Oxygen therapy

Overview of Treatment

Oxygen therapy is a medical technique that involves supplementing the body's oxygen needs with external oxygen, primarily used to improve tissue hypoxia. When patients experience insufficient blood oxygen levels due to illness or injury, high-concentration oxygen can be delivered through various devices to effectively increase arterial oxygen tension (PaO₂) and blood oxygen saturation (SpO₂). This therapy is commonly used in emergency, intensive care, and long-term treatment of chronic respiratory diseases, helping to alleviate symptoms such as dyspnea and syncope, and reducing the risk of organ failure.

Types and Mechanisms of Treatment

Oxygen therapy can be classified into four main types based on the delivery method:

• Nasal cannula oxygen: delivers 5-12 liters per minute of oxygen through nasal tubes, suitable for mild hypoxia.
• Mask oxygen: uses partial rebreathing masks (such as Venturi masks) to regulate oxygen concentration, suitable for moderate hypoxia cases.
• High-flow nasal cannula therapy (HFNC): supplies 30-60 liters per minute of high-flow mixed air and oxygen, reducing the work of breathing.
• Continuous positive airway pressure (CPAP): used in sleep apnea syndrome, combining oxygen with pressure support.

Its mechanism involves increasing oxygen partial pressure in the alveoli, enhancing gas diffusion to increase dissolved oxygen in the blood, and promoting aerobic metabolism in tissue cells.

Indications

This therapy is mainly suitable for conditions such as:

• Acute exacerbation of chronic obstructive pulmonary disease (COPD) causing hypoxemia.
• Pulmonary edema or peripheral tissue hypoxia caused by heart failure.
• Brain hypoxia following traumatic brain injury or carbon monoxide poisoning.
• Neonatal respiratory distress syndrome and premature infants with underdeveloped lungs.

In emergency settings, it is also used for post-cardiopulmonary resuscitation or acute high-altitude mountain sickness.

Usage and Dosage

The oxygen concentration should be adjusted based on blood gas analysis results, with the general adult target maintaining blood oxygen saturation at 90%-95%. High-flow oxygen (>60%) is usually limited in duration to prevent oxygen toxicity, while chronic patients may require 24-hour low-flow oxygen (1-2 liters per minute). The medical team will adjust the dosage based on arterial blood gas values (such as PaO₂<55 mmHg) or SpO₂<90%. Home oxygen therapy must strictly follow medical instructions and not be self-adjusted.

Benefits and Advantages

Main benefits include:

• Rapidly increasing blood oxygen levels, improving the function of critical organs such as the brain and heart.
• Reducing respiratory compensation, decreasing oxygen consumption.
• For premature infants, promoting surfactant synthesis in the lungs.

Compared to traditional oxygen delivery methods, HFNC can reduce nasal dryness and mucosal irritation, while CPAP can improve oxygen fluctuations during sleep apnea.

Risks and Side Effects

Over-oxygenation may induce oxygen toxicity, leading to pulmonary fibrosis or retinopathy (especially in premature infants). Other potential risks include:

• Carbon dioxide retention: COPD patients may experience worsening due to suppressed respiratory drive.
• Drying of the respiratory mucosa, potentially causing epistaxis.
• Long-term use may increase the risk of atelectasis.

Close monitoring of blood gas changes is necessary to avoid complications.

Precautions and Contraindications

Contraindications include:

• Patients with pneumothorax without adequate ventilation should avoid high-flow oxygen, as it may worsen the pneumothorax.
• Some heart failure patients need to limit oxygen concentration to maintain compensatory ventilation.

Strictly prohibit the use of open flames or flammable materials in oxygen-rich environments to prevent fire hazards. Devices should be regularly cleaned to prevent respiratory infections.

Interactions with Other Treatments

When combined with bronchodilators or steroids, oxygen concentration should be adjusted to prevent CO₂ retention. Using positive pressure oxygen (CPAP) may interact with anticoagulants, requiring monitoring of coagulation function. In preterm infants receiving high-concentration oxygen, coordination with surfactant therapy is necessary.

Therapeutic Outcomes and Evidence

Multicenter studies show that long-term oxygen therapy (LTOT) in COPD patients can improve 3-year survival rates to over 80%. In neonatal intensive care units, oxygen therapy has reduced the mortality rate of neonatal respiratory distress syndrome from 50% in the 20th century to currently 5%-10%. Targeted oxygen delivery strategies in emergency rooms can reduce complications in myocardial infarction patients.

Alternatives

When oxygen therapy is unsuitable, consider:

• Bilevel positive airway pressure (BiPAP) to improve ventilation.
• Inhaled nitric oxide for pulmonary hypertension.
• Use of erythropoietin (EPO) to improve tissue perfusion.

However, these alternatives should be selected based on specific conditions and cannot simply replace necessary oxygen delivery with respiratory rehabilitation.

 

Frequently Asked Questions

What preparations should patients make to ensure safety and effectiveness during oxygen therapy?

Before receiving oxygen therapy, patients should ensure their airway is clean and unobstructed, and avoid using flammable items in the treatment environment. Healthcare providers will adjust oxygen concentration based on vital signs. Patients should cooperate by maintaining a supine or semi-sitting position and report any discomfort to ensure safe and effective treatment.

What should be done if nasal or respiratory dryness occurs during oxygen therapy?

Dryness is a common side effect and can be alleviated by using humidifiers or saline nasal spray. If symptoms are severe, notify healthcare personnel to adjust the oxygen flow or add humidification devices. Do not modify device settings independently.

Can daily activities such as reading or eating be performed during oxygen therapy?

Low-flow oxygen therapy generally allows for mild activity but avoid excessive movement that could dislodge the tubing. When eating, be cautious to prevent liquid reflux. Smoking or being near fire sources is prohibited during therapy to prevent fire hazards in oxygen-rich environments.

What follow-up or care is required after oxygen therapy?

Post-treatment, regular follow-up is necessary to monitor blood oxygen saturation and lung function, and to record daily symptom changes. If breathing difficulty worsens or cyanosis occurs, seek medical attention immediately. The medical team will adjust subsequent treatment plans based on recovery progress.

How can patients determine if the oxygen therapy is effective?

The effectiveness should be assessed through blood gas analysis, monitoring blood oxygen levels, and symptom improvement. The general goal is to raise blood oxygen saturation above 90%, but specific standards depend on the disease type (such as COPD or heart failure), and progress should be regularly confirmed with the physician.