Chapter 15 Terms and Definitions

Diffusion

• O₂ / CO₂ across alveoli

• Surface area • membrane thickness

Tidal volume (TV) 

•is the amount of air that is exhaled after passive inspiration; this is the volume of air going in and out of the lungs at rest; in adults, this volume is approximately 500 mL.

Vital capacity (VC) 

•is the maximal amount of air that can be moved in and out of the lungs with forced inhalation and exhalation.

Forced vital capacity (FVC) 

is the maximal amount of air that is exhaled from the lungs during a forced exhalation.

Forced expiratory volume in 1 second (FEV₁)

• is the maximal amount of air that can be expired from the lungs in 1 second.

Residual volume (RV) 

•is the volume of air that remains in the lungs after maximal expiration.

Total lung capacity (TLC) 

is the total amount of air in the lungs when they are maximally expanded and is the sum of the VC and RV.

Hypoxemia

• Low arterial oxygen

• PaO₂ / SpO₂ clues

Hypercapnia

• CO₂ retention

• Hypoventilation risk

Clinical findings

• Dyspnea • tachypnea

• Accessory muscles • altered LOC

Emphysema

• Alveolar wall destruction

• Loss of elastic recoil

• Air trapping

Chronic bronchitis

• Mucus gland enlargement

• Chronic airway inflammation

• Productive cough