We developed a computer program in a style of a game to help study blood gases in respiratory care. The program generates five simulated patients from a pool of 11. The player selects one patient, then the program calculates the patient's condition according to initial condition and selected treatment. Condition of the simulated patient may improve or deteriorate accordingly. Every two hours, the program display the data, requests the diagnosis and asks addition/change of treatment. The program then judges if diagnosis is correct. This process is repeated up to 48 hours. Finally a score and comments are displayed according to the performance of the patient and of the player. Students and young physicians used the original disk 312 times and more than 30 copies are distributed throughout the country. It is useful by itself as a self-teaching tool, but even more useful when combined with verbal teaching by instructors.