Respiratory 2

Nota:

• Primary Volumes: 1. Inspiratory Reserve volume (IRV) 2. Total Volume 3. Expiratory Reserve Volume (ERV) 4. Residual Volume Capacities: 1. Total Lung Capacity (TLC) 2. Vital Capacity (VC) 3.Function Residual Capacity (FRC)

Nota:

• Lung volumes and capacity can be measured directly with a spirometer. 2 types: Volume Displacement and Flow Sensing It also measures: Forced Vital Capacity (FVC) Total volume lower than the VC. Forced expiratory Volume in 1 second (FEV1)

1. Diseases and Changes to the Graph

   Nota:

   • FEV1 is reduced because the airway is narrow or FVC is reduced due to chest wall diseases.

Nota:

• Indirect measurement of the lung volume. Uses Boyle's Law RV= v1 X (c1/c2)/C2 P3/v2=P4 (V2 + change in V)

Nota:

• Alveolar Ventilation: Fresh gas that enters 4200ml/min. Measured using Fowler's Method or Bohr's Method. Fowler's Method is measured by expired N2 as indicator. Bohr's Method is based on a measure of Carbon dioxide tensions in expired and alveolar gases. Dead Space = VT x (1- (mixed expired /mixed alveolar)) Determines dead space Dead space ventilation from normal ventilation.

Nota:

• Amount of oxygen used is dependent on body size and activity. Respiratory exchange ratio (R) is carbondioxide output/oxygen consumption. Normal value is about 0.8 to 0.85 The higher the R value (carbohydrate). lower, fatty.