Alveolar Ventilation Equation Calculator
Determines the total volume of fresh air entering the alveoli per minute.
Alveolar ventilation defines the total volume of air entering and leaving the respiratory zone (the alveoli) per minute and that participates in the gas exchange.
The first method determines alveolar ventilation based on tidal volume, pulmonary physiological dead space volume (from Bohr equation) and respiratory rate:
VA = (Vt –Vd) x RR
Where Vd = Vt x (PACO2 – PETCO2) / PACO2
The second method determines alveolar ventilation based on carbon dioxide output and arterial carbon dioxide tension:
VA = 0.863 x VCO2 / PaCO2
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Steps on how to print your input & results:
1. Fill in the calculator/tool with your values and/or your answer choices and press Calculate.
2. Then you can click on the Print button to open a PDF in a separate window with the inputs and results. You can further save the PDF or print it.
Please note that once you have closed the PDF you need to click on the Calculate button before you try opening it again, otherwise the input and/or results may not appear in the pdf.
Determining alveolar ventilation
1) The first method determines alveolar ventilation based on tidal volume, pulmonary physiological dead space volume (from Bohr equation) and respiratory rate:
VA = (Vt –Vd) x RR
Where Vd = Vt x (PACO2 – PETCO2) / PACO2
Tidal volume can be estimated based on ideal body weight, via height and gender:
IBW male = 50kg + 2.3 x (height in inches – 60)
IBW female = 45.5kg + 2.3 x (height in inches – 60)
- Tidal Volume: ranges between 6 x IBW mL/kg IBW and 8 x IBW mL/kg.
2) The second method determines alveolar ventilation based on carbon dioxide output and arterial carbon dioxide tension:
VA = 0.863 x VCO2 / PaCO2
Alveolar Ventilation rate, measured in ml/min or L/min is a critical physiological variable in determining the concentrations of oxygen and carbon dioxide in functioning alveoli.
Normal ranges for the variables used are included in the table below:
Variable | Lower limit | Higher limit |
Tidal volume (Vt) | 400 mL | 600 mL |
Physiological dead space volume (Vd) | 100 mL | 285 mL |
Respiratory rate (RR) | 10 resp/min | 16 resp/min |
Alveolar ventilation (VA) | 3000 mL/min | 5000 mL/min |
Carbon Dioxide Output (VCO2) | 150 mL | 320 mL |
Arterial CO2 Tension PaCO2 | 35 mmHg | 45 mmHg |
Alveolar ventilation (VA) | 3 L/min | 5 L/min |
References
Mithoefer JC, Bossman OG, Thibeault DW, Mead GD. The clinical estimation of alveolar ventilation. Am Rev Respir Dis. 1968;98(5):868-71.
Blackie SP, Fairbarn MS, McElvaney NG, Wilcox PG, Morrison NJ, Pardy RL. Normal values and ranges for ventilation and breathing pattern at maximal exercise. Chest. 1991; 100(1):136-42.
Anaesthesia, Pain, Intensive Care and Emergency Medicine — A.P.I.C.E. Proceedings of the 19th Postgraduate Course in Critical Care Medicine Trieste, Italy — November 12–15, 2004.
Specialty: Pulmonology
System: Respiratory
Published On: May 14, 2020 · 12:00 AM
Last Checked: May 14, 2020
Next Review: May 14, 2025