In this blog post, we will summarize the basic concepts of malignant neoplasms, their clinical characteristics with a focus on lung cancer, and the contraindications, advantages, disadvantages, and appropriate use scenarios for various oxygen therapy devices.

Overview of Malignant Neoplasms

A neoplasm refers to the autonomous, abnormal, and excessive proliferation of cells or tissues, and is classified as benign or malignant depending on its impact on the body. Tumors composed of epithelial cells are called carcinomas, while tumors originating from connective tissue or blood cells are called sarcomas or blood cancers. They are classified by site of origin into lung cancer, breast cancer, leukemia, skin cancer, and others. Unlike benign tumors, malignant tumors can metastasize to other parts of the body; therefore, complete surgical resection immediately upon detection is the best course of action. However, in most cases, they are discovered at a significantly advanced stage. In such cases, cancer cells may remain in the body even after surgery, necessitating chemotherapy, and there is a possibility of recurrence.
The primary cause of lung cancer is smoking; approximately 85% of all lung cancers are believed to be related to smoking. By the time symptoms such as coughing, shortness of breath, chest pain, and hemoptysis appear, the disease is often already quite advanced. Bronchial cancer primarily occurs in men over the age of 40, and the main cause is also smoking.

Oxygen Therapy and Characteristics by Device

Oxygen therapy is administered using various devices and methods to correct hypoxia and supply adequate oxygen to tissues. Below are the general indications, contraindications, and pros and cons of representative devices.

Nasal prongs

This is the most commonly used method for administering low-concentration oxygen (2 L to 6 L/min, approximately 20% to 40%) and is simple and convenient.
Contraindications: Weak respiratory effort, severe hypoxia, apnea, or when mouth breathing is predominant.
Advantages: Easy to use and applicable to almost all patients.
Disadvantages: Difficult to deliver high-concentration oxygen, and there may be a discrepancy between the set oxygen flow rate and the actual amount delivered to the patient.

Simple Face Mask

A face mask without a reservoir, used when administering oxygen at a flow rate of 6–8 L/min (approximately 40–60%).
Contraindications: Weak respiratory effort, severe hypoxia.
Advantages: More cost-effective and simpler than other masks.
Disadvantages: Difficult to provide high-concentration oxygen; may cause a stuffy feeling when worn.

Non-rebreather mask

A simple face mask with an attached reservoir that must be kept inflated at all times. It is reported to provide oxygen concentrations of approximately 60% at 6 L/min, approximately 80% at 8 L/min, and approximately 99% at 10 L/min, depending on the flow rate.
Contraindications: Apnea or weak respiratory effort.
Advantages: Can deliver high-concentration oxygen without intubation.
Disadvantages: High oxygen consumption; the wearer may feel suffocated.

Partial rebreather mask

Used when both elevated CO₂ and relatively high-concentration oxygen must be supplied simultaneously.
Contraindications: Apnea or weak respiratory effort.
Advantages: Designed to prevent mixing of external air and the administered gas, allowing for the delivery of high-concentration oxygen.
Disadvantages: When the flow rate exceeds 10 L/min, the oxygen concentration may not increase further.

Venturi mask

A standardized air inlet device allows for the delivery of oxygen at a relatively constant concentration. It is suitable for patients with COPD or others who require precise delivery of oxygen at a specific concentration. Oxygen can be delivered at desired concentrations such as 24%, 28%, 40%, and 53%.
Contraindications: Apnea, inadequate respiratory effort.
Advantages: The set FiO2 can be maintained relatively consistently, allowing for the stable delivery of large volumes of oxygen at a specific concentration.
Disadvantages: It is difficult to deliver very high concentrations of oxygen.