Ill-Fitting Masks Hamper Child Asthma Care
In some cases, almost no inhaled medication gets through, study finds
TUESDAY, Feb. 7, 2006 (HealthDay News) -- The face masks that some young children with asthma use to inhale their medicines just don't do the job, often because of poor fit and stiffness, a new study found.
"The authors felt that medication was incomplete with the face masks," said Dr. Jonathan Field, director of the Allergy/Immunology and Asthma Clinic at New York University School of Medicine/Bellevue Hospital in New York City. "There was a concern that children may be undertreated." Field was not involved in the study.
The findings appear in the February issue of Respiratory Care.
An estimated nine million children in the United States have been diagnosed with asthma. Symptoms include wheezing and shortness of breath. Each year, experts say, children miss almost 15 million school days as a result of the condition.
In addition, up to 200,000 American children are hospitalized each year because of asthma attacks. But a recent study suggested that up to half of those hospitalizations are preventable. Taking medications as scheduled and knowing how to use an inhaler or other equipment were cited as one way to avoid these hospitalizations.
Asthma medications are most effective if they gain access directly into the bronchial tubes, which is why patients use "puffers," or inhalers. Children may find it harder to manage their treatment, however, so various accessory devices have been developed to make it easier and more effective.
The most common is a valved holding chamber -- basically, a tube with the medication fitting at one end and a one-way valve connected to a mouthpiece at the other end. The medication is held in the chamber until the child inhales, at which point the valve opens and lets the medication into the airways.
Younger kids who can't use a mouthpiece need an added soft, face mask that connects to the holding chamber.
The problem is that most of these masks were developed for other reasons, such as anesthesia, resuscitation and aerosol therapy.
"We and others realized that one of the most important places things can go wrong is the interface between the medication and the patient, in other words, the mask," explained Dr. Bruce Rubin. He is senior author of the study and professor of pediatrics and biomedical engineering at Wake Forest-Virginia Tech Biomedical Engineering & Sciences in Winston-Salem, N.C.
"If it doesn't seal on the face, the child can't develop the force to pull the medication out," he said. "If the mask is uncomfortable, the child is going to be distressed and, if he or she cries, no medication will get in."
The volume of the mask also needs to be relatively small, otherwise the child will have to breathe several times to get the needed medication, Rubin said. Extra volume is called the "dead space."
In their study, Rubin and his co-authors assessed seven of the most widely used masks, in combination with pressurized, metered-dose inhalers for children. The masks were tested on the head portion of 2-year-old-sized mannequins typically used for teaching CPR, or cardiopulmonary resuscitation. The researchers measured the total volume of each mask, then tested how much force was needed.
"Some of the masks were great and some of them didn't seal at all under any force," Rubin said. "Some had huge amounts of dead space and didn't deform, and that made some of them inappropriate for use in children. They would get almost no medication."
"None of them worked ideally," Rubin said, although two -- the Optichamber and the Aerochamber -- did pretty well. The Pocket Chamber mask appeared not to seal at any level of force, Rubin said. The other masks tested were the Easivent, BreatheRite, Ace and Vortex inhalers.
The purpose of the study was not to instruct doctors and parents on which masks worked better, but rather to challenge manufacturers to build better masks, with the child in mind from the start, Rubin said.
"The U.S. Food and Drug Administration and the American Academy of Pediatrics realize that a lot of devices used in children are not designed for kids," Rubin said. "They are taken from adults and made smaller."
This includes not only masks but also implantable stents, orthopedic devices and various other medical devices.
A bill introduced in the U.S. Senate is aimed at providing incentives for manufacturers to design devices specifically for children, rather than just jerry-rigging adult devices.
"There's a huge bang for their buck," Rubin noted. "Designing and having a mask is much less expensive than new designer drugs."
Rubin is next planning to study how effectively medication is actually getting to the lungs of children with asthma.
For more on asthma and how to control it, head to the American Academy of Allergy, Asthma and Immunology.