science fiction tale about humans and aliens, in a world with a high-Xenon atmosphere.
Xenon is the perfect anaesthetic.

Xenon is the ideal anesthetic.

Xenon is a trace gas in Earth’s atmosphere, occurring at approximately 1 part per 11.5 million. It has 54 protons in its nucleus, so its atomic number is 54.
It has a density of 5.894 kg/m3, about 4.5 times the density of our atmosphere at sea level, so it would sink if the air were still.

This is a noble gas, one of the zero-valence elements, which don’t mix with “ordinary” elements (kind of a “Royal Family” – type thing)….. It will not take part in most common chemical reactions, such as combustion.
Xenon is a natural part of our atmosphere, found at a 1/12.5 million concentration (there must be a lot in the sea, too, because it dissolves in water).
It is environmentally friendly and is not a greenhouse gas.

Xenon can be breathed safely when mixed with 20% , or more, oxygen.
However, at 80% Xe/20% O2, concentration, Xenon produces deep anesthesia.


Xenon dissolves in blood. It can cross the blood–brain barrier and produces deep anesthesia when inhaled along with oxygen.
It is 44% more potent than N2O (laughing gas) as an anesthetic, it causes less nausea and vomiting after anesthesia and it has a lower risk of hypoxia.

Also, although modern systems recycle it (for economy) when it is used as an anaesthetic, any xenon that escapes to the atmosphere is just returning to its original source, so there is no environmental impact.

Therefore Xenon is the ideal anaesthetic and has been used, with oxygen, for general anaesthesia. However it is too expensive to use on a regular basis.

The brain and the heart

Xenon is not neurotoxic: it actually protects the brain cells.
It is also cardioprotective (it protects heart cells).
It can be used safely after ischemic insults ** to the brain and other organs.
Therefore it is an ideal anaesthetic and has been used, with oxygen, for general anaesthesia.
However it is too expensive to use on a regular basis.

** Periods of low oxygenation due to blood loss or blockage by blood clots.

Sports doping

Inhaling a xenon/oxygen mixture leads to elevation of erythropoietin, resulting in higher production of red blood cells, so the blood can carry more oxygen.
So theoretically Xenon could be abused by athletes, to increase red blood cell production and thereby, athletic performance.
Although there aren’t any tests to check on it, the World Anti Doping Agency (WADA) added Xenon (and argon) to the list of prohibited substances in 2014.
Reportedly (I don’t know if this is true) doping with Xenon inhalation has been used in Russia.

SpaceShips & ion drives:

Xenon can be safely kept in normal sealed glass or metal containers at standard temperature and pressure. However, it readily dissolves in, and will pass through, plastics and rubber, so containers need special seals.

Xenon is the preferred propellant for ion propulsion of spacecraft because it has low ionization potential per atomic weight, can be stored as a pressurised liquid at near room temperature and evaporates easily to feed the engine.

It is less corrosive, doesn’t explode and is environmentally friendly, and so is safer for an ion engine than other fuels.
Xenon was first used for satellite ion engines during the 1970s and later, it was used for JPL’s Deep Space 1 probe, Europe’s SMART-1 spacecraft and NASA’s Dawn Spacecraft.

Other interesting stuff
– The speed of sound in xenon gas (169 m/s) is less than that in air. Hence, xenon lowers voice tones: the opposite of the high-toned voice produced by helium.
– Our breathing mixes gases of different densities very effectively and rapidly, so heavier gases are purged along with the oxygen, and do not accumulate at the bottom of the lungs.
– There is, however, a danger associated with any heavy gas in large quantities: it may sit invisibly in a container, and a person who enters an area filled with an odorless, colorless gas may be anesthetised without warning. **
Xenon is rarely used in large enough quantities for this to be a concern, but it should be borne in mind.
** See XCRATH !, chapters 52-54.

Writing a SciFi tale about a planet with a high concentration of Xenon in the atmosphere was such HUGE fun !
We were in Saudi Arabia and while my work, including preparing lectures for the trainee doctors (residents), was just as interesting and absorbing as it had been in Toronto, I was only busy half the time ….. I was playing SPIDER solitaire for hours at a time and was bored stiff …..

