ABASE: A Multi‐Component Computer Program to Teach Acid‐Base Regulation a

To understand acid-base (AB) regulation, students must understand the behavior of the component subsystems and their underlying mechanisms, be able to mentally integrate the functions of individual components into a unified control system, and have a way to represent the events that occur in response to an acid-base disturbance. This requires that they have a chance to practice applying their knowledge and understanding to the solution of problems. The computer program ABASE assists students to do these things-it is not, however, intended to provide initial instruction. ABASE consists of four lessons, which interactively review these topics: buffers, respiratory and renal compensation, and the Davenport nomogram (DN). Although students are expected to have studied these subjects before working with ABASE, they often are uncertain about their knowledge and appreciate having a chance to review some of the material. Hence, ABASE permits lessons to be done at any time: (a) after a student initially signs on, (b) after one or more problems have been done, or (c) even from within a problem. In the lattermost case, students can branch out of a problem and return to the same point after completing as much of a lesson as they want. The program has seven problems (FIG. 1). Each of these represents a situation that causes acute and/or chronic acid-base changes. To solve a problem, students predict the qualitative changes (increase, decrease, no change) that occur in response to changes in five AB variables by making entries into a Predictions Table' (FIG. 2). They must predict changes that (1) occur in direct response to the disturbance, (2) result from respiratory compensation, (3) are present at the completion of respiratory compensation, (4) are caused by renal compensation, and (5 ) are present in the final AB state of the subject. ABASE evaluates these predictions and gives instruction for errors that were made. Next, the student traces the time course of the AB response on a DN by plotting points that represent the acid-base status of the subject in the procedure at each of the time periods represented in the Predictions Table. Student errors are once again critiqued and instruction is provided as necessary. Finally,