Alteration in blood gases consisting of either:

• PaO2 of less than 60 mmHg
• SaO2 of less than 90%
• PaCO2 > 50 mmHg with acidemia (pH < 7.30)

Classified as oxygenation failure, ventilatory failure or a combination of both.

Perfusion = normal

Ventilation = inadequate

Causes:

• Mechanical abnormality of chest wall or lungs
• Defect in resp center of brain
• Impaired ventilatory muscle fxn

Ventilation = normal

Lung perfusion = decreased

Causes:

• Pulmonary embolus
• Pneumonia - secretions occlude the a/w which interfere with gas exchange
• CHF with pulmonary edema
• High altitudes, smoke inhalation, carbon monoxide poisoning

Hypoventilation and inadequate gas exchange at the alveolar-capillary membrane

• More profound hypoxemic state
• RR increases until resp muscles unable to fxn effectively (= vent. failure)
• Seen in pt w/ abnormal lungs - emphysema, bronchitis, asthma
• Pt with cardiac failure and resp failure MOST SERIOUS - cardiac sys cannot compensate

Dyspnea

Orthopnea

Change in RR or pattern

Change in lung sounds - diminished airflow, rales or rhonchi

Hypoxemia - ABG's

Hypercapnia - ABG's

1. O2 therapy - maintain SaO2 > 90% or PaO2 > 60.
2. Position of comfort - upright
3. Energy conserving measures - no unnecessary procedures, minimal self care
4. Bronchodilators and antiinflammatory agents - systemically and MDI
5. Intubation and mechanical ventilation may be necessary

* Pt may like a fan in the room - "air hungry"