H: Hypoxia

Hypoxia just means the tissues of the body are not getting enough oxygen to function.

Hypoxia can also occur peripherally due to factors such as anemia, CHF, PAD, emboli or CO poisoning. (but we won't talk about those right now) I'm pretty sure the type of hypoxia they are talking about involves ventilation and gas exchange at the lungs.

There are MANY causes of hypoxia, here are a few I could think of:

Enviornmental: Decrease in inspired oxygen not secondary to organ failure. For instance, suffication (blocked airway) or high altitude.

Hypoventilation: A decrease in inspired oxygen due to altered ventilation pattern. Narcotic OD, or neurologic damage to respiratory drive.

Airway Inflammation/Increased Resistance  to Airflow: occurs in Asthma, Emphysema, Anaphlaxis, and Bronchitis.

Impared Gas Exchange at alevolar/capillary membrane-

Alveoli are blocked, collapsed or swollen: Pneumonia, Aspiration, Pneumothorax, Pulmonary Edema.

The alveolar membrane becomes thick:  emphesemia, Acute Respiratory Distress Syndrome, and Pulmonary Fibrosis. This inhibits gas exchange from the alveoli to the capillary.

Shunting (bypassing alveoli altogether): Anatomical heart defect, pulmonary edema, or atelectisis (alveoli collapse). 

Ventilation/Perfusion (V/Q) missmatch: Pneumonia.

Look for signs and symptoms of respiratory distress...

Not breathing

ANY difficulty breathing...rapid, slow, shallow, deep, involving rib cage

Restlessness and anxiety (eventually progressing to lethargy and coma)

Pale/blue skin-esspecially fingers or lips

Pulse Ox reading low. (Usually below 91 in adults is abnormal, however patients with known lung disease like COPD may have "normal" baseline that is below that)

Cold skin

Elevated BP

Elevated HR (eventually progressing to bradycardia)

Arterial Blood Gas Analysis

If the patient happens to be on a ventilator, there are a whole different set of things to monitor that belong on a respiratory therapy post.