""Carbogen" refers to a gaseous mixture of carbon dioxide (CO2) and oxygen (O2), most often administered via a mask attached to a regulator connected to a high-pressure cylinder. The ratio of 30% CO2 and 70% O2 is known as "Meduna's mixture", after Ladislas J. Meduna, a psychiatrist who pioneered its use as a therapeutic tool in the 1940s and 1950s. Although carbogen—sometimes described in the medical literature as a "panicogen"—is perhaps best known for inducing anxiety, sensations of suffocation, and unconsciousness, this extremely simple gas can cause surprisingly complex psychoactive effects when inhaled for even a few breaths.
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Most people remain relatively still for the duration of the experience. As few as 1–5 breaths can cause significant alterations of thought, perception, and mood; rushes of sensation in the body; and disorientation. During these first moments it may require a willful effort to continue inhaling the acidic-tasting gas. After a few more breaths, effects increase in intensity, and awareness of the external world fades away. People often close their eyes and those who keep them open exhibit an unseeing stare. Breath rate generally increases and breathing becomes somewhat labored.
After a few more breaths, effects increase in intensity and awareness of the external world fades away.
When inhaled at sufficient doses, carbogen has anaesthetic and dissociative effects, frequently accompanied by both open- and closed-eye visuals. These effects include brightening or darkening of the visual field, kaleidoscopic or swirling changes in color, and geometric patterning."
https://erowid.org/chemicals/carbogen/carbogen_article1.shtml
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Most people remain relatively still for the duration of the experience. As few as 1–5 breaths can cause significant alterations of thought, perception, and mood; rushes of sensation in the body; and disorientation. During these first moments it may require a willful effort to continue inhaling the acidic-tasting gas. After a few more breaths, effects increase in intensity, and awareness of the external world fades away. People often close their eyes and those who keep them open exhibit an unseeing stare. Breath rate generally increases and breathing becomes somewhat labored.
After a few more breaths, effects increase in intensity and awareness of the external world fades away.
When inhaled at sufficient doses, carbogen has anaesthetic and dissociative effects, frequently accompanied by both open- and closed-eye visuals. These effects include brightening or darkening of the visual field, kaleidoscopic or swirling changes in color, and geometric patterning."
https://erowid.org/chemicals/carbogen/carbogen_article1.shtml