My wife / life partner was concerned me just sitting and in 1998, she exclaimed
I started “XCRATH !” in November, 1998, In pencil, on paper, then switched to Dragon Dictate, via my computer.
I finally finished it, after seven proofreadings, in 2003 and Amazon printed it, through “create space”, in 2005.
– (BTW, Dragon version 6 was the best ever! – I eventually got up to version 15, in 2019, so I know – version 15 is semiliterate).

Note that these were taken from Wikipedia and I have not read them.

Sanders, Robert D.; Ma, Daqing; Maze, Mervyn (2005). “Xenon: elemental anaesthesia in clinical practice”. British Medical Bulletin. 71 (1): 115–35. doi:10.1093/bmb/ldh034. PMID 15728132.

Marx, Thomas; Schmidt, Michael; Schirmer, Uwe; Reinelt, Helmut (2000). “Xenon anesthesia” (PDF). Journal of the Royal Society of Medicine. 93 (10): 513–7. doi:10.1177/014107680009301005. PMC 1298124. PMID 11064688. Retrieved 2007-10-02.

“Chemistry: Where did the xenon go?”. Nature. 471 (7337): 138. 2011. Bibcode:2011Natur.471T.138.. doi:10.1038/471138d.

Neice, A. E.; Zornow, M. H. (2016). “Xenon anaesthesia for all, or only a select few?”. Anaesthesia. 71 (11): 1259–1272. doi:10.1111/anae.13569. PMID 27530275.

Banks, P.; Franks, N. P.; Dickinson, R. (2010). “Competitive inhibition at the glycine site of the N-methyl-D-aspartate receptor mediates xenon neuroprotection against hypoxia-ischemia”. Anesthesiology. 112 (3): 614–22. doi:10.1097/ALN.0b013e3181cea398. PMID 20124979.

Ma, D.; Wilhelm, S.; Maze, M.; Franks, N. P. (2002). “Neuroprotective and neurotoxic properties of the ‘inert’ gas, xenon”. British Journal of Anaesthesia. 89 (5): 739–46. doi:10.1093/bja/89.5.739. PMID 12393773.

Goto, T.; Nakata Y; Morita S (2003). “Will xenon be a stranger or a friend?: the cost, benefit, and future of xenon anesthesia”. Anesthesiology. 98 (1): 1–2. doi:10.1097/00000542-200301000-00002. PMID 12502969. S2CID 19119058.

Zona, Kathleen (March 17, 2006). “Innovative Engines: Glenn Ion Propulsion Research Tames the Challenges of 21st century Space Travel”. NASA. Archived from the original on September 15, 2007. Retrieved 2007-10-04.

“Dawn Launch: Mission to Vesta and Ceres” (PDF). NASA. Retrieved 2007-10-01.

I am a Toronto-trained Urologist. I practiced in downtown Toronto, from 1977 to 1997, when I went to Saudi Arabia as chief of Urology at the Armed Forces (teaching) hospital in Tabuk. Returning to Toronto in Y2000, I switched to family practice. In 2007, began to prescribe Hormone Restoration Therapy and in 2012, I became a member of the American Academy of Antiaging Medicine [A4M]. I successfully wrote the A4M's written examination in December, 2013 and In May, 2016 I passed the oral examination, for accreditation as a BHRT consultant. In 2014 I began BHRT practice in Collingwood, Ontario and in January, 2017, joined the Stone Tree Naturopathic Clinic. Now I am 82 and have retired, but it seems wasteful to jettison my learning and experience: the medical establishment knows nothing of BHRT / Functonal medicine and I feel obliged to offer my knowledge in the interest of those who are willing to think outside the box. MY QUALIFICATIONS: MB, BS, (from UWI), 1964. LMCC 1969. FRCSC (Urology), 1974. ECFMG 1984. Florida license 1998 [inactive], ABAARM Certification [A4M], 2016. I am a Member of CSAMM [the Canadian Society for Aging and Metabolic Medicine], the OMA&CMA, SUSO, CUA, RCP&S/C. PRACTICE TO DATE: Consultation in Functional Medicine, including assessment of Chronic Fatigue Syndrome, Fibromyalgia, Andropause, Menopause, Teenage and Postpartum Depression/Panic Attacks, Thyroid Hormone malfunction, Infertility, Sexual Dysfunction and “the Undiagnosable”. ALL ARE WELCOME to read, comment or question!


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