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Respiratory Phys EQ
WVSOM -- Respiratory Physiology Equations
| Question | Answer |
|---|---|
| Physiologic Dead Space | Vd = Vt X (PAco2 - PEco2)/PAco2 |
| minute ventilation | Tv X bpm |
| Alveolar ventilation | (Tv-Deadspace) x bpm |
| Dead Space | Vt X (PAco2-PEco2 / PAco2) |
| Normal value of FEV1/FVC | 0.8 |
| Total Lung Capacity | Sum of all 4 lung volumes |
| compliance | volume/pressure |
| Airflow | Q=P/R |
| Poiseuille's law | R= 8nl/(pi)r4 |
| Asthma FEV | decreased |
| COPD FEV1 | decreased |
| Fibrosis FEV | slightly decreased |
| Asma FVC | slightly decreased |
| COPD FVC | slightlly decreased |
| Fibrosis FVC | Greatly decreased |
| FEV1/FVC asthma | decreased |
| COPD FEV/FVC | drecreased |
| Fibrosis FEV/FVC | normal or increased |
| FRC asthma | increased |
| FRC COPD | increased |
| FRC Fibrosis | decreased |
| Partial Pressure | Total Pressure X Fractional gas concentration |
| Fractional Gas concentration of O2 | 0.21 |
| partial pressure of h2o | 47 mmHg |
| Partial pressure of Po2 in trachea | 150 |
| PO2 of dry air | 160 |
| Po2 of alvolar air | 100 |
| PO2 of arterial blood | 100 |
| PO2 of venous blood | 40 |
| Pco2 of arterial blood | 40 |
| Pco2 of venous blood | 46 |
| Pco2 of dry inspired air | 0 |
| O2 percentage in air | 21 |
| CO2 percentage in air | 0.03 |
| Percentage of N2 | 79% |
| Pulmonary Vascular Resistance | (Pa – Pv)/flow rate |
| The laboratory provides the following report on arterial blood from a patient: PCO2 32 mmHg, pH 7.25, HCO3- concentration 25 mmol/liter. | pH = 6.1 + log [HCO3-]/[CO2] = 6.1 + log (25/0.03 x 32) |
| alveolar gas equation | PAO2 = PIO2 – (PACO2/R) |