Boellaard W P, van Doorninck D J, Roldaan A C, van Klink H C
Diaconessenhuis, afd. Longziekten, Leiden.
Ned Tijdschr Geneeskd. 1991 Mar 30;135(13):567-70.
The breathing cassette (Hyperfree) was tested on 10 persons suffering from hyperventilation syndrome. Each subject performed a hyperventilation provocation of two minutes on three separate occasions. Immediately after the hyperventilation provocation the subject was asked to terminate the hyperventilation, firstly with no aid at all, later using a plastic bag or the breathing cassette. The %vol. CO2 in the exhaled air was recorded with a capnograph. The use of the plastic bag and the breathing cassette resulted in an equal restoration of the %vol. CO2. After using the cassette for six weeks the patients completed a questionnaire. All patients stated that they intended to continue using the breathing cassette, and that it was easy and handy to use. Most patients carried the cassette always with them, since it made them feel comfortable.
对10名患有换气过度综合征的患者进行了呼吸盒（Hyperfree）测试。每位受试者在三个不同场合分别进行了两分钟的换气过度激发试验。在换气过度激发试验后，立即要求受试者停止换气，首先完全不借助任何辅助手段，随后使用塑料袋或呼吸盒。用二氧化碳分析仪记录呼出气体中的二氧化碳体积百分比（%vol.CO₂）。使用塑料袋和呼吸盒后，二氧化碳体积百分比恢复情况相同。在使用该呼吸盒六周后，患者填写了一份问卷。所有患者均表示打算继续使用该呼吸盒，并且其使用方便、操作简单。大多数患者总是随身携带该呼吸盒，因为这让他们感觉舒适。
