Entonox is the trade name for the gaseous mixture of 50% oxygen and 50% nitrous oxide by volume, also known as ‘gas and air,’ which provides an effective and quick-acting pain relief.
It is commonly used in the casualty and labor ward settings to provide analgesia. When used, a two-stage pressure demand regulator is attached to the mixture gas cylinder. Gas flow can occur as the patient inspires through the mask or mouthpiece. Gas flow ceases at the end of an inspiratory effort.
Entonox is compressed into cylinders to a pressure of 13,700 kPa. Entonox cylinders should be stored at 10°C for 24 hours before use. If the temperature of the cylinder is decreased to below −5.5°C, liquefaction and separation of the two components occur (Poynting effect). This results in:
- A liquid mixture containing mostly nitrous oxide with about 20% oxygen dissolved in it.
- Above the liquid, a gas mixture of high oxygen concentration.
A gas with a high oxygen concentration is supplied first when used at a constant flow rate. It is followed by a gas of decreasing oxygen concentration as the liquid evaporates. It may lead to the supply of hypoxic mixtures with less than 20% oxygen, as the cylinder is nearly empty.
Rewarming and mixing the cylinder and its contents reverses the separation and liquefaction.
Pain Relief Gases
Supply & Distribution
Pain relief gases such as Entonox are supplied in color-coded high-pressure cylinders and are available from certified medical gas suppliers. Distribution is managed through hospitals, emergency services, and home care providers, ensuring strict compliance with safety and quality standards.
Ordering & Handling
Orders can be placed via authorized distributors. Proper storage is required in a cool, ventilated area. Medical staff should verify valve seals, cylinder pressure, and expiration date before administration. The gas is commonly administered through a demand valve system under medical supervision.
Product Specifications
Entonox is the trade name for the gaseous mixture of 50% oxygen and 50% nitrous oxide by volume, also known as ‘gas and air,’ which provides effective and quick-acting pain relief.
Technical Know How
Pain Relief Gases Uses
Medical and therapeutic uses of Nitrous Oxide gas
Anesthetic & Pain Relief
Used for its anesthetic and pain-reducing effects, especially in surgery and dentistr
Labor Support
Used during labor as a safe and effective aid for pain management in birthing women.
Emergency Pain Relie
Frequently inhaled to relieve pain during childbirth, trauma, oral surgery, and cardiac emergencies
SAFETY
Critical Safety Protocols for Medical
Pain Relief Gases
General Usage
Clinical Handling and Application
- 1. Commonly used in casualty and labor ward settings to provide analgesia.
- 2. Entonox cylinders must be stored at 10°C for 24 hours before use.
- 3. Below −5.5°C, liquefaction and separation of gases occur (Poynting effect).
Ventilation & Control
Preventing Gas Accumulation
- 1. Install a continuous-flow fresh-air ventilation system.
- 2. Use an N₂O scavenger system to eliminate waste-gas buildup.