Comprehensive Respiratory System Disorders Q 84

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A client states that the physician said the tidal volume is slightly diminished and asks the nurse what this means. The nurse explains that the tidal volume is the amount of air:

  

     A. Exhaled forcibly after a normal expiration.

     B. Exhaled after there is a normal inspiration.

     C. Trapped in the alveoli that cannot be exhaled.

     D. Forcibly inspired over and above a normal respiration.

    

    

Correct Answer: B. Exhaled after there is a normal inspiration.

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Tidal volume (TV) is defined as the amount of air exhaled after a normal inspiration. Tidal volume is the amount of air that moves in or out of the lungs with each respiratory cycle. It measures around 500 mL in an average healthy adult male and approximately 400 mL in a healthy female. It is a vital clinical parameter that allows for proper ventilation to take place.

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Option A: The expiratory reserve volume (ERV), about 1,200 mL, is the additional air that can be forcibly exhaled after the expiration of a normal tidal volume. When a person breathes in, oxygen from the surrounding atmosphere enters the lungs. It then diffuses across the alveolar-capillary interface to reach arterial blood. At the same time, carbon dioxide continuously forms as long as metabolism takes place. Expiration occurs to expel carbon dioxide and prevent it from accumulating in the body.

Option C: Residual volume (RV), about 1,200 mL, is the volume of air still remaining in the lungs after the expiratory reserve volume is exhaled. When emphysema develops, the alveoli and lung tissue are destroyed. With this damage, the alveoli cannot support the bronchial tubes. The tubes collapse and cause an “obstruction” (a blockage), which traps air inside the lungs.

Option D: The inspiratory reserve volume (IRV), about 3,100 mL, is the additional air that can be forcibly inhaled after the inspiration of a normal tidal volume. The volume of air occupying the lungs at different phases of the respiratory cycle subdivides into four volumes and four capacities. The four lung volumes are inspiratory reserve volume (IRV), expiratory reserve volume (ERV), tidal volume (V), and residual volume (RV), while the four lung capacities include total lung capacity (TLC), vital capacity (VC), inspiratory capacity (IC), and functional residual capacity (FRC).

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