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{{Short description|Mathematical model of tissue inert gas uptake and release with pressure change}}
The '''Bühlmann decompression model''' is a [[Haldane's decompression model|neo-Haldanian model]] which uses Haldane's or Schreiner's formula for inert gas uptake, a linear expression for tolerated inert gas pressure coupled with a simple parameterised expression for alveolar inert gas pressure and expressions for combining Nitrogen and Helium parameters to model the way [[inert gases]] enter and leave the human body as the [[ambient pressure]] and inspired gas changes.<ref name="AAB1984" /> Different parameter sets are used to create [[decompression tables]] and in personal dive computers to compute no-decompression limits and decompression schedules for dives in real-time, allowing [[Underwater diving|divers]] to plan the depth and duration for dives and the required [[decompression stops]].
The model (Haldane, 1908)<ref name="haldane" /> assumes [[Decompression theory#Perfusion limitedar tissues and parallel tissue models|perfusion limited gas exchange and multiple parallel tissue compartments]] and uses an [[Exponential decay|exponential formula]] for in-gassing and out-gassing, both of which are assumed to occur in the dissolved phase.
Multiple sets of parameters were developed by Swiss physician Dr. [[Albert A. Bühlmann]], who did research into decompression theory at the Laboratory of Hyperbaric Physiology at the University Hospital in [[Zürich]], [[Switzerland]].<ref name="AAB1982" /><ref name="spums1999" />
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===Alveolar inert gas pressure===
The Bühlmann model uses a simplified version of the [[alveolar gas equation]] to calculate alveolar inert gas pressure
<math>P_{alv} = [P_{amb} - P_{H_{2}0} + \frac{1 - RQ}{RQ} P_{CO_{2}}]\cdot Q</math>
Where <math>P_{H_{2}0}</math> is the water vapour pressure at 37
<math>P_{alv} = [P_{amb} - P_{H_{2}0}]\cdot Q</math>
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Since precomputed tables cannot take into account the actual diving conditions, Buhlmann specifies a number of initial values and recommendations.
* Atmospheric pressure
* Water density
* Initial tissue loadings
* Descent rate
* Breathing gas
* Ascent rate
In addition, Buhlmann recommended that the calculations be based on a slightly deeper bottom depth.
===Dive computers===
Buhlmann
==Versions==
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* ZH-L 16 C (air, nitrox): The set of parameters with more conservative “a” values for tissue compartments #5 to 15. For use in dive computers.
* ZH-L 16 (helium): The set of parameters for use with helium.
* ZH-L 16 ADT MB: set of parameters and specific algorithm used by Uwatec for their trimix-enabled computers. Modified in the middle compartments from the original ZHL-C, is adaptive to diver workload and includes [[Decompression practice#Profile determined intermediate stops|Profile-Determined Intermediate Stops]]. Profile modification is by means of "MB Levels", personal option conservatism settings, which are not defined in the manual.<ref name="Galileo"
'''ZH-L 6 (1988)'''
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* ZH-L 8 ADT MB: A version of the ZHL-8 ADT claimed to suppress MicroBubble formation.<ref name="Smart" />
* ZH-L 8 ADT MB PDIS: [[Decompression practice#Profile determined intermediate stops|Profile-Determined Intermediate Stops]].<ref name="dykcen"
* ZH-L 8 ADT MB PMG: Predictive Multi-Gas.<ref name="Scubapro-Luna-PMG" />
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|isbn=978-3-642-55939-6 |doi=10.1007/978-3-642-55939-6 |publisher=Springer-Verlag, p. 158 |date=2002 |lang=de }}</ref>
<ref name="Völlm-1">{{cite web |url=https://www.divetable.info/BS_ZH/Buehlmann_Algorithms.pdf |title=Bühlmann algorithm for dive computers |last=Völlm |first=Ernst |access-date=29 July 2023 |archive-date=10 September 2024 |archive-url=https://web.archive.org/web/20240910013821/https://www.divetable.info/BS_ZH/Buehlmann_Algorithms.pdf |url-status=live }}</ref>
<ref name="Buhlmann-2019">{{cite web|url=https://www.divetable.info/BS_ZH/altitude_diving.pdf
