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    90 Minute ventilation (VE)
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    90 Minute ventilation (VE)

    Minute ventilation: tidal volume × rate, resting values, hypoventilation and hyperventilation.

    Minute ventilation (VE) is the volume of air breathed in or out per minute: tidal volume multiplied by breathing rate. At rest an adult breathes about 12–16 times a minute with a tidal volume of about 0.5 L, giving a minute ventilation of roughly 5–8 L/min. Part of each breath fills the airways where no gas exchange occurs (dead space), so the useful part is the alveolar ventilation. Ventilation is controlled by the brainstem mainly according to the carbon dioxide level in the blood: more ventilation lowers CO₂, less ventilation raises it. During heavy exercise it can rise more than tenfold.

    BreathingVentilationCarbon dioxide
    FormulaVE = tidal volume × rate
    Adult at rest≈ 5–8 L/min
    Heavy exercisecan exceed 100 L/min
    Main regulatorarterial CO₂
    Resting minute ventilation in an adult: below about 5 litres per minute low, about 5 to 8 typical, above about 10 increased Minute ventilation at rest (L/min) Low below ≈ 5 5 Typical ≈ 5–8 8 Borderline 8–10 10 Increased above ≈ 10
    Figure 1. Approximate resting minute ventilation zones in an adult. Whether ventilation is adequate is judged by arterial CO₂, not by volume alone.
    Spirogram of lung volumes: tidal breathing, a maximal inspiration and a maximal expiration, with tidal volume, inspiratory and expiratory reserve volumes, residual volume, vital capacity, functional residual capacity and total lung capacity Lung volumes and capacities (typical adult) TV IRV ERV RV VC FRC TLC RV, FRC and TLC cannot be measured by simple spirometry; they need body plethysmography or gas dilution.
    Figure 1. Lung volumes on a spirogram. TV tidal volume, IRV/ERV inspiratory/expiratory reserve volume, RV residual volume, VC vital capacity, FRC functional residual capacity, TLC total lung capacity. Typical adult values: TV ≈ 0.5 L, RV ≈ 1.2 L, FRC ≈ 2.4 L, VC ≈ 4.8 L, TLC ≈ 6 L.

    Clinical significance

    Low ventilation (hypoventilation)

    Respiratory depression by opioids, sedatives or alcohol, neuromuscular weakness, severe obesity (obesity hypoventilation), chest wall disease, advanced COPD. Consequence: rising CO₂ (respiratory acidosis), drowsiness, headache.

    High ventilation (hyperventilation)

    Anxiety and pain, fever, metabolic acidosis (diabetic ketoacidosis, kidney failure), pneumonia, pulmonary embolism, asthma attack, sepsis, high altitude, pregnancy. Consequence: low CO₂ (respiratory alkalosis), tingling, dizziness.

    Minute ventilation is measured with spirometers, respirometers and ventilators, and continuously during cardiopulmonary exercise testing.

    Seek emergency care

    for very slow or shallow breathing with drowsiness, or rapid breathing with breathlessness, chest pain, confusion or bluish lips.

    References

    1. West JB, Luks AM. West’s Respiratory Physiology: The Essentials. 10th ed. Philadelphia: Wolters Kluwer; 2016.
    2. American Thoracic Society; American College of Chest Physicians. ATS/ACCP statement on cardiopulmonary exercise testing. Am J Respir Crit Care Med. 2003;167(2):211–277. doi:10.1164/rccm.167.2.211

    This article is for general information and does not replace a consultation with a doctor. Measurements must be interpreted by a physician together with symptoms and other tests.

    Published on 2 May 2024