PFO
Abbreviation for patent foramen ovale. It is a form of congenital heart
defect that enables blood flow between the left and right atria via the in-
teratrial septum.
PO
2
Abbreviation for oxygen partial pressure.
RGBM
Abbreviation for Reduced Gradient Bubble Model.
Reduced Gradient Bubble Model
Modern algorithm for tracking both dissolved and free gas in divers.
Repetitive dive
Any dive whose decompression time limits are affected by residual nitro-
gen absorbed during previous dives.
Residual nitrogen
The amount of excess nitrogen remaining in a diver after one or more
dives.
SURF TIME
Abbreviation for surface interval time.
Surface interval time
Elapsed time between surfacing from a dive and beginning a descent for
the subsequent repetitive dive.
Technical dive
A dive made with two or more breathing gas mixes.
Tissue group
Theoretical concept used to model bodily tissues for the construction of
decompression tables or calculations.
Trimix
A breathing gas mix of helium, oxygen and nitrogen.
UHMS
Abbreviation for Undersea and Hyperbaric Medical Society.
Whole-body toxicity
Another form of oxygen toxicity, which is caused by prolonged exposure
to high oxygen partial pressures. The most common symptoms are irrita-
tion in the lungs, a burning sensation in the chest, coughing and reduction
of the vital capacity. Also called Pulmonary Oxygen Toxicity. See also
OTU.
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