"MacLung - A Physiological Tutorial and Simulation of Pulmonary Gas Exchange for the Macintosh Computer."

DEVELOPMENT AND EVALUATION OF A COMPUTER TEACHING MODULE

Michael Kozaczek (NJMS 1996)
Sponsor: Joseph Boyle III, M.D.
UMD/New Jersey Medical School
Dept. of Physiology
185 South Orange Ave.
Newark, NJ 07103

ABSTRACT

A software package for the Macintosh computer will be demonstrated which consists of tutorial, simulation and quiz modules dealing with pulmonary physiology. All three components can be used independently by students for review or remediation. The simulation allows the user to alter 11 major variables affecting gas exchange or to run pre-programmed scenarios to demonstrate common clinical conditions. The simulation can be used as a laboratory experience or as a lecture or demonstration package to illustrate the effects of the various parameters on gas exchange.

PAPER

A number of Macintosh computer teaching programs were developed using Hypercard. The modules include a tutorial in gas diffusion through lung tissue, a computer simulation, and a comprehensive respiratory physiology exam.

"Breathe Easy" (the gas diffusion tutorial and simulation) consists of two Hypercard stacks, "Respiratory Tutorial" and "Diffusion Simulation ". "Respiratory Tutorial" outlines each of the factors determining the values of carbon dioxide and oxygen from the atmosphere to the body tissues. The topics treated include alveolar gas tensions, diffusion, oxygen content and hemoglobin, ventilation & perfusion, and hypoxia & gas exchange. A main tutorial menu allows the user to select one of these topics for study, or the user may proceed sequentially through the whole stack. The Hypercard stack "Diffusion Simulation " may be accessed from this tutorial at any point to aid in visualization. Conversely, the user may return to "Respiratory Tutorial" from "Diffusion Simulation " to the original point of departure.

"Diffusion Simulation" is a sophisticated visual simulation of gas exchange across the alveolus. User controlled input parameters include tidal volume, dead space, respiratory frequency, inspired oxygen fraction, oxygen consumption, pulmonary blood volume, cardiac output, diffusion, shunt flow, hemoglobin, and temperature. The calculated output parameters include minute ventilation, transit time, equilibrium time, oxygen capacity, venous and arterial oxygen content, venous and arterial oxygen partial pressure, venous and arterial carbon dioxide partial pressure, venous and arterial pH, alveolar ventilation, alveolar oxygen partial pressure, alveolar carbon dioxide partial pressure, pulmonary capillary oxygen partial pressure and arterial bicarbonate. The input parameters are alterable individually, or the user may run a variety of preset physiological scenarios from the menu (which alter a number of these). Screen graphics change to illustrate the physiological conditions as the input/output parameters change. A help screen instructs the user in the use of the simulation.

"Respiratory Exam" is a Hypercard stack presenting a comprehensive examination in respiratory physiology, as taught at New Jersey Medical School. It goes beyond the topics treated in the tutorial. The topics include statics, airway resistance, pressure, alveolar ventilation, pulmonary circulation, ventilation distribution, perfusion, work and hypoxia, gas laws, diffusion, gas transport, acid/base, and ventilation control (totaling about 150 questions). This module requires that the user choose an exam subject by clicking on one of the topic buttons on the main menu screen. Questions are answered by clicking the check box next to the answer choices. The answer may be changed before proceeding to the next question, but each question must be answered and a question missed on the first try will be recorded as a missed question. The user moves from question to question by pressing the "NEXT" button. At the end of the quiz, the user may review the questions missed on the first try by pushing the "REDO MISSED ?'s" button. Another missed question will be brought up each time the "CONTINUE MISSED" button is pressed. The user will return to the main menu when all the missed questions are reviewed. The user may also interrupt a session anytime by pressing the QUIZ MENU button. The module provides a score at the end of each completed section, as well as a running tally of correct answers during the session. There is a version of this module for fast Macintosh computers as well as one which will run on older, slower computers.

These teaching programs have been well received and will be used during the course of the academic year.
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