Professor
Professor (commonly abbreviated as Prof.) is an Academy, academic rank at university, universities and other post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin as a "person who pr ...
Albert Alois Bühlmann (16 May 1923 – 16 March 1994) was a Swiss
physician
A physician (American English), medical practitioner (Commonwealth English), medical doctor, or simply doctor, is a health professional who practices medicine, which is concerned with promoting, maintaining or restoring health through th ...
who was principally responsible for a number of important contributions to
decompression science at the Laboratory of Hyperbaric Physiology at the University Hospital in
Zürich
Zürich () is the list of cities in Switzerland, largest city in Switzerland and the capital of the canton of Zürich. It is located in north-central Switzerland, at the northwestern tip of Lake Zürich. As of January 2020, the municipality has 43 ...
, Switzerland.
His impact on diving ranged from complex
commercial and
military
A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. It is typically authorized and maintained by a sovereign state, with its members identifiable by their distinct ...
diving to the occasional
recreational diver
Recreational diving or sport diving is diving for the purpose of leisure and enjoyment, usually when using scuba equipment. The term "recreational diving" may also be used in contradistinction to "technical diving", a more demanding aspect of r ...
.
[ He is held in high regard for his professional ethics and attention to his research subjects.]
Background
After completing his education at the University of Zürich, Bühlmann specialized in pathophysiology
Pathophysiology ( physiopathology) – a convergence of pathology with physiology – is the study of the disordered physiological processes that cause, result from, or are otherwise associated with a disease or injury. Pathology is the ...
of the respiratory and circulatory systems.[ He was particularly interested in respiratory physiology at ]high altitude
Altitude or height (also sometimes known as depth) is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The exact definition and reference datum varies according to the context ...
s and high pressure environments.[
]
Bühlmann decompression algorithm
The Bühlmann decompression algorithm is used to create decompression tables.
In 1959, Hannes Keller became interested in deep diving and developed tables for mixed-gas decompression. Not a diver himself, Bühlmann was intrigued by project and suggested suitable breathing gases
A breathing gas is a mixture of gaseous chemical elements and compounds used for respiration. Air is the most common and only natural breathing gas, but other mixtures of gases, or pure oxygen, are also used in breathing equipment and enclosed h ...
. Keller successfully tested his idea in the Lake Zurich
__NOTOC__
Lake Zurich ( Swiss German/Alemannic: ''Zürisee''; German: ''Zürichsee''; rm, Lai da Turitg) is a lake in Switzerland, extending southeast of the city of Zürich. Depending on the context, Lake Zurich or ''Zürichsee'' can be used to ...
where he reached a depth of 400 feet and then Lake Maggiore where he reached a depth of 728 feet.
Building on the previous work of John Scott Haldane
John Scott Haldane (; 2 May 1860 – 14/15 March 1936) was a British physician and physiologist famous for intrepid self-experimentation which led to many important discoveries about the human body and the nature of gases. He also experimen ...
and Robert Workman, and with funding from Shell Oil Company
Shell USA, Inc. (formerly Shell Oil Company, Inc.) is the United States-based wholly owned subsidiary of Shell plc, a UK-based transnational corporation " oil major" which is amongst the largest oil companies in the world. Approximately 18,000 ...
,[ Bühlmann designed studies to establish the longest half-times of nitrogen and helium.][ These studies were confirmed by the ''Capshell'' experiments in the ]Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ea ...
in 1966.
The naming convention he used to describe his algorithms, for example, ZH-L16, comes from Zürich (ZH), limits (L) and the number of tissue compartments or M-value sets used (16).
In 1962, Keller set a new world record when he reached a depth of 1000 feet off the coast of California
California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...
utilizing Bühlmann's algorithm in a study funded by the United States Navy
The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...
.[
Two out of eight Swiss military divers suffered decompression sickness following dives 1800 meters above sea level in ]Lake Silvaplana
Lake Silvaplana (german: Silvaplanersee; rm, Lej da Silvaplauna) is a lake in the Upper-Engadine valley of Grisons, Switzerland. It takes its name from the village of Silvaplana. The lake is also connected to the nearby Lej da Champfèr. Together ...
