Tidalvolym

Tidalvolym, or tidal volume, is the amount of air that is inhaled or exhaled during a normal, resting breath. It is usually expressed in milliliters (ml) or liters (L) and is one of the primary measurements in pulmonary physiology. In healthy adults at rest, the tidal volume is typically about 0.5 liters, commonly stated as 6–8 ml per kilogram of body weight. The exact value varies with body size, age, sex, and cardiorespiratory status.

Tidal volume is a component of minute ventilation, which is the total amount of air moved in and out per minute and is calculated as tidal volume multiplied by respiratory rate. Alveolar ventilation, the portion of ventilation available for gas exchange, can be estimated as (tidal volume minus dead space) times the respiratory rate. Tidal volume is influenced by lung and chest wall compliance, airway resistance, and respiratory muscle strength, and it can change in response to disease, exercise, or changes in posture.

In clinical practice, tidal volume is a key parameter in mechanical ventilation. Modern practice emphasizes lung-protective ventilation, typically employing tidal volumes around 6 ml/kg of predicted body weight to minimize volutrauma and barotrauma, especially in patients with acute respiratory distress syndrome (ARDS). Tidal volume is measured using spirometry or other respiratory monitoring devices and is analyzed alongside other lung volumes and capacities to assess overall pulmonary function.