When an asthma attack occurs, many sufferers use a device -- a "spacer" -- to increase the chances that rescue medicine travels from an inhaler all the way down to the airways where it is needed. A new review of studies found no difference between the effectiveness of commercially manufactured devices and homemade spacers -- sometimes fashioned from a plastic soda bottle or a Styrofoam cup.
However, the spacers were not tested with the type of inhaler that is now standard in the United States, cautions a spokesman from the American Academy of Allergy Asthma & Immunology (AAAAI) who read the review.
A puff of aerosolized medicine can leave a metered-dose inhaler at nearly 60 miles an hour. It takes some coordinated timing to make sure a good dose of the drug makes it past the tongue and turns the corner at the back of the throat to reach the windpipe.
A spacer slows down the drug particles and can help patients synchronize their breathing better as they pump the inhaler. "Spacers are somewhat forgiving of bad technique, which is important for children," said Dr. Richard Wasserman, an asthma and allergy specialist in Dallas and an AAAAI spokesman.
The review appears in a recent issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.
In the United States, the price of a spacer varies widely, from under $10 to more than $30. In limited-resource countries, commercially manufactured spacers are less available and are relatively costly, so doctors sometimes counsel their patients to use a homemade version. Health researchers want to understand if this practice -- common in developing countries -- is as effective as other treatment methods.
The review culls data from six studies with more than 600 children who were suffering from a serious bout of wheezing or asthma. The reviewers found no significant differences in the two treatment procedures in terms of hospital admissions or need for further therapy. However, the authors write that considering the small number of study participants and the resulting level of uncertainty of the findings, they cannot conclude that homemade spacers and commercially made spacers work equally well.
It is not clear from the review, but Wasserman said he suspects that the inhalers tested in the six trials used chlorofluorocarbons (CFCs). CFCs are an ozone-depleting chemical used to propel medicine into the lungs. In 1987, the United States agreed to phase out production of chemicals that damage the Earth's ozone layer. By 2009, all inhalers must be CFC-free, so medical device manufacturers are already making the change. Most new inhalers use hydrofluoroalkane (HFA) propellant.
"There are certain differences in the characteristics of the two inhalers -- particle size, distribution, speed of the particles -- which could affect the behavior of the spacing devices," Wasserman said.
The review does not deal with propellants at all: "The biggest issue of uncertainty coming out of this Cochrane is the change of propellant in the inhalers," Wasserman said.
Journal reference: Rodriguez C, Sossa M, Lozano JM. "Commercial versus home-made spacers in delivering bronchodilator therapy for acute therapy in children (Review)." Cochrane Database of Systematic Reviews 2008, Issue 2.
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