.[ Bühlmann recognized the problems associated with ]altitude diving
Altitude diving is underwater diving using scuba or surface supplied diving equipment where the surface is or more above sea level (for example, a mountain lake). Altitude is significant in diving because it affects the decompression requiremen ...
, and proposed a method which calculated maximum nitrogen loading in the tissues at a particular ambient pressure. The tables developed were adopted by the Swiss military in 1972.[ An expedition to Lake Titicaca at 3800 meters above sea level in 1987 revealed no decompression issues while utilizing Bühlmann's ZH-L16 algorithm.][ In addition to altitude diving, his calculations also include considerations for repetitive ]dive profile
A dive profile is a description of a diver's pressure exposure over time. It may be as simple as just a depth and time pair, as in: "sixty for twenty," (a bottom time of 20 minutes at a depth of 60 feet) or as complex as a second by second grap ...
s.
The results of Bühlmann's research that began in 1959, was published in a 1983 German book entitled ''Dekompression-Dekompressionskrankheit'' (Decompression-Decompression Sickness).[ An English version of this book became available in 1984.] The book was regarded as the most complete public reference on decompression calculations and was used soon after in coding dive computer algorithm
In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algorithms are used as specificat ...
s. Two follow-up books were published in 1992 and 1995.
Versions of Bühlmann's ZHL-16 model have been used to generate the standard diving tables for a number of sports diving associations. Max Hahn
Max or MAX may refer to:
Animals
* Max (dog) (1983–2013), at one time purported to be the world's oldest living dog
* Max (English Springer Spaniel), the first pet dog to win the PDSA Order of Merit (animal equivalent of OBE)
* Max (gorilla) (1 ...
used Bühlmann's model to develop the Deco '92 Tables used by the Swiss Underwater Sport Association and the Association of German Sports Divers, and Bob Cole Robert Cole may refer to:
Entertainment
*Robert William Cole (1869–1937), British writer
*Bob Cole (composer) (1868–1911), American composer
*Bobby Cole (musician) (1932–1996), American musician
Sports
*Bob Cole (cricketer) (born 1938), for ...
and Bühlmann developed the Sub-Aqua Association
The Sub-Aqua Association or SAA is a diver training organization for scubadivers in the United Kingdom. The SAA and other UK-based diving groups have traditionally used a club-based system with unpaid instructors, while other training agencies ...
(SAA) Bühlmann System in 1987, which used the tables and a set of instructions for their use in recreational diving without decompression stops.[ The tables are still used in the 2020s and remain popular, while many dive computers use variations of the ZHL-8, ZH-L12, or ZHL-16 algorithm.
]
Death
Bühlmann died unexpectedly of heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, a ...
on 16 March 1994.[
]
Awards
The Undersea and Hyperbaric Medical Society gave Bühlmann the Oceaneering
Oceaneering International, Inc. is a subsea engineering and applied technology company based in Houston, Texas, U.S. that provides engineered services and hardware to customers who operate in marine, space, and other environments.
Oceaneering's ...
award in 1977.[
In 1993, the ]Divers Alert Network
Divers Alert Network (DAN) is a group of not-for-profit organizations dedicated to improving diving safety for all divers. It was founded in Durham, North Carolina, United States, in 1980 at Duke University providing 24/7 telephonic hot-line div ...
presented Bühlmann with an award for his life's work in the service of decompression science.[
]
See also
*
*
*
References
External links
An Explanation of Professor A.A. Buehlmann's ZH-L16 Algorithm
- An in-depth treatment of the mathematics involved
- describes the steps involved in using the algorithm to write a decompression program
On-line calculator on the basis of the model
Bühlmann Watches
- Official Bühlmann dive watches featuring the Bühlmann Decompression security stops algorithm
{{DEFAULTSORT:Buhlmann, Albert
1923 births
1994 deaths
Academic staff of the University of Zurich
Decompression researchers
Swiss physicians
Swiss medical researchers
it:Algoritmo Buhlmann