Computer-assisted diagnosis and teaching of disorders of electrolyte, acid-base, and water metabolism.

Application of the tools of graphics, animation, sound and hypertext integrated with expert knowledge may help overcome the difficulties in teaching electrolyte and acid-base metabolism and its disorders. Using the Macintosh computer and the application, Hypercard we have developed two related programs with the following characteristics. Each contains graphic maps, consisting of a nomogram for plasma pH, PCO2 and HCO3 with zones representing physiological adaptation for each acid-base disorder (the Acid-Base map), and a nomogram illustrating relationships between plasma [Na+] and osmolality in hypo- and hypernatremic and hypo- and hypertonic states (the Sodium-Osmolality map). These are incorporated graphically and mathematically into each of the two Hypercard programs: The Acid-Base Diagnostician and The Osmotic Diagnostician. In the diagnostic module of each program, a differential diagnosis is developed for each of several zones on each map and, after obtaining additional user-entered clinical information, the program applies the relevant expert algorithms and presents the most likely diagnosis and differential diagnosis on screen and in printout. Each program has a teaching module involving text, hypertext, color graphics, digitized speech, and animation which demonstrate and discuss normal physiology, pathophysiology, and diagnostic criteria. The comprehensiveness and flexibility of the programs enable use by students at all levels, residents in medical and surgical disciplines, and physicians in many specialties.