Pulmonary fibrosis (PF) is a progressive lung disease characterized by the buildup of scar tissue (fibrosis) within the lungs. This scarring causes the lung tissue to become stiff and thickened, making it difficult for the lungs to expand and fully take in air. The damaged tissue severely restricts the transfer of oxygen from the air sacs into the bloodstream, a process vital for supplying the body’s organs. Consequently, a significant question for those living with PF is when supplemental oxygen becomes necessary to manage their condition. The need for oxygen is determined by specific clinical measurements of how efficiently the lungs are functioning, not by a single disease stage.
Measuring Disease Severity in Pulmonary Fibrosis
Physicians assess the severity and progression of pulmonary fibrosis using specialized pulmonary function tests (PFTs). These tests track changes over time, providing a detailed picture of the disease state.
One primary measurement is the Forced Vital Capacity (FVC), which quantifies the total amount of air a person can forcibly exhale after taking the deepest breath possible. The FVC reflects the stiffness and reduced volume of the scarred lung tissue, showing how much air the lungs can physically hold.
Another important metric is the Diffusion Capacity of the Lung for Carbon Monoxide (DLCO), which measures how effectively oxygen is transferred from the air sacs into the red blood cells. Since scarring occurs directly at the gas exchange surface, the DLCO is often the first measurement to show a significant decline, even before changes in FVC are dramatic. A decrease in either FVC or DLCO over a six to twelve-month period is a clear sign that the disease is progressing. Monitoring these values allows the healthcare team to track the rate of decline and determine when supportive therapies are required.
Clinical Criteria for Supplemental Oxygen
The decision to prescribe supplemental oxygen is based on hypoxemia, an abnormally low level of oxygen in the blood. This is usually measured using a pulse oximeter, which calculates the oxygen saturation (SpO2) as a percentage of hemoglobin carrying oxygen. The accepted threshold for prescribing oxygen is a sustained SpO2 level that drops to 88% or below. This saturation level can be measured at rest, during sleep, or during physical activity.
For many patients with PF, the need for oxygen is first identified during physical exertion, a condition known as exertional hypoxemia. To identify this, doctors administer a 6-minute walk test, monitoring the patient’s SpO2 level while they walk at a comfortable pace. If the saturation drops below 88% or 90% during this test, a prescription for ambulatory (on-the-go) oxygen is warranted. This helps prevent damage to vital organs and improve exercise tolerance. Oxygen may also be prescribed for continuous use if the SpO2 remains below 90% even at rest, indicating advanced impairment.
Managing Oxygen Delivery Systems
Once supplemental oxygen is prescribed, patients choose a delivery system that aligns with their specific needs and lifestyle. The two main types of equipment are concentrators and tanks.
Stationary oxygen concentrators are large, electrical units designed for continuous, high-flow use at home, providing an unlimited supply by filtering oxygen from the surrounding air. Due to their size and reliance on a power outlet, they are not designed for mobility outside the home.
For activity outside the home, patients use portable oxygen concentrators (POCs) or compressed gas tanks. POCs are smaller, battery-powered devices that offer mobility and deliver oxygen using a pulse dose, which conserves battery life. Compressed gas tanks and liquid oxygen systems, while heavier, often deliver a higher flow rate, which may be necessary for patients with more severe needs or those engaging in strenuous activities.
The flow rate, measured in liters per minute (LPM), is determined by the physician through titration. This process sets the specific amount of oxygen required to maintain the SpO2 above the target level during different activity states.
Integrating Oxygen Therapy into Daily Life
The transition to using supplemental oxygen requires practical adjustments. Using oxygen can significantly decrease shortness of breath and fatigue, which allows patients to participate more fully in their daily routines and maintain their independence. Continued physical activity, especially through a structured program like pulmonary rehabilitation, is highly encouraged while using oxygen, as it helps strengthen other muscles and improve overall endurance.
Managing the equipment, especially for travel, requires careful planning, such as ensuring sufficient battery life for a portable unit or arranging for a supply delivery at their destination. While the equipment is visible, most people quickly adapt to its presence, recognizing that the oxygen is a form of treatment. Patients can successfully integrate oxygen use into their personal and social lives.