1) Learning five interventions that are useful in acid-base & respiratory simulations
After a brief introductory demo, you will 'experiment' on your own with each of the five interventions below by changing the listed variables (and any appropriate others you may find under 'List all variables') so as to effect an acid-base disturbance.
Use List All Variables option to find other relevant variables & parameters.
a) Infusion - simulates and IV infusion of controlled time, duration and content. [IFMIN, IFVOL, IFBIC]
b) controlling ventilation via the artificial respirator [ARTRES, ARVOL, ARRT]
c) controlling metabolism so that it produces more or less acid [BACID}
d) controlling atmospheric % CO2 &/or O2 [FCO2AT, F02AT]
e) controlling lung mean surface area (simulating emphysema) [MSA]
2) Sample simulation- induction of metabolic alkalosis via infusion of bicarbonate
a) set Tables for acid-base output to plot on a Davenport diagram
pH, PCO2, BICARB, AVENT, IFMIN
b) set up the infusion
IFVOL = 1000, IFMIN = 60, IFBIC = 240
c) run for 1H, 10 (min) between printouts
d) characterize acid-base status at 0.0, 0.5 & 1.0 Hr. by Davenport plot, identify the primary acid base problem and compensations (if present)
3) Problems to work out
a) Acid-base simulations - setup, run and characterize the other three possible primary acid-base disturbances and accompanying compensations by
- - designing an appropriate experiment
- - gathering data from web-HUMAN
- - plotting at least initial, final & one intermediate state on a Davenport diagram
- - very briefly analyze each result
b) simulate the loss of lung surface in emphysema by reducing pulmonary membrane surface area available for diffusion [MSA].
- Tables should show arterial & venous PO2, alveolar & arterial PC02, blood pH and lung ventilation.
- Run each simulation for 1D with 4H between printouts.
- Compare in a table values obtained at 100, 75, 50 & 25% surface area
- On the basis of the data characterize 1) problems being experienced by the subject including acid-base status and 2) compensations.
- In the 25% run, calculate the diffusivity for CO2 (Dco2) and demonstrate that it shows impaired diffusion (reference- diffusion chapter in West).