Shop for a bed wedge. These are available in different types and under many brand names, and you can find them at department stores, medical supply stores, pharmacies and online. Bed wedges most frequently are advertised to help relieve heartburn and gastroesophageal reflux disease (GERD).
Decide the type of bed wedge that will work best for you. Wedges are available in foam and in inflatable styles with a wide range of pricing, from about $30 to $200 as of 2009. An inflatable style is best if you'd like to be able to adjust the elevation. If you're certain 4 inches is optimum, then a foam one will work.
Place the foam bed wedge or the inflatable wedge between the mattress and box spring at the head of the bed. If you've purchased the inflatable type, use the hand pump to fill it with air to 4 inches in elevation. Many inflatable bed wedges come with an automatic pump instead, where you simply press a button to inflate the wedge to the optimum fullness.