Interpretation of acid-base disturbances is an essential skill for critical care nurses. Using the H model makes this process easy. When students and novice critical care nurses feel competent with certain skills, their confidence levels are greatly enhanced. One of us (K.M.K.) has been using the H model for many years to teach students how to interpret the results of arterial blood gas analysis. The students are often amazed at how easy and fun the model makes learning a subject many perceive as complex.