<ref name="dykcen">{{cite web|url=http://www.dykcen.dk/PDF/Instruktor%20info/PDIS_Algorithm.pdf|title=Diving with PDIS (Profile-Dependent Intermediate Stop)|last=Staff|work=Dykkercentret website|publisher=Dykkercentret ApS|access-date=5 March 2016|___location=Frederiksberg|archive-url=https://web.archive.org/web/20161017170523/http://www.dykcen.dk/PDF/Instruktor%20info/PDIS_Algorithm.pdf|archive-date=17 October 2016|url-status=dead|df=dmy-all}}</ref>
<ref name="Scubapro-Luna-PMG">{{cite web|url=https://scubapro.johnsonoutdoors.com/sites/default/files/2022-08/galileo_luna_pmg_multilanguage_3.pdf |title=Predictive Multi Gas for Galileo Luna|last=Scubapro|access-date=29 July 2023 }}</ref>▼
<ref name="Galileo" >{{cite book |title=Technical diving software for Galilio: User manual |url=https://www.scubapro.com/sites/scubapro_site/files/trimix_user_manual-eng.pdf |author=<!--not specified--> |publisher=Scubapro |access-date=18 September 2019 |archive-date=13 April 2019 |archive-url=https://web.archive.org/web/20190413220658/https://www.scubapro.com/sites/scubapro_site/files/trimix_user_manual-eng.pdf |url-status=live }}</ref>
<ref name="haldane">{{cite journal |last1=Boycott |first1=A.E. |last2=Damant |first2=G.C.C. |last3=Haldane |first3=John Scott |author-link3=John Scott Haldane |title=Prevention of compressed air illness |journal=Journal of Hygiene |publisher=Cambridge University Press |volume=8 |issue=3 |pages=342–443 |year=1908 |url=http://archive.rubicon-foundation.org/7489 |pmid=20474365 |access-date=2009-06-12 |pmc=2167126 |doi=10.1017/S0022172400003399 |archive-url=https://web.archive.org/web/20110324171946/http://archive.rubicon-foundation.org/7489 |archive-date=2011-03-24 |url-status=usurped }}</ref>
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<ref name="Pressure94">{{cite journal |last1=Völlm |first1=T.G. |title=Leading diving researcher dies unexpectedly: Albert A Bühlmann, 1923 - 1994 |journal=Pressure, Newsletter of the Undersea and Hyperbaric Medical Society |volume=23 |issue=3 |year=1994 |pages=1–3 |issn=0889-0242 }}</ref>
▲<ref name="Scubapro-Luna-PMG">{{cite web |url=https://scubapro.johnsonoutdoors.com/sites/default/files/2022-08/galileo_luna_pmg_multilanguage_3.pdf |title=Predictive Multi Gas for Galileo Luna |last=Scubapro |access-date=29 July 2023 |archive-date=29 July 2023 |archive-url=https://web.archive.org/web/20230729105615/https://scubapro.johnsonoutdoors.com/sites/default/files/2022-08/galileo_luna_pmg_multilanguage_3.pdf |url-status=live }}</ref>
<ref name="spums1999">{{cite journal |last1=Wendling |first1=J |last2=Nussberger |first2=P |last3=Schenk |first3=B |title=Milestones of the deep diving research laboratory Zurich |journal=South Pacific Underwater Medicine Society Journal |volume=29 |issue=2 |year=1999 |issn=0813-1988 |oclc=16986801 |url=http://archive.rubicon-foundation.org/6003 |access-date=2009-04-02 |archive-url=https://web.archive.org/web/20120203155311/http://archive.rubicon-foundation.org/xmlui/handle/123456789/6003 |archive-date=2012-02-03 |url-status=usurped }}</ref>
<ref name="Workman65">{{cite journal |last=Workman |first=Robert D. |title=Calculation of decompression schedules for nitrogen-oxygen and helium-oxygen dives.|year=1965 |journal=Navy Experimental Diving Unit Panama City Fl |volume=Research rept. |url=https://apps.dtic.mil/sti/citations/AD0620879 |access-date=2023-07-29 }}</ref>▼
▲<ref name="Workman65">{{cite journal |last=Workman |first=Robert D. |title=Calculation of decompression schedules for nitrogen-oxygen and helium-oxygen dives.|year=1965 |journal=Navy Experimental Diving Unit Panama City Fl |volume=Research rept. |url=https://apps.dtic.mil/sti/citations/AD0620879 |access-date=2023-07-29 }}</ref>
▲.<ref name="Smart">{{cite web|url=http://users.skynet.be/sky68333/Theorie/Tabellen/Ver_bijl.pdf|title=Smart microbubble management|last=Staff|work=In Depth|publisher=Uwatec|access-date=12 March 2016|archive-date=21 September 2005|archive-url=https://web.archive.org/web/20050921115411/http://users.skynet.be/sky68333/Theorie/Tabellen/Ver_bijl.pdf|url-status=dead}}</ref>
}}
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