A medical oxygen cylinder is a portable storage container that holds compressed, nearly pure oxygen gas for patients requiring respiratory support in a hospital setting. Made of high-strength materials like steel or aluminum, these cylinders safely contain oxygen at very high pressures, often exceeding 2,000 pounds per square inch (PSI) when full. The cylinder provides a reliable, self-contained oxygen source, useful for patient transport or in areas lacking a central oxygen supply. Proper assembly and operation are fundamental to ensuring the patient receives the exact therapeutic amount of oxygen prescribed by a clinician.
Key Components of the Oxygen System
The cylinder is part of a complete delivery system that includes a regulator, a flow meter, and a delivery interface. The pressure regulator reduces the extremely high pressure of the stored gas down to a safe, usable level for the patient, as the tank pressure is far too high for direct inhalation.
Attached to the regulator is the flow meter, which allows the user to set and measure the rate of oxygen delivery, typically expressed in Liters Per Minute (LPM). This component is distinct from the pressure gauge, which only indicates the pressure inside the tank. The flow meter ensures the prescribed therapeutic dose is administered accurately.
The oxygen then travels through tubing to the patient via a delivery device, such as a nasal cannula or an oxygen mask. A humidifier bottle may be connected to the system to add moisture to the dry compressed oxygen, which helps prevent irritation of the patient’s nasal passages and airways.
Step-by-Step System Assembly
Before attaching any components, the cylinder’s outlet port must be briefly opened, or “cracked,” to clear out any dust or debris. This action should be performed quickly, pointing the valve away from yourself and others, to ensure a clean connection surface. Next, the regulator is attached to the cylinder valve, often using a yoke-style connection where two pins align with corresponding holes on the cylinder post.
A clean, undamaged washer or sealing gasket must be properly seated within the regulator yoke to create a tight seal and prevent gas leaks. The regulator is then secured onto the cylinder valve by hand-tightening the T-handle or screw until the connection is firm. If the cylinder uses a threaded connection instead of a yoke, the regulator is screwed directly onto the valve outlet.
Once the regulator is securely in place, the oxygen tubing is attached to the flow meter’s outlet nipple. If a humidifier is required, it is filled with sterile water and attached to the flow meter before the tubing is connected to its outlet. The entire assembly should be stable and secured to a cart or stand to prevent the cylinder from falling during use.
Adjusting and Monitoring Oxygen Flow
After assembly, the main cylinder valve must be opened slowly, typically by turning the valve key or handle counter-clockwise. Opening the valve gently prevents a sudden surge of high-pressure gas from damaging the regulator components. The pressure gauge on the regulator will immediately indicate the internal pressure of the cylinder, showing the remaining oxygen supply.
The next step is to set the flow rate by adjusting the knob on the flow meter until the indicator aligns with the prescribed Liters Per Minute (LPM) setting. When reading a ball-type flow meter, look at the center of the ball to ensure accuracy. The pressure gauge reading (in PSI or bar) is distinct from the flow rate and must be continuously monitored to anticipate when the cylinder will deplete.
To estimate the remaining duration, multiply the current tank pressure by a cylinder-specific conversion factor and then divide the result by the flow rate in LPM. For example, a common E-cylinder has a conversion factor of approximately 0.28. Knowing this estimated duration is a safety measure that prevents the patient’s oxygen supply from unexpectedly running out, especially during transport.
Critical Safety and Handling Procedures
Because medical oxygen is stored under immense pressure and vigorously supports combustion, strict safety protocols must be followed during handling and use. A primary risk is fire; oxygen itself is not flammable but will cause other materials to ignite and burn with great intensity. Therefore, cylinders must be kept far away from all sources of heat, sparks, and open flames, and smoking must be prohibited near the equipment.
Never allow oil, grease, or any petroleum-based substance to contact the cylinder valve, regulator, or fittings. These substances can spontaneously ignite in the presence of high-pressure oxygen, causing a violent flash fire or explosion. Staff handling the equipment should ensure their hands are clean and dry.
Cylinders must always be secured upright, either strapped to a dedicated cart or chained to a wall, even when empty or being transported. An unsecured cylinder that is knocked over and has its valve broken off can become a projectile due to the force of the escaping high-pressure gas. The main cylinder valve should be closed when the system is not in use, and the pressure in the regulator should be “bled” off to protect the equipment and prevent slow gas leaks.