • This is significantly faster than normal chest compressions but slower than high-frequency techniques

3. Timing with breathing cycle:

   • Apply vibration during the expiratory phase only (in-phase vibration)
   • Begin vibration immediately as the patient starts to exhale
   • Continue through the entire expiration
   • Release before the next inspiration begins

4. Duration:

   • Apply vibration for the full expiratory phase of each breath
   • Continue for 5-10 breaths per treatment area
   • Perform 1-3 sessions per day based on clinical need

Clinical Applications and Considerations

• Effectiveness:

  • Chest wall vibration generates peak expiratory flow rates of approximately 0.97 L/s 2
  • While this is less than 20% of flow rates achieved with cough or huff, it exceeds those achieved with chest wall compression or relaxed expiration 2

• Patient populations:

  • Particularly beneficial for patients with neuromuscular weakness who have ineffective cough 1
  • Useful in bronchiectasis patients as part of airway clearance techniques 1
  • Can be used in patients with chronic respiratory diseases to assist with secretion mobilization 1

• Safety considerations:

  • Safe to use in patients with cardiac implantable electronic devices, but may require deactivation of accelerometer-based activity sensors in pacemakers 3
  • Avoid excessive force that could cause discomfort or injury
  • In-phase vibration (during expiration) decreases dyspnea, while out-of-phase vibration can worsen it 4

Potential Pitfalls and How to Avoid Them

1. Incorrect timing: Applying vibration during inspiration (out-of-phase) can increase dyspnea by 21.9 mm on visual analog scale. Always synchronize with expiration. 4

2. Inadequate force: Insufficient force will not effectively mobilize secretions. Ensure proper pressure is applied.

3. Inconsistent frequency: Maintain a steady vibration frequency of 5-6 Hz throughout the procedure for optimal effectiveness.

4. Ignoring patient comfort: Monitor patient for signs of discomfort or increased work of breathing and adjust technique accordingly.

5. Overlooking contraindications: Avoid in patients with unstable rib fractures, severe osteoporosis, or recent thoracic surgery.

By following these specific techniques, chest wall vibration can be performed effectively to enhance airway clearance, particularly in patients with neuromuscular weakness or chronic respiratory conditions who have difficulty clearing secretions.