CPT Pt 2: IPV vs Metaneb

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Seon Adams

Registered Respiratory Therapist with a diverse background in healthcare but a keen interest in trauma intensive care. Additional interests are ventilators, new innovations in healthcare, and traveling

The Pre-brief

As discussed in chest physiotherapy Part 1, CPT is a modality commonly utilized by respiratory therapists in patients in whom the chest x-ray reveals focal lung opacity, evidence of retained secretions, and/or ineffective cough. This can be performed in quite a number of ways dependent upon the patient, the lobe that requires the therapy, and any contraindication that can prevent a certain method of therapy. Like most modalities, Chest Physiotherapy is not only dependent on the practitioner performing it but the patients’ willingness to have it done and work with the practitioner. 

Atelectasis and secretion retention in combination are major risk factors for those prone to alveolar collapse such as those with muscular weakness, patients on ventilators, and the pediatric population.  In the event of having a patient who presents with any of the above-mentioned situations along with having a traumatic injury such as broken ribs, chest tubes, or low tolerance for other modalities, two modalities present themselves as an option; one being  IPV.

What is the Intrapulmonary Percussive Ventilation (IPV)

IPV is a pneumatic airway clearance device that combines mist with high flow pressurized jets of air to the airway at a rate of 100 to 300 cycles per minute via a mouthpiece, artificial airway, or placed inline a ventilator circuit. IPV promotes mobilization of secretions, provides nebulized therapy, and provides intrathoracic vibration and percussion, thus improving ventilation.  IPV utilizes short fast pressurized bursts of flow to deliver aerosolized medication to the airways and alveoli in efforts of lung recruitment and mobilization of secretions. The continuous mist helps hydrate secretions allowing for the facilitation of trapped sticky mucus.  In conjunction with mechanical ventilation, IPV has been shown to improve patients presenting with ARDS. According to Egans, comparative studies show that IPV is equivalent to other airway clearance strategies in improving short term pulmonary function tests results enhancing sputum expectoration in patients with cystic fibrosis.  The therapy is well tolerated by stable patients and appears to offer an alternative in patients with chest wall compliance.  

Instructions to Perform IPV Treatment

The duration of the treatment is controlled by the therapist and level of patient tolerance. 

  • Set the operational pressure (which controls the peak operational pressure) between 30-45.
  • Set the percussion control knob (which ranges from 100-300 cycles a minute) to easy then increase until appropriate chest wiggle is noticed during exhalation.  
  • Add 20 mL of normal saline or hypertonic saline to the medication cup. An albuterol dose can be added in conjunction. 
  • If performing by the mouthpiece, allow the patient to take a break and cough or huff cough. If performing with an artificial airway, deflate the cuff slightly during therapy remembering to re-inflate after therapy is completed.
  • After 20 minutes, or when the cup is empty, the treatment is complete. Please do not continue treatment with an empty medication cup as this can cause irritation.

What is Metaneb

Another modality option is Metaneb. Metaneb is utilized for mobilization of secretions, lung expansion, and can be used for the prevention and treatment of atelectasis. Indications would be worsening oxygenation, increasing FIO2 and/or PEEP, evidence of lung collapse or mucus plugging, and/or retained pulmonary secretions in the absence of an effective cough. Metaneb delivers aerosol treatment (saline, hypertonic saline, and/or albuterol) while oscillating the airways with continuous positive pressure. Metaneb like IPV can be done via mouthpiece, artificial airway, and in-line with the ventilator. Metaneb delivers high-frequency oscillatory breaths during both inspiration and expiration. This pressure gradient allows for the mobilization and hydration of sticky mucus.

Instructions to perform Metaneb

  • Add normal saline, hypertonic saline, and/or albuterol to the medication cup. 
  • Set mode to CPEP. Set CPEP 10-30 based on patient tolerance. CPEP mode provides aerosol combined with continuous positive pressure helping with lung expansion. 
  • Start the rotator ring in easy mode (1dot) and adjust higher as patient tolerance allows. 
  • After 2 ½ minutes of CPEP, switch to CHFO mode at a lower frequency setting. 
  • CHFO is the oscillatory mode sending pulsations into the airways. Continue on this for 2 ½ minutes then encourage the patient to cough or huff cough. 
  • During the 10 minute session, be sure to alternate between CPEP and CHFO.
  • If done in line with ventilation then the clinician can leave fragment in the CHFO mode. 

IPV VS Metaneb

Similar to the IPV, Metaneb employs the same type of High Frequency Oscillatory action. The main difference between the two modalities lies within the Venturi.  Metaneb has a fixed orifice while IPV has a sliding venturi which facilitates the oscillations. Unlike IPV, Metaneb allows the clinician to change rotate between the Oscillatory effect (CHFO) and the lung expansion mode (CPEP)

Alternating between the cycles of CPEP and CHFO helps maximize therapy effectiveness when combined with aerosol therapy. Between Metaneb and IPV there have been no studies to show significant differences.  Both have shown increased aeration, improvement in ventilation, and mucus clearance in both intubated and non-intubated patients.

Who may benefit from IPV or Metaneb

Patients who may benefit from IPV/Metaneb:

  • Cystic Fibrosis
  • Asthma
  • Chronic Bronchitis
  • Bronchiectasis
  • Neuromuscular disorders
  • Emphysema
  • COPD
  • Bronchiolitis
  • Restrictive lung disease with recurrent atelectasis
  • Bronchopneumonia
  • Mechanically ventilated patients with atelectasis
  • Post thoracic and abdominal surgery
  • Patient refractory to traditional bronchial hygiene methods
  • Patients unable to clear secretions

Contraindications

  • Untreated pneumothorax
  • Hemoptysis
  • Active tuberculosis

The Debrief

  • IPV/Metaneb both utilize High Frequency Oscillatory therapy in conjunction with aerosol therapy to facilitate secretions from smaller airways to larger airways where it can then  be expectorated or suctioned. The use of oscillatory therapy also helps promote lung expansion
  • No major difference has shown between choosing over the other as the method of therapy
  • Both therapies have shown to be helpful in patients with chest wall complications

References

  1. Kacmarak, R., Stroller, J., Heuer,A. (2013).  Egan’s Fundamentals of Respiratory Care. Elsevier Publishing. 
  2. Metaneb System.  (2016, September 22). Retrieved from https://www.hillrom.com/en/products/the-metaneb-system/
  3. Ortiz-Pujols, S., Boschini, L. A., Klatt-Cromwell, C., Short, K. A., Hwang, J., Cairns, B. A., & Jones, S. W. (2013). Chest high-frequency oscillatory treatment for severe atelectasis in a patient with toxic epidermal necrolysis. Journal of burn care & research : official publication of the American Burn Association, 34(2), e112–e115. https://doi.org/10.1097/BCR.0b013e318257d83e

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