Reduced gradient bubble model

The reduced gradient bubble model (RGBM) is an algorithm developed by Bruce Wienke for calculating decompression stops needed for a particular dive profile. It is related to the Varying Permeability Model.^[1] but is conceptually different in that it rejects the gel-bubble model of the varying permeability model.^[2]^[3]

It is used in several dive computers, particularly those made by Suunto, Aqwary, Mares, HydroSpace Engineering,^[1] and Underwater Technologies Center. It is characterised by the following assumptions: blood flow (perfusion) provides a limit for tissue gas penetration by diffusion; an exponential distribution of sizes of bubble seeds is always present, with many more small seeds than large ones; bubbles are permeable to gas transfer across surface boundaries under all pressures; the haldanean tissue compartments range in half time from 1 to 720 minutes, depending on gas mixture.^[1]

Some manufacturers such as Suunto have devised approximations of Wienke's model. Suunto uses a modified haldanean nine-compartment model with the assumption of reduced off-gassing caused by bubbles. This implementation offers both a depth ceiling and a depth floor for the decompression stops. The former maximises tissue off-gassing and the latter minimises bubble growth.^[4] The model has been correlated and validated in a number of published articles using collected dive profile data.^{[citation needed]}^{[clarification needed]}

^ ^a ^b ^c Cite error: The named reference wienke2002 was invoked but never defined (see the help page).
^ Campbell, Ernest S (30 April 2009). "Reduced gradient bubble model". Scubadoc's Diving Medicine. Retrieved 12 January 2010. – Bruce Wienke describes the differences between RGBM and VPM
^ Craciun, Alexandru (19 May 2018). "Decompression Algorithms – RGBM and VPM, a comparative approach" (PDF). Proceedings of the International Conference on Applied Informatics - ICDD2018. Sibiu: 69–83.
^ Cite error: The named reference suunto2003 was invoked but never defined (see the help page).

[wienke2002-1] Cite error: The named reference wienke2002 was invoked but never defined (see the help page).

[Scubadoc-2] Campbell, Ernest S (30 April 2009). "Reduced gradient bubble model". Scubadoc's Diving Medicine. Retrieved 12 January 2010. – Bruce Wienke describes the differences between RGBM and VPM

[3] Craciun, Alexandru (19 May 2018). "Decompression Algorithms – RGBM and VPM, a comparative approach" (PDF). Proceedings of the International Conference on Applied Informatics - ICDD2018. Sibiu: 69–83.

[suunto2003-4] Cite error: The named reference suunto2003 was invoked but never defined (see the help page).

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