What is "trimix"

n. A mixture of oxygen, helium and nitrogen used in deep diving

Trimix is a breathing gas, consisting of oxygen, helium and nitrogen, and is often used in deep commercial diving, during the deep phase of dives carried out using technical diving techniques, and in advanced recreational diving.

The helium is included as a substitute for some of the nitrogen, to reduce the narcotic effect of the breathing gas at depth. With a mixture of three gases it is possible to create mixes suitable for different depths or purposes by adjusting the proportions of each gas. Oxygen content can be optimised for the depth to limit the risk of toxicity, and the inert component balanced between nitrogen, which is cheap but narcotic, and helium, which is not narcotic and reduces work of breathing, but expensive and conducive to heat loss.

The mixture of helium and oxygen with a 0% nitrogen content is generally known as Heliox. This is frequently used as a breathing gas in deep commercial diving operations, where it is often recycled to save the expensive helium component. Analysis of two-component gases is much simpler than three component gases.

Trimix may refer to:

• Trimix (breathing gas), a gas mixture used in deep-sea diving
• Trimix (injection), an injection used to treat erectile dysfunction

Trimix is an injectable three-drug prescribed medication used to treat erectile dysfunction. The active ingredients in the mixture are usually alprostadil, papaverine, and phentolamine. The injection must be compounded by a pharmacy and administered via intracavernosal injection (an injection at the base of the penis). Trimix is typically compounded by a pharmacy in a sterile environment and then frozen. The compound is stable for up to 6 months while stored frozen and for 1 month if stored refrigerated beginning at the time of manufacture.