Gas Exchange and Oxygen Therapy Safety

Physical Assessment Findings

During a physical exam, clinicians may observe:

• Early Signs: Anxiety, use of accessory muscles, and pale skin.
• Late Signs: Cyanosis (a bluish discoloration), which is a critical indicator of hypoxemia.
• Lung Sounds: Abnormal sounds can provide clues to the cause. Crackles (popping/bubbling) may indicate heart failure or pulmonary edema, while wheezing (high-pitched squeaking) often suggests asthma or COPD. A stridor (harsh crowing sound) is a medical emergency indicating upper airway obstruction.

Oxygen Therapy: Targets and Delivery Devices

Oxygen is a medication and must be prescribed with specific targets and delivery methods.

Setting Saturation Targets

One of the most common errors in oxygen therapy is applying a "one size fits all" approach to $SpO_2$ targets.

• Regular Patients: The goal is typically $94%–98%$.
• Chronic Patients (e.g., COPD): These patients may rely on a "hypoxic drive" for respiration. Their target is lower, typically $88%–92%$.

Selecting the Right Device

The choice of device depends on the required flow rate and the patient's clinical stability:

Safety, Complications, and Nursing Interventions

Oxygen Safety Precautions

Oxygen is highly combustible. To prevent fires, nurses must implement strict safety protocols:

• Keep oxygen away from heat, smoke, flames, and flammable products.
• Store oxygen cylinders in an upright position.
• Educate patients to avoid using electric razors near oxygen sources.

Potential Complications

Improper use of oxygen can lead to serious physiological issues:

• Oxygen Toxicity: Damage to lung tissue caused by excessive oxygen concentrations.
• $CO_2$ Retention: Particularly in COPD patients, over-oxygenation can lead to a buildup of carbon dioxide.
• Dry Mucous Membranes: High flow rates can dry out the airway; humidification should be used for long-term therapy.
• Skin Breakdown: Pressure from masks or tubing can cause skin injury.

Nursing Best Practices

When administering therapy, always follow the five rights: right task, right circumstance, right person, right dose (direction), and right communication/evaluation.

In post-operative settings, nurses should encourage the use of an incentive spirometer. This device provides visual feedback to the patient, helping them perform deep breathing exercises that increase inspiratory volume and prevent complications like atelectasis or pneumonia.

Exam Tip: If a patient with COPD is receiving oxygen and their respiratory rate suddenly decreases while their $CO_2$ levels rise, suspect $CO_2$ retention due to excessive oxygen administration. Always check the prescribed $SpO_2$ target!

Documentation

Accurate documentation is vital for continuity of care. Ensure you record:

1. The delivery method (e.g., Nasal Cannula) and flow rate (e.g., $2\text{ L/min}$).
2. The patient's $SpO_2$ and respiratory rate.
3. The patient's response to the therapy and any education provided.