PATHOPHYSIOLOGIC RESPONSETO

RESPIRATORY DYSFUNCTION

A. Hypoxia1. Hypoxia refers to inadequate cellular oxygena-

tion.2. It may result from;

a. Insufficient oxygen intakeb. Insufficient perfusion of oxygen in the

pulmonary system or the peripheral or-gans and tissues

c. Inability of blood to transport oxygend. Insufficient oxygen-carrying capacity of

the blood, which would occur with low levels of hemoglobin

B. Cyanosis: a bluish discoloration of the skin indicat-ing hypoxia; it result when oxygenation does not oc-cur and carbon dioxide does not leave the blood.

C. Dyspnea: difficult breathing. May occur as the need for oxygen exceeds the supply.

D. Increased work of breathing: occurs when energy expenditure for respirations is excessive and great ef-fort is required for breathing.

E. Tachypnea: rapid breathing with respiratory rates higher than 24 to 26 breaths per minute.

F. Cough:a. An effective cough allows the body to expel

excessive mucus, keeping the airway clear.b. An effective cough compromises airway

clearance by preventing mucus from being expelled.

c. Along with the mucocilliary system, cough is a defensive mechanism of the respiratory system.

G. Adventitious breath soundsa. As fluid and mucus accumulate, abnor-

mal breath sounds can be heard.b. Fluid is heard as rales (crackles); mucus is

heard as rhonchi (gurgles).

H. Clubbing of fingersa. Clubbing is an increase in the normal angle

between the nail and its base (from 160° to 180° or more).

b. It usually is accompanied by a softening of the nail base.

I. Fatigue: feelings of tiredness and exhaustion that usually result when energy requirements for breath-ing become excessive.

J. Paina. May or may not present

b. Pain due to rib-cage injury, infection, or chest surgery may cause hypoventilation.

K. Hypoventilationa. Hypoventilation refers to a ventilation

rate that is insufficient to meet the body’s metabolic needs.

b. It may result in respiratory acidosis because the acid (carbon dioxide) is not removed when ventilation is decreased.

L. Hyperventilationa. Hyperventilation refers to a ventilation

rate that exceeds the body’s metabolic needs.

b. It may result in respiratory alkalosis because acids (carbon dioxide) are eliminated in ex-cessive amounts, leaving excess base (bicar-bonate) in the blood.

M. Respiratory acidosisa. This condition is commonly caused by hy-

poventilation, which reduces elimination of carbon dioxide (CO2), leaving too much acid in the serum, revealing a low pH.

b. The renal system tries to compensate by re-taining HCO3 to buffer the acid, moving the pH toward neutral; this occurs over a period of many hours to days.

c. Arterial blood gas (ABG) values reveal a low pH, a high CO2, and a normal HCO3

when renal compensatory mechanisms are not in place.

N. Respiratory alkalosisa. This condition is commonly caused by hy-

perventilation, which increases the re-moval of carbon dioxide, leaving too much base (HCO3) in the serum, reveal-ing a high pH.

b. The renal system tries to compensate by in-creasing HCO3 elimination in order to main-tain the balance of HCO3 to CO2, thus mov-ing th pH toward neutral; this occurs over a period of many hours to days.

c. ABG values reveal a high pH, a low Co2 and a normal to high HCO3 when renal compen-satory mechanisms are not in place.

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