Understanding Lung Volume and Capacity

• Lung volume, also known as lung capacity, defines the maximum air amount held in the lungs.

Lung Volume Norms

• The lung volume of an average adult male measures 6 L.
• The average female capacity is 10-12% smaller, around 5.2 - 5.4 L
• Height and gender affects lung volume, altering the size of the thoracic cavity and lungs.
• Quiet breathing involves inhaling and exhaling only about 0.5 L of air.

Spirometer

• A spirometer is a tool designed to measure lung capacity.
• One specific type is the wet spirometer.
• You breathe into a specific tube
• This tube links to an upside-down container
• This container floats on water.

Spirograph

• Spirograph represents the volume of air moving in and out of lungs with each breath.
• Tidal volume is the air volume breathed in and out during a normal breath.
• Usually, this is about 0.50 L.
• Just about 0.35 L reaches the alveoli, while the remainder fills the trachea, bronchi, and bronchioles.
• Given an average respiratory rate of 12-20 breaths per minute, approximately 4.2 L - 7 L of air are exchanged each minute.

Inspiratory Reserve

• Inspiratory reserve volume is the additional volume of air that can be inhaled beyond a normal breath (tidal volume).
• It expands the lungs more than usual.
• It recruits neck and abdominal muscles alongside the diaphragm and intercostal muscles.

Expiratory Reserve

• Expiratory reserve volume refers to extra air that can be exhaled.
• This is the air forced out of the lungs after a normal breath.

Inspiratory Capacity

• This defines the total air amount that can be inhaled.
• Tidal volume and inspiratory reserve volume equals the inspiratory capacity.

Vital Capacity

• The vital capacity is the total gas volume that can be moved in and out of the lungs.
• Inspiratory capacity plus expiratory reserve volume equates to vital capacity.

Residual Volume

• Residual volume is the gas amount that remains in the lungs and passageways, even after forced exhalation.
• Roughly 1 L of air remains.
• The lungs and respiratory passages don't collapse thanks to this volume.

Total Lung Volume

• The total lung volume is the total amount of gas that can be held in the lungs.
• Residual volume and vital capacity determines total lung volume.

Marathon Training Effect

• Marathon training affects lung volume and capacity.
• Extended exercise strengthens muscles involved in breathing.
• Tidal volume and vital capacity increases as a result.

Effect of the Flu

• Having the flu would affect lung volume and capacity.
• Illness reduces vital capacity and tidal volume.
• This occurs by impacting the quantity of alveoli that can successfully exchange gas.
• Weakening breathing muscles also has a similar effect.

Patient Data Analysis

• Patient data provides insights into respiratory health.
• Tidal volume reflects regular breaths, comparing against vital capacity, which shows the maximum air that can be inhaled/exhaled.
• Patient 5, with a large vital capacity and a low respiratory rate, is a likely candidate for a long-distance runner.
• Patient 3 shows a low tidal volume, suggesting constricted airways.
• Given the high respiratory rate, this patient is likely affected by a respiratory disorder.