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Indications for Positive Airway Pressure Therapy |   |
Positive airway pressure adjuncts are used mainly for two purposes: to mobilize secretions and treat atelectasis. PEP therapy was originally developed as an to mobilize secretions, but has been applied to treat atelectasis. EPAP and CPAP are primarily used treat atelectasis. Indications for positive airway pressure therapy include:
- To reduce air trapping in asthma and COPD
- To prevent or reverse atelectasis
- To aid in mobilization of retained
- To optimize bronchodilator delivery
PEP therapy has been shown to reduce air trapping in obstructive lung diseases by improving the distribution of ventilation, increasing the FRC, and opening up lung regions that are otherwise closed off in cystic fibrosis. In treating asthma and COPD, CPAP reduces the load on the inspiratory muscle improves their efficiency, and decreases the energy cost of breathing.
Regarding postoperative complications, both PEP and CPAP can increase the FRC lower the P(A-a)02, and decrease the incidence atelectasis in patients having undergone major surgery.
While CPAP therapy is beneficial in the treatment of postoperative atelectasis, the duration of its effects appears limited, with the corresponding increase in FRC often being lost within 10 minutes after the end of tbc treatment. As a result, many recommend that CPAP be used on a continuous, rather than intermittent basis.
CPAP therapy delivered via a mask has also been successful in treating cardiogenic pulmonary edema because it reduces venous return and cardiac filling pressures, and improves compliance and decreases the work of breathing.
Contraindications
There have been no absolute contraindications reported relating to the use of intermittent PEP, EPAP, or CPAP therapies. However, there are several factors that the RCP should evaluate before a decision is made to initiate positive airway pressure therapy. Potential contraindications for administering positive airway pressure therapy include:
- patients unable to tolerate an increased work of breathing
- Intracranial pressure > 20 mm Hg
- Hemodynamic instability
- Recent facial, oral, or skull surgery or trauma
- Acute sinusitis
- Epistaxis
- Esophageal surgery
- Active hemoptysis
- Nausea
- Middle ear pathology, (e.g., tympanic membrane rupture)
- Untreated pneumothorax