Owner's Manual blood pressure monitor

Section 6: Reference
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ZH-L8 ADT Calculation Model
The Monitor 3 Air uses a new calculation model known as
the ZH-L8 ADT. This model uses eight compartments or
"tissue" groups with half-times ranging from 5 to 640
minutes. This calculation model is based on the most
current research conducted by the late Dr. A.A. Buhlmann.
Most computer decompression models only take into
account time and depth; the Monitor 3 Air model also
factors in other physiological factors, including tempera-
ture, breathing rate and workload.
Workload and Temperature
Blood perfusion to the body's organs is not constant. Skin
and muscle tissues are especially subject to changes in
blood perfusion, depending on temperature and workload.
Changes in blood perfusion to these organs change their
nitrogen saturation tolerance. The ZH-L8 ADT model takes
these effects into account and thus the "skin" and "muscle"
compartments in the Monitor 3 Air have variable half-time
periods and saturation tolerances.
Decompression information is calculated according to the
diver's individual workload and decrease in skin tempera-
ture. The decrease in skin temperature is based upon the
water temperature and the dive time. By considering these
changes in saturation, the time that must be spent at the
surface prior to flying can be considerably lengthened,
depending on the depth, time, and temperature of a dive, as
well as the diver's workload during that dive.
Microbubble Formation
The ZH-L8 ADT model considers nitrogen in both its
dissolved and gaseous phase (microbubbles). Formation of
microbubbles is considered to be a strong indicator of a
high risk of decompression sickness. The model calculates
the formation of microbubbles depending on various
assumed influences in arterial and venous blood. During
normal, slow ascents, microbubbles form mainly in venous
blood. During fast ascents, microbubbles may also form in
arterial blood and the body's tissues. If a particular dive
profile results in the formation of microbubbles, decreased
bottom time and/or increased decompression times, and
increased wait-to-fly times, will be indicated.
Microbubbles can form if the diver makes a fast ascent,
ignores decompression stops, or makes repeated ascents
during a dive (yo-yo diving). These microbubbles can form
in arterial blood and body tissues. If these microbubbles
partially impair circulation, the rate of gas diffusion and
saturation tolerance of surrounding tissues are changed. If
required, both decompression time and remaining bottom
time will be adjusted in such a way that already existing
microbubbles will stop growing. Increased decompression