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Contraindications for IPPB

There are several clinical situations in which IPPB should definitely not be used, including:

• Tension pneumothorax: Involves the trapping of air in the pleural space. As the patient continues to breathe the pocket of entrapped air increases to the point where it encroaches on the affected lung creating a large shunt and shifting of the thoracic structures, including the heart, mediastinum trachea. Without intervention the affected lung will eventually collapse. IPPB administration could pose a life-threatening situation for such a patient.
  
  This contraindication is the most clear of all those for IPPB, because if administered to a patient with untreated pneumothorax, the patient's condition could seriously worsen. After a chest tube has been placed, IPPB could be applied, however the RCP needs to be certain that IPPB is really needed. Patients with a history of spontaneous pneumothorax, cysts or bullous disease require special care when applying IPPB, and lower pressures should be used.
  
  Chart review is the best way to avoid inappropriate administration of IPPB. If untreated pneumothorax is not noted on the chart, the RCP can easily recognize its presence by evidence of sharp, increasing chest pain and increasing rise in ventilatory pressure, dyspnea, shortness of breath and cyanosis. IPPB should be immediately terminated, and the attending physician notified.
  
  
• Subcutaneous or mediastinal emphysema. Patients with subcutaneous emphysema should be considered at risk for developing pneumothoraces and should be not be considered candidates for IPPB because as positive pressure is applied, their condition could worsen.
  
  
• Active untreated tuberculosis. Localized pulmonary infections like TB could spread as a result of IPPB administration. It could also cause rupture of the cavities seen in the advanced stages of untreated TB. Since tubercle bacillus is infectious and droplet-borne, the exhaled particulate moisture from IPPB nebulizers can act as a vector for the disease. IPPB should not be administered if TB is suspected or until the condition has been ruled out.
  
  
• Intracranial pressure: Positive pressure in the thorax also can retard cerebral venous return. Impedance to the outflow of blood engorges the cerebral circulation, and can increase intracranial pressure to >15 mm Hg or higher. In instances where increased intracranial pressures are problematic, such as after neurosurgery or brain trauma, IPPB generally is contraindicated.
  
  
• Hemodynamic instability: Hemodynamically unstable patients are poor candidates for IPPB. Marked hypotension and cardiovascular insufficiency are also relative contraindications to IPPB.
  
  Upon inspiration during normal breathing patterns, a negative pressure is developed in the thoracic cavity as it expands. Air movement into the lung is caused by the pressure differential between the mouth and lungs. during inspiration the negative pressure is transmitted across the pleura to the inferior and superior vena cava, sending venous blood into the right atrium. That blood then travels through the pulmonary vascular beds and eventually returns to the left atrium, fully oxygenated. This action would be compromised with IPPB therapy, since the normal negative pressure would be replaced with positive pressure as the driving force of inspirations, causing reduced cardiac output.
  
  Patients can present with signs of shock as a direct result of decreased cardiac output exacerbated by the positive pressure in IPPB. Therefore, patients with preexisting conditions of decreased cardiac output, such as congestive heart failure or mitral valve stenosis, must be observed closely during IPPB therapy. By observing the following rules, complications can be avoided by:
  
  

• Using the lowest possible pressure to improve tidal volume effectively.
• Using the shortest effective inspiratory time to reduce the overall time of positive pressure.
• Allowing patients adequate expiratory time.
• Allowing patients rest if they feel the need.

In treating these patients, RCPs need to weigh the benefits of therapy against the potential hazards for each individual situation.

• Active hemoptysis: is usually a medical emergency in which lung expansion therapy is clearly contraindicated. If pulmonary tissue is actively bleeding, positive pressure may only worsen the situation.
  
  
• Tracheoesophageal fistula and recent esophageal surgery: Patients with a T-E fistula (neonates) are rarely good candidates for IPPB because if positive pressure were applied to their airways, gas could enter the esophagus, resulting in gastric insufflation. In adults, recent esophageal surgery also contraindicates IPPB.
  
  
• Radiographic evidence of bleb: The fragility of emphysematous blebs (as identified by X-ray) may also contraindicate IPPB.
  
  
• Other conditions in which IPPB is considered contraindicated include: Recent facial, oral, or skull surgery; Singulation (hiccups); Air swallowing; and, Nausea.

With the exception of untreated tension pneumothorax, most of these contraindications are relative. As with all therapeutic procedures, a sound knowledge of the patient's condition, tempered with common sense, should guide the RCP in the decision-making process. Thus, a patient with any of the conditions listed above should be carefully evaluated before a decision is made to commence administration of IPPB therapy.