Respiratory Physiology

Respiratory Physiology Models

Description: Alveolar Gas enables the user to change variables like tidal volume, dead space, and frequency of breathing and then calculate the alveolar PO2 and PCO2. Simulations include hyper- and hypoventilation, hypocapnia, exercise, a patient on a ventilator, oxygen therapy, etc.

History: Fenn, Rahn, and Otis published their famous alveolar gas equations in 1946. After personal computers became available in the 1970s, Dr. Harold I. Modell, using BASIC for IBM PCs, created what was probably the first series of educational computer programs used for self-instruction in respiratory physiology. In the 1980s and 90s, Shepherd and colleagues took advantage of the advent of the Mac and LabView's graphic user interface (GUI) to create self-instructional software for medical and graduate students. The "Alveolar Gas" learning exercise consisted of a LabView computer program and a paper worksheet to guide the student through specific simulations.

Status & Availability: Free LabView® versions of Alveolar Gas are available in the American Physiological Society's archive of teaching materials: http://www.lifescitrc.org/searchResultsAll.cfm?contactID=857

The iPad app "Alveolar Gas" is available in Apple's App Store (SM). In the iPad version, the GUI and the worksheet are combined into a single, self-contained app. http://itunes.apple.com/us/app/alveolar-gas/id552766731?mt=8

An iPhone app is also available: https://itunes.apple.com/us/artist/sangrelux-inc./id552766734

Description: Blood Oxygen enables the user to change variables like the PO2, hemoglobin concentration, and hemoglobin's affinity for oxygen and calculate the concentrations of oxygen in the form of oxyhemoglobin and dissolved oxygen. Simulations include anemia, polycythemia, compaaring the effects of oxygen inhalation in a pulmonary "patient" with a normal person, carbon monoxide poisoning, hyperbaria, etc., as well as the concepts of the Fick Principle and the arteriovenous oxygen difference.

History: In the 1980 and 90s, Shepherd and colleagues took advantage of LabView's graphic user interface (GUI) to create self-instructional software. The LabView® version of the Blood Oxygen exercise consisted of the computer program and a paper worksheet to guide the user through specific simulations. This exercise was used in a lab course for medical and graduate students.

Status & Availability: Free LabView® versions of Blood Oxygen for Macs and Windows are available in the American Physiological Society's archive of teaching materials: http://www.lifescitrc.org/searchResultsAll.cfm?contactID=857

An iPad/iPhone app of "Blood Oxygen" is being developed.

http://www.lifescitrc.org/searchResultsAll.cfm?contactID=857
Description: "Sat Curves" lets the user conveniently select values for the factors that affect the oxyhemoglobin dissociation curve: PCO2, pH, temperature, and 2,3-DPG concentration. Unlike numerous websites that show only one graph at a time of the oxyhemoglobin dissociation curve, Sat Curves shows two graphs side by side so that changes in the shape and position of the curves are easy to see. For example the factors that alter the dissociation curve can initially be set to arterial values for both graphs. Then the student or instructor can change one factor at a time to show its effect at a typical mixed venous PO2. Possible simulations include the Bohr Effect, the unloading of oxygen in systemic capillaries under resting conditions, and the oxygenation of exercising skeletal muscle.

History: The LabView version of "Sat Curves" consisted of the computer program and a paper worksheet to guide the user through specific simulations. This exercise was used in a lab course for medical and graduate students.

Status & Availability: Free LabView® versions for Macs and Windows are in the American Physiological Society's archive of teaching materials: http://www.lifescitrc.org/searchResultsAll.cfm?contactID=857

An iPad/iPhone app of "Sat Curves" is being developed.