FORT LAUDERDALE, FLA. – Despite a lack of definitive evidence, airway clearance strategies are commonly employed in children with cystic fibrosis and other lung diseases, Dr. Veda L. Ackerman said.
"Unfortunately, we don’t really know very much about airway clearance. We do it a lot, but we don’t have a lot of data," Dr. Ackerman said at a seminar on pediatric pulmonology, which was sponsored by the American College of Chest Physicians and the American Academy of Pediatrics.
For instance, the only pediatric study comparing airway clearance to no such therapy was published in 1983 and assessed eight patients with cystic fibrosis (J. Pediatr. 2003;103:538-42).
"Intuitively and intellectually, airway clearance makes a lot of sense. But [it is important to] think about whether we are helping or hurting when we prescribe airway clearance," said Dr. Ackerman, a pediatric intensivist at Riley Hospital for Children and a pediatric pulmonologist in private practice in Indianapolis.
Oxygen desaturation, gastroesophageal reflux, aspiration, hyperventilation, and "guilt for the family from lack of adherence" are potential adverse events associated with prescription of airway clearance, Dr. Ackerman said.
There are "no data to support the use of one airway clearance technique over the other," Dr. Ackerman said. Chest physiotherapy (CPT), positive expiratory pressure (PEP) valve, Cardinal Health’s Flutter device, Smiths Medical’s Acapella system, Medical Acoustics’ Lung Flute device, airway clearance vests, and Smiths Medical’s EzPAP device are among the options.
No definitive data exist to support use of CPT in an asymptomatic child with cystic fibrosis, Dr. Ackerman said. This patient population is prone to adverse events, especially gastroesophageal reflux with or without aspiration. CPT also requires a significant time commitment on the part of families. Despite these concerns, "I still do recommend it" for some patients.
Airway clearance devices "jiggle, shake, or use sound waves to loosen mucus off the airway walls so secretions can be coughed up," Dr. Ackerman said. Success with these devices is often technique dependent.
The PEP valve is portable, takes 10-15 minutes to clear the airway, and can be used with aerosolized medications. However, Dr. Ackerman’s institution uses the Flutter "much more than the PEP valve," she said. This device "tends to be used for families who cannot put time into CPT or when the child goes to Grandma’s or on a sleepover." The device loosens mucus through expiratory oscillation, so it may be less effective at lower airflows, such as those used for small children or patients with more severe lung disease. The device has to be held at a precise angle to maximize oscillation, she added. Each use of the Flutter device takes about 10-15 minutes.
The Acapella system combines the benefits of the PEP valve and airway vibrations to mobilize secretions, Dr. Ackerman said. The mechanism of action is similar to that of the Flutter, except that the Acapella has a valve-magnet device to interrupt expiratory flow and thus can be used at any angle.
"All of these devices cost less than $100," Dr. Ackerman said. "These may – and I said may – be better than doing nothing at all."
Contraindications to the PEP valve, Flutter, and Acapella include pneumothorax, hemoptysis, and esophageal varices. Lung surgery is another contraindication, Dr. Ackerman said, because use of airway-clearance devices can cause an air leak or can break down an anastomosis site. A pulmonary embolus is another contraindication, but "fortunately we do not see this often in pediatrics." A perforated ear drum is also a contraindication to these airway devices "because it causes pain."
The Lung Flute uses a different strategy (acoustic waves) to increase mucociliary clearance. It vibrates the chest in a way that is similar to the way a reed instrument vibrates when it’s played, Dr. Ackerman said. "There are no pediatric data, but it is cheap and easy to use." The Lung Flute is used more commonly for patients with chronic obstructive pulmonary disorder and not as much in cystic fibrosis.
Airway clearance vests deliver pulses of air pressure to the chest wall. The vest loosens mucus through shearing at the air/mucus interface, and compression causes clearance through repetitive peak expiratory flows that expel mucus like small coughs.
"You should not get compression of the airway itself; only the chest wall is compressed," Dr. Ackerman said. In contrast, "if you blow hard enough with the Acapella, Flutter, or PEP, you could get airway collapse." An airway clearance vest costs approximately $10,000, and obtaining insurance approval can be difficult; reimbursement policies vary from state to state.
The EzPAP device clears airways through positive airway pressure in a way that is similar to intermittent positive pressure breathing. It is approved by the Food and Drug Administration for lung expansion therapy and the prevention and treatment of atelectasis. Although no peer-reviewed data are available, many children are using EzPAP because respiratory therapists believe in this device, Dr. Ackerman said.